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Teicoplanin and A40926 (natural precursor of dalbavancin) are clinically relevant glycopeptide antibiotics (GPAs) produced by Actinoplanes teichomyceticus NRRL B-16726 and Nonomuraea gerenzanensis ATCC 39727. Their biosynthetic enzymes are coded within large biosynthetic gene clusters (BGCs), named tei for teicoplanin and dbv for A40926, whose expression is strictly regulated by pathway-specific transcriptional regulators (PSRs), coded by cluster-situated regulatory genes (CSRGs). Herein, we investigated the “cross-talk” between the CSRGs from tei and dbv, through the analysis of GPA production levels in A. teichomyceticus and N. gerenzanensis strains, with knockouts of CSRGs cross-complemented by the expression of heterologous CSRGs. We demonstrated that Tei15* and Dbv4 StrR-like PSRs, although orthologous, were not completely interchangeable: tei15* and dbv4 were only partially able or unable to cross-complement N. gerenzanensis knocked out in dbv4 and A. teichomyceticus knocked out in tei15*, implying that the DNA-binding properties of these PSRs are more different in vivo than it was believed before. At the same time, the unrelated LuxR-like PSRs Tei16* and Dbv3 were able to cross-complement corresponding N. gerenzanensis knocked out in dbv3 and A. teichomyceticus knocked out in tei16*. Moreover, the heterologous expression of dbv3 in A. teichomyceticus led to a significant increase in teicoplanin production. Although the molecular background of these events merits further investigations, our results contribute to a deeper understanding of GPA biosynthesis regulation and offer novel biotechnological tools to improve their production.

Coagulase-negative staphylococci (CoNS), members of the skin commensal microbiota, are increasingly associated with local or systemic infections due to a shift in patient populations in recent decades. Subsequently, more CoNS strains have been subjected to antibiotic susceptibility testing (AST), thus leading to the increased detection of teicoplanin resistance. However, data concerning teicoplanin resistance among CoNS strains remain limited, heterogeneous, and inconclusive. We collected 162 consecutive CoNS strains identified using Vitek-2 as teicoplanin-resistant and tested them with a range of AST methods. The results of standard and high inoculum broth microdilution (sBMD; hBMD), agar dilution (AD) after 24 h and 48 h incubation, standard and macrogradient diffusion strip (sGDT, MET), screening agar, and disc diffusion were compared to assess their robustness and to establish a diagnostic algorithm to detect teicoplanin resistance. sBMD was used as the reference method, and the lowest number of strains were teicoplanin-resistant using this method. sGDT and disc diffusion generated similar results to sBMD. Compared with sBMD, AD-24 h generated the lowest number of false teicoplanin-resistant strains, followed by hBMD, AD-48 h, and Vitek-2. sGDT, a fast, easy, affordable method in diagnostic settings, generated the highest rate of false teicoplanin-susceptible strains. Vitek-2 testing produced the highest number of teicoplanin-resistant strains. Only in two strains was the initial Vitek-2 teicoplanin resistance confirmed using five other AST methods. In conclusion, the different antibiotic susceptibility testing methods generated inconsistent, inconclusive, and discrepant results, thus making it difficult to establish a diagnostic algorithm for suspected teicoplanin resistance. Teicoplanin testing proved to be challenging and easily influenced by technical factors. This study aimed not only to raise awareness of teicoplanin resistance testing but also of the need for future studies focusing on the clinical efficacy of teicoplanin in relation to its susceptibility results.

Objectives: The aim of this study was to evaluate the occurrence of glycopeptide resistance in enterococci and coagulase-negative staphylococci (CoNS) and to determine the susceptibilities of the identified glycopeptide-resistant isolates to dalbavancin. Methods: Twenty-two medical laboratories participated in the study conducted in 2016/17 by the Paul-Ehrlich-Society for Chemotherapy. Each laboratory was asked to collect 30 Enterococcus spp. (limited to Enterococcus faecalis and Enterococcus faecium) and 30 CoNS isolates consecutively from hospitalised patients with a proven or suspected infection. Results: A total of 1285 isolates were collected, comprising 364 E. faecalis, 291 E. faecium and 630 CoNS. No E. faecalis isolates (0%) but 76 E. faecium isolates (26.1%) were vancomycin-resistant, of which 21 showed the VanA type and 55 the VanB type. The proportion of vancomycin-resistant strains among E. faecium isolates from patients in intensive care units (21.6%) was significantly lower than that from patients on regular wards (30.5%). Among the CoNS, 67 isolates (10.6%) were teicoplanin-resistant but none were vancomycin-resistant, with resistance only detected in Staphylococcus epidermidis (12.2%), Staphylococcus haemolyticus (17.9%) and Staphylococcus hominis (13.2%). Dalbavancin at ≤0.25 mg/L inhibited all VanB-type enterococci and 95.5% of teicoplanin-resistant CoNS. Conclusion: The level of glycopeptide resistance in E. faecalis remains very low in Germany but achieved 26% in E. faecium and was >10% in CoNS. Dalbavancin appears to be a feasible option for treating infections caused by VanB-type vancomycin-resistant E. faecium and teicoplanin-resistant CoNS.

The microbiological profile, associated risk factors and demographic characteristics of patients with IE has changed in the recent times. In the present study, the antibiotic susceptibility profile of 66 isolates (40 from IDU and 26 from non IDU) recovered over a period of three years from the the patients with definitive diagnosis of IE along with their absolute minimum inhibitory concentrations (MIC-μg/ml) was determined as per CLSI, 2017 guidelines. Staphylococcus aureus was found to be the predominant pathogen associated with IE out of which 90.2% isolates were MRSA, although none of the isolates were found resistant to vancomycin, teicoplanin, daptomycin and linezolid. Pseudomonas aeruginosa isolates were 100% susceptible to carbapenams, however variable resistance was observed against other antimicrobials. All Enterococci were found to be 100% susceptible to linezolid and daptomycin, whereas vancomycin resistant enterococci phenotype was observed in 25% of the Enterococcal isolates. A noticeable difference in the antimicrobial susceptibility profile and their MICs were observed in the present study, as compared to published literature across the globe and within the country. However, no statistically significant difference (λ 2 test, p>0.01)in the AST pattern of isolates from IDU vs. Non IDU was observed. After reviewing the local antibiogram it seems that we need to have our own regional guidelines, which may partially replace the currently prevailing AHA/ESC guidelines.

BACKGROUND: Vancomycin-resistant Enterococcus faecium (VREfm) is an important agent of hospital-acquired infection. VanA phenotype is characterized by resistance to high levels of vancomycin and teicoplanin and is encoded by the vanA gene, whereas VanD phenotype is characterized by resistance to vancomycin and susceptibility or intermediate resistance to teicoplanin; however, some isolates carry a VanD phenotype with a vanA genotype, but there are many gaps in the knowledge about the genetic mechanisms behind this pattern. OBJECTIVE: To characterize the genetic structure, clonality, and mobile genetic elements of VRE isolates that display a VanD-vanA phenotype. RESULTS: All vanA VRE-fm isolates displayed minimum inhibitory concentration (MIC) for vancomycin > 32µg/mL and intermediate or susceptible MIC range for teicoplanin (8–16µg/mL). The isolates were not clonal, and whole-genome sequencing analysis showed that they belonged to five different STs (ST478, ST412, ST792, ST896, and ST1393). The absence of some van complex genes were observed in three isolates: Ef5 lacked vanY and vanZ, Ef2 lacked vanY, and Ef9 lacked orf1 and orf2; moreover, another three isolates had inverted positions of orf1, orf2, vanR, and vanS genes. IS1542 was observed in all isolates, whereas IS1216 in only five. Moreover, presence of other hypothetical protein-encoding genes located downstream the vanZ gene were observed in six isolates. CONCLUSION: VRE isolates can display some phenotypes associated to vanA genotype, including VanA and VanB, as well as VanD; however, further studies are needed to understand the exact role of genetic variability, rearrangement of the transposon Tn1546, and presence of insertion elements in isolates with this profile.

