Search

Background and Aim: Methicillin-resistant Staphylococcus aureus (MRSA) causes infectious diseases that are clinically problematic. Methicillin resistance is encoded by the mecA gene on the mobile staphylococcal cassette chromosome mec (SCCmec), with SCCmec types I to V being the most prevalent. Staphylococcal protein A gene (spa) typing is a genotyping method designed for S. aureus. This study aimed to use SCCmec and spa genotyping-based methods to identify the genetic diversity of clinical MRSA isolates. Methods: Fifty MDR-MRSA isolates from tertiary hospitals in Egypt were subjected to molecular-based typing using multiplex PCR to identify SCCmec types I to V and detect spa types via spa DNA sequence analysis. Results: The predominant SCCmec types were SCCmec Ⅴ (34%) and SCCmec Ⅳ (32%). The spa sequence analysis revealed 13 definite spa types, with t084 (24.2%) being the most prevalent, followed by t688 (15.1%). Based on both genotyping methods, 20 diverse MRSA clones were identified, with the most predominant MRSA clones being CC15-SCCmecⅤ-t084 and CC15-SCCmecⅣ-t084 (12.1%). Conclusion: MRSA bacteria in Egyptian hospitals are genetically different, indicating that the strains have diverse origins. Thus, regular surveillance of MRSA diversity is required to detect emergent clones for precise epidemiological evaluation and improved procedures to prevent the spread of this superbug. [ABSTRACT FROM AUTHOR]

ABSTRACT: Background: Heterogeneous vancomycin-intermediate Staphylococcus aureus is considered one of the main causes in treatment failure of vancomycin, which leads to poor clinical outcomes. Herein, we comprehensively evaluated characteristics such as global prevalence, trend, and genetic backgrounds of these strains. Methods: In this study, we conducted a meta-analysis based on PRISMA checklist 2020. In the beginning, global databases were searched to achieve the studies related to the prevalence of hVISA in clinical isolates of methicillin-resistant Staphylococcus aureus. After retrieving the eligible English studies, the prevalence of hVISA isolates and their trend changes were assessed using event rate with 95% confidence intervals. Results: In the present study, the prevalence of 114 801 MRSA isolates (of 124 studies) was 64%. According to our results, although the frequency of infection with hVISA is increasing in recent years, there is not a significant difference between Asian countries and Europe/America (6.1% vs. 6.8%). In addition, infection with hVISA bacteria was higher in bacteraemic patients than other infections (9.4% vs. 5.5%), which increases hospitalization, treatment costs, and mortality in these patients. Isolates harbouring SCCmec types II and III are most common genotypes in hVISA strains. Conclusions: The prevalence of hVISA is increasing, which will reduce the effectiveness of vancomycin treatment in the coming years. The presence of hVISA stains in blood samples was higher than the other samples, which is threatening for bacteraemic patients. The results of the current study indicate a universal program to identify and control the spread of such strains in nosocomial infections.

Background: Staphylococcus aureus (S. aureus) associated with COVID-19 has not been well documented. This cross-sectional study evaluated the association between nasal S. aureus carriage and COVID-19. Methods and results: Nasopharyngeal samples were collected from 391 participants presenting for COVID-19 test in Lagos, Nigeria, and S. aureus was isolated from the samples. Antimicrobial susceptibility test was done by disc diffusion method. All S. aureus isolates were screened for the presence of mecA, panton-valentine leucocidin (PVL) and toxic shock syndrome toxin (TSST) virulence genes by polymerase chain reaction. Staphylococcal protein A (spa) typing was conducted for all the isolates. Participants with COVID-19 had double the prevalence of S. aureus (42.86%) compared to those who tested negative (20.54%). A significant association was seen between S. aureus nasal carriage and COVID-19 (p = 0.004). Antimicrobial sensitivity results showed resistance to oxacillin (100%), cefoxitin (53%), and vancomycin (98.7%). However, only 41% of the isolates harbored the mecA gene, with SCCmecV being the most common SCCmec type. There was no association between the carriage of virulence genes and COVID-19. A total of 23 Spa types were detected, with t13249 and t095 being the two most common spa types. Conclusion: This study examined the association between nasal S. aureus carriage and SARS-COV-2 infection. Further research is required to fully explore the implications of S. aureus co-infection with COVID-19. [ABSTRACT FROM AUTHOR]

Wei-Yao Wang,1,2 Yi-Hsin Chen,3– 5 Yu-Lin Lee,1,2 Chen-Feng Chiu,6 Shih-Ming Tsao1,2 1School of Medicine, Chung Shan Medical University, Taichung, Taiwan; 2Department of Internal Medicine, Chung Shan Medical University Hospital, Taichung, Taiwan; 3Department of Nephrology, Taichung Tzu Chi Hospital, Taichung, Taiwan; 4School of Medicine, Tzu Chi University, Hualien, Taiwan; 5Department of Artificial Intelligence and Data Science, National Chung Hsing University, Taichung, Taiwan; 6Department of Internal Medicine, Feng Yuan Hospital, Ministry of Health and Welfare, Taichung, TaiwanCorrespondence: Shih-Ming Tsao, Department of Internal Medicine, Chung Shan Medical University Hospital, &num; 110, Section 1, Jianguo North Road, Taichung City, 40201, Taiwan, Tel +886 4 24739595 ext.34718, Fax +886-4-23248172, Email tsmhwy@ms24.hinet.netBackground: Determining oxacillin susceptibility using reference methods and automated systems is crucial for treating invasive infections caused by Staphylococcus aureus. This study compares the oxacillin susceptibility results from the two automated systems with agar dilution and correlates them with genotypes of invasive S. aureus.Methods: Non-duplicate S. aureus invasive isolates were collected over an 11-year period. The oxacillin susceptibility was determined with Phoenix 100 (Jan 2011 to Aug 2018) or Vitek 2 (Sep 2018 to Dec 2021), and susceptibility for oxacillin and cefoxitin was determined with agar dilution. Methicillin-resistant S. aureus (MRSA) was confirmed with mecA existence, and the genotype was determined using SCCmec. The association between genotype and antibiotic susceptibility using two automated systems and agar dilution was evaluated.Results: A total of 842 invasive S. aureus, including 443 mecA+ MRSA and 399 mecA- MSSA, were collected. The susceptibility rates of oxacillin determined by two automated systems and agar dilution were 68.8% (76.8% for Phoenix 100 and 57.6% for Vitek 2) and 54.0%, respectively. When compared with the oxacillin susceptibility using agar dilution, the categorical agreement for Phoenix 100 and Vitek 2 were 0.46% and 0.88%, respectively (p < 0.001). One hundred and forty-three isolates were misinterpreted as oxacillin-susceptible S. aureus (OSSA) using automated systems while comparing with agar dilution, among which molecularly community-associated MRSA (CA-MRSA) outnumbered healthcare-associated MRSA (HA-MRSA) (99 vs 34, p < 0.001). There were 70 mecA+ OSSA (OS-MRSA) using agar dilution, among which 42 harbored SCCmec types were predominantly categorized as CA-MRSA (38, p < 0.001).Conclusion: The categorical agreement of Vitek 2 in determining oxacillin susceptibility and predicting mecA existence is comparable with agar dilution, whereas Phoenix 100 is not. Most of those ORSA determined by agar dilution but misinterpreted as OSSA by automated systems and OS-MRSA are categorized as CA-MRSA.Keywords: oxacillin susceptibility, automated systems, agar dilution, SCCmec, CA-MRSA

Background: Patients with diabetic feet are prone to be infected due to the impaired immune system. However, the prognostic outcome of different microbial infections remains controversial. Identification and rapid screening of the pathogenic microorganisms that pose the greatest threat to the prognosis of patients with diabetic foot infections (DFIs) is critical. Methods: Clinical data were statistically analyzed, which were obtained from 522 patients with DFIs, including pathogenic bacterial culture results and treatment outcomes at the last return visit. In addition, a loop-mediated isothermal amplification (LAMP) detection method was developed to identify the prevalent subtype of methicillin-resistant Staphylococcus aureus (MRSA) in DFIs patients. This study was approved by the Ethics Committee of Nanfang Hospital (NFEC-202012-K6) and registered on ClinicalTrials.gov (NCT04916457) on June 1, 2021. Results: We found that the proportion of patients with infections of Staphylococcus aureus (S. aureus) and MRSA was 27.7% (145/522) and 33.7% (49/145), respectively. Additionally, the incidence of osteomyelitis was 46.9% (23/49) and amputation/disability was 40.8% (20/49) in patients with MRSA infection, which were significantly higher compared to patients with other types of bacterial infections such as methicillin-susceptible Staphylococcus aureus (MSSA). Notably, we demonstrated that the main prevalent subtype of MRSA in DFIs patients in our hospital was Staphylococcal chromosomal cassettes mec (SCCmec) type II. In addition, it only takes 1.5 h to complete the entire experimental procedure in this LAMP assay, providing high sensitivity (100%) and specificity (77.8%) in hospitalized patients with DFIs. Conclusions: We demonstrated there is a very high rate of MRSA isolation in patients with DFIs and revealed that patients infected with MRSA are at a higher risk of developing osteomyelitis, and amputation or disability. Importantly, we have developed a method for quickly screening newly admitted patients for MRSA. [ABSTRACT FROM AUTHOR]

