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Abstract Background Combination therapy including an aminoglycoside antibiotic and a cell-wall active agent is considered the most suitable option to treat invasive infections with methicillin-resistant Staphylococcus aureus (MRSA). Dual drug therapy enhances the effectiveness of treatment and reduces the risk of resistance development. This study aims to elucidate the phenotypic and molecular resistance to aminoglycosides and methicillin, and the molecular epidemiologic characteristics of S. aureus in Ardabil northwest Iran. Methods Totally, 118 S. aureus isolates collected from clinical specimens were investigated. Identification was performed using standard microbiological and molecular approaches. Aminoglycoside and methicillin resistance were evaluated using the disk diffusion assay, and the minimum inhibitory concentrations (MICs) of aminoglycosides were determined via the agar dilution method. The mecA gene encoding methicillin resistance and aminoglycoside modifying enzymes (AMEs) genes were detected using PCR. Molecular epidemiologic features of the isolates were determined using staphylococcal cassette chromosome mec (SCCmec) typing spa typing and ERIC-PCR assays. Results Of the isolates, 42.4% (n = 50) and 57.6% (n = 68) were identified as MRSA and MSSA, respectively. All MRSA isolates were mecA-positive. Among MRSA isolates, SCCmec type IVa (17; 34%) was predominant, followed by types IVc, V, III, II, and I. Resistance rates to gentamicin, kanamycin, tobramycin, and amikacin were 16.1%, 17.8%, 8.5%, and 8.5%, respectively. Overall, the aminoglycoside resistance and most non-aminoglycoside antibiotics were significantly higher in MRSA versus MSSA isolates. The prevalence of AME genes was as follows: aac(6’)-Ie-aph(2’’) (30; 76.9%), aph(2’’)-Ib (22; 56.4%), and ant(4’)-Ia (14; 35.9%). About 60% of aminoglycoside-resistant isolates harbored ≥ 2 AME genes. The t030 type was the most common spa type identified. The ERIC-PCR profiles categorized the isolates into 19 unique ERIC types. Conclusions This study reveals high aminoglycoside and methicillin resistance in S. aureus isolates from Ardabil hospitals. Predominant SCCmec type IVa and spa type t030 indicate specific molecular patterns. These findings highlight the need for continuous surveillance and targeted treatment strategies for MRSA infections. Clinical trial number Not applicable. more...

Background: Characteristics of non-clinical strains of methicillin-resistant Staphylococcus aureus (MRSA) especially from fishery environment are poorly understood. This research, in addition to comprehensive characterisation, sought to delineate the genetic relatedness between the MRSA strains originating from clinical as well as non-clinical settings. Out of 39 methicillin-resistant staphylococcal isolates from 197 fish samples, 6 (Three each of methicillin-resistant S. haemolyticus (MRSH) and MRSA) with distinct resistance profiles were selected for whole-genome sequencing. Using respective bioinformatics tools, MRSA genomes were comprehensively characterized for resistome, virulomes, molecular epidemiology and phylogenetic analysis. Simultaneously, MRSH genomes were specifically examined to characterize antimicrobial resistance genes (ARGs), owing to the fact that MRSH is often recognized as a reservoir for resistance determinants. Results: Three MRSA clones identified in this study include ST672-IVd/t13599 (sequence type-SCCmec type/spa type), ST88-V/t2526, and ST672-IVa/t1309. Though, the isolates were phenotypically vancomycin-sensitive, five of the six genomes carried vancomycin resistance genes including the VanT (VanG cluster) or VanY (VanM cluster). Among the three MRSA, only one harbored the gene encoding Panton-Valentine Leukocidin (PVL) toxin, while staphylococcal enterotoxin (SEs) genes such as sea and seb, associated with staphylococcal food poisoning were identified in two other MRSA. Genomes of MRSH carried a composite of type V staphylococcal cassette chromosome mec (SCCmec) elements (5C2 & 5). This finding may be explained by the inversion and recombination events that may facilitate the integration of type V elements to the SCC elements of S. aureus with a methicillin-susceptible phenotype. Phylogenetically, MRSA from a non-clinical setting displayed a considerable relatedness to that from clinical settings. Conclusion: This study highlights the genetic diversity and resistance profiles of MRSA and MRSH, with non-clinical MRSA showing notable relatedness to clinical strains. Future research should explore resistance gene transfer mechanisms and environmental reservoirs to better manage MRSA spread. [ABSTRACT FROM AUTHOR] more...