The purpose of the study: to compare the activity of vancomycin, teicoplanin and linezolid and to determine their place in the current treatment of nosocomial infections caused by gram-positive microflora.Material and Methods. 640 gram-positive microorganisms (S. aureus, E. faecium, E. faecalis) isolated in 2018 from various pathological materials from cancer patients treated at N.N. Blokhin National Medical Research Center of Oncology were studied. Literature data from 1982 to 2019, concerning efficacy of glycopeptides (vancomycin, teicoplanin) and linezolid against these pathogens were analyzed.Results. Data analysis showed that percentage of methicillin-resistant Staphylococcus aureus (MRSA) was 89 % and percentage of vancomycinresistant enterococci (VRE) was 5.1 % among Enterococcus faecalis and 16.4 % among Enterococcus faecium. The susceptibility of the studied gram-positive microorganisms to teicoplanin, vancomycin and linezolid ranged from 83.3 to 98.8 % (p>0.5). In general, teicoplanin, vancomycin, and linezolid had equally high microbiological activity against nosocomial strains of S. aureus and Enterococcus spp. Also, according to the literature data, a comparative assessment of the clinical effectiveness and cost-effectiveness of glycopeptides and linezolid was assessed.Conclusion. Vancomycin and teicoplanin are still the main drugs for the treatment of various infections caused by resistant gram-positive microflora. However, teicoplanin, with an efficacy equal to that of vancomycin, has a number of significant advantages over the latter: better tolerability, lower frequency of adverse reactions, and pharmacokinetic features that make it possible to use it once a day both intravenously and intramuscularly. Both drugs, along with linezolid, can be used to treat infections caused by gram-positive microorganisms in cancer patients.

Background and Rationale: Enterococci have long been recognised as low virulence bacteria occurring as commensals in the human intestine. However in the last two decades they emerged as one of the leading causes of nosocomial infections with the development of resistance to antibiotics. So appropriate identification and characterization and antimicrobial susceptibility testing of Enterococcal species is necessary for management and prevention of these infections. Materials and Methods: 150 isolates of Enterococcal species were obtained from various clinical samples. Characterisation was done by standard Microbiological methods and antibiotic susceptibility testing was done by Kirby- Bauer disc diffusion method and Vancomycin MIC tested by E- test. Results: Out of 150 isolates from various clinical samples like urine 93(62%), pus 45(30%), blood 7(4.6%) and other body fluids 5(3%), E.faecalis 131(87.3%) was the predominant isolate followed by E.faecium 14(9.3%), E.avium 2(1.3%), E.raffinosus 2(1.3%) and E.durans 1(0.6%). All isolates were sensitive to Vancomycin, Teicoplanin and Linezolid. Sensitivity to High level Gentamicin was 92%. Rate of resistance to Penicillin 150(100%), Tetracycline 95(63.3%), Ciprofloxacin 103(68.6%) and Ampicillin 67(44.6%). Conclusions: Even though no Vancomycin resistant strains were isolated from our study, there is incidence of Vancomycin resistant Enterococci are emerging as potent pathogen. So methods for characterization, antimicrobial susceptibility testing and MIC of Vancomycin should be done routinely for Enterococcal species. Keywords: Enterococcus, Efaecalis, Efaecium, High level Gentamicin, Vancomycinresistant Enterococci

This study reports the distribution of enterotoxigenic determinants among staphylococci and the susceptibility of staphylococci to various classes of antibiotics. We observed all the isolates as resistant to beta-lactam antibiotics and a few as resistant to non-beta-lactam antibiotics such as clindamycin (47.4%), erythromycin (44.7%), gentamicin (23.7%), norfloxacin (34.2%), tetracycline (26.3%), trimethoprim-sulfamethoxazole (15.8%) etc. The resistance of S. sciuri (n = 1) and S. haemolyticus (n = 1) to rifampicin and intermediate resistance of S. gallinarum (n = 2) to teicoplanin, a high-end antibiotic, are also observed in this study. The multidrug-resistance (≥ 3 classes of antibiotics) was recorded in 23 (60.5%) isolates. The virulomes such as sea, seb, seg and sei were identified predominantly in S. haemolyticus. Surprisingly, certain isolates which were phenotypically confirmed as biofilm-producers by Congo red agar (CRA) test did not harbor biofilm-associated loci. This implies the protein-mediated mechanism of biofilm formation as an alternative to polysaccharide intercellular adhesin (PIA) in staphylococci. However, icaAD locus which encodes PIA was identified in 10 (26.3%) isolates and the eno locus, encoding elastin-binding protein which can accelerate the biofilm production, is identified in all the isolates. The possession of type V SCCmec elements by the S. haemolyticus (15.8%) raised the concern about the rapid dissemination of mecA gene to other species of staphylococci including the virulent S. aureus. In short, this study acknowledges the toxigenicity of coagulase-negative staphylococci (CoNS). Through this study, surveillance of antimicrobial resistance and transference of virulomes in staphylococci is warranted.

Objectives This study reports antimicrobial activity for ceftaroline and comparators against bacterial isolates from patients with skin and skin structure infections (2015–2018). Methods A central laboratory performed susceptibility testing according to CLSI broth microdilution methodology. EUCAST breakpoints were used. Results Isolates were collected in Europe, 14,408 isolates (53.9%); Asia/South Pacific (SP), 5,317 (19.9%); Latin America, 4,268 (16.0%); and Africa/Middle East (ME), 2,753 (10.3%). In all regions, all 7,950 methicillin-susceptible Staphylococcus aureus (MSSA) isolates were susceptible to ceftaroline and vancomycin; susceptibility to daptomycin, linezolid, teicoplanin, and tigecycline was ≥99.6%. Susceptibility of all 9,174 methicillin-resistant S. aureus (MRSA) isolates to daptomycin, linezolid, teicoplanin, tigecycline and vancomycin was ≥97.7%, with 90.8%–96.5% susceptible to ceftaroline. The ceftaroline MIC90 was 0.008 mg/L against Streptococcus pyogenes, 0.015–0.03 mg/L against Streptococcus agalactiae, and 0.008–0.015 mg/L against Streptococcus dysgalactiae. All β-hemolytic streptococci were susceptible to vancomycin. Susceptibility of extended-spectrum β-lactamase (ESBL)-negative Escherichia coli to ceftaroline ranged from 67.0% in Asia/SP to 91.0% in Africa/ME; susceptibility to amikacin, meropenem and tigecycline was ≥96.7% in all regions. Susceptibility of ESBL-negative Klebsiella pneumoniae to ceftaroline ranged from 78.4% in Europe to 83.2% in Africa/ME, and among ESBL-negative Klebsiella oxytoca was 76.3% in Asia/SP, and 89.0%–93.5% in the other regions. Among ESBL-negative K. pneumoniae and ESBL-negative K. oxytoca, susceptibility was highest to amikacin (93.7%–96.4% and 95.7%–100%, respectively) and meropenem (89.7%–97.4% and 98.3%–100%, respectively). Conclusions Ceftaroline was active against the Gram-positive isolates collected; susceptibility of ESBL-negative Gram-negative isolates showed regional variations.

