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Objective: To provide an inclusive blend of extant meta-analyses on the burden of Staphylococcus (S.) aureus and its resistant strains across diverse study populations, settings, and temporal contexts. Methods: The study has adopted PRISMA 2020-based guides and registered its protocol on Open Science Framework with an extensive literature search. Study quality was assessed by QUOROM and AMSTAR techniques. Data analysis included parsing of study-level statistical power, assessment of primary study overlap, pooling of meta-analysis results, subgroup and temporal analysis. Results: Totally 41 studies (64 meta-analyses) were selected by the inclusion criteria. The summary meta-analysis revealed global prevalence rates for S. aureus [24.8%, 95%C1 0.248(0.204-0.293), I2 = 93%], methicillin resistant S. aureus (MRSA) [5.8%, 95% CI 0.058(0.044-0.073), I2 = 92%], vancomycin intermediate S. aureus [1.7%, 95%C1 0.017(0.013–0.021), I2 = 36.4%], heterogeneous vancomycin intermediate S. aureus [5.2%, 95% CI 0.052(0.038–0.056), I2 = 36.4%], community-associated methicillin-resistant S. aureus [19.9%, 95%C1 0.199(-0.170–0.568), I2 = 96.67%), livestock-associated-MRSA [13.6%, 95% CI 0.136(-0.028–0.243), I2 = 97.7%], and mupirocin resistant S. aureus [7.6%, 95% CI 0.076(0.062–0.090), 12 = 0%]. Temporal analysis revealed that the burden community-associated methicillin-resistant S. aureus notably increased from 1.3% in 2003 to 39.0% in 2014. Coagulase-negative staphylococci rose from 23.2% in 2021 to 29.8% in 2022. Vancomycin resistant S. aureus peaked at 9.0% in 2018, declining to 2.6% in 2020. Livestock-associated-MRSA significantly increased to 19.0% in 2020. MRSA fluctuated, peaking at 52.7% in 2012 and 31.0% in 2022. Conclusions: The study reveals a considerable global prevalence of S. aureus at 24.8%. Regional differences were apparent, with Africa facing a high burden of MRSA at 40.8% of S. aureus and temporal trends exposed a dynamic state. [ABSTRACT FROM AUTHOR]

To better understand host–phage interactions and the genetic bases of phage resistance in a model system relevant to potential phage therapy, we isolated several spontaneous mutants of the USA300 S. aureus clinical isolate NRS384 that were resistant to phage K. Six of these had a single missense mutation in the host rpoC gene, which encodes the RNA polymerase β' subunit. To examine the hypothesis that mutations in the host RNA polymerase affect the transcription of phage genes, we performed RNA-seq analysis on total RNA samples collected from NRS384 wild-type (WT) and rpoCG17D mutant cultures infected with phage K, at different timepoints after infection. Infection of the WT host led to a steady increase of phage transcription relative to the host. Our analysis allowed us to define 53 transcriptional units and to categorize genes based on their temporal expression patterns. Predicted promoter sequences defined by conserved −35, −10, and, in some cases, extended −10 elements, were found upstream of early and middle genes. However, in many cases, sequences upstream of late genes did not contain clear, complete, canonical promoter sequences, suggesting that factors in addition to host RNA polymerase are required for their expression. Infection of the rpoCG17D mutant host led to a transcriptional pattern that was similar to that of the WT at early timepoints. However, beginning at 20 min after infection, transcription of late genes (such as phage structural genes and host lysis genes) was severely reduced. Our data indicate that the rpoCG17D mutation prevents the expression of phage late genes, resulting in a failed infection cycle for phage K. In addition to illuminating the global transcriptional landscape of phage K throughout the infection cycle, this study will inform our investigations into the basis of phage K's control of its transcriptional program as well as mechanisms of phage resistance. [ABSTRACT FROM AUTHOR]

Objective: To provide an inclusive blend of extant meta-analyses on the burden of Staphylococcus (S.) aureus and its resistant strains across diverse study populations, settings, and temporal contexts. Methods: The study has adopted PRISMA 2020-based guides and registered its protocol on Open Science Framework with an extensive literature search. Study quality was assessed by QUOROM and AMSTAR techniques. Data analysis included parsing of study-level statistical power, assessment of primary study overlap, pooling of meta-analysis results, subgroup and temporal analysis. Results: Totally 41 studies (64 meta-analyses) were selected by the inclusion criteria. The summary meta-analysis revealed global prevalence rates for S. aureus [24.8%, 95%C1 0.248(0.204-0.293), I2 = 93%], methicillin resistant S. aureus (MRSA) [5.8%, 95%CI 0.058(0.044-0.073), I2 = 92%], vancomycin intermediate S. aureus [1.7%, 95%C1 0.017(0.013–0.021), I2 = 36.4%], heterogeneous vancomycin intermediate S. aureus [5.2%, 95%CI 0.052(0.038–0.056), I2 = 36.4%], community-associated methicillin-resistant S. aureus [19.9%, 95%C1 0.199(-0.170–0.568), I2 = 96.67%), livestock-associated-MRSA [13.6%, 95%CI 0.136(-0.028–0.243), I2 = 97.7%], and mupirocin resistant S. aureus [7.6%, 95%CI 0.076(0.062–0.090), 12 = 0%]. Temporal analysis revealed that the burden community-associated methicillin-resistant S. aureus notably increased from 1.3% in 2003 to 39.0% in 2014. Coagulase-negative staphylococci rose from 23.2% in 2021 to 29.8% in 2022. Vancomycin resistant S. aureus peaked at 9.0% in 2018, declining to 2.6% in 2020. Livestock-associated-MRSA significantly increased to 19.0% in 2020. MRSA fluctuated, peaking at 52.7% in 2012 and 31.0% in 2022. Conclusions: The study reveals a considerable global prevalence of S. aureus at 24.8%. Regional differences were apparent, with Africa facing a high burden of MRSA at 40.8% of S. aureus and temporal trends exposed a dynamic state.

Background: Today, Methicillin-Resistant Staphylococcus Aureus (MRSA) has become one of the public health concerns due to its resistance to antimicrobial drugs, and this problem makes treating patients with infections caused by this bacterium difficult. Infections caused by methicillin-resistant Staphylococcus aureus (MRSA) strains are pervasive in both community and hospital settings, primarily attributable to Staphylococcus aureus' capacity to colonize areas like the nose or skin. In this study, with the aim of comparing phenotypic (disc diffusion method) and genotypic (PCR) methods, to detect methicillin-resistant Staphylococcus aureus isolated from patients of hospitals under supervision of Tehran university of medical sciences, and also detection of nor A, that is the one of the most important genes in efflux pump cluster genes. Methods: The present research was a cross- sectional study that was conducted from February 2022 to September 2023. In this research, 43 isolated strains of Staphylococcus aureus from wound discharge and blood samples, were collected from different departments of Tehran hospitals and had submitted to the research laboratory of the school of allied medical sciences in Tehran university of medical sciences. After identifying the strains, the resistance of the isolates to 14 types of antibiotics was checked by disk diffusion method. Results: Staphylococcus aureus diagnostic tests including gram staining on colonies, catalase, coagulase, DNase tests were performed and it was found that all strains were Staphylococcus aureus. In the next step, all samples were resistant to Cloxacillin by disc diffusion method, and the presence of mec A gene in them was confirmed by PCR method, thus the presence of MRSA strains was confirmed from the genotypic point of view. Of the 43 Staphylococcus aureus strains, 26 samples were identified as having the nor A gene by PCR and electrophoresis. Conclusion: The results of the present research have shown that the prevalence of Staphylococcus aureus bacteria in hospital samples is significant and resistance to methicillin and ciprofloxacin has increased in the strains of this bacteria.

Aims: To know the spectrum of the aerobic bacteria causing post operative wound infections. Materials and methods: The present study was undertaken to know the bacteriological profile of SSIs in Obstetrics & Gynaecology ward, including their antibiogram and find the preventive measures. Age group 20-60 years, Presence of post operative SSI’s, involves only the skin or subcutaneous tissue were included in study. Results: In 94(45.7%) culture isolates, 42(44.70%) were Gram negative enteric rods, 26(27.65%) were Staphylococcus species and 26(27.65%) were Non fermenters. Predominant isolates were Klebsiella pneumoniae (28.72%) Pseudomonas aeruginosa (25.53%) & Staphylococcus aureus (17.04%) respectively. Wound infection rate was more in emergency Obstetric cases (96.3%) compared to elective cases of Gynaec (77%) & Obstetric (73.3%). Methicillin resistant CoNS (60%). 6 CoNS were resistant out of 10 isolates which is significant hence speciation of CoNS should be done. Antibiogram in sensitive strains of Enterobacteriaceae shows highest sensitivity to Amikacin (86.3%). The antibiogram in resistant strains of Enterobacteriaceae shows highest sensitivity to Colistin (95%) & Imipenem (90%) and lowest sensitivity to AmoxyClav (30%). Sensitivity pattern in non-fermenters shows highest sensitivity to Imipenem (88.46%), whereas MBL producers shows highest sensitive to Colistin (100%) & Polymyxin (100%). Antibiogram of the Staphylococcus species shows highest sensitive to Clindamicin (100%) whereas for MRSA strains highest sensitive to Linezolid (100%). Conclusion: Drug resistance mechanisms which include ESBL, Amp C betalactamases, MBL producers exhibited by the predominant Gram-negative rods and MRSA strains in Gram positive isolates are due to overuse of antibiotics leading to selective pressure. Government has to intervene in strict implementation of antibiotic policy in all health care institutions. Availability of drug to patient is restricted only on doctor prescription. [ABSTRACT FROM AUTHOR]