The emergence and spread of Staphylococcus aureus, which is resistant to quinolone antibacterial agents, has made it difficult to treat infectious diseases. Accordingly, this study examined the molecular epidemiological characteristics of quinolone-resistant S. aureus (QRSA) to obtain helpful data for treatment. Mutations in mecA and SCCmec typing, gyrA, and gyrB genes were investigated for QRSA strains isolated from the blood culture specimens at a general hospital in Daejeon Metropolitan City. The ciprofloxacin-resistant strains in SCCmec typing were II (44 strains, 73%), IVa (five strains, 8%), III, and V (one strain, 2%); the non-typeable strains (11 strains, 18%), and levofloxacin (LVX) and moxifloxacin (MXF) strains were II (44 strains, 73%), IVa (five strains, 8%), III, and V (one strain, 2%); the non-typeable strains were 10 (17%). In both gyrA and gyrB regions, there were 58 mutations, or 96.7%. In LVX, there were 56 mutations or 93.3%, and in MXF, there were 57 mutations or 95%. Twelve mutations, six mutations each in gyrA and gyrB, were identified for the QRSA strain. The resistance rate for the quinolone antibiotics of QRSA studied was approximately 98%, and 12 mutations, six each in gyrA and gyrB, were identified in the QRSA strain. Therefore, the rational use of antibiotics needs to be improved. more...

Abstract Mastitis is considered one of the most widespread infectious disease of cattle and buffaloes, affecting dairy herds. The current study aimed to characterize the Staphylococcus aureus isolates recovered from subclinical mastitis animals in Pothohar region of the country. A total of 278 milk samples from 17 different dairy farms around two districts of the Pothohar region, Islamabad and Rawalpindi, were collected and screened for sub clinical mastitis using California Mastitis Test. Positive milk samples were processed for isolation of Staphylococcus aureus using mannitol salt agar. The recovered isolates were analyzed for their antimicrobial susceptibility and virulence genes using disc diffusion and PCR respectively. 62.2% samples were positive for subclinical mastitis and in total 70 Staphylococcus aureus isolates were recovered. 21% of these isolates were determined to be methicillin resistant, carrying the mecA gene. S. aureus isolates recovered during the study were resistant to all first line therapeutic antibiotics and in total 52% isolates were multidrug resistant. SCCmec typing revealed MRSA SCCmec types IV and V, indicating potential community-acquired MRSA (CA-MRSA) transmission. Virulence profiling revealed high prevalence of key genes associated with adhesion, toxin production, and immune evasion, such as hla, hlb, clfA, clfB and cap5. Furthermore, the Panton-Valentine leukocidin (PVL) toxin, that is often associated with recurrent skin and soft tissue infections, was present in 5.7% of isolates. In conclusion, the increased prevalence of MRSA in bovine mastitis is highlighted by this study, which also reveals a variety of virulence factors in S. aureus and emphasizes the significance of appropriate antibiotic therapy in combating this economically burdensome disease. more...

Abstract Methicillin-resistant Staphylococcus (MRS) has been associated with neonatal infections, with colonization of the anovaginal tract being the main source of vertical transmission. The COVID-19 pandemic has altered the frequency of antibiotic usage, potentially contributing to changes in the dynamics of bacterial agents colonizing humans. Here we determined MRS colonization rates among pregnant individuals attending a single maternity in Rio de Janeiro, Brazil before (January 2019–March 2020) and during (May 2020–March 2021) the COVID-19 pandemic. Anovaginal samples (n = 806 [521 samples before and 285 during the pandemic]) were streaked onto chromogenic media. Colonies were identified by MALDI-TOF MS. Detection of mecA gene and SCCmec typing were assessed by PCR and antimicrobial susceptibility testing was done according to CLSI guidelines. After the onset of the pandemic, MRS colonization rates increased significantly (p more...