Few pieces of research have focused on Micrococcus luteus bloodstream infection (BSI) because of its low incidence; hence data is needed to illustrate this uncommon infection. This study aimed to explore the clinical characteristics of patients with M. luteus BSI. From January 2010 to December 2019, inpatients that met the criteria for M. luteus BSI were included in this study. Data was collected by reviewing electronic records. Ninety-seven patients were enrolled in this study. Sixty-three percent of the patients have a higher neutrophil percentage (NEUT%). The average blood C-reactive protein (CRP) concentration was 5.5 ± 6.4 mg/dl. 48.5% of the patients had malignancy, and 40.2% underwent invasive surgeries. Linezolid was found to have the largest average diameter of the inhibition zone (36 mm), while erythromycin was found to have the smallest average zone diameter (15 mm). However, some M. luteus strains had a potentially broad antimicrobial resistance spectrum. Cephalosporins (59.2%) and quinolones (21.4%) were the most commonly used antibiotics for empirical therapies. In conclusion, M. luteus BSI mainly happens in immunocompromised patients or those with former invasive surgeries or indwelling catheters. M. luteus strains are less responsive to erythromycin. Cephalosporins and quinolones are effective empirical antibiotics for M. luteus BSI; however, vancomycin and teicoplanin should be considered for potentially broadly drug-resistant M. luteus strains.

Objectives Long-acting lipoglycopeptides are promising therapeutic options in Staphylococcus aureus bone and joint infections (BJIs). This study evaluated the ability of dalbavancin to eradicate the intraosteoblastic reservoir of S. aureus, associated with BJI chronicity. Methods Osteoblastic cells were infected with a standardized inoculum of the S. aureus reference strain HG001 and incubated for 24 h with dalbavancin, vancomycin or rifampicin using the MIC, 10×MIC, 100×MIC and/or the intraosseous concentrations reached using standard therapeutic doses (i.e. vancomycin, 10 mg/L; rifampicin, 2 mg/L; and dalbavancin, 6 mg/L). The remaining intracellular bacteria were quantified by plating cell lysates. Results MICs of dalbavancin, vancomycin and rifampicin were 0.125, 1 and 0.004 mg/L, respectively. Dalbavancin significantly reduced the intracellular inoculum of S. aureus starting at a concentration equal to the MIC, with a significant dose effect, ranging from a reduction of 31.4% (95% CI = 17.6%–45.2%) at MIC to 51.6% (95% CI = 39.8%–63.4%) at 100×MIC compared with untreated cells. Of note, dalbavancin was the only molecule to significantly reduce the intraosteoblastic inoculum at low concentration (MIC). At intraosseous concentrations, dalbavancin reduced the intracellular inoculum by 49.6% (95% CI = 45.1%–54.1%) compared with untreated cells (P Conclusions Dalbavancin was able to decrease the intraosteoblastic S. aureus inoculum by 50% at intraosseous concentrations reached during standard human therapeutic dosing, with no difference compared with vancomycin, and remained less efficient than rifampicin. However, it was the only molecule significantly active at low concentration.

Introduction An increase in recent years in the isolation of Vagococcus spp. is suggestive of emerging infection by this pathogen in our hospital. Methods Prospective, descriptive study. Period: July 2014–January 2019. Phenotypic identification of 15 isolates of Vagococcus spp. was performed by conventional biochemical tests, automated methodology and mass spectrometry (MALDI-TOF MS). Molecular identification was achieved by sequencing the 16S rRNA gene. The Vitek™ 2C automated system was used to test antibiotic susceptibility. Results The molecular method identified 11 Vagococcus fluvialis, one Vagococcus lutrae and three Vagococcus spp. MALDI-TOF MS facilitated the rapid recognition of the genus. The most active antibiotics were ampicillin, trimethoprim/sulfamethoxazole, vancomycin, teicoplanin and linezolid. Most of the cases of isolation were associated with skin and soft tissue or osteoarticular infections in patients with diabetes. Conclusion This article is the most extensive review of cases of Vagococcus spp. infection reported in the literature and highlights the microbiological and clinical aspects of this pathogen.

Introduction Vancomycin-resistant Enterococcus faecium (VREfm) carrying vanA was first isolated from patient at Siriraj Hospital, Thailand in 2004. Since then, VREfm isolates have been detected increasingly in this 2500-bed university hospital. To understand the epidemiology of vanA VREfm in this setting, the isolates collected during 2004–2013 were characterized. Methods A total of 49 vanA VREfm isolates previously confirmed by multiplex PCR were characterized by determining resistance phenotypes to vancomycin, teicoplanin, ampicillin and ciprofloxacin by broth microdilution method. Multilocus sequence typing (MLST) and virulence genes of those isolates were investigated. The Tn1546 structure diversity was studied by long-range overlapping PCR and primer walking sequencing. Results Of all isolates studied, 9 sequence types (ST17, ST80, ST78, ST730, ST203, ST18, ST280, ST64, ST323) in clonal complex 17 and a novel ST1051 were revealed. The esp-positive isolates were 73.5%. Of all vanA operons characterized, at least 9 types of Tn1546-like structures were detected. All of vanA determinants contained 5′-end different from the Tn1546 prototype. Approximately 47% of them also carried the insertion sequence IS1251 at the intergenic region between vanS and vanH. Interestingly, another IS (ISEfa4) was found to be inside the sequence of IS1251 in ST17 isolate. Conclusion Heterogeneity of vanA VREfm was observed. Nearly all of isolates studied belonged to CC17. One novel ST1051 strain was detected. Isolates in the initial period carried vanA operon similar to the prototype. The diversity of vanA determinants has been increased in the recent isolates. A novel vanA operon structure was detected.

Objectives The aim of this study was to investigate the trends in serotypes and in vitro antimicrobial susceptibility of Streptococcus pneumoniae causing adult invasive pneumococcal disease (IPD) to dalbavancin, telavancin, tedizolid, eravacycline, omadacycline and other comparator antibiotics from 2017–2020 following implementation of the 13-valent pneumococcal conjugate vaccine (PCV-13) and during the COVID-19 (coronavirus disease 2019) pandemic. Methods During the study period, 237 S. pneumoniae isolates were collected from non-duplicate patients, covering 15.0% of IPD cases in Taiwan. Antimicrobial susceptibility testing was performed using a Sensititre® system. A latex agglutination method (ImmuLex™ Pneumotest Kit) was used to determine serotypes. Results Susceptibility rates were high for vancomycin (100%), teicoplanin (100%) and linezolid (100%), followed by ceftaroline (non-meningitis) (98.3%), moxifloxacin (94.9%) and quinupristin/dalfopristin (89.9%). MIC50 and MIC90 values of dalbavancin, telavancin, tedizolid, eravacycline and omadacycline were generally low. Non-vaccine serotype 23A was the leading cause of IPD across the adult age range. Isolates of serotype 15B were slightly fewer than those of PCV-13 serotypes in patients aged ≥65 years. The overall case fatality rate was 15.2% (36/237) but was especially high for non-PCV-13 serotype 15B (21.4%; 3/14). Vaccine coverage was 44.7% for PCV-13 and 49.4% for the 23-valent pneumococcal polysaccharide vaccine (PPSV-23), but was 57% for both PCV-13 and PPSV-23. Conclusion The incidence of IPD was stationary after PCV-13 introduction and only dramatically decreased in the COVID-19 pandemic in 2020. The MIC50 and MIC90 values of dalbavancin, telavancin, tedizolid, eravacycline, omadacycline were generally low for S. pneumoniae causing adult IPD.