Bulaşıcı hastalıklar yıllardan beri dünya çapında ölümlerin önde gelen nedenlerinden biridir. Özellikle çoklu ilaç direncine sahip Metisiline Dirençli Staphylococcus aureus (MRSA) suşları, dünya çapında halk sağlığını tehdit eden en önemli unsurların başında gelir. Basidiomycetes grubu mantarlar umut verici bir antibakteriyel bileşik kaynağı olarak bilinmektedirler. Bu çalışmada Ramaria aurea (Schaeff.) Quél.'nın metanol ve etanol ekstraktlarının patojen standart mikroorganizmalara karşı antimikrobiyal ve klinik örneklerden izole edilen MRSA suşlarına karşı anti-MRSA aktivitesinin belirlenmesi amaçlanmıştır. Antimikrobiyal aktiviteyi belirlemek için sıvı mikrodilüsyon metodu kullanılmıştır. Kullanılan suşlara ekstraktların 12.5-0.006 mg/ml arasındaki konsantrasyonları uygulanmıştır. Metanol ve etanol ekstraktlarının, standart bakteri suşlarına karşı 0.19-6.25 mg/ml aralığındaki dozlarda antibakteriyal aktiviteye sahip olduğu tespit edilirken, her iki ekstraktın da en etkili olduğu suşun 0.19 mg/ml dozla Bacillus cereus suşu olduğu görülmüştür. Ayrıca metanol ve etanol ekstraklarının her ikisinin de antifungal bir etkisi belirlenememiştir. Metanol ekstraktının çalışılan tüm MRSA suşlarına karşı 0.04-6.25 mg/ml aralığındaki dozlarda anti-MRSA aktivitesi gösterdiği belirlenirken, etanol ekstraktının bu suşların tamamına karşı 0.19-3.12 mg/ml aralığındaki dozlarda anti-MRSA aktivitesine sahip olduğu tespit edilmiştir. Sonuç olarak çalışılan Ramaria aurea ekstraklarının antibakteriyal ve anti-MRSA etkiye sahip olduğu belirlenmiş olup bu türün antimikrobiyal ajanların doğal bir kaynağı olabileceği ve farmakoloji endüstrisinde kullanılabileceği söylenebilir. Infectious diseases have been one of the leading causes of death worldwide for years. Especially multidrug-resistant Methicillin-Resistant Staphylococcus aureus (MRSA) strains are among the most important threats to public health worldwide. Basidiomycetes group fungi are known as a promising source of antibacterial compounds. This study aimed to determine the antimicrobial activity of methanol and ethanol extracts of Ramaria aurea (Schaeff.) Quél. against pathogenic standard microorganisms and anti-MRSA activity against MRSA strains isolated from clinical samples. Broth microdilution method was used to determine the antimicrobial activity. Concentrations between 12.5-0.006 mg/ml of the extracts were applied to the strains used. While methanol and ethanol extracts were found to have antibacterial activity against standard bacterial strains at doses ranging from 0.19 to 6.25 mg/ml, the most effective strain of both extracts was Bacillus cereus at a dose of 0.19 mg/ml. In addition, no antifungal effect was determined for both methanol and ethanol extracts. While methanol extract was found to have anti-MRSA activity against all studied MRSA strains at doses ranging from 0.04 to 6.25 mg/ml, ethanol extract was found to have anti-MRSA activity against all these strains at doses ranging from 0.19 to 3.12 mg/ml. As a result, it was determined that the studied Ramaria aurea extracts had antibacterial and anti-MRSA activity, and it can be said that this species may be a natural source of antimicrobial agents and may be used in the pharmaceutical industry. [ABSTRACT FROM AUTHOR]

Background: Most nosocomial infections are caused by bacteria that proliferate within quorum sensing mediated biofilms. The disruption of quorum sensing signals in biofilm-forming bacteria is the potential substitution strategy. Purpose: The current study focuses on the evaluation of isolated juglone derivatives from Reynoutria japonica as anti-biofilm agents and enzyme inhibitors against Methicillin Resistant Staphylococcus aureus (MRSA). Methods: The antibacterial and anti-biofilm activity of the juglone derivatives were investigated against laboratory strains MRSA using well and disc diffusion method. In addition, we evaluated the anti-biofilm inhibition potential of the juglone derivatives using a crystal violet-based assay in 96-well micro-titer plate. The suppression of S. aureus β-hemolytic, coagulase and proteolytic activity was evaluated using standard assay protocols. High Performance Liquid Chromatography (HPLC) was performed to analyze the acyl homoserine lactones (AHLs) signals degradation by juglone derivatives. Furthermore, all three ligand molecules were docked into the binding site of the S. aureus coagulase protein. Results: All the three juglone derivatives showed potent antimicrobial activity against clinical strains of MRSA. Among these compounds, 2-ethoxy-6-acetyl-7-methyljuglone displayed potent inhibitory activity with zones of inhibition of 15 ± 0.03 and 17 ± 0.03 against MRSA respectively. In the spectrophotometric assay, we confirmed that juglone derivatives inhibit biofilm formation. All the compounds markedly inhibited the coagulase, β-hemolytic and proteolytic activity of MRSA. The application of compounds as a treatment resulted in a notable decrease in biofilm density and thickness, as demonstrated by HPLC. The untreated MRSA exhibited quorum sensing signals of N-Butanoyl-l-homoserine lactone (C4-HSL) with retention time 3.6 min and of N-hexanoyl-l-Homoserine lactone (C6-HSL) at 5.8 minutes’ vs the treated with MRSA where no peaks were observed. The docking studies and Molecular dynamics (MD) simulation results revealed that all molecules are actively binding in the target site that correlates well with the in-vitro inhibitory properties of compounds against S. aureus. Conclusion: our results demonstrated the potential of juglone derivatives from R. japonica as a promising anti-biofilm agent and as quorum quencher for future therapy to combat multi-drug resistant infections in particular MRSA.

Background and Objectives: Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of nosocomial and community acquired infections. Nanoparticles are considered as proper tools to overcome the therapeutic problem of antimicrobial-resistant infections because of the drug concentration increment at the desired location and protection from enzymatic degradation. The goal of this study was to evaluate the effect of the antibacterial and antibiofilm activities of zingerone and niosome containing zingerone against pre-formed biofilm of MRSA isolates. Materials and Methods: 62 MRSA isolates cultured from patients with diabetic ulcers were investigated. Niosomes were synthesized and characterized by X-ray diffraction, zeta potential and scanning electron microscopy (SEM). The size of niosomal particles measured by SEM and zetasizer. Results: The surface charge of prepared niosomes was about -37 mV. The effect of the zingerone and noisome containing zingerone was evaluated against biofilms of MRSA isolates. Also, the antibiofilm activity of prepared niosomes on gene expression of MRSA biofilms was evaluated using Real Time PCR. Our results demonstrated that the niosome containing zingerone had a diameter of 196.1 nm and a -37.3-mV zeta potential. Zingerone removed one and three-day old biofilms of MRSA at the concentration of 1000 µg/ml, while the zingerone-laoded niosomes removed 1, 3-and 5-days old biofilms at the concentration of 250 µg/ml, 250 µg/ml, and 500 µg/ml. Conclusion: The results indicated that niosome containing zingerone eliminated MRSA and its biofilms faster compared with free zingerone and it suggested that zingerone-encapsulated niosomes could be considered as a promising treatment against MRSA and its biofilms. [ABSTRACT FROM AUTHOR]

Aims: Methicillin-Resistant Staphylococcus aureus cause many nosocomial, and community-acquired infections, burdening healthcare systems globally. The aim of the current study was to identify the potent inhibitors of MRSA strains as first step towards drug discovery against MRSA related infections. Methods and Results: Clioquinol derivatives 1–10 were evaluated against MRSA strains, using microplate alamar blue assay (MABA). Among them compounds 1–3, and 6–8 were found to be active with MIC values within the range of 61.08–213.58 µM. Compounds 1, and 7 were found highly potent with MIC values of 64.04 and 61.08 µM, respectively. Both these compounds also showed non-covalent interactions with active site key residues of topoisomerase IV enzyme in molecular docking studies. Mechanisms of action of the most active compounds 1, and 7 were further studied through AFM, and fluorescence microscopy. It was observed that compounds 1, and 7 caused a massive destruction in shape, and greatly reduced the size and number of viable cells. Flow cytometry analysis showed a significant rise in DiBAC4(3) fluorescence, and a non-significant rise in PI fluorescence indicating increased bacterial membrane depolarization of treated cells. Most importantly the clioquinol derivatives 1, and 7 did not cause any hemolytic effect. Moreover, all the compounds were found to be non-cytotoxic to BJ (Human fibroblast) normal cell line. Conclusion: Our findings suggest that clioquinol derivatives 1, and 7 possess highly potent antibacterial activity against three MDR, and one sensitive strains of S. aureus. Significance and impact of the study: Clioquinol derivatives 1, and 7 could be further studied as potential antibacterial agents.

Background: Staphylococcus aureus is one of the most common causes of nosocomial and community-acquired infections in all parts of the world. Prevalence of methicillin resistance in staphylococci has increased and become a serious concern worldwide. Clindamycin resistance is on the rise among clinically important staphylococcal isolates. Objectives: Identification and antimicrobial susceptibility testing of Staphylococcus aureus isolates from different clinical samples by using Standard Microbiological procedures as per CLSI guidelines. Detection of Methicillin resistant Staphylococcus aureus was carried out by using Cefoxitin screening test. Inducible clindamycin resistance among clinical isolates of Staphylococcus aureus was tested by using D-test and Vitek -2 compact automated system. Methods: Total 107 Staphylococcus aureus isolates from different clinical specimens were processed in the microbiology department at B.K.L. Walawalkar rural medical college. All samples were tested for Cefoxitin screening test and detection of Inducible clindamycin resistance was carried out by using D test and Vitek 2 panel automated system. Results: Out of 107 samples of Staphylococcus aureus isolates, cefoxitin screening test result showed 19(17.75%) positive result (MRSA). Percentages of inducible clindamycin resistance were higher amongst MRSA as compared to MSSA. The study revealed 32 (29.90 %) isolates are inducible clindamycin resistance detection result were positive (are Macrolides/ Lincosamides/ Streptogramins MLSB phenotype inducible) by Vitek 2 automated system. Conclusion: Detection of inducible clindamycin resistance should be included in the routine antimicrobial susceptibility testing, as it will help in guiding the empirical therapy.