Introduction: Methicillin-resistant Staphylococcus aureus (MRSA) has been known as an infectious pathogen worldwide since 1960. The epidemiological distribution of MRSA may have shifted due to outbreaks reported from several nations, making it more challenging to differentiate among CA-MRSA and HA-MRSA. It is currently important to develop a strain-based explanation for HA and CA-MRSA due to its distinct epidemiology, genetic profile, antibiogram, and quantifiable features. The study aimed to distinguish CA and HA-MRSA by Staphylococcal Cassette Chromosome mec (SCCmec) typing. Materials and Method: The study involved a total of 381 S. aureus isolates, which were processed in the department of Microbiology, JSS Hospital, Mysore. All isolates were confirmed as MRSA, initially by disk diffusion method using cefoxitin 30µg and oxacillin 1μg disk and later by using PCR technique for the detection of mecA-gene. All mecA-gene positive samples were amplified for SCCmec typing by multiplex PCR for detection of SCCmec type I, II, III, IVa, IVb, IVc, IVd, V and XI respectively. Results: PCR confirmed a total of 66% isolates as mecA-positive MRSA. Multiplex PCR method revealed only 53% isolates were SCCmec-typeable. The mainstream of the isolates belonged to SCCmec type IV (53.48%) and type V (44.18%), followed by type III (9.30%), type II (3%) and type I (1.16%) respectively. The study also demonstrated the presence of multiple SCCmec types in 10.46% of MRSA isolates. Staphylococcal cassette chromosome recombinase (ccr) typing determined only 43% of isolates were typeable. Conclusion: The study found that hospital-associated SCCmec type IV and type V were the most circulating strains in our healthcare setting. The research identified a few MRSA isolates with diverse SCCmec types. The presence of CAMRSA infection in in-patients and HA-MRSA infection in out-patients were also recognised. The situation indicates the spreading of hospital-acquired strains into the community and vice versa, necessitating the molecular characterisation of MRSA isolates in order to administer the appropriate antibiotic medication. [ABSTRACT FROM AUTHOR] more...

Introduction: Methicillin-resistant Staphylococcus aureus (MRSA) has been known as an infectious pathogen worldwide since 1960. The epidemiological distribution of MRSA may have shifted due to outbreaks reported from several nations, making it more challenging to differentiate among CA-MRSA and HA-MRSA. It is currently important to develop a strain-based explanation for HA and CA-MRSA due to its distinct epidemiology, genetic profile, antibiogram, and quantifiable features. The study aimed to distinguish CA and HA-MRSA by Staphylococcal Cassette Chromosome mec (SCCmec) typing. Materials and Method: The study involved a total of 381 S. aureus isolates, which were processed in the department of Microbiology, JSS Hospital, Mysore. All isolates were confirmed as MRSA, initially by disk diffusion method using cefoxitin 30µg and oxacillin 1μg disk and later by using PCR technique for the detection of mecA-gene. All mecA-gene positive samples were amplified for SCCmec typing by multiplex PCR for detection of SCCmec type I, II, III, IVa, IVb, IVc, IVd, V and XI respectively. Results: PCR confirmed a total of 66% isolates as mecA-positive MRSA. Multiplex PCR method revealed only 53% isolates were SCCmec-typeable. The mainstream of the isolates belonged to SCCmec type IV (53.48%) and type V (44.18%), followed by type III (9.30%), type II (3%) and type I (1.16%) respectively. The study also demonstrated the presence of multiple SCCmec types in 10.46% of MRSA isolates. Staphylococcal cassette chromosome recombinase (ccr) typing determined only 43% of isolates were typeable. Conclusion: The study found that hospital-associated SCCmec type IV and type V were the most circulating strains in our healthcare setting. The research identified a few MRSA isolates with diverse SCCmec types. The presence of CA-MRSA infection in in-patients and HA-MRSA infection in out-patients were also recognised. The situation indicates the spreading of hospital-acquired strains into the community and vice versa, necessitating the molecular characterisation of MRSA isolates in order to administer the appropriate antibiotic medication. more...