Introduction: Enterococci from being intestinal commensals have evolved in becoming pathogens and are associated with significant morbidity and mortality Aims & Objectives: This study was done to speciate the uropathogenic Enterococci using the chromogenic medium and to determine the antibiogram also to detect virulence factors phenotypically. Materials and methods: The study included a total of 30 uropathogenic Enterococci isolated over 6 months. Speciation was done using HiCrome Enterococcus faecium agar base. Antibiotic sensitivity was done by the Kirby Bauer Disc Diffusion method as per Clinical and Laboratory Standards Institute (CLSI) guidelines. Among the virulence factors hemolysin, haemagglutination, and gelatin liquefaction tests were done. Results: Amongst the 30 enterococci isolates, 17 were Enterococcus faecalis (E. faecalis) (56.66%) & 13 were Enterococcus faecium (E. faecium) (43.33 %). 100% of the Enterococcus species were sensitive to Vancomycin & Teicoplanin. 66.67% of the Enterococci showed hemolysis, 10% haemagglutination, and 43.33% gelatinase property. Conclusion: Most common isolated species were Enterococcus faecalis. The changing patterns of antibiotic sensitivity to Enterococci in patients with urinary tract infection possess difficulty in selection of the antibiotics. Failure to synergistic therapy is seen in cases of resistance to High-level Gentamicin. Therefore, speciation and antibiotic sensitivity patterns will help in setting up an empirical therapy and thereby help in the reduction of morbidity and mortality. Key words: Antibiotic susceptibility, Chrome agar, Enterococcus species, virulence factors.

The objective of the study was to analyze the taxonomic structure of urinary infection pathogens and determine the susceptibility of ESKAPE group microorganisms (Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterococcus spp.) isolated from cancer patients with nosocomial infections in 2018—2020 to antimicrobials.Materials and methods. 413 (71.9 %) strains of ESKAPE group bacteria from 228 patients were studied. Microorganisms were identified and antibiotic resistance was determined using Vitek-2 System (France) and MicroScan WalkAway (Germany / USA) analyzers.Results and conclusion. All gram-positive microorganisms were highly sensitive to vancomycin and teicoplanin, linezolid, tigecycline, and daptomycin, which can be used in the treatment if clinical indications are seen. Among gram-negative bacteria, the percentage of ESBL producers was 60—70 %, the percentage of carbapenem-resistant bacteria was minimalfor E. coli, rnmpared to the rest - 40—50 %, demonstrating the need to limit the use of carbapenems in the clinic.

Background/Aim: The frequency and severity of respiratory tract infections increase with aging. The aim of this study was to determine the bacterial profile of respiratory tract samples in geriatric patients and evaluate the antibiotic susceptibility patterns of the pathogens. Methods: In this cross-sectional study, a total of 509 clinical samples which were obtained from 302 geriatric patients over 65 years of age and sent to the microbiology laboratory between June 2019-January 2021 were investigated retrospectively. The identification and antibiotic susceptibilities of strains were evaluated with BD-Phoenix-100 fully automated microbiology system. Results: Of the 302 geriatric patients, 166 (%55) were males and 136 (%45) were females. The most isolated pathogens were Klebsiella pneumoniae (25.3%) Pseudomonas aeruginosa (22.5%) and Acinetobacter baumannii (10.2%), Corynebacterium striatum (7.3%), Escherichia coli (6.4%), Staphylococcus aureus (6.4%) and coagulase-negative staphylococci (4.2%). The production of ESBL in Klebsiella pneumoniae strains (52.3%) was higher than in Escherichia coli (41%) strains. All Corynebacterium striatum samples were resistant to ciprofloxacin, tetracycline, rifampin, and penicillin. Methicillin resistance among Staphylococcus aureus (MRSA) isolates was 22.7% and they were 100% susceptible to vancomycin and teicoplanin. Above 90% of K. pneumoniae, P. aeruginosa and A. baumannii positive patients were hospitalized in intensive care units (P

Introduction: The spread of multidrug resistant bacteria has added a new angel to the problem of wound infections which are a major cause of morbidity. To avoid difficulty in treatment of such infections it is mandatory for every pus sample to undergo Culture and sensitivity. Aim: To isolate and study the antibiogram of the aerobic bacteria from pus samples. Materials and Methods: A total of 426 pus samples received from various wards in the Microbiology department. Andhra Medical College, Visakhapatnam were processed as per standard guidelines in the laboratory. All the aerobic bacterial isolates obtained were kept for antibiogram by Kirby Bauer’s disc diffusion method as per CLSI Guidelines. Results: Out of 426 samples 394 (92.4%) were culture positive. Among culture positive samples 90.6% were pure cultures and 9.4% were mixed isolates. Gram negative bacilli were 72.8% of the total isolates and 27.2% were Gram positive cocci. Escherichia coli and Klebsiella pneumonia were the predominant isolates (30.3% and 28.9%) followed by Pseudomonas aeruginosa (24%), Proteus species (9.7%) and Acinetobacter species (6.9%). Among Gram positive cocci Staphylococcus aureus (62.6%), Enterococci (20.5%) and Coagulase Negative Staphylococcus (11.2%) and Streptococci (3.7%). GNB were more sensitive to Colistin (92%), Amikacin (86%), Imipenem and Meropenem (86% and 84.4%), Piperacillin Tazobactam (84%), Gentamycin (78%), Cefaperazone Sulbactam (76.2%) and Ciprofloxacin (56%). Gram positive cocci were sensitive to Linezolid and Teicoplanin (98% each), Vancomycin (96.2%), Clindamycin (84%), Gentamycin (79%), Azithromycin (76.4%), Ciprofloxacin (66%) and Amoxiclav (54%) out of 62.6% Staphylococcus aureus isolates 31.4% were MRSA and out of 72.8% of Gram negative bacilli 38.2% were ESBLS. Conclusion: As multidrug resistant bacterial strains are emerging in various infectious and pyogenic wound infection is most important cause of morbidity, it is important for a clinician to send all pus samples for microbiological analysis and their antibiogram before putting cases on antibiotics. Keywords: Pus samples, Multidrug resistance, Gram negative bacilli, Gram positive cocci, Antimicrobial sensitivity.