To better understand host–phage interactions and the genetic bases of phage resistance in a model system relevant to potential phage therapy, we isolated several spontaneous mutants of the USA300 S. aureus clinical isolate NRS384 that were resistant to phage K. Six of these had a single missense mutation in the host rpoC gene, which encodes the RNA polymerase β’ subunit. To examine the hypothesis that mutations in the host RNA polymerase affect the transcription of phage genes, we performed RNA-seq analysis on total RNA samples collected from NRS384 wild-type (WT) and rpoCG17D mutant cultures infected with phage K, at different timepoints after infection. Infection of the WT host led to a steady increase of phage transcription relative to the host. Our analysis allowed us to define 53 transcriptional units and to categorize genes based on their temporal expression patterns. Predicted promoter sequences defined by conserved −35, −10, and, in some cases, extended −10 elements, were found upstream of early and middle genes. However, in many cases, sequences upstream of late genes did not contain clear, complete, canonical promoter sequences, suggesting that factors in addition to host RNA polymerase are required for their expression. Infection of the rpoCG17D mutant host led to a transcriptional pattern that was similar to that of the WT at early timepoints. However, beginning at 20 min after infection, transcription of late genes (such as phage structural genes and host lysis genes) was severely reduced. Our data indicate that the rpoCG17D mutation prevents the expression of phage late genes, resulting in a failed infection cycle for phage K. In addition to illuminating the global transcriptional landscape of phage K throughout the infection cycle, this study will inform our investigations into the basis of phage K’s control of its transcriptional program as well as mechanisms of phage resistance.

Background: Staphylococcus aureus is a Gram-positive cocci commonly inhabiting the nasal cavity as a commensal. Methicillin-resistant type of Staphylococcus aureus results in invasive infections that are difficult to treat with regular antibiotics. This study helps us determine the prevalence of MRSA among healthcare workers who pose a potential risk of being the carriers of the MRSA strains, leading to infections in hospital patients. Materials & Methods: A descriptive cross-sectional study was conducted six months (January-June 2023) at a Tertiary care hospital, Ananthapuramu. A total of 100 nasal swabs from healthcare workers were collected, and Staphylococcus aureus was isolated and identified using standard conventional culture methods and biochemical tests. The isolated Staphylococcus aureus was tested for the presence of MRSA by using a cefoxitin (30 µg) disc in Muller Hinton Agar Medium by Kirby-Bauer disk diffusion method according to Clinical Laboratory Standards Institute (CLSI) guidelines. Results: Out of 100 samples, 14(14%) samples were positive for nasal carriage of Staphylococcus aureus, and 4 (4%) isolates were positive for MRSA. The prevalence of MRSA was 4% in our study among the healthcare workers. Conclusion: The study revealed the prevalence of Methicillin-Resistant Staphylococcus aureus in nasal carriers among healthcare workers as 4%, which may threaten the spread of MRSA among patients admitted to the hospital. Thus, the present study helps us highlight the need to regularly screen carriers in apparently asymptomatic healthcare workers to prevent nosocomial infections. [ABSTRACT FROM AUTHOR]

Background and Objectives: Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of nosocomial and community acquired infections. Nanoparticles are considered as proper tools to overcome the therapeutic problem of antimicrobial-resistant infections because of the drug concentration increment at the desired location and protection from enzymatic degradation. The goal of this study was to evaluate the effect of the antibacterial and antibiofilm activities of zingerone and niosome containing zingerone against pre-formed biofilm of MRSA isolates. Materials and Methods: 62 MRSA isolates cultured from patients with diabetic ulcers were investigated. Niosomes were synthesized and characterized by X- ray diffraction, zeta potential and scanning electron microscopy (SEM). The size of niosomal particles measured by SEM and zetasizer. Results: The surface charge of prepared niosomes was about -37 mV. The effect of the zingerone and noisome containing zingerone was evaluated against biofilms of MRSA isolates. Also, the antibiofilm activity of prepared niosomes on gene expression of MRSA biofilms was evaluated using Real Time PCR. Our results demonstrated that the niosome containing zingerone had a diameter of 196.1 nm and a -37.3-mV zeta potential. Zingerone removed one and three-day old biofilms of MRSA at the concentration of 1000 µg/ml, while the zingerone-laoded niosomes removed 1, 3- and 5-days old biofilms at the concentration of 250 µg/ml, 250 µg/ml, and 500 µg/ml. Conclusion: The results indicated that niosome containing zingerone eliminated MRSA and its biofilms faster compared with free zingerone and it suggested that zingerone-encapsulated niosomes could be considered as a promising treatment against MRSA and its biofilms.

Background & Aims: Staphylococcus aureus is a common bug responsible for infections ranging from minor skin infections to fatal sepsis. Common colonizing sites include anterior nares, hand surfaces. Inadequate use of antibiotics has led to development of resistance giving rise to bugs like MRSA. Nursing staff particularly has a greater duration of patient contact and is thus more likely to become MRSA carrier- hence chosen as study population. This study aimed to study the prevalence and antimicrobial sensitivity profile of MRSA isolated from nasal carriers among nursing staff. Material & Methods: A short-term cross-sectional study done in which nursing staff members were screened for nasal carriage of MRSA by collecting swabs from anterior nares. S.aureus isolates were screened for Methicillin susceptibility using cefoxitin disc. MRSA thus obtained were studied for antibiotic sensitivity profile by using Vitek-2 compact. Results: Study showed the nasal carriage of MRSA as 13.3%. Maximum carriage was in staff members with >5 years of work experience in hospital. All isolates showed 100% resistance to Ampicillin, Erythromycin, Amoxiclav. Sensitivity reported was 12.5% to Ciprofloxacin; 37.5% to Clindamycin and Amikacin; 87.5% to Cotrimoxazole. All isolates were 100% sensitive to Linezolid, Vancomycin, Teicoplanin and Rifampin. Conclusion: This study showed a significant carriage of MRSA in the nursing staff. Considering that nurses are more involved in-patient care activity, regular screening should be done. Also, the importance of handwashing should be emphasized. Strict implementation of hospital infection control norms is necessary.

Background: Today, Methicillin-Resistant Staphylococcus Aureus (MRSA) has become one of the public health concerns due to its resistance to antimicrobial drugs, and this problem makes treating patients with infections caused by this bacterium difficult. Infections caused by methicillin-resistant Staphylococcus aureus (MRSA) strains are pervasive in both community and hospital settings, primarily attributable to Staphylococcus aureus' capacity to colonize areas like the nose or skin. In this study, with the aim of comparing phenotypic (disc diffusion method) and genotypic (PCR) methods, to detect methicillin-resistant Staphylococcus aureus isolated from patients of hospitals under supervision of Tehran university of medical sciences, and also detection of nor A, that is the one of the most important genes in efflux pump cluster genes. Methods: The present research was a cross- sectional study that was conducted from February 2022 to September 2023. In this research, 43 isolated strains of Staphylococcus aureus from wound discharge and blood samples, were collected from different departments of Tehran hospitals and had submitted to the research laboratory of the school of allied medical sciences in Tehran university of medical sciences. After identifying the strains, the resistance of the isolates to 14 types of antibiotics was checked by disk diffusion method. Results: Staphylococcus aureus diagnostic tests including gram staining on colonies, catalase, coagulase, DNase tests were performed and it was found that all strains were Staphylococcus aureus. In the next step, all samples were resistant to Cloxacillin by disc diffusion method, and the presence of mec A gene in them was confirmed by PCR method, thus the presence of MRSA strains was confirmed from the genotypic point of view. Of the 43 Staphylococcus aureus strains, 26 samples were identified as having the nor A gene by PCR and electrophoresis. Conclusion: The results of the present research have shown that the prevalence of Staphylococcus aureus bacteria in hospital samples is significant and resistance to methicillin and ciprofloxacin has increased in the strains of this bacteria. [ABSTRACT FROM AUTHOR]

Staphylococcus aureus bacteria, especially Methicillin Resistant Staphylococcus aureus (MRSA), is one of the main causes of antibiotic resistance. MRSA is a bacteria that is resistant to the β-lactam class of penicillin antibiotics. MRSA infections can cause a variety of health problems, including skin infections, pneumonia, and bacteremia. This problem requires alternative resources that can be an option. Propolis from the stingless bee species Tetragonula laeviceps can be a potential alternative for treating MRSA infections. This research is classified as a true experiment with a posttest control group design. The concentration of propolis ethanol extract tested was 20%; 10%; 5%; 2.5%; 1.25%; and 0.625% in the diffusion and dilution methods. These two methods provide assessment output in the form of inhibition zone diameter, minimum inhibition concentration, and minimum bactericidal concentration. The data obtained will be tested statistically using One-way Anova and Fisher's exact tests. Test results show that the ethanol extract of Tetragonula laeviceps propolis has an antimicrobial effect against MRSA bacteria. The diffusion test showed that the average diameter of the inhibition zone formed by the ethanol extract of propolis successively from a concentration of 20% to 1,25% with six repetitions was 12.7 ± 1.23 mm; 11.36 ± 0.67 mm; 10.24 ± 0.61 mm; 7.59 ± 1.69 mm; and 6.5 ± 1.14 mm. From these averages, the One-Way Anova test revealed a statistically significant difference in the diameter of the inhibition zone (F(7,40) = [ 192.79], p = 0.000). [ABSTRACT FROM AUTHOR]

With the overuse and misuse of antibiotics, multi-drug resistant organisms have become a prominent issue in healthcare, increasing morbidity and mortality in affected patients. One such organism of concern is methicillin-resistant Staphylococcus aureus (MRSA) which is a leading cause of a variety of clinical infections. Therefore, in the interest of finding alternate substances to antibiotics, there has been increased interest in the antibacterial properties of lavender essential oil (LEO). This systematic review aims to collate information regarding the antibacterial properties of LEO against S. aureus and MRSA. A systematic search was conducted across four databases between the years 2002 and 2022, and through this, 23 studies were included in this paper. These studies used a variety of methods to ascertain the antibacterial effectiveness of LEO alone or in combination with other substances. Overall, there were mixed results regarding the antibacterial effectiveness of LEO against S. aureus and MRSA, with some studies reporting significant effectiveness, while other studies reporting a minimal to negligible effect. However, findings suggest that LEO works synergistically with other antibacterial substances, and it would be beneficial for additional research to be conducted in this area.