The increasing emergence of Staphylococcus aureus as the primary causative agent of otitis externa has been noted; however, detailed information regarding the molecular characteristics of these strains in Iran remains scarce. The current study aims to investigate both genotypic and phenotypic attributes of S. aureus strains implicated in ear infections. In the present work, we analyzed 60 S. aureus strains isolated from cases of otitis externa over a period of 45 months. The resistance patterns were determined using disk diffusion and microbroth dilution methods. All S. aureus isolates were confirmed by the nucA polymerase chain reaction assay, and their biofilm production was assessed by a microtiter plate assay. Molecular characterization of the isolates was performed using the staphylococcal cassette chromosome mec, multilocus sequence typing, and staphylococcus protein A typing methods. Overall, the results indicated that 44 out of 60 S. aureus isolates (73.3 %) were methicillin-resistant Staphylococcus aureus. Resistance to mupirocin and vancomycin was observed in 13.3 % and 1.7 % of the tested isolates, respectively. Furthermore, out of the 60 S. aureus isolates, 56 strains (93.4 %) were classified as positive biofilm strains at different levels. Twelve distinct clonal lineages were identified. The vast majority of S. aureus isolates belonged to CC30/ST30-MRSA IV/t019 (41.7 %). Among the 31 strong biofilm producers, the majority (64.5 %) belonged to CC30/ST30-MRSA IV/t019 clone. Biofilm negative isolates belonged to CC22/ST22 (2 isolates), CC8/ST585 (one isolate), and CC8/ST8 (one isolate). Our result revealed that about three-quarters of PVL-positive strains belonged to CC30/ST30. Our data confirmed the presence of MSSA strains among CC30/ST30 and CC22/ST22 isolates. The mupirocin resistant isolates (n = 8) belonged to CC8/ST585-MRSA III/t713 (37.5 %), CC8/ST239-MRSA III/t030 (25 %), CC8/ST8-MRSA IV/t008 (12.5 %), CC8/ST239-MRSA III/t037 (12.5 %), and CC22/ST22-MRSA IV/t790 (12.5 %) lineages. The VRSA strain belonged to the CC8/ST8-MRSA IV/t008 lineage, carrying the vanA determinant. iMLSB phenotypes (n = 14) were distributed across different lineages, including CC30/ST30-MRSA IV/t019 (21.5 %), CC30/ST30-MSSA/t021 (21.5 %), CC22/ST22-MSSA/t005 (14.3 %), CC8/ST239-MRSA III/t030 (14.3 %), CC22/ST22-MSSA/t1869 (7.1 %), CC22/ST22-MRSA IV/t790 (7.1 %), CC8/ST239-MRSA III/t037 (7.1 %), and CC1/ST772-MRSA IV/t10795 (7.1 %). These findings highlight significant genotypic diversity and high biofilm formation among our isolates. The frequent occurrence of the CC/ST30 clone in S. aureus strains isolated from otitis externa reflects the emergence of these lineages as a predominant clone in Iran, posing a significant public health concern.

ObjectiveTo outline the epidemiology of puerperal mastitis caused by methicillin-resistant Staphylococcus aureus (MRSA) and evaluate the effect of an infection control bundle on its incidence.MethodsA surge in MRSA puerperal mastitis was noted in a community hospital in September 2009. MRSA samples from mastitis cases and the environment underwent typing using multilocus sequence typing (MLST), staphylococcal cassette chromosome mec (SCCmec), gene encoding surface protein A (spa), accessory gene regulator (agr), and pulsed-field gel electrophoresis (PFGE). The phenotypic characteristics, including superantigen toxin profiles, gene encoding Panton-Valentine leucocidin (pvl), and minimal inhibitory concentration (MIC) against vancomycin, were ascertained. Subsequently, an infection control bundle emphasizing contact precautions was introduced, and mastitis incidence rates pre- and post-intervention were compared.ResultsThe majority of cases occurred within 6 weeks post-delivery in first-time mothers. Of the 42 S. aureus isolates (27 from mastitis and 15 from colonized staff and environmental sources), 25 (92.6%) clinical and 3 (20%) colonized MRSA were identified as ST59-SCCmecVT-spa t437-agr group I with a vancomycin MIC of 1 mg/L, pvl-positive, and predominantly with a consistent toxin profile (seb-selk-selr). PFGE revealed 13 patterns; pulsotype B exhibited clonal relatedness between two clinical and three colonized MRSA samples. Post-intervention, the incidence of both mastitis and MRSA mastitis notably decreased from 13.01 to 1.78 and from 3.70 to 0.99 episodes per 100 deliveries, respectively.ConclusionDistinct community-associated MRSA (CA-MRSA) clones were detected among puerperal mastitis patients and colonized staff. The outbreak was effectively controlled following the implementation of a targeted infection control bundle.

Background: Since asymptomatic nasal carriage of Methicillin-resistant S. aureus (MRSA) is on the rise among healthcare professionals (HCPs), their prompt detection and decolonization would substantially decrease disease transmission. The study's primary goal was to identify MRSA nasal carriers among dental students/CRIs and determine their SCCmec type and their susceptibility to mupirocin. Methods: Anterior nasal swabs from 102 healthy dental students/ CRIs were collected aseptically and subjected to standard microbiological testing. The antibiotic susceptibility pattern of the S. aureus isolates was determined by Kirby Bauer disc diffusion method and mecA-mediated oxacillin (methicillin) resistance was determined using the cefoxitin disc method. PCR analysis of MRSA isolates determined the presence of mecA and their SCCmec types. D test deduced inducible clindamycin resistance. Results: Of the 102 participants screened, only 8(7.8%) carried S. aureus. Antibiotic susceptibility testing revealed that 5/8(62.5%) were MRSA isolates. Of which, only 2 MRSA isolates harbored mecA, and both belonged to the SCCmec type V. All S. aureus isolates were sensitive to Vancomycin, teicoplanin, and tigecycline when tested using agar screening method while 2/8 (25%) of the S. aureus isolates were D test positive and belonged to iMLSB phenotype. Conclusion: MRSA nasal carriers amongst HCWs/dental students are a cause of concern as they are a significant reservoir for transmission of MRSA among their co-workers as well as the community. Our results signify the need for screening for MRSA carriage and decolonization with mupirocin to substantially decrease the transmission of MRSA among dental students/patients.

There have been few reports regarding the long-term trends in the genotypes of methicillin-resistant Staphylococcus aureus (MRSA) bloodstream isolates. Therefore, this study was performed to investigate the longitudinal trends in the genotypes of MRSA bloodstream isolates obtained from hospitalized patients during a 12-year study period from 2010 to 2021 at a tertiary care university hospital. Over the 12-year period from 2010 to 2021, we conducted a genetic investigation focusing on 245 MRSA strains isolated from the blood of hospitalized patients. The genotypes of the MRSA bloodstream isolates were determined by Staphylococcal Cassette Chromosome mec (SCCmec) typing, accessory gene regulator (agr) typing, PCR-based ORF typing (POT), and multilocus sequence typing (MLST). Strains with the same POT type detected in two or more isolates were designated as epidemic clones, while strains without a common POT type were classified as sporadic clones. Until 2015, isolates with SCCmec II/agr II were prevalent, but isolates with SCCmec IV/agr III increased from 2016. A total of 128 strains (52%) were identified as epidemic clones, while 117 strains (48%) were classified as sporadic clones. The detection rate of sporadic clones increased significantly since 2016 (p < 0.05). The epidemic clones were classified into three clusters, with MRSA of clonal complex (CC) 1 being prominent after 2016. This study showed that the genotypes of MRSA bloodstream isolates underwent a shift from SCCmec II/agr II type to SCCmec IV/agr III type, with a notable increase in MRSA of CC1, after 2016. There was a significant increase in the proportion of sporadic strains among the isolates, suggesting the diversification of genotypes.

Abstract Background Peritonitis is the most important complication of peritoneal dialysis (PD) and coagulase-negative staphylococci (CNS) are a frequent cause of dialysis-related infections. The association between SCCmec typing with psm-mec positivity in staphylococci and PD-related infections has not been identified. We aim to investigate the molecular epidemiology of CNS isolated from PD-peritonitis in a single Chinese center, focusing on the genetic determinants conferring methicillin resistance. Methods We collected 10 genetically unrelated CNS isolates from 10 patients with CNS PD-related peritonitis. The patients were divided into two groups based on the results of MIC to oxacillin: the methicillin-resistant CNS (MRCNS) and methicillin-sensitive CNS (MSCNS) groups. The biofilm formation group (BFG) and the non-biofilm formation group (NBFG) were used as the control groups. Phenotypic and molecular methods were used to analyze SCCmec types I, II and III, associated genes and biofilm formation and the existence of psm-mec. The demographic data and clinical indicators were collected. Results Ten CNS PD-related peritonitis patients were enrolled for this study. There were 6 MRCNS and 4 MRCNS isolates. SCCmec types were fully determined in 10 isolates. Seven staphylococci (70%) carried SCCmec, of which 4 isolates carried single SCCmec type I (40%) and 3 isolates had multiple SCCmec elements (I + III). Of the 6 MRCNS isolates, 3 carried SCCmec type I (50%) and 2 isolates carried SCCmec type I + III (33.3%). A high diversity of ccr types, mec complexes and ccr-mec complex combinations was identified among the 10 CNS isolates. The psm-mec gene was detected in 2/10 (20%) CNS isolates. There was no mutation in the psm-mec gene. Conclusions The majority of isolates were hospital-associated isolates. Furthermore, 2 psm-mec positive isolates were MRCNS in the NBFG. The PD patients frequent exposure to hospital would be the main risk factor. The presence of the psm-mec signal in the spectra of the MRCNS tested here demonstrates the presence of certain SCCmec cassettes that convey methicillin resistance.