Background: Methicillin-resistant Staphylococcus aureus (MRSA), is considered a potential and aggressive nosocomial pathogen. It accounts for 50% of S. aureus isolates in tertiary hospitals in Iran, however, there is no sufficient evolutionary and epidemiological investigation about this medically important bacterium. We aimed to study the lineage and evolution of MRSA in Northwest Iran during 2021–2022 based on the obtained phenotypic and genotypic characteristics. Materials and methods: Seventy-two non-duplicate MRSA isolates were collected from 3 referral hospitals in Tabriz, Ardebil, and Urmia cities. The antimicrobial susceptibility patterns were determined by disk diffusion test and micro broth dilution methods. Thereafter 4 virulence genes (eta, etb, pvl, tst) and 5 types of staphylococcal cassette chromosome mec (SCCmec) were detected by PCR. In the final step, representative isolates were selected to be studied by Multilocus sequence typing (MLST). Results: The highest resistance was observed to erythromycin and clindamycin at a rate of 76.4%, followed by ciprofloxacin (61.1%), gentamicin (54.2%), rifampin (38.9%), and co-trimoxazole (27.8%). All isolates were susceptible to vancomycin. The virulence genes of etb, pvl, tst, and eta were detected in 50%, 29.2%, 21.8%, and 13.9% of isolates, respectively. SCCmec types III and I were the most prevalent types, followed by types IV, II, and V. MLST analysis revealed 6 sequence types: ST6854, ST5282, ST127, ST7804, ST1607, and ST7784. Two MLST-based clonal complexes (CC8, and CC97) were identified as well. Conclusion: The ST numbers were non-repetitive. CC8 as a pandemic clone and an individual lineage and clinically significant clade was reported as the most prevalent clonal complex. It is essential periodic evaluations of antibiotic susceptibility patterns and study the evolutionary characteristics of medical-challenging microorganisms in particular MRSA to effectively treat and restrict the outbreaks. [ABSTRACT FROM AUTHOR] more...

Macau, recognized as a global tourism hub and the world's most densely populated region, provides a unique environment conducive to methicillin-resistant Staphylococcus aureus (MRSA) transmission in healthcare and community settings, posing a significant public health concern both locally and globally. The epidemiology and molecular characteristics of MRSA in the distinct city of Macau remain largely unelucidated. This five-year longitudinal study (2017–2022) examined the local prevalence and molecular typing of MRSA in Macau, with future MRSA type distribution predicted through ARIMA modeling. We subsequently analyzed the epidemiological characteristics of MRSA, including specimen source, clinical department, collection year, season, patient age, sex, and the annual number of tourists. Comprehensive antibiotic resistance profiles of the strains were also assessed. Of 504 clinically isolated S. aureus strains, 183 (36.3%) were identified as MRSA by the cefoxitin disk diffusion method and validated through multi-locus sequence typing (MLST). The MRSA detection rate showed an upward trend, increasing from 30.1% in 2017 to 45.7% in 2022. SCCmec type IV was predominant (28.9%), followed by types II (25.4%), III (22.1%), and V (22.1%). The primary sources of MRSA isolates were sputum (39.2%) and secretions (25.6%). Older age emerged as a risk factor for MRSA infection, whereas no significant associations were found with seasonal variations, gender, or the annual number of tourists. Despite displaying universal resistance to cefoxitin, oxacillin, and benzylpenicillin, MRSA isolates in Macau remained fully sensitive to vancomycin, tigecycline, quinupristin, nitrofurantoin, and linezolid. Continuous surveillance and analysis of MRSA distribution in Macau could provide invaluable insights for the effective management of MRSA prevention and control measures within healthcare settings. [ABSTRACT FROM AUTHOR] more...

Objective: To determine the antibiotic resistance profile (ARP) of Staphylococcus (S.) aureus isolates and molecular typing of the methicillin-resistant S. aureus (MRSA) isolates from Tuanku Mizan Armed Forces Hospital (TMAFH), Kuala Lumpur. Methods: The ARP and presence of the pvl gene were determined for 209 S. aureus isolates from clinical specimens. Of these, 123 were methicillin-susceptible S. aureus (MSSA) isolates and 86 were MRSA isolates. All MRSA isolates were characterized using SCCmec typing and spa typing. Descriptive analysis was performed to compare the demographic data with the phenotypic and genotypic variables of the S. aureus isolates. Results: No vancomycin-intermediate and -resistant S. aureus (VISA and VRSA, respectively) were detected among the study isolates. The MSSA isolates showed low resistance rates to all tested antibiotics, were commonly invasive (28/42, 66.7%), and mostly harboured pvl (35/42, 83.3%). Meanwhile, MRSA isolates showed high resistance to penicillin (86/86, 100%), ampicillin (86/86, 100%), sulbactam/ampicillin (86/86, 100%), cefuroxime (81/86, 94.19%), cefoperazone (76/86, 88.37%), azithromycin (56/86, 65.12%), and erythromycin (54/86, 62.79%). The majority of MRSA isolates were of SCCmec type IVh (65/86, 75.58%), spa type t032 (55/85, 63.95%), and grouped into spaCC-t022 (66/85, 77.65%). The t032 type was found to be associated with resistance traits to azithromycin and erythromycin (P more...