IntroductionMethicillin resistant Staphylococcus aureus (MRSA) is a major contributor to the global burden of antimicrobial resistance (AMR). As MRSA continues to evolve, the need for continued surveillance to evaluate trends remains crucial. This study was carried out to assess MRSA trends in the United Arab Emirates (UAE) based on analysis of data from the national AMR surveillance program.MethodsWe carried out a 12-year (2010–2021) retrospective analysis of MRSA demographic and microbiological data collected as part of the UAE national AMR surveillance program. Participating centers from across the country routinely submit AMR surveillance data collected by trained personnel to the National AMR Surveillance Committee, where data is analyzed using a unified WHONET platform. Data on non-duplicate isolates associated with clinical infections were obtained and included in the analysis.ResultsA total of 29,414 non-duplicate MRSA isolates associated with clinical infections were reported between 2010 and 2021 (2010: n = 259; 2021: n = 4,996). MRSA represented 26.4% of all S. aureus (n = 111,623) isolates identified during the study period. In 2010, among the S. aureus isolates with reported oxacillin testing, 21.9% (n/N = 259/1,181) were identified as MRSA and this showed an increase to 33.5% (n/N = 4,996/14,925) in 2021. Although there was variation in the distribution of MRSA across the seven emirates of the country, most had an upward trend. Patient demographics reflected a male preponderance, with most being adults and from the outpatient setting. Isolates were mostly from skin and soft tissue infection specimens (72.5%; n/N = 21,335/29,414). Among the inpatients (N = 8,282), a total of 3,313 MRSA isolates were from specimens obtained ≤ 48 h after admission indicative of community acquired infection. Increasing resistance trends were observed for most antibiotics including ciprofloxacin, levofloxacin, moxifloxacin, erythromycin, gentamicin, trimethoprim-sulfamethoxazole, and quinupristin/dalfopristin. Low levels of resistance (0.0–0.8%) were sustained for linezolid except for 2015, 2016, and 2017 with 2.5, 2.6, and 2.9%, respectively. No confirmed vancomycin resistance was reported.ConclusionThe increasing trend of MRSA isolates associated with clinical infections in the hospital and community settings is a concern. Continued monitoring including incorporation of genomic surveillance and infection control measures are recommended to stem the dissemination.

Background & Aims: Chronic Suppurative Otitis Media (CSOM) is defined as chronic inflammation of middle ear and mastoid cavity that may present with recurrent ear discharges. Its importance lies in its refractoriness to treatment and chronicity, leading to complications. CSOM is almost always associated with mixed bacterial flora. Knowledge of the local microbial flora as well as continuous, periodic evaluation of microbiological pattern, and antibiogram of isolates are necessary to decrease the potential risk of complications by early institutions of appropriate treatment. Materials & Methods: In this prospective cross-sectional study, a total of 134 consecutive swab samples of the patients diagnosed with CSOM, referred to a tertiary care hospital in Kashmir Valley, India were included. The bacterial colonies were identified in line with standard procedures. Antimicrobial sensitivity testing (AST) was carried out according to the Clinical Laboratory Standards Institute (CLSI) guidelines by modified Kirby-Bauer disc diffusion method on Mueller Hinton agar (MHA) medium. The data was analysed using SPSS version 24 and the prevalence of the organisms was determined and expressed in percentages. Results: Out of total 134 ear swabs processed, microbial growth was seen in 111 (83%). The most common organism isolated was Methicillin Resistant Staphylococcus aureus (MRSA) in 43 (39%) of the patients, followed by Pseudomonas in 37 (27.6%). 9 (8%) of the cases had fungal etiology. Linezolid (LZ) showed 100% sensitivity in Gram-positive Cocci whereas, Tigecycline (TIG) showed 100% sensitivity in Gram-negative Bacilli. All MRSA were 100 % sensitive to tetracycline, linezolid, amikacin. All the isolates of Pseudomonas were 100 % sensitive to Tigecycline, Ofloxacin, Colistin, Imipenem, Aztreonam, Cefepime. Conclusion: Isolation of various aerobic, anaerobic, and fungal isolates shows that different conditions of CSOM could be differentiated on microbiological grounds. Thus, for better management of CSOM, microbial classification of infection as well as drug sensitivity test of organisms recovered are essential for making appropriate decision of antimicrobials that will effectively eradicate the pathogen.

Food sold in healthcare facilities and environments are underestimated as sources of exposure of customers to potential pathogens. In the current study, we investigated the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in selected food items sold in two hospitals located in Benin City, Edo State, South-South Nigeria. A total of 100 food samples were obtained from food vendors and screened by pour plate method for the presence of heterotrophic bacterial and Staphylococcus aureus. Their antibiotic sensitivity patterns were determined by disc diffusion method and the presence of toxigenic and pathogenic genes by polymerase chain reaction and gel electrophoresis. Majority of the food samples investigated harbored Staphylococcus aureus, with varying levels of antibiotics resistance pattern. Only 5 of the isolates were observed to be methicillin resistant, with only one harboring the mecA gene. The results of this study are an indication that methicillin resistant Staphylococcus aureus could be a source of contaminant in ready-to-eat food sold in hospital facilities, and effort must be taken to prevent the occurrence of diseases arising from their presence. [ABSTRACT FROM AUTHOR]

The impact of preoperative nasal colonization with methicillin resistant staphylococcus aureus (MRSA) on total joint arthroplasty (TJA) outcomes is not well understood. This study aimed to evaluate complications following TJA based on patients' preoperative staphylococcal colonization status. We retrospectively analyzed all patients undergoing primary TJA between 2011 and 2022 who completed a preoperative nasal culture swab for staphylococcal colonization. Patients were 1:1:1 propensity matched using baseline characteristics, and stratified into 3 groups based on their colonization status: MRSA positive (MRSA+), methicillin sensitive staphylococcus aureus positive (MSSA+), and MSSA/MRSA negative (MSSA/MRSA−). All MRSA+ and MSSA + underwent decolonization with 5% povidone iodine, with the addition of intravenous vancomycin for MRSA + patients. Surgical outcomes were compared between groups. Of the 33,854 patients evaluated, 711 were included in final matched analysis (237 per group). The MRSA + TJA patients had longer hospital lengths of stay (P =.008), were less likely to discharge home (P =.003), and had higher 30-day (P =.030) and 90-day (P =.033) readmission rates compared to MSSA+ and MSSA/MRSA-patients, though 90-day major and minor complications were comparable across groups. MRSA + patients had higher rates of all-cause (P =.020), aseptic (P =.025) and septic revisions (P =.049) compared to the other cohorts. These findings held true for both total knee and total hip arthroplasty patients when analyzed separately. Despite targeted perioperative decolonization, MRSA + patients undergoing TJA have longer lengths of stay, higher readmission rates, and higher septic and aseptic revision rates. Surgeons should consider patients' preoperative MRSA colonization status when counseling on the risks of TJA. [ABSTRACT FROM AUTHOR]

Infective endocarditis (IE) with Staphylococcus aureus is associated with intravenous drug abuse or infected cardiac devices and commonly presents with non-specific constitutional symptoms. A 53-year-old female presented to the hospital with back pain, altered mental status, fever, and tachycardia. Due to patient's lethargy and decline in respiratory effort, she was intubated and lumbar puncture was performed that revealed neutrophil-predominant leukocytosis of the cerebrospinal fluid. The patient was empirically started on ceftriaxone and vancomycin, and blood cultures were positive for methicillin resistant Staphylococcus aureus (MRSA). A chest X-ray demonstrated pulmonary congestion and an implanted pacemaker; furthermore, a transesophageal echocardiogram (TEE) revealed a vegetation on the atrial lead of the pacemaker. As the patient's condition improved after a few days, she was extubated and was able to provide a clear history. The source of her infection was a pus pocket around her pacemaker which was placed two months prior to her admission. As expected, the infection resolved with proper source control and antibiotic therapy.

Background:Azadirachta indica has been used against a few disease in traditional medicine and have long history of use, and their use is worldwide in both developing and devolved countries, also have multiple health benefits. This study aimed to evaluate the antibacterial activity of Neem leaves extract against standard bacterial strain and only one drug resistant strain of important human pathogenic bacteria by using in vitro methods. Methods: This study aimed to evaluate the antimicrobial effects of Azadirachta indica (Neem) leaves extracts against selected pathogens. The present study was carried out to screen and evaluate antimicrobial activity of leaves of Azadirhta indica (Neem)methanol and petroleum ether extracts. Azadirchta indica extracts were tested against standard strains of S. aureus ATCC 6538, E. coli ATCC 25922, P. aeroginosa ATCC 9027, K. pneumonia ATCC 700603, and S. typhimurium ATCC 14028. The effeminacy of the extracts was studied and determined by applying different concentration of extracts on the selected bacterial strains and synthetic antimicrobial discs were used as positive control by using disc diffusion method. Results: With the statistical test analysis the comparison done showed that, no significant different between the two extracts used, and Staphylococcus aureus and Methicillin resistant staphylococcus aureus were the only bacteria susceptibly affected by this Neem extracts used. Conclusions: The result obtained indicate the leaves extracts of Neem plant have enormous antimicrobial effect, and may be exploited for the treatment of various infectious diseases

Introduction: Urinary tract infections (UTIs) represent widespread human microbial disorders involving any part of the urinary tract. Urinary tract infections (UTIs) are prevalent all over the world and are known to affect approximately 150 million people each year worldwide. Objectives: The aim of this study was to assess the demographic and bacterial profile of patients presenting with symptoms of urinary tract infections. Methods: A retrospective study on urine bacteriology over a period of one year between June 2021 to July 2022 was done in the Department of Microbiology, University College of Medical sciences and associated GTB Hospital, Delhi. The data collected was analyzed using Statistical Package for Social Sciences (SPSS) software, Chicago,version 20.0. Result: In this study, a total of 21359 samples were received for urine culture and sensitivity testing. 2265 samples were positive with an overall positivity rate of 10.60% with majority of the positive samples from females. The majority of positive samples (1559; 68.83%) were from age group between 21-60 years of age, females again being predominant gender (914; 58.62%). In outpatient department, inpatient department and in ICU services, Gram negative bacilli were the predominant microorganisms isolated. In case of Staphylococcus aureus, majority ,i.e., 66 (61.68%) out of total 107 of isolates were resistant to methicillin. Conclusion: Our findings support the fact that females in the age group 21-60 are more prone to develop UTIs as compared to males. There is a shift in methicillin resistance of Staphyloccus aureus from hospital acquired to community acquired cases.