Zhuru Hou,1,2,&ast; Ling Liu,2– 4,&ast; Jianhong Wei,1 Benjin Xu2– 4 1Department of Basic Medicine, Fenyang College of Shanxi Medical University, Fenyang, People’s Republic of China; 2Key Laboratory of Lvliang for Clinical Molecular Diagnostics, Fenyang, People’s Republic of China; 3Department of Medical Laboratory Science, Fenyang College of Shanxi Medical University, Fenyang, People’s Republic of China; 4Department of Clinical Laboratory, Fenyang Hospital of Shanxi Province, Fenyang, People’s Republic of China&ast;These authors contributed equally to this workCorrespondence: Jianhong Wei, Department of Basic Medicine, Fenyang College of Shanxi Medical University, Fenyang, 032200, People’s Republic of China, Email wjh5123@163.com Benjin Xu, Department of Medical Laboratory Science, Fenyang College of Shanxi Medical University, Fenyang, 032200, People’s Republic of China, Email bj0726@sxmu.edu.cnAbstract: Staphylococcus aureus is a common human pathogen with a variety of virulence factors, which can cause multiple infectious diseases. In recent decades, due to the constant evolution and the abuse of antibiotics, Staphylococcus aureus was becoming more resistant, the infection rate of MRSA remained high, and clinical treatment of MRSA became more difficult. The genetic diversity of MRSA was mainly represented by the continuous emergence of epidemic strains, resulting in the constant changes of epidemic clones. Different classes of MRSA resulted in different epidemics and resistance characteristics, which could affect the clinical symptoms and treatments. MRSA had also spread from traditional hospitals to community and livestock environments, and the new clones established a relationship between animals and humans, promoting further evolution of MRSA. Since the resistance mechanism of MRSA is very complex, it is important to clarify these resistance mechanisms at the molecular level for the treatment of infectious diseases. We firstly described the diversity of SCCmec elements, and discussed the types of SCCmec, its drug resistance mechanisms and expression regulations. Then, we described how the vanA operon makes Staphylococcus aureus resistant to vancomycin and its expression regulation. Finally, a brief introduction was given to the drug resistance mechanisms of biofilms and efflux pump systems. Analyzing the resistance mechanism of MRSA can help study new anti-infective drugs and alleviate the evolution of MRSA. At the end of the review, we summarized the treatment strategies for MRSA infection, including antibiotics, anti-biofilm agents and efflux pump inhibitors. To sum up, here we reviewed the epidemic characteristics of Staphylococcus aureus, summarized its classifications, drug resistance mechanisms of MRSA (SCCmec element, vanA operon, biofilm and active efflux pump system) and novel therapy strategies, so as to provide a theoretical basis for the treatment of MRSA infection.Keywords: biofilm, efflux pump, MRSA, prevalence, resistance mechanism, SCCmec

Sandip Patil,1,2 Shaowei Dong,2 Devender Shrama,3,4 Bruno Silvester Lopes,5,6 Alfizah Hanafiah,7 Xiaowen Chen,2 Feiqiu Wen1,2 1Department of Haematology and Oncology, Shenzhen Children’s Hospital, Shenzhen, People’s Republic of China; 2Paediatric Research Institute, Shenzhen Children’s Hospital, Shenzhen, People’s Republic of China; 3Department of Microbiology, Himachal Dental College, Sundar Nagar, Himachal Pradesh, India; 4School of Biotechnology, Shoolini University, Solan, Himachal Pradesh, India; 5School of Health and Life Sciences, Teesside University, Middlesbrough, TS1 3BA, UK; 6National Horizons Centre, Teesside University, Darlington, DL1 1HG, UK; 7Department of Medical Microbiology and Immunology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur, MalaysiaCorrespondence: Feiqiu Wen, Department of Haematology and Oncology, Shenzhen Children’s Hospital, Shenzhen, Guangdong, People’s Republic of China, Tel +86-755-83009888, Email fwen62@163.comAim: Methicillin-resistant Staphylococcus aureus (MRSA) is a common cause of severe and difficult-to-treat infections in humans and animals. We aimed to identify the predominant lineages of methicillin-resistant S. aureus in Himachal Pradesh, India, to understand the genomic epidemiology along with the genotypic and phenotypic characteristics.Methods: We isolated 250 S. aureus from two district hospitals in Himachal Pradesh, India. Methicillin-Resistant S. aureus (MRSA) isolates were subjected to MLST, SCCmec typing, and resistance as well as virulence determinants were determined by PCR and sequencing. Bio-typing was also performed for source tracking.Results: A 17.6% (44/250) of isolates were classified as MRSA by both the MRSA detection kit and disc diffusion methods. Antimicrobial Susceptibility Testing of MRSA isolates (n = 44) showed high resistance to oxacillin (77.27%), erythromycin (77.27%), tetracycline (75%), cefoxitin (65.9%), and gentamicin (61.36%), while low resistance was observed for teicoplanin (36.36%), vancomycin and levofloxacin (31.81%) and fusidic acid (18.18%). All isolates were sensitive to linezolid, quinupristin-dulfopristin, dalbavancin, and cefazoline. The SCCmec-II was observed in 20.45% of isolates, SCCmec-I in 11.36%, SCCmec-III in 9%, SCCmec-IV in 40.9% and SCCmec-V in 18.18%. The mecA gene was present in all isolates (n = 44) and 50% also had the vanA gene. 35% of isolates had the lukS-PV/lukf-PV toxin gene and 11.36% had the co-existence of mecA, vanA, and lukS-PV/lukf-PV. The major strain was ST398 (39%) followed by ST239 (27%), ST217 (16%), ST121 (11%), and ST338 (7%). The MRSA isolates produced staphylokinase and β-hemolysis but were negative for bovine plasma coagulation tests.In Conclusion: The predominant MRSA clones in Himachal Pradesh, India, were hospital-associated multi-drug resistant-MRSA ST239 with PVL and community-associated MRSA ST398.Keywords: MRSA, molecular epidemiology, antimicrobial resistance, SCCmec, vanA, lukS-PV/lukf-PV

Background: In this study, our objective was to characterize Staphylococcus lugdunensis isolated from sterile body fluids (SBFs) in a medical center in Taiwan between 2009 and 2020. Methods: We used MALDI-TOF MS, disk diffusion testing, agar dilution assay, SCCmec typing, and antibiotic resistance gene screening to identify and investigate the characteristics of oxacillin-resistant S. lugdunensis (ORSL). Results: A total of 438 S. lugdunensis isolates were collected and 146 (33.3%) isolates were identified as ORSL. SCCmec type V was dominant (65.7%) in our ORSL isolates, followed by SCCmec type II (18.5%), and type IV (8.9%). After 2013, a slight increase in SCCmec types IV and V was revealed. Moreover, all ORSL isolates with type II and untypable SCCmec were highly resistant to oxacillin (MIC >32 μg/mL), compared to ORSL that had SCCmec types IV, V, and VT. All 146 ORSL isolates were resistant to penicillin and susceptible to teicoplanin and vancomycin. High resistance rates of ORSL to clindamycin (43.2%), erythromycin (43.2%), gentamicin (78.1%) and tetracycline (46.6%) was observed. Moreover, only two (1.4%) and six (4.1%) ORSL isolates were resistant to trimethoprim/sulfamethoxazole and ciprofloxacin, respectively. The erythromycin-resistant ORSL isolates mostly exhibited constitutive MLSB resistant phenotype (61/63, 96.8%) and contained either ermC alone (27/63, 42.9%) or a combination of ermC with ermA (28/63, 44.4%). Conclusion: Our present study showed a stable rate of ORSL from SBFs during 2009–2020. Moreover, teicoplanin, vancomycin, trimethoprim/sulfamethoxazole, and ciprofloxacin were shown to be highly efficient for the treatment of ORSL in vitro.

Background: Peritonitis is the most important complication of peritoneal dialysis (PD) and coagulase-negative staphylococci (CNS) are a frequent cause of dialysis-related infections. The association between SCCmec typing with psm-mec positivity in staphylococci and PD-related infections has not been identified. We aim to investigate the molecular epidemiology of CNS isolated from PD-peritonitis in a single Chinese center, focusing on the genetic determinants conferring methicillin resistance. Methods: We collected 10 genetically unrelated CNS isolates from 10 patients with CNS PD-related peritonitis. The patients were divided into two groups based on the results of MIC to oxacillin: the methicillin-resistant CNS (MRCNS) and methicillin-sensitive CNS (MSCNS) groups. The biofilm formation group (BFG) and the non-biofilm formation group (NBFG) were used as the control groups. Phenotypic and molecular methods were used to analyze SCCmec types I, II and III, associated genes and biofilm formation and the existence of psm-mec. The demographic data and clinical indicators were collected. Results: Ten CNS PD-related peritonitis patients were enrolled for this study. There were 6 MRCNS and 4 MRCNS isolates. SCCmec types were fully determined in 10 isolates. Seven staphylococci (70%) carried SCCmec, of which 4 isolates carried single SCCmec type I (40%) and 3 isolates had multiple SCCmec elements (I + III). Of the 6 MRCNS isolates, 3 carried SCCmec type I (50%) and 2 isolates carried SCCmec type I + III (33.3%). A high diversity of ccr types, mec complexes and ccr-mec complex combinations was identified among the 10 CNS isolates. The psm-mec gene was detected in 2/10 (20%) CNS isolates. There was no mutation in the psm-mec gene. Conclusions: The majority of isolates were hospital-associated isolates. Furthermore, 2 psm-mec positive isolates were MRCNS in the NBFG. The PD patients frequent exposure to hospital would be the main risk factor. The presence of the psm-mec signal in the spectra of the MRCNS tested here demonstrates the presence of certain SCCmec cassettes that convey methicillin resistance. [ABSTRACT FROM AUTHOR]