Background Methicillin-resistant Staphylococcus aureus (MRSA) is a widely recognized multidrug-resistant bacteria presenting a major therapeutic challenge to clinicians. Staphylococcus aureus possesses a number of pathogenicity factors that attribute to the severity of infections. This study was undertaken to investigate the common virulence genes in clinical isolates of Staphylococcus aureus , determine their antimicrobial susceptibility profile, and to characterize the staphylococcal cassette chromosome mec (SCCmec) types among MRSA in a tertiary care center. Materials and Methods A total of 133 clinical isolates were included in this study. Susceptibility to various antibiotics was determined by disc diffusion method. Methicillin resistance was screened using cefoxitin disc; m ecA and mecC genes were detected using polymerase chain reaction (PCR). PCR was done to detect 12 virulence factors such as hla , hlb , fnbA , fnbB , sea , seb , sec , icaA , clfA , tst , pvl, and eta. SCCmec typing was done by multiplex PCR. Results Of the 133 clinical isolates, 54 (40.6%) were MRSA. The most common virulence gene detected was hlb (61.6%), hla (39%), and fnbA (37%). SCCmec type I was the most predominant. Mortality rate of 6.7% was observed among patients with staphylococcal infections. Univariate analysis of mortality associated virulence genes did not reveal any significant association between virulence genes and mortality. Conclusion The distribution of virulence genes is similar in both MRSA and methicillin-sensitive Staphylococcus aureus. MRSA belongs to the SCCmec types I to IV. Possession of multiple virulence factors and multidrug resistance profile makes Staphylococcus aureus a formidable pathogen in clinical settings. [ABSTRACT FROM AUTHOR] more...

Objective: To determine the antibiotic resistance profile (ARP) of Staphylococcus (S.) aureus isolates and molecular typing of the methicillin-resistant S. aureus (MRSA) isolates from Tuanku Mizan Armed Forces Hospital (TMAFH), Kuala Lumpur. Methods: The ARP and presence of the pvl gene were determined for 209 S. aureus isolates from clinical specimens. Of these, 123 were methicillin-susceptible S. aureus (MSSA) isolates and 86 were MRSA isolates. All MRSA isolates were characterized using SCCmec typing and spa typing. Descriptive analysis was performed to compare the demographic data with the phenotypic and genotypic variables of the S. aureus isolates. Results: No vancomycin-intermediate and -resistant S. aureus (VISA and VRSA, respectively) were detected among the study isolates. The MSSA isolates showed low resistance rates to all tested antibiotics, were commonly invasive (28/42, 66.7%), and mostly harboured pvl (35/42, 83.3%). Meanwhile, MRSA isolates showed high resistance to penicillin (86/86, 100%), ampicillin (86/86, 100%), sulbactam/ampicillin (86/86, 100%), cefuroxime (81/86, 94.19%), cefoperazone (76/86, 88.37%), azithromycin (56/86, 65.12%), and erythromycin (54/86, 62.79%). The majority of MRSA isolates were of SCCmec type IVh (65/86, 75.58%), spa type t032 (55/85, 63.95%), and grouped into spaCC-t022 (66/85, 77.65%). The t032 type was found to be associated with resistance traits to azithromycin and erythromycin (P<0.05). We also found several spa types that are typically associated with hospital-, community-, and livestock-associated MRSA co-existing in our MRSA population. Conclusions: This study reflected the consistent absence of VISA and VRSA and corroborated the clonal shifting of MRSA isolates in the Malaysian MRSA isolates. [ABSTRACT FROM AUTHOR] more...

Macau, recognized as a global tourism hub and the world’s most densely populated region, provides a unique environment conducive to methicillin-resistant Staphylococcus aureus (MRSA) transmission in healthcare and community settings, posing a significant public health concern both locally and globally. The epidemiology and molecular characteristics of MRSA in the distinct city of Macau remain largely unelucidated. This five-year longitudinal study (2017–2022) examined the local prevalence and molecular typing of MRSA in Macau, with future MRSA type distribution predicted through ARIMA modeling. We subsequently analyzed the epidemiological characteristics of MRSA, including specimen source, clinical department, collection year, season, patient age, sex, and the annual number of tourists. Comprehensive antibiotic resistance profiles of the strains were also assessed. Of 504 clinically isolated S. aureus strains, 183 (36.3%) were identified as MRSA by the cefoxitin disk diffusion method and validated through multi-locus sequence typing (MLST). The MRSA detection rate showed an upward trend, increasing from 30.1% in 2017 to 45.7% in 2022. SCCmec type IV was predominant (28.9%), followed by types II (25.4%), III (22.1%), and V (22.1%). The primary sources of MRSA isolates were sputum (39.2%) and secretions (25.6%). Older age emerged as a risk factor for MRSA infection, whereas no significant associations were found with seasonal variations, gender, or the annual number of tourists. Despite displaying universal resistance to cefoxitin, oxacillin, and benzylpenicillin, MRSA isolates in Macau remained fully sensitive to vancomycin, tigecycline, quinupristin, nitrofurantoin, and linezolid. Continuous surveillance and analysis of MRSA distribution in Macau could provide invaluable insights for the effective management of MRSA prevention and control measures within healthcare settings. more...