Methicillin-resistant Staphylococcus aureus (MRSA) is responsible for skin and soft tissue infections with multi-resistance to many antibiotics. It is thus imperative to explore alternative antimicrobial treatments to ensure future treatment options. Nisin (NIS), an antibacterial peptide produced by Lactococcus lactis, was selected to combine with Oxacillin (OX), to evaluate the antimicrobial effect and potential mechanism against MRSA. The synergistic antimicrobial effect of OX and NIS was verified by Minimal Inhibitory Concentration (MIC) assays, checkerboard analysis, time-kill curve, biofilm producing ability, and mice skin infection model in vivo. For the potential synergistic antimicrobial mechanism, the microstructure and integrity change of MRSA cells were determined by Scanning and Transmission Electron Microscope (SEM and TEM), intracellular alkaline phosphatase activity and propidium iodide staining were assayed; And transcription of mecA, main gene of MRSA resistant to OX, were detected by qRT-PCR. The results showed NIS could restore the sensitivity of MRSA to OX and inhibit biofilm production; OX + NIS can make MRSA cell deform; NIS may recover OX sensitivity by inhibiting the transcription of mecA. In vivo, mice skin infection models indicate that OX + NIS can substantially alleviate MRSA infections. As a safe commercially available biological compound, NIS and the combination of antibiotics are worth developing as new anti-MRSA biomaterials. [ABSTRACT FROM AUTHOR]

Background: MRSA strains are the most common causes of community and hospital acquired infections. Antimicrobial medications have become a significant issue in the healthcare sector as a result of the increased death rate from Staphylococcus aureus infections, the appearance of methicillin-resistant and other multi-drug resistant strains. The study’s goals and objectives were determining the prevalence of MRSA and assessing the antibiotic efficacy of MRSA isolates from various clinical samples. Materials and Methods: A total of 395 MRSA were isolated from various clinical specimens and identified by using standard microbiological techniques at tertiary care hospital of Mysore, South India. Methicillin resistance was determined by standard Kirby-Bauer disc diffusion test using cefoxitin 30μg disk. Antimicrobial resistance patterns were determined by automated Vitek2 system. Results: A total of 246 (62.27%) isolates were identified as MRSA out of 395 S. aureus isolates collected from various clinical samples such as pus samples (86.17%), blood (3.65%), Et swabs (3.65%), ear swabs (2.84%), sputum (1.6%), urine (0.81%), and other sterile body fluids (1.21%). All MRSA isolates were susceptible (100%) to vancomycin, linezolid and daptomycin followed by other antibiotics like rifampicin (99%), tigecycline (96.74%), tetracycline (95.93%), teicoplanin (95.5%), gentamicin (73.17%). Most of the MRSA isolates were resistant to oxacillin (97.15%), trimethoprim/sulfamethoxazole (95.12%), Levofloxacin (93.49%), ciprofloxacin (92.68%), clindamycin (87.80%), erythromycin (63.41%). Conclusion: In our study, we found MRSA isolates were susceptible to most active and reliable routinely used antibiotics. Good infection control procedures like thorough hand washing, identifying and treating MRSA carriers, and prudent use of antimicrobial medicines are advised to prevent the formation of drug-resistant isolates. In addition to the Vitek 2 approach, we may conclude that cefoxitin disc diffusion is an essential test to diagnose MRSA. [ABSTRACT FROM AUTHOR]

Pathogens in public areas e.g. public transport system can be a critical public health issue due to ease of transfer. Present study deals with isolation and characterization of pathogenic bacteria from touch surfaces of railway station premises. A total of 53 swab samples taken from different touch surfaces were processed by classical microbiological procedures. Isolates were subjected to antibiotic sensitivity test. Further modified disinfectant challenge test was used to compare effectiveness of four commonly used disinfectants. Overall total 73 isolates were obtained. After morphological, cultural and biochemical analysis 7 isolates were identified as Methicillin resistant Staphylococcus aureus (MRSA) and 6 isolates as extended spectrum β-lactamase producing (ESBL) Escherichia coli. By virtue, these all were multidrug resistant. A disinfectant challenge test revealed Sodium hypochlorite, Dettol, MEDNTEK - R82 were effective while Santavis, a locally available disinfectant cum floor cleaner was not effective at recommended dilutions. Presence of multi drug resistant pathogenic bacteria in premises of railway station is extremely worrisome finding. Appropriate cleaning and disinfection measures required to prevent dissemination of these pathogens. [ABSTRACT FROM AUTHOR]

Faiqa Arshad,1 Sidrah Saleem,1 Romeeza Tahir,2 Shah Jahan,2 Kokab Jabeen,3 Aneela Khawaja,4 Zille Huma,1 Muhammad Roman,1 Faheem Shahzad2 1Department of Microbiology, University of Health Sciences, Lahore, Punjab, Pakistan; 2Department of Immunology, University of Health Sciences, Lahore, Punjab, Pakistan; 3Department of Pathology, Ammer ud Din Medical College, PGMI, Lahore, Punjab, Pakistan; 4Department of Pathology, Rahbar Medical & Dental College, Lahore, Punjab, PakistanCorrespondence: Faiqa Arshad, Department of Microbiology, University of Health Sciences, Khayaban-e-Jamia, Block D Muslim Town, Lahore, Punjab, 54600, Pakistan, Email drfaiqaimran@gmail.comBackground: The association of treatment failure and mortality with vancomycin minimum inhibitory concentration creep (MIC) is a matter of serious concern in patients with severe methicillin resistant Staphylococcus aureus (MRSA) infections. The purpose of the study was to identify and characterize staphylococcal cassette chromosome mec (SCCmec) and clonal types of MRSA strains, exhibiting the vancomycin MIC creep phenomenon.Methods: A total of 3305 S. aureus strains were isolated from various clinical samples of Lahore General Hospital, Lahore, Pakistan. MRSA strains were identified by cefoxitin resistant (≤ 21mm) followed by mecA and mecC gene genotyping. Vancomycin MIC creep was determined by E-test. Isolates having MIC values > 1.5 μg/mL were further subjected for SCCmec typing (I–V and XI) and multiple-locus variable number tandem repeat analysis (MLVA) by amplification of spa, sspA, clfA, clfB, and sdrCDE genes. A dendrogram was created based on the similarity index using bioneumerics software.Results: About 13.3% (440/3305) isolates were MRSA with 99.3% (437/440) and 0.7% (3/440) carried mecA and mecC genes, respectively. In 120 MRSA isolates, the MIC of vancomycin was > 1.5μg/mL. In MRSA isolates with high vancomycin MIC (> 1.5μg/mL), the most common SCCmec type was SCCmec III (38.3%), followed by SCCmec IVa (15.8%), SCCmec IIIa (13.3%,), SCCmec IVc (7.5%), SCCmec IVe (5.8%), SCCmec IVd (5.8%), SCCmec IVb (4.2%), SCCmec II (2.5%), SCCmec V (1.7%), SCCmec I (1.7%) and SCCmec XI (1.7%). MLVA revealed 60 genotypic groups of MRSA isolates having a 92% similarity index.Conclusion: SCCmec III was the most common type in genetically related MRSA isolates showing vancomycin MIC creep. The presence of SCCmec XI may further add burden to infection control measures.Keywords: methicillin resistant Staphylococcus aureus, staphylococcal chromosomal cassette, multilocus variable number tandem repeat analysis

Abstract Staphylococcus aureus is a common mastitis pathogen in dairy cows, and methicillin-resistant S. aureus (MRSA) has been found in dairy farms all over the world. The study carried out on bovines from three governorates in Egypt, with the goal of determining the prevalence of MRSA in positive milk samples of subclinical mastitis, performing an antibiotic susceptibility test against MRSA isolates and determining the risk factors associated with MRSA. A total of 350 quarter milk samples (n = 200 mixed breed cow; n = 150 water buffalo) were collected and examined for subclinical mastitis using the California mastitis test (CMT) before being exposed to standard microbiological procedures for S. aureus isolation. The disc diffusion method was used to phenotypically analyse the positive S. aureus isolates for MRSA, which was verified by a PCR assay targeting the mecA gene. According to the findings of the study, 41.4% (145/350) milk samples were positive based on CMT, while 35.7% (125/350) of positive samples identified as MRSA based on PCR assay. However, the obtained results revealed non-significant disparity between cattle and buffalo and all predicted risk factors were strongly associated with prevalence of subclinical mastitis. The in-vitro antibiotic susceptibility test revealed that cefoxitin was completely resistant, whereas linezolid, ciprofloxacin, and trimethoprim + sulphamethoxazole were sensitive against the MRSA isolates. The relevance of S. aureus to public health, as well as the development of resistance to antibiotics like methicillin, needs ongoing testing of antimicrobial medications against MRSA isolates.