In blood cultures that test positive for staphylococcal bacteria, rapid identification of methicillin-resistant Staphylococcus aureus (MRSA) or methicillin-susceptible Staphylococcus aureus (MSSA) by molecular assay is useful for appropriate antimicrobial treatment of bloodstream infections. Although the Xpert MRSA/SA BC assay is widely available in clinical settings in Japan, its efficacy has not yet evaluated thoroughly. We retrospectively studied 100 blood culture cases positive for S. aureus at Sapporo Medical University Hospital between March 2019 and May 2022. Cycle threshold (CT) values for target genes from the Xpert MRSA/SA BC assay were compared to phenotypic results. Genotyping and genetic analysis of the orfX -SCC mec junction region was performed for selected isolates. We analyzed 25 and 75 isolates assigned to MRSA and MSSA, respectively, using the Xpert MRSA/SA BC assay. Of these, 99 isolates from agar cultures showed compatible susceptibility to oxacillin. One genetically misidentified case of MRSA was found to be caused by the mixed growth of MSSA and methicillin-resistant S. hominis on agar culture. Of the 73 MSSA with pure growth on agar culture, 45 (61.6%) were found to be orfX -SCC mec -positive, spa -positive, and mecA -negative in this assay. These MSSA belong to diverse spa and coa types. The Xpert MRSA/SA BC assay accurately identified MRSA and MSSA in positive blood cultures. However, over half of the MSSA isolates showed positive results for orfX -SCC mec , presumably due to genetic diversity in the orfX -associated region of MSSA. Therefore, the coexistence of MSSA and mecA -harboring coagulase-negative staphylococci may cause confusion about identification of MRSA. [ABSTRACT FROM AUTHOR]

Increase in antibiotic resistance in Staphylococcus aureus isolated from ear infection is a serious public health problem. The objective of this investigation was to determine the antibacterial resistance profile and genetic variability of the S. aureus isolated from adult patients with otitis externa (OE) and otitis media (OM) infections, Tehran- Iran. The disk diffusion was employed to detect the susceptibility of 45 S. aureus strains. Biofilm production was evaluated by microtiter plate assay. Genetic diversity of the isolates was determined by staphylococcal cassette SCC mec , spa , and MLST techniques. Resistance to mupirocin and vancomycin were identified in 40 and 2.2% of isolates. Out of the 45 S. aureus isolates, 41 (91.2%) strains were considered as positive biofilm strains at different levels. According to our results, S. aureus isolated from OM (44.4%, 20/45) were including CC8/ST239-SCC mec III corresponded to spa types t860, t030, t037, t234, t421 (70%, 14/20) and CC/ST30-SCC mec IV corresponded to spa types t605 and t019 (30%, 6/20) while S. aureus isolated from OE (55.6%, 25/45) were including CC/ST30-SCC mec IV corresponded to spa types t605, t345 and t1130 (52%, 13/25), CC/ST22-SCC mec IV corresponded to spa type t790 (20%, 5/25), CC8/ST8-SCC mec IV corresponded to spa type t008 (16%, 4/25), and CC/ST45-SCC mec IV corresponded to spa types t004 and t038 (12%, 3/25). This study highlighted genetic variability and strong biofilm formation ability among our isolates revealing its crucial role in enhancing the resistance of this bacteria to drugs. Thus, it is necessary to continue the epidemiological analysis to improve the control of ear infections related to S. aureus. [ABSTRACT FROM AUTHOR]

Majority of the global population have been affected by food-borne diseases, and Staphylococcus aureus is one of the causes of this disease. S. aureus can be transmitted through contaminated food and is a risk to universal human health because of its ability to produce toxins-staphylococcal enterotoxins. Additionally, methicillin resistant Staphylococcus aureus (MRSA) furthered public health concerns. Although MRSA has been identified in food worldwide, little information is available on this topic locally and internationally. This review presents information on MRSA that was collected as evidence of such infections globally and in Saudi Arabia.

Abstract Staphylococcus pseudintermedius is an opportunistic pathogen commonly associated with skin infections in dogs. Twenty-three methicillin-resistant S. pseudintermedius (MRSP) isolated in Argentina from dogs with pyoderma were analyzed using whole genome sequencing (WGS) and classified into sequence types (ST) by multilocus sequence typing (MLST) and staphylococcal chromosome cassette mec (SCCmec) types. Based on the WGS analysis, MLST, and SCCmec type results, we report for the first time in Argentina two MRSP strains, one each, belonging to ST71-SCCmec III and ST45-ΨSCCmec 57395 from dogs with pyoderma. We also identified seven isolates with ST339, which had been previously reported in only two isolates in Argentina. Additionally, we identified ten MRSP isolates harboring variants of the SCCmec V found in S. aureus, seven SCCmec V (5C2&5) with two ccrC1 recombinases, and three SCCmec V (5C2) with one ccrC1 recombinase. Our findings provide important insights into the evolution and geographic spread of these hypervirulent dominant clones that threaten the health of our companion animals and represent a significant risk for zoonotic infections.

Background and Objectives: Methicillin-resistant Staphylococcus aureus (MRSA) is a major concern in Jordanian hospitals in terms of infection control. The purpose of this study was to identify the resistance patterns of Staphylococcus aureus strains isolated from surfaces of critical locations within the Al-Karak Governmental Hospital in 2019. Additionally, the study aimed to conduct whole-genome sequencing on the isolates. Materials and Methods: In February 2019, fourteen S. aureus strains were isolated from surfaces in critical sites in the Al-Karak Governmental Hospital. These isolates underwent antibiogram testing to determine their resistance profile. Genome sequencing using the Illumina MiSeq platform was applied to the extracted DNA from these isolates. The genomic data, including coding sequences, were analyzed to identify lineage, resistance genes, and plasmids. Results: The antibiogram results revealed that 11 of the 14 isolates were resistant to oxacillin, 6 to linezolid, and 1 to rifampicin, while none showed resistance to chloramphenicol. Eleven isolates were identified as MRSA, with a novel spa type (t4407) not previously reported in Jordan. High-quality sequencing data were obtained for only one isolate, i.e., A29, the genome showed 2,789,641 bp with a 32.7% GC content and contained 2650 coding sequences. Genomic analysis indicated the ST6 lineage, mecA gene (SCCmec type IVa(2B)), and a hybrid plasmid (pJOR_blaZ) carrying the blaZ gene for β-lactam resistance. Genomic data were deposited in NCBI (CP104989). The A29 genome closely resembled an MRSA genome isolated from a Danish hospital in 2011. The SNP analysis revealed identical antimicrobial resistance genes in these two genomes. Conclusions: This study unveils the first genomic sequence of an MRSA isolate from Jordan, marked by distinctive genotypic traits. The findings enhance our understanding of the MRSA types circulating in Jordan and the region and substantiate the phenomenon of intercontinental MRSA transmission.

Staphylococcus pseudintermedius is a frequent cause of infections in dogs. Infectious isolates of this coagulase-positive staphylococcal species are often methicillin- and multidrug-resistant, which complicates therapy. In staphylococci, methicillin resistance is encoded by determinants found on mobile genetic elements called Staphylococcal Chromosome Cassette mec (SCCmec), which, in addition to methicillin resistance factors, sometimes encode additional genes, such as further resistance factors and, rarely, virulence determinants. In this study, we analyzed SCCmec in a collection of infectious methicillin-resistant S. pseudintermedius (MRSP) isolates from predominant lineages in the United States. We found that several lineages characteristically have specific types of SCCmec elements and Agr types and harbor additional factors in their SCCmec elements that may promote virulence or affect DNA uptake. All isolates had SCCmec-encoded restriction–modification (R-M) systems of types I or II, and sequence types (STs) ST84 and ST64 had one type II and one type I R-M system, although the latter lacked a complete methylation enzyme gene. ST68 isolates also had an SCCmec-encoded CRISPR system. ST71 isolates had a psm-mec gene, which, in all but apparently Agr-dysfunctional isolates, produced a PSM-mec peptide toxin, albeit at relatively small amounts. This study gives detailed insight into the composition of SCCmec elements in infectious isolates of S. pseudintermedius and lays the genetic foundation for further efforts directed at elucidating the contribution of identified accessory SCCmec factors in impacting SCCmec-encoded and thus methicillin resistance-associated virulence and resistance to DNA uptake in this leading canine pathogen.