The rise in Pantone-Valentine leucocidin (PVL) and gAMMA-haemolysin (Hlg) producing Enterococcus spp., among the people is a serious concern on evolution of antibiotic resistance. Recent reports suggested that the synergistic association of PVL toxin and necrotic lesions that lead to infections in skin and mucosa. To study the prevalence of Enterococcus isolated from the various clinical samples from both inpatient and out - patient department at a Tertiary care hospital. The resistance to Pantone-Valentine leucocidin (PVL) and gAMMA-haemolysin (Hlg) is further tested by using E-test strips for gentamicin test showed 26.8% of isolated populations had resistance to cell wall active agents. In our study all the intermediately sensitive to vancomycin isolates were found to be vancomycin sensitive by both the Epsilometer test and automated Vitek 2 system. The minimum inhibitory concentration ranging from 0.5 - 4 ug/ml. Hence my study confirmed good activity of the vancomycin, linezolid and Teicoplanin against isolated Enterococci spp.

Objective: to determine antimicrobial resistance of Enterococcus faecium and Enterococcus faecalis isolated from blood culture of hematological patients during different study periods.Materials and methods. Antimicrobial susceptibility of Enterococcus spp., collected as part of the multicenter study was tested by the broth microdilution method (USA Clinical and Laboratory Standards Institute (CLSI), 2018), to daptomycin by Etest (bioMeriéux, France). High-level gentamicin resistance (HLGR) and high-level streptomycin resistance (HLSR) was performed by the agar dilution method (CLSI (Oxoid, UK), 2018).Results. The susceptibility of 366 E. faecium (157 in 2002-2009 and 209 in 2010-2017) and 86 E. faecalis (44 in 20022009 and 42 in 2010-2017) was studied. In the second study period (2010-2017) the rise of vancomycin-resistant E. faecium (VREF) increased from 8.3 % to 23.4 % (p = 0.0001), and two linezolid-resistant (LREF) were identified. All VREF and LREF remained susceptible to daptomycin and tigecycline. The rate of susceptible to tetracycline E. faecium remained the same (73.9 and 74.6 %), and an increase in susceptibility to chloramphenicol (74.5 and 82.3 %) was observed. Susceptibility of E. faecium to tetracycline was detected with almost the same rate and in a part of isolates, the increase of susceptibility to chloramphenicol was registered during the analyzed periods. The rise of E. faecium susceptible to HLGR and HLSR has increased significantly in 2010-2017 compared to 2002-2009. Erythromycin, levofloxacin, ampicillin and penicillin had the least activity against E. faecium (less than 5 %).All E. faecalis were susceptible to tigecycline, linezolid, and teicoplanin. Only one of E. faecalis had intermediate resistance to vancomycin. High susceptibility to ampicillin in E. faecalis remained unchanged (97.7 and 97.6 %, respectively). In the second period of the study the rise of susceptible E. faecalis decreased significantly to penicillin (from 97.7 % to 76.2 %), to levofloxacin (from 59.1 % to 31 %), to HLSR (from 52.3 % до 31 %), and to HLGR (from 47.7 % to 26.2 %), remained unchanged to chloramphenicol (52.3 % and 50 %) and was minimal to erythromycin and tetracycline.Conclusion. The study demonstrated higher rates of antibiotic resistance among E. faecium, which consisted of an increase in VREF and the appearance of linezolid-resistant strains. High susceptibility to ampicillin remained in E. faecalis, but there was an increase in resistance to penicillin and aminoglycosides.

Hanzada T Nour El-Din,1 Aymen S Yassin,1 Yasser M Ragab,1 Abdelgawad M Hashem1,2 1Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Cairo, 11562, Egypt; 2Department of Microbiology and Immunology, Faculty of Pharmacy, British University in Egypt, El-Sherouk City, Cairo, 11837, EgyptCorrespondence: Aymen S YassinDepartment of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Kasr Eleini Street, Cairo, 11562, EgyptTel +2-02-23620122Fax +2-02-23620122Email aymen.yassin@pharma.cu.edu.egIntroduction: Methicillin-resistant Staphylococcus aureus (MRSA) presents a profound hazard to public health. MRSA colonizing skin, mucous membranes, and the anterior nares without clinical symptoms is termed “colonizing MRSA”. Upon manifestation of clinical symptoms, it is termed “infectious MRSA”. Here, we characterize and differentiate colonizing and infectious MRSA, and analyze the phenotypic-genotypic and antibiotic susceptibility correlations.Methodology: Clinical MRSA isolates were recovered from intensive care units (ICUs) of two major Egyptian hospitals and their biofilm formation ability was tested. Antibiograms against 16 antibiotics were determined, in addition to the minimum inhibitory concentrations (MICs) of vancomycin and linezolid. The entire collection was typed by enterobacterial repetitive intergenic consensus (ERIC)-PCR, as well as multi-locus sequence typing (MLST). Representative resistance and virulence genes were detected by PCR amplification.Results: Forty-nine isolates were confirmed as MRSA, of which 30 isolates were infectious and 19 were colonizing. Versatile resistance patterns were observed in both groups of isolates. We report a higher tendency for biofilm-formation and borderline minimum inhibitory concentrations among infectious isolates. A Positive antibiotic correlation was observed between susceptibility to protein synthesis inhibitors and cell wall inhibitors. Positive correlations were observed between isolation site and rifampicin resistance: nasal samples were enriched in rifampicin-resistant isolates, while urine and blood samples were enriched in susceptible ones. Furthermore, biofilm formation ability was slightly associated with amikacin resistance, and an association between teicoplanin resistance and the presence of the Panton-Valentine leukocidin gene was the only significant phenotype-genotype correlation observed. Finally, ERIC typing and MLST had congruent results.Conclusion: Linezolid and vancomycin are still the most convenient choice for MRSA treatment. ERIC PCR and MLST show promising typing combination that could be easily used periodically for tracking the genotypic changes of MRSA, especially within the healthcare facilities. Several correlations were established between groups of antibiotics and the genotypes/phenotypes of the selected isolates.Keywords: methicillin-resistant Staphylococcus aureus, MRSA carriage, MRSA colonization, multi-drug-resistant bacteria, virulence, phenotype correlations

Background: Staphylococcus aureus is a common health problem occuring as an important nosocomial pathogen, causing urinary tract infection, surgical site, blood stream and soft tissue infection. The aim of this research was conducted to determine MRSA and VRSA from the pus samples of admitted patients. Aim & Objective: The aim and objective of study was to isolate the resistance pattern of Staphylococcus aureus in pus samples and their AST. Materials and Methods: A total of 158 positive culture Staph aureus were taken from pus samples for the study during December 2019 - October 2020. Samples were cultured on Blood and MacConkey agar then incubated at 37C for 24 hours. The modified Kirby Bauer's disc diffusion method was used to test antibiotic sensitivity of staphylococcus isolates. Result: In total of 158 positive culture of Staphylococcus aureus, 66 (41.7%) were found to be MRSA and 4 (2.5%) were found to be VRSA. Out of 158 Staph aureus, 146 (92.4%) were resistant to Penicillin, followed by Amoxycillin 140 (88.6%), Ampicillin 139 (87.9%), Erythromycin 91 (57.5%), Cefoxitin 66 (41.7%), Gentamycin 56 (35.4%), Amikacin 52 (32.9%) and Teicoplanin 37 (23.4%). Conclusion : An antibiotic policy and screening of susceptibility patterns of MRSA may help in reducing the prevalence rate of MRSA and antibiotic resistance. To stop its spread to the population, it is very important to eliminate MRSA colonization in patients and health care workers. Accurate treatment helps to reduce the rate of morbidity and improvement of patient’s outcome. Keywords: Staphylococcus aureus, MRSA, VRSA