Introduction: The most important pathogen isolated from Skin and Soft Tissue Infections (SSTIs) is a gram positive organism, Staphylococcus aureus (S. aureus). Wide range of emerging Methicillin Resistant Staphylococcus aureus (MRSA) infections is leading to global threat causing Community Acquired-MRSA (CA-MRSA) or Hospital Acquired MRSA (HA-MRSA). Minimum Inhibitory Concentration (MIC) is done to ensure that antibiotics are chosen efficiently in the clinical settings by Vitek 2, Epsilometertest (E-test) and Broth Microdilution (BMD) method. Aim: To determine the clinical spectrum of MRSA and comparison of vancomycin MICs obtained by E-test, Vitek 2C and BMD method. Materials and Methods: This was a cross-sectional study conducted at Nizam’s Institute of Medical Sciences, Hyderabad, Telangana, India, during the period of November 1st 2019 to December 31st, 2020 from Inpatient Department (IPD) and Outpatient Department (OPD). Among 464 SSTIs, 132 were S. aureus, out of which 38 isolates were MRSA. Identification and sensitivity of the isolates such as pus, wound swabs and tissues were identified through Vitek 2 compact system. Statistical analysis of the demographic and clinical characteristics was represented as frequency and percentages. Results: Among the total 464 SSTIs, S. aureus were 132 of which MRSA were 38 (29%) and Methicillin sensitive Staphylococcus aureus (MSSA) were 94 (71%) with male predominance of 29 (76.3%) with MRSA. Most of the patients were in the age group of 21-30 years (26%). Amongst the total 38 patients analysed, 25 were from IPD and 13 were from OPD. Around 23/38 were wound swabs (60%) 12/38 of pus (31.5%) and 3/38 (8%) were tissues. The predominant risk factor observed was Surgical Site Infections (SSI) in 19 cases (50%) followed by prior antibiotic therapy in 17 (44.7%) cases. The median duration of hospitalisation was 31.5 days. Vancomycin susceptibility by all three methods with an MIC range of 0.5-2 μg/m by all three methods, except for one isolate where the MIC was >32 ug/mL by Vitek 2C and 8 ug/mL by E-test, which was sensitive by BMD with an MIC of 0.25 µg/mL. Conclusion: Implementing infection control practices and controlling the risk factors will help in management of MRSA infections. Drug resistance to glycopeptides can be avoided by regular screening of vancomycin creeps by different susceptibility methods in order to avoid treatment failures.

Latar Belakang: Chlorhexidine gluconate merupakan antiseptik yang sering digunakan untuk mencegah penyebaran infeksi karena luasnya cakupan antiseptik tersebut dalam membunuh bakteri. Antiseptik ini juga sering digunakan untuk mencegah penyebaran infeksi beberapa bakteri MDRO, salah satunya bakteri MRSA. Akan tetapi, seringnya penggunaan antiseptik tersebut dikhawatirkan dapat meningkatkan resistensi bakteri MRSA terhadap chlorhexidine gluconate. Objektif: Studi ini bertujuan untuk mengetahui efektivitas antiseptik dengan kandungan chlorhexidine gluconate terhadap bakteri strain MRSA. Metode: Kajian literatur naratif ini menggunakan artikel hasil pencarian Google Scholar dan PubMed dengan kata kunci “Methicillin Resistant Staphylococcus aureus”, “MRSA”, “Anti-Infective Agents, Local”, dan “Chlorhexidine gluconate” yang diterbitkan dalam 10 tahun terakhir (2010-2020), dan menggunakan Bahasa Inggris. Artikel yang tidak bisa didapatkan secara lengkap dan literature review dieksklusi. Artikel kemudian dinilai menggunakan critical appraisal checklist untuk dikaji. Hasil: Hasil pencarian menampilkan 355 artikel, dimana 345 artikel dieliminasi berdasarkan kriteria inklusi dan eksklusi, sehingga didapatkan 8 artikel. Delapan artikel yang ditinjau terdiri dari empat studi terkontrol acak, dua studi laboratorium, satu uji hewan, dan satu studi observasional. Kesimpulan: Penelitian ini mendapatkan 8 literatur untuk dikaji. Lima literatur melaporkan bahwa chlorhexidine gluconate menurunkan prevalensi infeksi bakteri MRSA, walaupun dua literatur menyatakan bahwa penurunan tersebut tidak signifikan. Tiga literatur lain melaporkan adanya penurunan sensitivitas bakteri MRSA terhadap chlorhexidine gluconate, terutama pada isolat yang diidentifikasi memiliki gen qacA/B atau gen smr. Background: Chlorhexidine gluconate is an antiseptic that can prevent infection because of its broad-spectrum antimicrobial activity. It can prevent MDRO infection, including MRSA. However, frequent use of chlorhexidine gluconate may result in the emergence of MRSA with reduced susceptibility or even resistance against it. Objective: This study aims to determine the effectiveness of an antiseptic containing chlorhexidine gluconate against MRSA. Methods: A literature search of PubMed and Google Scholar was performed with keywords such as “Methicillin Resistant Staphylococcus aureus”, “MRSA”, “Anti-Infective Agents, Local”, and “Chlorhexidine gluconate”. Articles published from the last 10 years in English were included. Articles that were not available in full text as well as literature reviews were excluded. These articles were appraised using critical appraisal checklist for review. Results: We identified 355 articles, of which 345 were eliminated based on the inclusion and exclusion criteria, leaving 8 articles. These eight articles consisted of four randomized controlled studies, two laboratory studies, one animal study, and one observational study. Conclusion: Five studies reported that chlorhexidine gluconate reduces rate of MRSA infection, although two studies stated that the rates are not significant. Three studies reported reduced susceptibility against chlorhexidine gluconate in MRSA isolates with qacA/B or smr genes.

Background: Nasal colonization of Staphylococcus aureus is very common among health care workers, as part of a comprehensive Methicillin Resistant Staphylococcus aureus (MRSA) decolonization strategy, Mupirocin (Pseudomonic acid) is a topical antibiotic largely used to eradicate staphylococcal nasal carriage. Increased mupirocin use predisposes to mupirocin resistance, which is significantly associated with persistent MRSAcarriage. This resistance is both low level as well as high level among the isolated strains. Aim and Objectives: To estimate the nasal carriage of MRSA in Healthcare Workers (HCWs) and to detect level of Mupirocin resistance in isolated MRSA strains. Material and Methods: A total 670 nasal swabs of HCWs (doctors, nursing staff and housekeeping staff) from various high risk areas were tested. High level and low level Mupirocin resistance among the isolated MRSA strains was detected by Kirby Bauer disc diffusion method. Minimum Inhibitory Concentration (MIC) of Mupirocin resistance was determined by E test. Results: Among 670 nasal swabs, 280 (41.79 %) showed growth of Staphylococcus aureus and 353 (52.68%) were Coagulase Negative Staphylococci (CONS). Of 280 Staphylococcus aureus strains, 61 (21.78%) strains were methicillin-resistant (MRSA). Mupirocin resistance both low level and high level was observed in 1 (1.63%) MRSAcarrier only. Conclusion: The present study showed a high incidence of nasal carriage of MRSA among health care workers. Therefore we suggest MRSA screening of HCWs as a routine practice and insist on Mupirocin resistance detection so that in case if resistance detected alternative treatment can be given.

Introduction: Osteomyelitis is an inflammatory process that affects bone due to the contiguous infection, direct inoculation, or haematogenous spread of microorganisms. It is an infectious disease that is difficult to diagnose and treatment is complex because of its heterogeneity, pathophysiology, clinical presentation and management. Aim: To determine microbiological profile osteomyelitis and antibiotic resistance pattern of bacterial isolates with special reference to Multidrug Resistance (MDR) strains. Materials and Methods: A cross-sectional study was conducted in the Department of Microbiology and Department of Orthopedics Rama Medical College Hospital and Research Centre Kanpur, Uttar Pradesh, India. A total of 100 samples from osteomyelitis cases were aerobically cultured and isolates from culture positives were identified by standard procedures. Antimicrobial Susceptibility Testing (AST) was done following Clinical and Laboratory Standards Institute (CLSI) guidelines. Staphylococcal isolates were screened for methicillin resistance and Gram negative bacilli were screened for MDR production. Results: Out of 100 samples, 76% were culture positive and 24% were culture negative. Males were more affected than females. Staphylococcal spp. (47.3%) was predominant, E. coli (14.4%) and Klebsiella spp. (11.8%), Pseudomonas spp. (9.2%), Proteus spp. (5.2%), Coagulase-Negative Staphylococci (CoNS) (3.9%). Among the MDR strains, Methicillin Resistant Staphylococcus aureus (MRSA) was 44.4%. All the MDR Staphylococcal isolates were 100% sensitive for linezolid. Among the MDR Gram negative bacilli were Extended Spectrum Beta Lactamases (ESBL) (50%), AmpC (17.6%) and Metallo Beta Lactamase (MBL) (14.7%) and they were 100% sensitive for polymixin B and colistin. Conclusion: The microbiological profile of osteomyelitis in the present study showed high prevalence of MRSA44% as the commonest agent, sensitive only to linezolid. E. coli ESBL (50%) and MBL-14.7% were sensitive only to colistin and polymixin B, therefore proper infection control practices and antibiotic policy has to be followed to reduce the incidence of MDR strains.