DNA-mimicking proteins encoded by viruses can modulate processes such as innate cellular immunity. An example is Ung-family uracil-DNA glycosylase inhibition, which prevents Ung-mediated degradation via the stoichiometric protein blockade of the Ung DNA-binding cleft. This is significant where uracil-DNA is a key determinant in the replication and distribution of virus genomes. Unrelated protein folds support a common physicochemical spatial strategy for Ung inhibition, characterised by pronounced sequence plasticity within the diverse fold families. That, and the fact that relatively few template sequences are biochemically verified to encode Ung inhibitor proteins, presents a barrier to the straightforward identification of Ung inhibitors in genomic sequences. In this study, distant homologs of known Ung inhibitors were characterised via structural biology and structure prediction methods. A recombinant cellular survival assay and in vitro biochemical assay were used to screen distant variants and mutants to further explore tolerated sequence plasticity in motifs supporting Ung inhibition. The resulting validated sequence repertoire defines an expanded set of heuristic sequence and biophysical signatures shared by known Ung inhibitor proteins. A computational search of genome database sequences and the results of recombinant tests of selected output sequences obtained are presented here. [ABSTRACT FROM AUTHOR]

Background: Patients with invasive infections caused by methicillin-resistant Staphylococcus aureus (MRSA), especially those with an elevated minimal inhibitory concentration (MIC) of vancomycin (VA), are likely to have treatment failure and poor outcomes. The aim of this study was to delineate and correlate the genotypes and phenotypes of clinical VA-intermediate S. aureus (VISA) from invasive infections in Taiwan. Methods: Between 2006 and 2010, a total of 670 non-duplicate MRSA isolates were collected from patients with invasive infections, mostly from blood, as part of a nationwide antimicrobial surveillance program named Tigecycline in vitro Surveillance in Taiwan. Among them, 10 (1.5%) VISA (VA MIC = 4 mg/L) isolates were identified. Molecular typing with staphylococcal cassette chromosome mec (SCCmec), multilocus sequence typing, staphylococcal protein A (spa), mec-associated hypervariable region (dru), accessory gene regulator (agr), and pulse-field gel electrophoresis, and phenotypic analysis including antibiotic susceptibility testing, gene encoding Panton-Valentine leukocidin (pvl), and superantigenic toxin profiles, were analyzed. Results: All but one isolate was defined as molecular health-care-associated MRSA: 6 as SCCmecIII-ST239-spa t037-agrI-dru7 (1 isolate) and dru14 (5 isolates), 2 as SCCmecII-ST5-spa t586-agrII-dru4, and one as SCCmecII-ST89-spa t3520-agrIII-dru7. One isolate was defined as SCCmecIV-ST59-spa t437-agrI-dru8, which was categorized as molecular community-associated MRSA. Five pulsotypes were identified; only one had a positive D-test and 3 were insusceptible to daptomycin (MIC ≧1 mg/L). Five isolates possessed sea-selk-selq, among them 4 belonged to SCCmecIII-ST239-spa t037-agrI. Conclusion: In this study, VISA was rarely isolated from invasive MRSA infections, and most cases harbored limited genotypes and corresponding phenotypes.

Purpose: Our aim was to evaluate the biofilm formation of 2 genetically diverse Staphylococcus aureus isolates, 10379 and 121940, under different concentrations of beta-lactam antibiotics on biomass content and biofilm viability. Methods: Biofilm formation and methicillin resistance genes were tested using PCR and multiplex PCR. PCR was combined with bioinformatics analysis to detect multilocal sequence typing (MLST) and SCCmec types, to study the genetical correlation between the tested strains. Then, the crystal violet (CV) test and XTT were used to detect biomass content and biofilm activity. Antibiotic susceptibility was tested using a broth dilution method. According to their specific MIC, different concentrations of beta-lactam antibiotics were used to study its effect on biomass content and biofilm viability. Results: Strain 10379 carried the icaD, icaBC, and MRSA genes, not the icaA, atl, app, and agr genes, and MLST and SCCmec typing was ST45 and IV, respectively. Strain 121940 carried the icaA, icaD, icaBC, atl, and agr genes, not the aap gene, and MLST and SCCmec typed as ST546 and IV, respectively. This suggested that strains 10379 and 121940 were genotypically very different. Two S. aureus isolates, 10379 and 121940, showed resistance to beta-lactam antibiotics, penicillin, ampicillin, meropenem, streptomycin and kanamycin, some of which promoted the formation of biofilm and biofilm viability at low concentrations. Conclusion: Despite the large differences in the genetic background of S. aureus 10379 and 121940, some sub-inhibitory concentrations of beta-lactam antibiotics are able to promote biomass and biofilm viability of both two isolates. [ABSTRACT FROM AUTHOR]

Majority of the global population have been affected by food-borne diseases, and Staphylococcus aureus is one of the causes of this disease. S. aureus can be transmitted through contaminated food and is a risk to universal human health because of its ability to produce toxins-staphylococcal enterotoxins. Additionally, methicillin resistant Staphylococcus aureus (MRSA) furthered public health concerns. Although MRSA has been identified in food worldwide, little information is available on this topic locally and internationally. This review presents information on MRSA that was collected as evidence of such infections globally and in Saudi Arabia. [ABSTRACT FROM AUTHOR]

Staphylococcus pseudintermedius is an opportunistic pathogen commonly associated with skin infections in dogs. Twenty-three methicillin-resistant S. pseudintermedius (MRSP) isolated in Argentina from dogs with pyoderma were analyzed using whole genome sequencing (WGS) and classified into sequence types (ST) by multilocus sequence typing (MLST) and staphylococcal chromosome cassette mec (SCCmec) types. Based on the WGS analysis, MLST, and SCCmec type results, we report for the first time in Argentina two MRSP strains, one each, belonging to ST71-SCCmec III and ST45-ΨSCCmec57395 from dogs with pyoderma. We also identified seven isolates with ST339, which had been previously reported in only two isolates in Argentina. Additionally, we identified ten MRSP isolates harboring variants of the SCCmec V found in S. aureus, seven SCCmec V (5C2&5) with two ccrC1 recombinases, and three SCCmec V (5C2) with one ccrC1 recombinase. Our findings provide important insights into the evolution and geographic spread of these hypervirulent dominant clones that threaten the health of our companion animals and represent a significant risk for zoonotic infections. [ABSTRACT FROM AUTHOR]

Introduction: Methicillin resistance Staphylococcus aureus is a very potential human pathogen, and its significant antibiotic resistance further complicates the management of this pathogen. Methicillin resistance in S. aureus is conferred by the presence of SCCmec elements but there are different types of SCCmec in MRSA which results in the need of typing of SCCmec elements. Material & Methods: This cross-sectional study was conducted to determine the current antibiotic resistance pattern and prevalence of different types of SCCmec elements in the circulating MRSA at Hayatabad Medical Complex, Peshawar. A total of 60 non repetitive MRSA isolates collected from pus aspirate and wound swab were enrolled in the study. All the MRSA isolates were tested by disc diffusion method against the ten antibiotics and further subjected to the SCCmec typing through two multiplex PCR reactions. Results: Out of the total tested MRSA isolates 80% were resistant to Ciprofloxacin, 63.4% to Erythromycin, 58.4% to Gentamicin, 55.0% to Cotrimoxazole, 51.6% to Tetracycline, 48.4% Fusidic acid, 46.6% to Clindamycin, 35.0% to Doxycycline, while Quinupristin/Dalfopristin and Linezolid kill 100% strains of the MRSA included in the study. SCCmec typing of MRSA isolates showed that prevalence of SCCmec type-III was 3.3% (3/60), types-IV was 58.3% (35/60), and type-V was 38.3% (23/60). Conclusion: The studied MRSA showed worrisome resistance, but Quinupristin/Dalfopristin and Linezolid kill all the strains of MRSA. The prevalence of SCCmec types IV and V is very high which indicates that the circulating MRSA clone are community associated, because they harbour SCCmec type IV and V.

Methicillin-resistant Staphylococcus aureus (MRSA) bacteria are often multi-drug resistant, resulting in a high rate of treatment failure. This study aimed to identify the antibiotics resistance profile and molecular characteristics of MRSA strains isolated from patients' samples, including skin, wounds, and burns, which are the most common infections, and collected from hospitals. The samples included 34 MRSA isolates gathered from January 2020 to September 2020. All isolates were tested using the Kirby-Bauer method to determine MRSA susceptibility against antibiotics using the minimum inhibitory concentration protocol and the E-test. The polymerase chain reaction was used for the detection of antibiotic resistance genes, including tetracycline, erythromycin, linezolid, gentamicin, rifampicin, ciprofloxacin, quinupristin-dalfopristin, clindamycin, and mecA. Staphylococcal Cassette Chromosome mec (SCCmec) was determined by multilocus sequence typing of all isolates; accordingly, the findings indicated that the sensitivity of linezolid, quinupristin-dalfopristin, rifampin, daptomycin, and vancomycin differed. Moreover, multidrug resistance of MRSA was shown to be more than 90% for penicillin and 91.1% for erythromycin. It was revealed that SCCmec III was resistant to at least four to five different antibiotics. ST585 (2.9%), ST240 (8.8%), ST45 (14.7%), ST22 (17.6%), and ST239 (higher rate) were the five sequence types found in STs (55.8%). Finally, it was indicated that the emergence of MRSA in these Iraqi hospitals highlighted further research to better understand how the infection might be effectively controlled.

Background/purpose: Staphylococcus lugdunensis is a Gram-positive coagulase-negative bacterium and is recognized as a critical pathogenic species recently. Here, we aimed to evaluate the cefoxitin disk diffusion (CDD), oxacillin agar dilution (OAD), and mecA PCR for detecting oxacillin-resistant S. lugdunensis (ORSL) isolates. Methods: Multilocus sequence typing (MLST) analysis was performed to determine the clonality of 117 S. lugdunensis isolates isolated between May 2009 and Jul 2014. CDD, OAD, and mecA PCR were used to identify oxacillin-resistant S. lugdunensis (ORSL). Results: MLST results showed that the most common sequence type (ST) of our S. lugdunensis isolates was ST6 (35.9%) followed by ST3 (28.2%), ST27 (17.9%), and ST4 (6.8%). CDD and OAD showed that 39 and 43 isolates were ORSL, respectively. 4 ST3 CDD-susceptible S. lugdunensis (OSSL) isolates had MIC values ≥ 4 for oxacillin. mecA PCR results showed that 43 OAD-resistant S. lugdunensis and 3 OAD-susceptible ST27 S. lugdunensis had the mecA gene. Therefore, OAD was used as the gold standard to evaluate the performance of CDD and mecA PCR for identifying ORSL. The overall sensitivity, specificity, and accuracy of CCD for ORSL detection was 90.7%, 100%, and 96.8%, respectively. The sensitivity, specificity, and accuracy of mecA PCR for identifying ORSL was 100%, 95.9%, and 97.44%, respectively. Conclusion: Our results indicate that OAD shows higher accuracy for ORSL detection compared with CDD and mecA PCR.