The global emergence of methicillin-resistant Staphylococcus aureus (MRSA) that unsusceptible to a wide selection of antimicrobial agents and any newly introduced antimicrobial over the past decades has triggered more extensive holistic measures to put an end to this situation. Molecular surveillance of MRSA clones is important to understand their evolutionary dynamics for investigating outbreaks, propagating precautionary measures, as well as planning for appropriate treatment. This review includes peer-reviewed reports on the molecular characterisation of clinical Staphylococcus aureus isolates within Malaysian hospitals from year 2008 to 2020. This work highlights the molecular clones of hospital-acquired MRSA (HA-MRSA) and community-acquired MRSA (CA-MRSA) isolates from Malaysian hospitals, with description on their ever-changing pattern. Among HA-MRSA, the ST22-t032-SCCmec IV MRSA clone was reported to supplant the previous dominating clone, ST239-t037-SCCmec III. Meanwhile, ST30, ST772, ST6 and ST22 were repeatedly detected in CA-MRSA, however, none of the strains became predominant. Future in-depth study on molecular epidemiology of MRSA clone is essential for the investigation of the extent of the clonal shift, especially in Malaysia. [ABSTRACT FROM AUTHOR] more...

Background: Staphylococcus aureus is often considered as a potential pathogen and resistant to a wide range of antibiotics. The pathogenicity of this bacterium is due to the presence of multiple virulence factors and the ability to form biofilm. SCCmec types I, II and III are mainly attributed to HA-MRSA, while SCCmec types IV and V have usually been reported in CA-MRSA infections. Methods and results: In this study, we performed a cross-sectional study to determine the antimicrobial resistance, adhesion and virulence factors, biofilm formation and SCCmec typing of clinical S. aureus isolates in Iran. S. aureus isolates were identified using microbiological standard methods and antibiotic susceptibility tests were performed as described by the Clinical and Laboratory Standards Institute (CLSI) guidelines. Inducible resistance phenotype and biofilm formation were determined using D-test and tissue culture plate methods, respectively. Multiplex-PCRs were performed to detect adhesion and virulence factors, antibiotic resistance genes, biofilm formation and SCCmec typing by specific primers. Among 143 clinical samples, 67.8% were identified as MRSA. All isolates were susceptible to vancomycin. The prevalence of cMLSB, iMLSB and MS phenotypes were 61.1%, 22.2% and 14.8%, respectively. The TCP method revealed that 71.3% of isolates were able to form biofilm. The predominant virulence and inducible resistance genes in both MRSA and MSSA isolates were related to sea and ermC respectively. SCCmec type III was the predominant type. Conclusions: Data show the high prevalence rates of virulence elements among S. aureus isolates, especially MRSA strains. This result might be attributed to antibiotic pressure, facilitating clonal selection. [ABSTRACT FROM AUTHOR] more...

Background Coagulase-negative staphylococci (CoNS) are emerging as clinically significant pathogens. A high proportion of methicillin resistance along with intense biofilm-producing ability&nbsp;render CoNS-related infections challenging to treat. This study was undertaken to investigate the mechanisms of methicillin resistance, identify genes encoding for virulence, and their association with clinical outcomes among clinical isolates of Staphylococci in a tertiary care center. Methods A total of 203 clinical isolates were included in this study. Susceptibility to various antibiotics was determined by the disc diffusion method. Methicillin resistance was screened using cefoxitin disc, mecA  and mecC genes were detected using polymerase chain reaction (PCR). PCR was performed to detect five virulence genes:  atlE , aap , fbe , embp, and icaAB . Staphylococcal cassette chromosome mec (SCCmec) types were identified by multiplex PCR. Statistical analysis was performed using SPSS software (IBM Inc., Armonk, New York). The Chi-squared test was used to compare the distribution of virulence genes among methicillin-susceptible resistant CoNS. A p-value of less than 0.5 was considered significant. Results In the current study, 60% (122/203) of CoNS were methicillin-resistant, and SCCmec type I was the most common. Among the 203 CoNS, 24.6% (50/203) isolates harbored one or more virulence genes in them.  Conclusion CoNS have relatively low virulence as only 24.6% of isolates carried the virulence genes. Nevertheless, the variety of diseases linked to these species indicates the necessity for accurate identification and precise reporting of antimicrobial susceptibility to avoid adverse outcomes., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. Institutional Ethics Committee of Sri Ramachandra Institute of Higher Education and Research issued approval IEC-NI/19/FEB/68/12. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Khodabux et al.) more...