Introduction and Aim: It has been observed that there is rise of MRSA related morbidity and mortality worldwide. Due to its antibiotic resistance nature, it is difficult to treat. So, in this study our aim was to detect the prevalence and antibiotic resistance of MRSA strains, isolated from blood culture in PT. B.D. Sharma institute of medical science, PGIMS, Haryana. Materials and Methods: Total 7510 samples were sent to Microbiology Laboratory of between 1st June 2021 to 31st December 2021. All blood culture bottles after an incubation period of 24 hrs were plated onto a blood agar plate and the plates were incubated at 35°C for 24 to 48 h. Staphylococcus spp. was identified by doing gram staining, catalase test, coagulase test and antibiotic susceptibility tests were performed by Kirby-Bauer Disk Diffusion method. Methicillin resistance was detected by cefoxitin disc diffusion test. Results: Total of 104 Staphylococcus aureus positive samples were detected. Interestingly, 40 (38.4%) of total Staphylococcus aureus positive samples were Methicillin-Resistant Staphylococcus aureus and 64 (61.6%) of them were Methicillin-Sensitive Staphylococcus aureus. The prevalence of MRSA strains was higher in males 27 (67.5%) than females 13 (32.5%). Maximum numbers of MRSA strains isolates were from inpatient 28 (70%) than outpatient 12 (30%). Maximum MRSA strains were isolated from patients in age group of 0-14 yrs, 15 (37.5%) followed by >60 years of age group9, (22.5%). The maximum number of MRSA strains were isolated from the patients of intensive care units 14 (35%) followed by surgery 10 (25%). When the antibiotic resistance profiles among MRSA strains isolates were checked, it was seen that penicillin resistance seen in all the isolates i.e. 100 %, erythromycin resistance seen in 77.5% isolates, clindamycin resistance in67.5%, gentamicin resistance in 67.5%, ciprofloxacin resistance in 62.5% and cotrimoxazole resistance in 55%. Most MRSA strains were sensitive to second line of antibiotics like Vancomycin 100 %, Linezolid 92.5%. Conclusions: The antibiotic resistance is getting increased by uncontrolled antibiotic usage and wrong choices in empiric therapy day by day. Each hospital/institute has to detect its own antibiotic resistance profiles and apply empiric therapy according to these profiles. Strict infection control policies must be implemented to check its spread in hospital. [ABSTRACT FROM AUTHOR]

Previous research on methicillin susceptible Staphylococcus aureus (MSSA) belonging to livestock-associated (LA-) sequence type (ST) 398, isolated from pigs and their local surroundings, indicated that differences between these MSSA and their methicillin resistant predecessors (MRSA) are often limited to the absence of the staphylococcal cassette chromosome mec (SCCmec) and few single nucleotide polymorphisms. So far, our understanding on how LAMRSA endure the environmental conditions associated with pig-farming as well as the putative impact of this particular environment on the mobilisation of SCCmec elements is limited. Thus, we performed in-depth genomic and transcriptomic analyses using the LA-MRSA ST398 strain IMT38951 and its methicillin susceptible descendant. We identified a mosaic-structured SCCmec region including a putative replicative SCCmecVc which is absent from the MSSA chromosome through homologous recombination. Based on our data, such events occur between short repetitive sequences identified within and adjacent to two distinct alleles of the large cassette recombinase genes C (ccrC). We further evaluated the global transcriptomic response of MRSA ST398 to particular pig-farm associated conditions, i.e., contact with host proteins (porcine serum) and a high ammonia concentration. Differential expression of global regulators involved in stress response control were identified, i.e., ammonia-induced alternative sigma factor B-depending activation of genes for the alkaline shock protein 23, the heat shock response and the accessory gene regulator (agr)-controlled transcription of virulence factors. Exposure to serum transiently induced the transcription of distinct virulence factor encoding genes. Transcription of genes reported for mediating the loss of methicillin resistance, especially ccrC, was not significantly different compared to the unchallenged controls. We concluded that, from an evolutionary perspective, bacteria may save energy by incidentally dismissing a fully replicative SCCmec element in contrast to the induction of ccr genes on a population scale. Since the genomic SCCmec integration site is a hotspot of recombination, occasional losses of elements of 16 kb size may restore capacities for the uptake of foreign genetic material. Subsequent spread of resistance, on the other hand, might depend on the autonomous replication machinery of the deleted SCCmec elements that probably enhance chances for reintegration of SCCmec into susceptible genomes by mere multiplication. [ABSTRACT FROM AUTHOR]

The genus Grewia are known for their medicinal properties. We isolated and characterized five endophytic fungi from Grewialasiocarpa for in vitro antibacterial and antioxidant activities. Five [Aspergillus fumigatus (MK243397.1), Aspergillus fumigatus (MK243451.1), Penicillium raistrickii (MK243492.1), Penicillium spinulosum (MK243479.1), Meyerozyma guilliermondii (MK243634.1)] had inhibitory activity (62.5-1000 µg/mL) against methicillin-resistant Staphylococcus aureus (MRSA). Antioxidant responses were 66.5 and 98.4% for 2,2-diphenyl-1-picrylhydrazyl and Ferric Ion Reducing Antioxidant Power, respectively. In silico evaluation of the phytochemicals of the extract (containing majorly n-hexadecanoic acid) was performed against penicillin-binding protein 2a (PBP2a) implicated in the broad clinical resistance of MRSA to conventional beta-lactams. Molecular dynamic simulation analyses revealed that the phytosterol constituents of the extract, especially dehydroergosterol (- 46.28 kcal/mol) had good stability (4.35 Å), and compactness (35.08 Å) with PBP2a relative to the unbound PBP2a and amoxicillin-PBP2a complex during the 100 ns simulation period, reinforcing them as putative leads that may be developed as viable alternatives to beta-lactams against infections caused by MRSA. However, the prediction that dehydroergosterol lacks oral bioavailability with poor water solubility suggests that it could benefit from structural optimisation for improved druggability. Hence, isolating and derivatizing dehydroergosterol for subsequent evaluation against PBP2a in vitro and in vivo, is recommended., (© 2024 Wiley‐VCH GmbH.)

Previous research on methicillin susceptible Staphylococcus aureus (MSSA) belonging to livestock-associated (LA-) sequence type (ST) 398, isolated from pigs and their local surroundings, indicated that differences between these MSSA and their methicillin resistant predecessors (MRSA) are often limited to the absence of the staphylococcal cassette chromosome mec (SCCmec) and few single nucleotide polymorphisms. So far, our understanding on how LA-MRSA endure the environmental conditions associated with pig-farming as well as the putative impact of this particular environment on the mobilisation of SCCmec elements is limited. Thus, we performed in-depth genomic and transcriptomic analyses using the LA-MRSA ST398 strain IMT38951 and its methicillin susceptible descendant. We identified a mosaic-structured SCCmec region including a putative replicative SCCmecVc which is absent from the MSSA chromosome through homologous recombination. Based on our data, such events occur between short repetitive sequences identified within and adjacent to two distinct alleles of the large cassette recombinase genes C (ccrC). We further evaluated the global transcriptomic response of MRSA ST398 to particular pig-farm associated conditions, i.e., contact with host proteins (porcine serum) and a high ammonia concentration. Differential expression of global regulators involved in stress response control were identified, i.e., ammonia-induced alternative sigma factor B-depending activation of genes for the alkaline shock protein 23, the heat shock response and the accessory gene regulator (agr)-controlled transcription of virulence factors. Exposure to serum transiently induced the transcription of distinct virulence factor encoding genes. Transcription of genes reported for mediating the loss of methicillin resistance, especially ccrC, was not significantly different compared to the unchallenged controls. We concluded that, from an evolutionary perspective, bacteria may save energy by incidentally dismissing a fully replicative SCCmec element in contrast to the induction of ccr genes on a population scale. Since the genomic SCCmec integration site is a hot-spot of recombination, occasional losses of elements of 16 kb size may restore capacities for the uptake of foreign genetic material. Subsequent spread of resistance, on the other hand, might depend on the autonomous replication machinery of the deleted SCCmec elements that probably enhance chances for reintegration of SCCmec into susceptible genomes by mere multiplication.

Nosocomial infections are proving to be a menace for the whole health care system, with methicillin resistant Staphylococcus aureus (MRSA) being a very notorious causative agent. Along with the role of mecA gene producing penicillin-binding protein (PBP2a), production of beta-lactamase enzyme by Staphylococcus aureus makes the organism resistant to all ß-lactam agents. This study aims at phenotypic detection of methicillin resistance and ß-Lactamase production in all S. aureus isolates by Cefoxitin disk diffusion test and Penicillin zone-edge test, respectively. In this prospective crosssectional study, samples were obtained from patients admitted to different departments and were processed according to the standard laboratory protocols. As per the CLSI guidelines, phenotypic detection of resistance to methicillin was done by Cefoxitin Disk Diffusion test, whereas production of beta-lactamase enzyme was phenotypically detected by penicillin zone edge test. Among 179 isolates of S. aureus, 116 (64.8%) were MRSA, whereas the remaining 63 (35.2%) isolates were methicillin-sensitive Staphylococcus aureus (MSS A). Staphylococcus aureus infection among ICU and non-ICU patients were found to be 24(13%) and 155(86.6%) respectively. Among 24 ICU patients, 19 had MRSA infection, whereas among 155 non-ICU patients, 97 had MRSA infection. Out of 63 MSS A isolates, only 2 (3.17%) were found to be sensitive to Penicillin by Zone-edge test, 04 isolates showed presence of ß-lactamase production, while remaining 57 isolates were resistant to Penicillin. At the same time, several class of antibiotics were found to be ineffective against these MRSA isolates. Cases of methicillin-resistant and b-lactamase producing Staphylococcus aureus infections are on the rise in our hospital settings. [ABSTRACT FROM AUTHOR]

Background. Methicillin-resistant Staphylococcus aureus (MRSA) rates have increased in cystic fibrosis (CF) patients. This study aimed to determine the rate of MRSA, define risk factors, and clarify the effect of MRSA on pulmonary functions, annual pulmonary exacerbation (aPEx) in children with MRSA positive CF. Methods. This was a retrospective case control study. CF patients who had =1 MRSA (+) respiratory culture between September 2016-2019 were included. MRSA growth rate, colonization status, clinical characteristics, hospitalization rates, FEV1 %predicted, and z-score one year prior to the MRSA isolation, at MRSA growth and one year after MRSA growth were recorded. The aPEx rate changes before-after MRSA growth were evaluated. Results. Sixty-one subjects who had =1MRSA growth and 66 controls were enrolled. There was no statistically significant difference between the spirometry indices at first, and 12th month after MRSA acquisition. The mean aPEx was 0.6 one year prior to MRSA acquisition and this rate significantly increased to 1.2 one year after MRSA growth(p<0.05). The mean hospitalization rate before and after one year of MRSA acquisition significantly increased from 0.17(±0.12) to 0.48 (±0.3)(p:0.008) admissions per year. Conclusions. MRSA growth was related to increased aPEx. Increased aPEx and hospitalization rates after MRSA acquisition suggest MRSA should be eradicated when detected. [ABSTRACT FROM AUTHOR]