Mobile genetic elements can encode a wide variety of genes that support their own stability and mobility as well as genes that provide accessory functions to their hosts. Such genes can be adopted from host chromosomes and can be exchanged with other mobile elements. Due to their accessory nature, the evolutionary trajectories of these genes can differ from those of essential host genes. The mobilome therefore provides a rich source of genetic innovation. We previously described a new type of primase encoded by S. aureus SCCmec elements that is composed of an A-family polymerase catalytic domain in complex with a small second protein that confers single-stranded DNA binding. Here we use new structure prediction methods in conjunction with sequence database searches to show that related primases are widespread among putative mobile genetic elements in the Bacillota. Structure predictions show that the second protein adopts an OB fold (common among single-stranded DNA binding (SSB) proteins) and these predictions were far more powerful than simple sequence comparisons in identifying its homologs. The protein-protein interaction surface varies among these polymerase—SSB complexes appear to have arisen repeatedly by exploiting partial truncations of the polymerase’s N-terminal accessory domains.

Purpose: Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most common pathogens of community- and hospital-acquired infections, and its prevalence is increasing globally. Guiyang is the capital city of Guizhou Province, Southwest China; as the transport and tourism centre of Southwest China, Guizhou Province is bordered by Yunnan, Sichuan, Chongqing, and Guangxi Provinces. Although MRSA prevalence is increasing, little is known about its aspects in the area. The purpose of this study was to analyse MRSA molecular characteristics, antimicrobial resistance, and virulence genes in Guiyang. Methods: In total, 209 MRSA isolates from four hospitals (2019– 2020) were collected and analysed by antimicrobial susceptibility testing and molecular classification by the MLST, spa, and SCCmec typing methods. Isolate antibiotic resistance rates were detected by a drug susceptibility assays. PCR amplification was used to detect the virulence gene-carrying status. Results: Twenty-four STs, including 4 new STs (ST7346, ST7347, ST7348, and ST7247) and 3 new allelic mutations, were identified based on MLST. The major prevalent ST type and clone complex were ST59 (49.8%) and CC59 (62.7%), respectively. Spa type t437 (42.1%) and SCCmec IV (55.5%) were identified by spa and SCCmec typing methods as the most important types. Drug sensitivity data showed that the multidrug resistance rate was 79.0%. There were significant differences in multidrug resistance rates and virulence gene-carrying rates for seb, hla, hlb, cna and bap between ST59 and non-ST59 types. Conclusion: ST59-SCCmecIV-t437 is a major epidemic clone in Guiyang that should be monitored by local medical and health institutions. The situation differs from other adjacent or middle provinces of China, which may be due to the special geographical location of the region and the trend in antibiotic use or lifestyle. This study provides empirical evidence for local medical and health departments to prevent and control the spread of MRSA. [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]

Sepsis caused by methicillin-resistant coagulase-negative staphylococci (MRCoNS) seriously affects the morbidity and mortality of neonates. However, the hand carriage and genotypic diversity of MRCoNS within surgical staff remain unclear in China. In the study, antimicrobial susceptibility tests and genotypic characterisation were applied to MRCoNS. One hundred and one samples were collected from the hands of gynaecological surgical staff. Eighty staphylococcal isolates were identified, of which 75 (94%) were resistant to at least one antibiotic. mecA gene was determined in 50 (62.5%) staphylococcal isolates. Panton–Valentine leukocidin (pvl) and ica genes were determined in 17 (21%) and 12 (15%) staphylococcal isolates, respectively. About 52% of staphylococci carried SCCmec IV and V, followed by SCCmec type I, II, and III (38%). In addition, two new STs types were assigned as ST844 and ST845. The high level of hand MRCoNS colonisation rate in gynaecological surgical staff is of concern, and hand hygiene management should be emphasised among surgical assistants. What is already known on this subject? Coagulase-negative staphylococci (CoNS) are the predominant cause of neonatal sepsis. Exposure to antimicrobial-resistant CoNS might put neonates at increased risk of infection. However, little is known about the carriage and genetic diversity of methicillin-resistant CoNS (MRCoNS) of gynaecological surgeons and surgical assistants. What do the results of this study add? This is the first study on the molecular characterisation of MRCoNS recovered from gynaecological surgeons and surgical assistants in China. MRCoNS carriage rate in surgical assistants was significantly higher than in surgeons. Seventy-five (94%) coagulase-negative staphylococci were resistant to at least one antibiotic. SCCmec I, II and III was the dominant types identified in MRCoNS that were recovered from surgical staff. Fifty (62.5%) staphylococcal isolates that were recovered from surgical staff harboured the mecA gene. Pathogenic clones of MRCoNS were disseminated in surgical staff, and half of mecA-positive Staphylococcus epidermidis harboured the ica gene. What are the implications of these findings for clinical practice and/or further research? The high level of hand MRCoNS colonisation rate among gynaecological surgical staff is of concern. The alarming outcome of this study suggested that hygiene measures should be emphasised among gynaecological surgical assistants. [ABSTRACT FROM AUTHOR]

Staphylococcus pseudintermedius is the most common opportunistic pathogen in dogs and methicillin resistance (MRSP) has been identified as an emerging problem in canine pyoderma. Here, we evaluated the antimicrobial resistance (AMR) features and phylogeny of S. pseudintermedius isolated from canine pyoderma cases in Argentina (n = 29) and the United States (n = 29). 62% of isolates showed multi-drug resistance. The AMR genes found: mecA, blaZ, ermB, dfrG, catA, tetM, aac(6′)-aph(2″), in addition to tetK and lnuA (only found in U.S. isolates). Two point mutations were detected: grlA(S80I)-gyrA(S84L), and grlA(D84N)-gyrA(S84L) in one U.S. isolate. A mutation in rpoB (H481N) was found in two isolates from Argentina. SCCmec type III, SCCmec type V, ΨSCCmec57395 were identified in the Argentinian isolates; and SCCmec type III, SCCmec type IVg, SCCmec type V, and SCCmec type VII variant in the U.S. cohort. Sequence type (ST) ST71 belonging to a dominant clone was found in isolates from both countries, and ST45 only in Argentinian isolates. This is the first study to comparatively analyze the population structure of canine pyoderma-associated S. pseudintermedius isolates in Argentina and in the U.S. It is important to maintain surveillance on S. pseudintermedius populations to monitor AMR and gain further understanding of its evolution and dissemination.

Yinjuan Guo,1 Bingjie Wang,1 Lulin Rao,1 Xinyi Wang,1 Huilin Zhao,1 Meilan Li,2 Fangyou Yu1 1Department of Clinical Laboratory, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai, 200433, People’s Republic of China; 2Respiratory Intensive Care Unit, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai, 200433, People’s Republic of ChinaCorrespondence: Meilan LiRespiratory Intensive Care Unit, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, 3rd Floor, Building 2, No. 507 Zhengmin Road, Yangpu District, Shanghai, People’s Republic of ChinaEmail lml73@163.comFangyou YuDepartment of Clinical Laboratory, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, 3rd Floor, Building 2, No. 507 Zhengmin Road, Yangpu District, Shanghai, People’s Republic of ChinaTel +86 13575440803Email wzjxyfy@163.comIntroduction: Methicillin-resistant Staphylococcus aureus (MRSA) infections have become a leading cause of severe infections in both healthcare and community settings. Mutations in the rpoB gene cause resistance to rifampin (RIFR), a critical antibiotic for the treatment of multidrug-resistant Staphylococcus aureus. The aim of this study was to detect the molecular characteristics of RIFR MRSA and analyze the rpoB gene mutations involved in RIF resistance.Methods: A total of 49 RIFR MRSA and 38 RIFS MRSA isolates collected from seven cities in China were analyzed by multilocus sequence typing, staphylococcus chromosomal cassette mec (SCCmec) typing, spa typing, and rpoB gene mutations.Results: ST239-III-t030 (35/49, 71.4%), the major clone in RIFR MRSA isolates; ST45-IV-t116 (16/38, 42.1%), the major clone in RIFS MRSA isolates with rpoB mutations. RIFR MRSA isolates were resistant to erythromycin, ciprofloxacin, tetracycline, gentamicin, and clindamycin. By contrast, RIFS MRSA isolates with rpoB mutation were more susceptible to ciprofloxacin, tetracycline, and gentamicin. Forty-three (87.8%) isolates present the mutational change H481N and L466S, conferring 128– 512 μg/mL RIF resistance. The four isolates with RIF MIC ≥ 1024 μg/mL had additional amino acid substitution: H481N, L466S, A473T (n=2); H481Y (n=2), associated with a high-level RIF resistance. Of 38 RIFS MRSA isolates, two mutations were observed, including H481N (n=37) and A477D (n=1).Conclusion: In conclusion, the predominant RIFR MRSA clones in China were ST239-III-t030. Molecular characteristics, antibiotic-resistant profiles, and rpoB mutations between RIFR MRSA and RIFS MRSA were diverse. Antibiotics for treating patients with MRSA infections can be selected based on molecular characteristics.Keywords: MRSA, rifampin, rpoB mutations, MLST, SCCmec, spa

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.