Introduction Diabetic foot infections (DFIs) are among the most severe complications of diabetes. The aim of this study was to determine the etiological pathogens of DFIs in different Wagner's and IDSA/IWGDF grades, and to assess their antimicrobial susceptibility pattern together with molecular characterization of antibiotic resistance genes. Methods A prospective study was conducted on 120 DFI patients at Main Alexandria University Hospital, Egypt. The aerobic and anaerobic etiological pathogens were determined using semi-quantitative culture and PCR respectively. The antimicrobial susceptibility pattern was done according to Clinical Laboratory Standards Institute guidelines. Detection of carbapenemases and class-1 integron genes was carried out by polymerase chain reaction (PCR). Results A total of 178 (124 aerobic, 54 anaerobic) pathogens were identified from patients with DFI, with an average of 1.82 isolates/subject. Among aerobic pathogens, Gram-negative predominated (98/124; 79%), of which Pseudomonas spp. and Proteus spp. were the most common. MRSA constituted more than 50% of Gram-positive isolates. Polymicrobial infection was found in 42 (42.9%) subjects. The proportion of Gram-negative bacteria and anaerobes increased with increased DFI grades and severity. Multidrug and extensively drug resistant isolates were observed in 86 patients (87.7%). PCR identified carbapenemases genes in 14 (11.7%) and class 1 integron in 28 (23.3%) DFI cases. Vancomycin, teicoplanin, linezolid were the most effective antimicrobial agents against Gram-positive pathogens, while colistin, imipenem, meropenem, and piperacillin-tazobactam were effective against Gram-negative pathogens. Conclusions Multidrug and extensively drug resistant Gram-negative bacteria were the dominant pathogens among all DFI severity grades. However, the proportion of Gram-positive bacteria decreased with the severity of infection. The clinical role of our relatively high rate of anaerobes should be investigated. The results found in this study could be beneficial for designing future empiric antimicrobial protocols in relation to the severity of DFIs.

Objectives Pharmacokinetic/pharmacodynamic (PK/PD) analysis using murine infection models is a well-established methodology for optimising antimicrobial therapy. Therefore, we investigated the PK/PD indices of teicoplanin againstStaphylococcus aureus using a murine thigh infection model. Methods Mice were rendered neutropenic by administration of a two-step dosing of cyclophosphamide. Then, isolates of methicillin-susceptibleS. aureus (MSSA) or methicillin-resistant S. aureus (MRSA) were inoculated into the thighs of neutropenic mice. PK/PD analyses were performed by non-linear least-squared regression using the MULTI program. Results Target values offCmax/MIC (r2 = 0.94) of teicoplanin for static effect and 1 log10 kill against MSSA were 4.44 and 15.44, respectively. Target values of fAUC24/MIC (r2 = 0.92) of teicoplanin for static effect and 1 log10 kill against MSSA were 30.4 and 70.56, respectively. Target values of fCmax/MIC (r2 = 0.91) of teicoplanin for static effect and 1 log10 kill against MRSA were 8.92 and 14.16, respectively. Target values of fAUC24/MIC (r2 = 0.92) of teicoplanin for static effect and 1 log10 kill against MRSA were 54.8 and 76.4, respectively. Conclusion These results suggest thatfCmax/MIC and fAUC24/MIC are useful PK/PD indices of teicoplanin against MSSA and MRSA.

Objectives In this meta-analysis, we assessed the clinical efficacy and safety of dalbavancin compared with commonly used anti-Gram-positive agents. Methods PubMed, Embase and Cochrane Library databases were searched from inception up to 25 February 2020. Randomised controlled trials (RCTs) comparing the efficacy and safety of dalbavancin with other antibiotics against Gram-positive infections were included. Reviews, conference abstracts, editorials, case reports, studies on healthy people, or those lacking a comparator group or focusing on different dosages were excluded. Results Seven RCTs comprising 2665 patients were included. Five RCTs included 2109 patients with skin and skin-structure infections (SSSIs) and the other two included patients with catheter-related bloodstream infections (CRBSIs) and osteomyelitis, respectively. Clinical and microbiological responses to dalbavancin were similar to other antibiotics in treating infections caused by Gram-positive bacteria, including the SSSI subgroup. Clinical response to dalbavancin showed superiority in the CRBSI and osteomyelitis subgroups. No significant difference was observed between dalbavancin and other treatments in terms of adverse events (AEs), adverse drug reactions (ADRs) and serious AEs. However, the single-dose regimen had significantly more AEs compared with the comparator group, while the dual-dose regimen resulted in fewer AEs and ADRs and a lower incidence of diarrhoea compared with the comparator group. Moreover, the dalbavancin group showed a decreased mortality risk compared with other treatments. Conclusion Dalbavancin was comparable with other antibiotics in treating chronic Gram-positive infections in terms of efficacy and safety. The dual-dose regimen showed a better safety profile compared with the single-dose regimen in the treatment of SSSIs.

Objectives To evaluate the in vitro activity of dalbavancin compared with vancomycin, daptomycin and other agents against a large collection of coagulase-negative staphylococci (CoNS) isolates. Methods A total of 5088 CoNS causing clinically significant infection were consecutively collected from 122 medical centres in the USA and Europe over 6 years (2014–2019). Isolates were tested for susceptibility by the reference broth microdilution method. Species identification was confirmed by MALDI-TOF. Most isolates were from bloodstream infections (BSIs) (53.5%) or skin/skin structure infections (28.5%). Results Staphylococcus epidermidis was the most common species overall (54.6%) and for BSI (61.3%). The second most common species were Staphylococcus lugdunensis overall (12.3%) and Staphylococcus hominis for BSI (14.7%). Dalbavancin (MIC50/90, 0.03/0.06 mg/L) inhibited >99.9% of CoNS isolates at ≤0.25 mg/L (susceptible breakpoint for Staphylococcus aureus per CLSI). All species were inhibited at ≤0.25 mg/L dalbavancin, except some S. epidermidis (>99.9%) and Staphylococcus warneri (98.9%) isolates. Staphylococcus capitis and Staphylococcus simulans exhibited the lowest dalbavancin MIC50/90 values (0.015/0.03 mg/L) and Staphylococcus haemolyticus and Staphylococcus saprophyticus the highest (MIC50/90, 0.06/0.12 mg/L); 47.8% of S. epidermidis and 34.7% of S. haemolyticus exhibited decreased susceptibility to vancomycin (MIC ≥ 2 mg/L) and 23.2% of S. capitis and 28.4% of S. warneri showed decreased susceptibility to daptomycin (MIC ≥ 1 mg/L). Conclusion Antimicrobial susceptibility varied widely among CoNS species. Dalbavancin inhibited >99.9% and 99.1% of isolates at the US-FDA and EUCAST breakpoints, respectively. Clinical studies of dalbavancin for treatment of CoNS infections should be considered based on these in vitro data.