In this study the mode of action of Cinnamomum impressicostatum on Methicillin Resistant Staphylococcus aureus (MRSA) was evaluatewd. Cinnamon is one of the most popular spices used by mankind to enhance the flavour of his cuisine. In addition, cinnamon contains medicinally important essential oils in its leaves, stems, twigs, fruits and inner and outer bark. Many species of cinnamon are widely used in traditional medicinal systems around the world for the treatment of a wide variety of infectious diseases including tuberculosis and salmonellosis. The crude stem - bark water extract of C. impressicostatum was generated using sequential soxhlet extraction. The antibacterial activity of the extract was investigated by performing broth microdilution assays and determination of the Minimum Inhibitory Concentration (MIC). A time kill study was performed to determine the killing efficiency of the extract. Potential bacteriolytic activity of the extract against MRSA was evaluated. Potential summative or synergistic killing effects of the extract when supplemented with 7.5% NaCl was also determined. Leakage of intracellular cytoplasmic components through the bacterial plasma membrane was analysed by determining absorbance at 260 nm. Scanning Electron Microscopy was used to study the damaging effects of the extract on the cell wall of MRSA. The Soxhlet crude water extract of C. impressicostatum stem --1 and its Minimum Bactericidal Concentration -1. The combinatorial effect of the extract supplemented with 7.5% NaCl resulted in a marked decrease in bacterial growth suggesting enhanced killing with the use of NaCl that may be summative or synergistic in nature. Evidence suggests that treatment with the crude extract causes cytoplasmic leakage, possibly by damage to the bacterial cell wall or cytoplasmic membrane. This was substantiated by post treatment scanning electron microscopic analysis which revealed alterations in cell wall topology, possible damage to the bacterial cell wall and plasma membrane and the presence of vast amounts of cellular debris. The results of this study indicate that the killing efficacy of C.impressicostatum stem - bark extract against MRSA is enhanced by NaCl and that treatment with the plant extract induces gross and irreversible cellular damage eventually leading to bacteriolysis. The bioactive compound(s) contained in the plant extract thus show immense potential for development into efficacious antibacterial drugs. [ABSTRACT FROM AUTHOR]

Background: Azadirachta indica has been used against a few disease in traditional medicine and have long history of use, and their use is worldwide in both developing and devolved countries, also have multiple health benefits. Objectives: This study aimed to evaluate the antibacterial activity of Neem leaves extract against standard bacterial strain and only one drug resistant strain of important human pathogenic bacteria by using in vitro methods. Methods: This study aimed to evaluate the antimicrobial effects of Azadirachta indica (Neem) leaves extracts against selected pathogens. The present study was carried out to screen and evaluate antimicrobial activity of leaves of Azadirhta indica (Neem)methanol and petroleum ether extracts. Azadirchta indica extracts were tested against standard strains of S. aureus ATCC 6538, E. coli ATCC 25922, P. aeroginosa ATCC 9027, K. pneumonia ATCC 700603, and S. typhimurium ATCC 14028. The effeminacy of the extracts was studied and determined by applying different concentration of extracts on the selected bacterial strains and synthetic antimicrobial discs were used as positive control by using disc diffusion method. Results: With the statistical test analysis the comparison done showed that, no significant different between the two extracts used, and Staphylococcus aureus and Methicillin resistant staphylococcus aureus were the only bacteria susceptibly affected by this Neem extracts used. Conclusions: The result obtained indicate the leaves extracts of Neem plant have enormous antimicrobial effect, and may be exploited for the treatment of various infectious diseases. [ABSTRACT FROM AUTHOR]

Introduction: A rising incidence of Multidrug Resistance Organisms (MDRO) have become a major challenge to human health infections due to MDRO results in higher mortality rates, longer durations of hospital stays, and higher healthcare costs. MDRO contribute to over 50% of Healthcare Associated Infections (HAIs). Aim: To monitor the trends of Antimicrobial Resistance (AMR) among bacterial pathogens over a period of three years by using Cumulative Antibiogram (CA). Materials and Methods: A retrospective study was done to measure the trends of AMR among gram positive and gram negative organisms over a period of three years. CA capturing the susceptibility data was prepared for Enterobacteriacae, Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter spp. and Enterococcus spp. once in every three year (2017, 2018 and 2019) in the month of January. Results: A total of 1032 isolates, of 10 medically important bacteria were analysed. Total of 21.49%, 30.38% and 54.55% isolates were Extended Spectrum β Lactamase (ESBL) producer in 2017, 2018 and 2019, respectively. There was a rising carbapenem resistance in 2019 (15.5% in E.coli, 26% in Klebsiella pneumonaie an 21% in P. aeruginosa). Among isolates of S. aureus identified in 2019, 56% were Methicillin Resistant Staphylococcus aureus (MRSA). Conclusion: CA helps in monitoring resistance trends among clinical isolates which helps in preparation of antibiotic policy. There is rising incidence of ESBL and carbapenem resistance among gram negative bacilli.

Occurrence of Staphylococcus aureus in children with osteomyelitis. This study was conducted at K. M. M. C. & Hospital, Mathura (UP). A total of 60 patients with osteomyelitis contributed to this study from October 2017 to October 2019. Patients with known immunodeficiency syndromes were excluded. Specimen collections were meticulously performed to avoid contamination which was accomplished by needle aspiration or surgical sampling. Staphylococcus aureus was recovered in more than half of the cases of osteomyelitis in both infants and children. Amikacin, Clindamycin and Cefazolin were effective in such cases. The distal end of the femur and upper-end tibia were the most common sites of infection where boys were more infected than girls. The haematogenous route was the main cause of the transmission of osteomyelitis in children. Principally Staphylococcus aureus causes the majority of cases of osteomyelitis in children followed by H. influenza, Group B Streptococcus, P. aeruginosa, E. coli and Serratia marcescens.

ABSTRACT In a study of antibiotic resistance in Staphylococcus aureus, specific cell wall mutants were previously generated for the peptidoglycan biosynthesis gene murF, by the insertion of an integrative plasmid. A collection of 30 independent mutants was obtained, and all harbored a variable number of copies of the inserted plasmid, arranged in tandem in the chromosome. Of the 30 mutants, only 3, F9, F20 and F26, with a lower number of plasmid copies, showed an altered peptidoglycan structure, lower resistance to β-lactams and a different loss-of-function mutation in rho gene, that encodes a transcription termination factor. The rho mutations were found to correlate with the level of oxacillin resistance, since genetic complementation with rho gene reestablished the resistance and cell wall parental profile in F9, F20 and F26 strains. Furthermore, complementation with rho resulted in the amplification of the number of plasmid tandem repeats, suggesting that Rho enabled events of recombination that favored a rearrangement in the chromosome in the region of the impaired murF gene. Although the full mechanism of reversion of the cell wall damage was not fully elucidated, we showed that Rho is involved in the recombination process that mediates the tandem amplification of exogeneous DNA fragments inserted into the chromosome. IMPORTANCE The cell wall of bacteria, namely, peptidoglycan, is the target of several antibiotic classes such as β-lactams. Staphylococcus aureus is well known for its capacity to adapt to antibiotic stress and develop resistance strategies, namely, to β-lactams. In this context, the construction of cell wall mutants provides useful models to study the development of such resistance mechanisms. Here, we characterized a collection of independent mutants, impaired in the same peptidoglycan biosynthetic step, obtained through the insertion of a plasmid in the coding region of murF gene. S. aureus demonstrated the capacity to overcome the cell wall damage by amplifying the copy number of the inserted plasmid, through an undescribed mechanism that involves the Rho transcription termination factor.

Introduction: Levonadifloxacin is a novel antibiotic belonging to the benzoquinolizine subclass of fluoroquinolone with potent activity against Methicillin Resistant Staphylococcus aureus (MRSA) and Quinolone Resistant Staphylococcus aureus (QRSA). Both intravenous levonadifloxacin and its oral formulation have recently been approved in India for the treatment of acute bacterial skin related infections. Aim: To assess the activity of levonadifloxacin against gram positive clinical isolates collected from Intensive Care Units (ICUs) using the disk-diffusion method. Materials and Methods: The present descriptive study where non duplicate isolates of Staphylococcus aureus (S. aureus) and other gram positive isolates from various clinical samples from all Intensive Care Units (ICUs) were collected from June to December 2020 and subjected to levonadifloxacin susceptibility testing (disk diffusion method) as per the Clinical and Laboratory Standards Institute (CLSI) guidelines, 2020. Data analysis was performed using Statistical Package for the Social Sciences (SPSS) software, version 25.0. Results: A total of 142 gram positive clinical isolates collected from all ICUs of the hospital were analysed. These isolates included coagulase negative S. aureus 109 (76.8%), S. aureus 21 (14.8%) and Enterococcus faecalis 12 (8.4%). All the gram positive isolates of the study were susceptible to levonadifloxacin as per the prespecified interpretive criteria identified based on population pharmacokinetic model and Monte Carlo simulation enabled probability of pharmacodynamic target attainment analysis. Conclusion: Results of this in vitro study shows good activity of levonadifloxacin against gram positive isolates including difficult to-treat methicillin resistant staphylococcal isolates collected from ICU patients.

ObjectiveTo investigate the prevalence, antimicrobial susceptibility, and enterotoxin gene of Staphylococcus aureus (S. aureus) isolates in ready-to-eat (RTE) foods in Guangzhou from 2008 to 2019.MethodsRTE food samples were randomly collected from retail outlets and supermarkets in 11 districts of Guangzhou and the isolation and identification of S. aureus were performed. All isolated S. aureus were tested for antimicrobial susceptibility, enterotoxin genes and multilocus sequence typing (MLST). Methicillin resistant S. aureus (MRSA) isolates were further characterized by staphylococcal cassette chromosome mec (SCCmec) typing.ResultsA total of 157 S. aureus isolates(11.22%) were detected from 1 399 RTE food samples in Guangzhou from 2009 to 2018. The prevalence of S. aureus in cooked pork samples was significantly higher than those in non-meat samples (17.95% vs 9.43%, P