Staphylococcal cassette chromosome mec (SCCmec) typing is crucial for investigating methicillin-resistant Staphylococcus aureus (MRSA), relying primarily on the combination of ccr and mec gene complexes. To date, 19 ccr genes and 10 ccr gene complexes have been identified, forming 15 SCCmec types. With the vast release of bacterial genome sequences, mining the database for novel ccr gene complexes and SCC/SCCmec elements could enhance MRSA epidemiological studies. In this study, we identified 12 novel ccr genes (6 ccrA, 3 ccrB, and 3 ccrC) through mining of the National Center for Biotechnology Information (NCBI) database, forming 12 novel ccr gene complexes and 10 novel SCC elements. Overexpression of 5 groups of novel Ccr recombinases (CcrA9B3, CcrA10B1, CcrC3, CcrC4, and CcrC5) in a mutant MRSA strain lacking the ccr gene and extrachromosomal circular intermediate (ciSCC) production significantly promoted ciSCC production, demonstrating their biological activity. This discovery provides an opportunity to advance MRSA epidemiological research and develop database-based bacterial typing methods., Competing Interests: Potential conflicts of interests. All authors: No reported conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2024. Published by Oxford University Press on behalf of Infectious Diseases Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

There have been few reports regarding the long-term trends in the genotypes of methicillin-resistant Staphylococcus aureus (MRSA) bloodstream isolates. Therefore, this study was performed to investigate the longitudinal trends in the genotypes of MRSA bloodstream isolates obtained from hospitalized patients during a 12-year study period from 2010 to 2021 at a tertiary care university hospital. Over the 12-year period from 2010 to 2021, we conducted a genetic investigation focusing on 245 MRSA strains isolated from the blood of hospitalized patients. The genotypes of the MRSA bloodstream isolates were determined by Staphylococcal Cassette Chromosome mec (SCC mec ) typing, accessory gene regulator ( agr ) typing, PCR-based ORF typing (POT), and multilocus sequence typing (MLST). Strains with the same POT type detected in two or more isolates were designated as epidemic clones, while strains without a common POT type were classified as sporadic clones. Until 2015, isolates with SCC mec II/ agr II were prevalent, but isolates with SCC mec IV/ agr III increased from 2016. A total of 128 strains (52%) were identified as epidemic clones, while 117 strains (48%) were classified as sporadic clones. The detection rate of sporadic clones increased significantly since 2016 ( p < 0.05). The epidemic clones were classified into three clusters, with MRSA of clonal complex (CC) 1 being prominent after 2016. This study showed that the genotypes of MRSA bloodstream isolates underwent a shift from SCC mec II/ agr II type to SCC mec IV/ agr III type, with a notable increase in MRSA of CC1, after 2016. There was a significant increase in the proportion of sporadic strains among the isolates, suggesting the diversification of genotypes.

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is an important pathogen that can cause many community and hospital-acquired infections. This study was conducted to investigate the SCCmec gene types responsible for methicillin resistance in MRSA isolates isolated from hospitalised patients., Material and Methods: MRSA isolates isolated from samples sent from various clinics to Gaziantep University Hospital Microbiology Laboratory between March 2021-January 2022 were included in the study. Bacteria were identified using by VITEK 2 automated system. Cefoxitin (FOX) resistance was determined by the disc diffusion method according to EUCAST standards. Cefoxitin resistance was confirmed by the Penicillin Binding Protein 2' latex agglutination test. Types of mecA, mecC, coa, nuc, Panton Valentin Leukocidin (PVL), ccrC2, class A mec, SCCmec types in isolates detected as MRSA were investigated by real-time PCR., Results: In this study, 116 isolates meeting the study criteria were examined. By detecting the nuc and coa genes in all isolates by PCR, the phenotypic identification of S.aureus was confirmed. While the mecA gene was detected in all MRSA isolates, no mecC gene was detected in any isolates. Detected SCCmec types were as follows; SCCmec Type 1 (2.6%), Type II (28.4%), Type III (12.9%), Type IVa (11.2%), Type IVb (3.4%), Type IVc (3.4%), Type IVg (12.1%), Type V (0.9%), Type VII (4.3%), Type VIII (18.1%), Type IX (0.9%), Type XII (1.7%). On the other hand, SCCmec Type VI, X, XI and XIII were not found in any isolate. It was determined that four of the MRSA isolates (3.4%) carried the PVL gene that two (50%) of these were found in SCCmec Type VIII., Conclusion: Monitoring of FOX resistance is an effective and safe method for determination of MRSA isolates. The change in the mec gene causes resistance, which should be monitored regularly with molecular methods. Our study is the first study in Turkey., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

ABSTRACT Staphylococcus haemolyticus and Staphylococcus hominis subsp. hominis are common coagulase-negative staphylococcus opportunistic pathogens. In Thailand, the clinical strains S. haemolyticus 1864 and 48 and S. hominis subsp. hominis 384 and 371 have been recovered from sick dogs. These strains were methicillin resistant with the nontypeable staphylococcal cassette chromosome mec (NT-SCCmec). The SCCmec element distribution in the clinical isolates from dogs was analyzed using whole-genome sequencing, which revealed the presence of different SCCmec composite islands (CIs) and gene structure. The SCCmec-CIs of ψSCCmec1864 (13 kb) and ψSCC1864 (11 kb) with a class C1 mec complex but no ccr gene were discovered in S. haemolyticus 1864. The CIs of ψSCCmec48 with a C1 mec complex (28 kb), SCC48 with ccrA4B4 (23 kb), and ψSCC48 (2.6 kb) were discovered in S. haemolyticus 48. In SCC48, insertion sequence IS256 contained an aminoglycoside-resistant gene [aph(2″)-Ia]. Two copies of IS431 containing the tetracycline-resistant gene tet(K) were found downstream of ψSCC48. In S. hominis subsp. hominis, the SCCmec-CI in strain 384 had two separate sections: ψSCCmec384 (20 kb) and SCCars (23 kb). ψSCCmec384 lacked the ccr gene complex but carried the class A mec complex. Trimethoprim-resistant dihydrofolate reductase (dfrC) was discovered on ψSCCmec384 between two copies of IS257. In strain 371, SCCmec VIII (4A) (37 kb) lacking a direct repeat at the chromosomal end was identified. This study found SCCmec elements in clinical isolates from dogs that were structurally complex and varied in their genetic content, with novel organization. IMPORTANCE In Thailand, the staphylococcal cassette chromosome mec (SCCmec) element, which causes methicillin resistance through acquisition of the mec gene, has been studied in clinical coagulase-negative Staphylococcus isolates from various companion animals, and Staphylococcus haemolyticus and Staphylococcus hominis subsp. hominis were found to have the most nontypeable (NT)-SCCmec elements. These species are more prone to causing illness and more resistant to a variety of antimicrobials than other coagulase-negative staphylococci. However, full characterization of NT-SCCmec in clinical S. haemolyticus and S. hominis subsp. hominis isolates from such animals has been limited. Our findings support the use of full nucleotide sequencing rather than PCR designed for Staphylococcus aureus in further research of novel SCCmec elements. Moreover, several antimicrobial resistance and heavy metal resistance genes were identified on the SCCmec elements; these are important as they could limit the therapeutic options available in veterinary medicine.

DNA-mimicking proteins encoded by viruses can modulate processes such as innate cellular immunity. An example is Ung-family uracil-DNA glycosylase inhibition, which prevents Ung-mediated degradation via the stoichiometric protein blockade of the Ung DNA-binding cleft. This is significant where uracil-DNA is a key determinant in the replication and distribution of virus genomes. Unrelated protein folds support a common physicochemical spatial strategy for Ung inhibition, characterised by pronounced sequence plasticity within the diverse fold families. That, and the fact that relatively few template sequences are biochemically verified to encode Ung inhibitor proteins, presents a barrier to the straightforward identification of Ung inhibitors in genomic sequences. In this study, distant homologs of known Ung inhibitors were characterised via structural biology and structure prediction methods. A recombinant cellular survival assay and in vitro biochemical assay were used to screen distant variants and mutants to further explore tolerated sequence plasticity in motifs supporting Ung inhibition. The resulting validated sequence repertoire defines an expanded set of heuristic sequence and biophysical signatures shared by known Ung inhibitor proteins. A computational search of genome database sequences and the results of recombinant tests of selected output sequences obtained are presented here.

Methicillin-resistant Staphylococcus aureus (MRSA) bacteria are often multi-drug resistant, resulting in a high rate of treatment failure. This study aimed to identify the antibiotics resistance profile and molecular characteristics of MRSA strains isolated from patients' samples, including skin, wounds, and burns, which are the most common infections, and collected from hospitals. The samples included 34 MRSA isolates gathered from January 2020 to September 2020. All isolates were tested using the Kirby-Bauer method to determine MRSA susceptibility against antibiotics using the minimum inhibitory concentration protocol and the E-test. The polymerase chain reaction was used for the detection of antibiotic resistance genes, including tetracycline, erythromycin, linezolid, gentamicin, rifampicin, ciprofloxacin, quinupristin-dalfopristin, clindamycin, and mecA. Staphylococcal Cassette Chromosome mec (SCCmec) was determined by multilocus sequence typing of all isolates; accordingly, the findings indicated that the sensitivity of linezolid, quinupristin-dalfopristin, rifampin, daptomycin, and vancomycin differed. Moreover, multidrug resistance of MRSA was shown to be more than 90% for penicillin and 91.1% for erythromycin. It was revealed that SCCmec III was resistant to at least four to five different antibiotics. ST585 (2.9%), ST240 (8.8%), ST45 (14.7%), ST22 (17.6%), and ST239 (higher rate) were the five sequence types found in STs (55.8%). Finally, it was indicated that the emergence of MRSA in these Iraqi hospitals highlighted further research to better understand how the infection might be effectively controlled. [ABSTRACT FROM AUTHOR]