Introduction: vancomycin-resistant Enterococcus faecium (VREfm) is a major public health problem worldwide. The aim of our study was to determine the microbiological, epidemiological and molecular characteristics of VREfm isolated in north-central, eastern and western Algeria. Methodology: a collection of 48 VREfm isolated from September 2010 to April 2017 in several Algerian hospitals were studied. Minimum inhibitory concentrations (MICs) were determined by E-test method according to CLSI guidelines. the detection of van genotype of all strains was performed by PCR. Clonal relationship of five VREfm targeted by region were characterized using multilocus sequence typing (MLST). Results: All isolates have multidrug-resistance (MDR) and were resistant to at least five classes of antibiotics; however, all were susceptible to tigecycline and daptomycin with MIC50 at 0.094 µg/mL and 2 µg/mL respectively. All strains belonged to vanA genotype and have high level of resistance to vancomycin and teicoplanin. MLST revealed two sequence types (STs): ST80 (from the four regions of Algeria) and ST789, both belonging to the former hospital-adapted clonal complex CC17. Conclusions: the alarming dissemination of MDR E. faecium vanA and the ST80 in several regions of Algeria suggest a clonal spread of VREfm strains, which urgently require implementation of adequate infection control measures.

Background: Staphylococcus aureus (S. aureus) is a well recognized nosocomial and community acquired pathogen which is implicated in causing a wide spectrum of superficial, deep pyogenic infections and toxin mediated illnesses. Localized infections sometimes progress to systemic infections, while ‘spontaneous’ bacteraemia also occur without an evident septic focus, particularly in chronic debilitated immunocompromised patients. Emergence of drug resistance to penicillins and penicillinase-resistant penicillins (i.e., oxacillin and methicillin) is a globally recognized problem. Methicillin Resistant Staphylococcus aureus isolates are also important with respect to the range of nosocomial infections it causes, leading to an increase in the hospital expenditure and mortality or morbidity rate. The increased prevalence of such resistant strains has narrowed down the list of available therapeutic options. Therefore, information regarding the prevalence of S. aureus infections in a health care setting and determining its current antibiotic resistance profile becomes crucial in selecting appropriate treatment regime. Therefore, the current study was done in the department of Microbiology to determine the prevalence of S. aureus infections and the antibiotic resistance pattern of S. aureus isolates from various clinical specimens at our tertiary care hospital in North India. Materials and Methods: A one year prospective study was carried out in the Department of Microbiology, at a tertiary care hospital in North India where non-duplicate strains of S. aureus isolated from various clinical specimens received in the Microbiology laboratory were studied. All S. aureus isolates were subjected to Antibiotic Susceptibility Testing using Kirby Bauer’s disk diffusion method on Mueller Hinton Agar plates in accordance to CLSI guidelines. The antibiotics tested included Penicillin (10U), Amoxicillin-clavulanic acid (20/10μg), Sulphamethoxazole-trimethoprim (1.25/23.75μg), Ciprofloxacin (5μg), Erythromycin (15μg), Clindamycin (2μg), Vancomycin (30μg), Teicoplanin (30μg) and Linezolid (30μg). Results: A total of 23,699 clinical specimens were processed in the laboratory while conducting this study, from which 1233 clinical isolates of S. aureus were identified and processed further. Among all clinical specimens, pyogenic samples (63.1%) yielded maximum number of S. aureus strains followed by blood samples (29.9%) and urine samples (4.8%). S. aureus infection was more evident in hospitalized 71.2% patients than in OPD patients 28.8%. Seasonal variation was also seen in isolation of S. aureus , with a higher percentage of isolates obtained during summer season than during winter season. On antibiotic susceptibility testing, 49.6% strains were Methicillin Resistant. Majority of the isolates were found resistant to Penicillin (92.1%), followed by Erythromycin (59%). Almost half of the total isolates were resistant to Sulphamethoxazole-Trimethoprim (49.3%) followed by Amoxicillin- Clavulanic acid (47.8%), Ciprofloxacin (43.4%) and Clindamycin (18.4%). Antibiotics to which all isolates showed 100% susceptibility included Vancomycin, Teicoplanin, Linezolid. Conclusion: Given the high prevalence of resistance to antibiotics seen in this study, effective treatment of infections caused by multidrug resistant Staphylococcal strains may become challenging. Drugs like Vancomycin, Teicoplanin and Linezolid promise to work as miracle drugs against the multidrug resistant MRSA strains but we need to warrant judicious use of these wonder drugs to conserve them for future use.

Objective Neonatal sepsis remains to be a major cause of neonatal mortality and morbidity in developing countries like India. This study was aimed to identify the bacterial isolates and study antimicrobial profile among admitted babies with neonatal sepsis.Methods A cross-sectional retrospective study was conducted in the sick neonatal wards and neonatal intensive care unit of Burdwan Medical College from March 2017 to February 2018. A total of 299 neonates suspected of neonatal sepsis was evaluated. Diagnosis of neonatal sepsis was made through positive blood culture. Positive samples were subcultured on specific media like blood, chocolate agar, nutrient, Muller–Hinton agar, and MacConkey plates, and the organisms were identified by gram staining and biochemical reactions. Antibiotic susceptibility was tested by Kirby–Bauer disc diffusion method.Results Overall, 118 blood cultures out of 299 patients (39.46%) were bacteria-positive. Of these, 31.3% cases had early-onset septicemia (EOS), while 68.6% had late-onset septicemia (LOS). The prevalence of sepsis was higher in males (55.9%), preterm babies (58.47%), and low birth weight neonates (37.29%). The highest bacterial strains isolated were Klebsiella spp. (33.8%) followed by Staphylococcus aureus (25.8%), Escherichia coli (22.8%), coagulase-negative Staphylococcus (12.5%), Pseudomonas spp. (2.5%), Enterococcus spp. (1.6%), Acinetobacter spp. (0.8%), and Burkholderia spp. (0.8%). Resistance is high among the gram-negative bacteria, like Enterobacter and Pseudomonas, for piperacillin–tazobactam and cephalosporins but they are mostly sensitive to meropenem, colistin, and levofloxacin. Gram-positive bacteria, like S. aureus, are mostly resistant to amoxicillin–clavulanic acid but highly sensitive to linezolid, vancomycin, azithromycin, and teicoplanin.Conclusion K. spp. and S. aureus are the most common isolates in our study. The level of resistance among the organisms toward conventional antibiotics like amoxicillin, cephalosporins, and piperacillin–tazobactum is alarmingly high. This warrants formulation of a hospital-specific guideline for antibiotic use and periodic review of the same.

Antibiotic therapy comes with disturbances on human microbiota, resulting in changes of bacterial communities and thus leading to well-established health problems. In this study, we demonstrated that targeted teicoplanin administration maintains the faecal microbiota composition undisturbed in a mouse model while reaching therapeutic improvements for S. aureus infection.

Glycopeptides are the basis of the treatment of infections caused by MRSA (Methicillin-Resistant Staphylococcus aureus). Previously, it was demonstrated that antibiotic tolerant phenotypes are formed during selection of resistance under the influence of high concentrations of antibiotics. The present study uses a similar in vitro selection model with vancomycin. Clinical isolates of MRSA belonging to genetic lines ST8 and ST239, as well as the MSSA (ATCC29213) strain, were included in the experiment. Test isolates were incubated for five hours in a medium with a high concentration of vancomycin (50 μg/ml). Test cultures were grown on the medium without antibiotic for 18 hours after each exposure. A total of ten exposure cycles were performed. Vancomycin was characterized by bacteriostatic action; the proportion of surviving cells after exposure was 70–100%. After selection, there was a slight increase in the MIC to vancomycin (MIC 2 μg/ml), teicoplanin (MIC 1.5–3 μg/ml) and daptomycin (MIC 0.25–2 μg/ml). According to the results of PAP analysis, all strains showed an increase in the area under curve depending on the concentration of vancomycin after selection, while a heteroresistant phenotype (with PAP/AUC 0.9) was detected in three isolates. All isolates showed walK mutations (T188S, D235N, E261V, V380I, and G223D). Exposure to short-term shock concentrations of vancomycin promotes the formation of heteroresistance in both MRSA and MSSA. Formation of VISA phenotypes is possible during therapy with vancomycin.