ABSTRACT: Objectives: The aim of this study was to explore the antimicrobial resistance, virulence genes and molecular characteristics of Staphylococcus aureus from bovine mastitis cases. Methods: A total of 125 non-duplicate S. aureus isolates from bovine mastitis cases in Ningxia, China, were characterised by antimicrobial susceptibility and molecular testing to determine the antimicrobial resistance, virulence genes and molecular characteristics. Results: All methicillin-resistant S. aureus (MRSA) isolates were resistant to ampicillin, oxacillin, ceftiofur, erythromycin, gentamicin and clindamycin, with resistance to nine different categories of antibiotics observed amongst the MRSA isolates. Of the methicillin-susceptible S. aureus (MSSA) isolates, 62.1% were resistant to ampicillin and sulfisoxazole. Nine clonal complexes (CCs) and 16 spa types were identified by multilocus sequence typing (MLST) and spa typing. The dominant CCs were CC97 (51.2%) and CC50 (30.4%), while t224 (30.4%), t518 (20.0%) and t359 (16.8%) were the most common spa types. A relatively high proportion (27.2%) of the S. aureus isolates belonged to ST4053, a novel sequence type identified in this study. In addition, two CC30 MSSA isolates and two CC59 MRSA isolates were positive for Panton–Valentine leukocidin, while one CC239 MRSA isolate and three CC5 MSSA isolates were positive for TSST-1. All MRSA isolates carried the immune evasion cluster (IEC) genes, including scn (100%; 9/9) and sak (100%; 9/9), which were classified into type E. Conclusion: Our study indicates severe antibiotic resistance and complicated molecular characterisation of S. aureus causing bovine mastitis. Additional studies should be conducted to monitor infection and transmission of S. aureus.

Staphylococcus aureus is a microorganism that is highly resistant to environmental conditions and is widely found in environmental sources. It can cause a large number of infections in both humans and animals. Resistance to methicillin in S. aureus strains occurs due to the production of low affinity penicillin binding proteins (PBP2a). PBP2a is encoded by the mecA gene. The mecA gene is located on a mobile, large genetic element called the staphylococcal cassette chromosome mec (SCCmec). Until now, 13 SCCmec (I-XIII) types have been identified in S. aureus strains. In this study, in diff erent 7 regions (Marmara, Aegean, Central Anatolia, the Black Sea, the Mediterranean, Eastern and Southeastern Anatolia) of Turkey obtained from a variety of points of 700 food items in the [(dairy products (n:560), bakery products (n:89), ready meal (n:40), meat product (n:11)], after the isolation of cultural S. aureus and verification by PCR, MRSA detection and SCCmec typing were aimed. 67 (9.57%) S. aureus strains were isolated from 700 food samples analyzed within the scope of the study. Only 1 (0.14%) of the 67 S. aureus strains isolated, both phenotypically and genotypically, was found to be MRSA and when SCCmec was typed, it was found to be Type IV. Community-acquired MRSA strains can cause clinical cases ranging from skin infections to fatal pneumonia and sepsis, as well as foodborne diseases. As a result, it is considered that MRSA strains can be an important source of contamination for humans with the consumption of food of animal origin.

Aim To characterize methicillin-resistant S. aureus (MRSA) strains phenotypically and genotypically and to determine their clonal affiliation, representation and antibiotic resistance profile. Methods A total of 62 randomly selected MRSA isolates of different clinical samples collected from 2009 to 2017 were phenotypically and genotypically analysed. Phenotypic analyses were performed by standard microbiological procedures, and using VITEK 2/AES instrument as well as MALDI-TOF (matrix-assisted laser desorption/ionization) technology. Genotypic characterization included spa, MLST (multilocus sequence typing) and SCCmec typing, and detection of the Panton-Valentine leukocidin (PVL) and other enterotoxin encoding genes. Results The largest number of isolates, 21 (33.87%) belonged to ST228-MRSA-I, spa type t041, t1003 and t001. Other major clones were: ST239-MRSA-III, spa type t037 and t030 (27.41%); ST8-MRSA-IV, spa type t008 and t121 (12.9%); ST247-MRSA-I, spa type t051 (4.83%). PVL was detected in 10 isolates (SCCmec IV/V). During 2009 and 2010 the most frequent MRSA strain was South German clone, ST228-MRSA-I (80% and 90%, respectively), while in later years it was replaced with Brazilian-Hungarian clone ST239-MRSA-III (75% in 2015 and 2016). The South German clone, spa type t041 in 90.48% of cases was resistant to clindamycin, ciprofloxacin, erythromycin, cefoxitin, gentamicin, kanamycin, tobramycin and penicillin, while 70.58% samples of the Brazilian-Hungarian clone spa type t037 were additionally resistant to tetracycline and rifampicin. Conclusion This research can supplement the existing knowledge about the clonal distribution of MRSA in Bosnia and Herzegovina and their sensitivity to antibiotics in order to improve the national control of these infections.

Abstract Objective This study was designed to discover the dissemination of virulence genes in Methicillin-resistant Staphylococcus aureus from clinical, community and environmental settings. Results This study includes 1165 isolates collected from hospital, community and environmental settings. Among them sixty three were confirmed as MRSA with varied SCCmec types viz; type I, type II, type III, type IV, type V, type VI, type VII, type VIII and type XII. The virulence gene such as sea (n = 54), seb (n = 21), eta (n = 27), etb (n = 2), cna (n = 24), ica (n = 2) and tst (n = 30) was also revealed from this study. The study underscores coexistence of resistance cassette and virulence genes among clinical and environment isolates which is first of its kind from this part of the world.

Pet food have been considered as possible vehicles of bacterial pathogens. The sudden boom of the pet food industry due to the worldwide increase in companion animal ownership calls for pet food investigations. Herein, this study aimed to determine the frequency, antimicrobial susceptibility profile, and molecular characteristics of coagulase-negative staphylococci (CoNS) in different pet food brands in Brazil. Eighty-six pet food packages were screened for CoNS. All isolates were identified at species level by MALDI-TOF MS and species-specific PCR. Antimicrobial susceptibility testing was performed by disc diffusion and broth microdilution (vancomycin and teicoplanin only) methods. The D-test was used to screen for inducible clindamycin phenotype (MLS-B). SCC mec typing and detection of mecA , vanA , vanB , and virulence-encoding genes were done by PCR. A total of 16 (18.6 %) CoNS isolates were recovered from pet food samples. Isolates were generally multidrug-resistant (MDR). All isolates were completely resistant (100 %) to penicillin. Resistances (12.5 % - 75 %) were also observed for fluoroquinolones, sulfamethoxazole-trimethoprim, tetracycline, rifampicin, erythromycin, and tobramycin. Isolates were susceptible to vancomycin (MICs <0.25–1 μg/mL) and teicoplanin (MICs <0.25–4 μg/mL). Intriguingly, 3/8 (37.5 %) CoNS isolates with the ERYRCLIS antibiotype expressed MLS-B phenotype. All isolates harboured bla Z gene. Seven (43.8 %) isolates carried mecA ; and among them, the SCC mec Type III was the most frequent (n = 5/7; 71.4 %). Isolates also harboured seb , see , seg , sej , sem , etb , tsst , pvl , and hla toxin virulence-encoding genes (6.3 % - 25 %). A total of 12/16 (75 %) isolates were biofilm producers, while the icaAB gene was detected in an S. pasteuri isolate. Herein, it is shown that pet food is a potential source of clinically important Gram-positive bacterial pathogens. To the best of our knowledge, this is the first report of MLS-B phenotype and MR-CoNS in pet food in Latin America. • The CoNS isolates reported in this study harboured blaZ and virulence genes. • Biofilm-forming methicillin-resistant CoNS harbouring mecA gene were recovered. • SCC mec Type III was the most predominant among mecA -positive CoNS isolates. • CoNS with inducible clindamycin resistance phenotype (MLS-B) were reported. [ABSTRACT FROM AUTHOR]

As the prevalence of Staphylococcus aureus infections is of worldwide concern, phenotype and genotype in prevalent MRSA strains require longitudinal investigation. In this study, the antibiotic resistance, virulence gene acquisition, and molecular type were determined on a large scale of nosocomial S. aureus strains in Southern China during 2009–2015. Bacterial identification and antimicrobial susceptibility to 10 antibiotics were tested by Vitek-2. Virulence genes encoding staphylococcal enterotoxins (SEA, SEB, SEC, SED, and SEE), exfoliative toxins (ETA and ETB), Panton–Valentine leukocidin (PVL), and toxic shock syndrome toxin (TSST) were detected by PCR, with SCCmec typing also conducted by multiplex PCR strategy. Genotypes were discriminated by MLST and spaA typing. MLST was performed by amplification of the internal region of seven housekeeping genes. PCR amplification targeting the spa gene was performed for spa typing. No resistance to vancomycin, linezolid, or quinupristin and increase in the resistance to trimethoprim/sulfamethoxazole (55.5%) were identified. A total of nine SCCmec types and subtypes, thirteen STs clustered into thirteen spa types were identified, with ST239-SCCmec III-t037 presenting the predominant methicillin-resistant S. aureus (MRSA) clone. Typically, SCCmec type IX and ST546 were emergent types in China. Isolates positive for both pvl and tsst genes and for both eta and etb genes were also identified. Important findings in this study include: firstly, we have provided comprehensive knowledge on the molecular epidemiology of MRSA in Southern China which fills the gap since 2006 or 2010 from previous studies. Secondly, we have presented the correlation between virulence factors (four major groups) and genotypes (SCCmec, ST and spa types). Thirdly, we have shown evidence for earliest emergence of type I SCCmec from 2012, type VI from 2009 and type XI from 2012 in MRSA from Southern China.