Objective: To determine the species of Enterococcus prevalent in the gastrointestinal tract (GIT) of patients in hospitals and community and to determine the antimicrobial susceptibility pattern for the isolates. Materials and Methods: Enterococcus species were isolated from stools and rectal swabs using selective media. Antimicrobial susceptibility pattern for 9 antibiotics were evaluated by Kirby-Bauer’s disc diffusion method. Phenotypic characterization of vancomycin resistant enterococcus (VRE) isolate was done by determining the minimum inhibitory concentration (MIC) to vancomycin and teicoplanin by agar dilution method. Results: Enterococcus species were isolated from gastrointestinal tracts among 74.4% of hospitalized patients and 90% of community patients. E. faecium was the frequent species isolated from both patients. Hospitalized patients had lesser number of other unusual Enterococcus species. Resistance to antibiotics was higher among isolates from hospitalized patients and 1.49% of hospitalized patients showed colonization with VanB phenotype VRE. Conclusion: Gastrointestinal carriage of antibiotic resistant enterococci including VRE among hospitalized patients mandates the need for periodic surveillance among high risk patients in order to prevent infections and dissemination. Keywords: Gastrointestinal carriage, Enterococcus, Antibiotic resistance, VRE, Hospitalized and community patients.

Introduction: Staphylococcus is a major pathogen of community and hospital acquired infections. Vancomycin is used in MRSA caused infections. Emergence of VISA and VRSA has been of great concern in clinical aspects. Materials and Methods: All clinical samples were processed in the laboratory according to standard procedure. Inoculated plates were incubated at 37? C for 24-48 hours. Only S. aureus isolates were included in the present study. Antibiotic susceptibility testing was done by Kirby-Bauer disc diffusion method using a panel of drugs. Cefoxitin disc was used to identify methicillin resistance. The MIC of vancomycin for MRSA isolates was carried out by Agar dilution method and E-test according to standard methods. Heteroresistance to vancomycin was detected by using BHI screen agar. Results: 190 S. aureus were isolated from various clinical samples. Most of the isolates were resistant to amoxyclav (96.2%) followed by ciprofloxacin (84.2%), erythromycin (33.2%), Clindamycin (31.2%), Cotrimoxazole (14.6%), Teicoplanin (4.2%), Mupirocin (2.1%) and none of the isolates were resistant to linezolid. Out of 190 S. aureus isolates, 97 (51.1%) were identified as MRSA. None of the isolates were resistant to vancomycin by agar dilution method and E-test method. Four out of 97 (4.1%) MRSA isolates showed intermediate susceptibility to vancomycin. Among the isolates with MIC of 2µg/ml, 5 (19.2%) showed heteroresistance to vancomycin by BHI screen agar method. Conclusion: Rapid identification of patients harboring VRSA, VISA or hVISA and adherence to infection control protocols are very important in controlling the dissemination of these pathogens. Keywords: MRSA, VISA, VRSA, Heterointermediate resistant Staphylococcus aureus (hVISA), Agar dilution method, E-test.

Antibiotic resistance has become a major world health challenge and has limited the ability of physician's treatment. Staphylococcus aureus the most notorious pathogens causes morbidity and mortality especially in burn patients. However, Staphylococcus aureus rapidly acquired resistance to multiple antibiotics. Vancomycin, a glycopeptide antibiotic remains a drug of choice for treatment of severe Methicillin Resistance S. aureus infections. This study aimed to detect the emergence of beta-lactam and glycopeptide resistance genes. 50 clinical specimens of S. aureus collected from burn patients in burn and plastic surgery units in Sulaimani-Iraq city. All specimens were confirmed to be positive for S. aureus. All the isolates were assessed for their susceptibility to different antibiotics depending on NCCL standards, followed by Extended Spectrum Beta Lactamase detection by double disk diffusion synergy test. The production of ?- lactamases was evaluated in the isolated strains by several routine methods and polymerase chain reaction. Among the isolates 94% were Methicillin resistance and 34.28% were Extended Spectrum Beta Lactamase producer. PCR based molecular technique was done for the bla genes related to ?- lactamase enzymes by the specific primers, as well as genes which related to reduced sensitivity to Vancomycin were detected. The results indicated that all isolated showed the PBP1, PBP2, PBP3, PBP4, trfA and trfB, graSR, vraS except the vraR gene and the prolonged therapy of Methicillin resistance infection with teicoplanin have been associated with progress of resistance and the rise of tecoplanin resistance may be a prologue to evolving Vancomycin resistance. In conclusion, beta-lactam over taking can rise Vancomycin- Intermediate S. aureus strains leading to appearance of Vancomycin resistance although the treatment of Vancomycin resistant infections is challenging.

International audience; Objectives: This multicenter study aimed to assess the performances of gradient diffusion (GD) method in comparison to broth microdilution (BMD) method for susceptibility testing of dalbavancin, daptomycin, vancomycin, and teicoplanin.Methods: Minimum Inhibitory Concentrations (MICs) were retrospectively determined concomitantly by BMD and GD methods, for 93 staphylococci and enterococci isolated from clinical samples. BMD was considered as the gold standard. Essential (EA) and categorical agreements (CA) were calculated. Discordant categorical results were categorized as major (ME) and very major errors (VME).Results: EA and CA were 95.7% and 96.8%, 82.8% and 100%, 97.8% and 96.8%, and 94.6% and 95.7% for dalbavancin, daptomycin, vancomycin, and teicoplanin respectively. Concerning dalbavancin, 3 ME without any VME were observed and discrepancies were low (≤ to 2 two-fold dilutions) between both methods. VME were noted in 1 and 3 cases for vancomycin and teicoplanin, respectively, and resulted from 1 two-fold dilution discrepancy in each case. EA was lower for daptomycin. When they were discrepant, BMD MICs were systematically higher than GD ones. Nevertheless, no categorical discrepancy was noted.Conclusions: GD appears as an acceptable and convenient alternative for dalbavancin, vancomycin, and teicoplanin MICs determination. Our study also emphasizes how achieving accurate daptomycin MICs remains challenging.

Microbial metabolism involves a complex set of interactions between metabolic pathways that include proteins of both known and uncharacterized function. While investigating the physiological strategy used by actinomycetes with two RpoB paralogs, Damiano et al. uncovered the endonuclease activity of a member of the Rid family (F. Damiano, M. Calcagnile, D. Pasanisi, A. Talà, et al., J Bacteriol, 204:e00462-21, 2022, https://doi.org/10.1128/JB.00462-21). While this finding was peripheral to the original question posed by the authors, it has considerable significance. The study by Damiano et al. highlights how unexpected, but fundamental, information can be gained by following phenotypic leads.