In India, limited studies are available on the epidemiological aspects of methicillin-resistant Staphylococcus aureus (MRSA) infections in both animal and human settings. Herein, we investigated the prevalence, antimicrobial resistance profile and molecular characteristics of MRSA isolates recovered from cattle using the One Health approach. Out of 66 mec A-positive staphylococci, species-specific multiplex PCR detected 24 % ( n =16) of isolates as MRSA. Maximum antibiotic resistance was seen against cloxacillin (94 %, n =15) and least for enrofloxacin and cephalothin (each 13 %, n =2). Overall, 13 % ( n =2) of MRSA isolates were multidrug-resistant. Molecular characterization by SCC mec typing identified 88 % ( n =14) of MRSA isolates as type V. Twelve isolates (75 %) belonged to novel spa -type t17242, of which 67 % ( n =8) belonged to agr type I. MLST analysis revealed ST 1687 (50 %, n =8) as the most predominant sequence type. Circulation of different MRSA clones among the cattle populace offers a risk of transmission to humans through direct contact, food chain or environmental contamination. Thus, continuous monitoring of MRSA strains is imperative for early diagnosis and for establishing effective treatment strategies to restrain the disease burden caused by MRSA infections., Competing Interests: The authors declare that they have no competing interests., (© 2023 The Authors.) more...

Background: Staphylococcus aureus is a major cause of a wide diversity of infections in humans, and the expression of Panton-Valentine Leukocidin (PVL) has been associated with severe clinical syndromes., Objectives: The present study aimed to investigate the prevalence of PVL-encoding genes in S. aureus isolated from clinical samples of inpatients with invasive infections in a teaching hospital in Southern Brazil. Furthermore, phenotypic and genotypic characteristics of bacterial isolates were analyzed., Methods: A total of 98 S. aureus isolates recovered from different body sites were characterized according to their antimicrobial susceptibility profile, methicillin-resistance and SCCmec typing, genetic relatedness and occurrence of virulence-encoding genes, such as icaA, lukS-PV/lukF-PV, and tst., Results: Sixty-eight (69.4%) isolates were classified as methicillin-resistant, and among them, four (5.9%) did not harbor the mecA gene. The mecA-harboring methicillin-resistant S. aureus (MRSA) isolates were grouped into SCCmec types I (6.3%), II (64.1%), III (6.3%), IV (15.6%), V (4.7%), and VI (1.6%). One isolate (1.6%) was classified as non-typeable (NT). Seventy isolates (71.4%) were classified as multidrug-resistant. The overall prevalence of virulence-encoding genes was as follows: icaA, 99.0%; tst, 27.5%; and lukS-PV/lukF-PV, 50.0%. The presence of tst gene was significantly higher (p < 0.001) in methicillin-susceptible S. aureus (MSSA) compared to MRSA isolates., Conclusion: The present study reports a high prevalence of multidrug-resistant S. aureus harboring lukS-PV/lukF-PV and tst genes in invasive infections. The continuous monitoring of the antimicrobial susceptibility profile and virulence of S. aureus is an important measure for the control of infections caused by this bacterium., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.) more...

To reduce the high rates of morbidity and mortality caused by methicillin-resistant Staphylococcus aureus (MRSA) strains, it is essential to prevent their transmission. This can be achieved through molecular surveillance of the infecting strains, for which the detection of the entry of new strains, the analysis of antimicrobial resistance, and their containment are essential. In this study, we have analyzed 190 MRSA isolates obtained at the Consorcio Hospital General Universitario de Valencia (Spain) from 2013 to 2018 with three approaches: Multilocus Sequence Typing, spa, and SCC mec typing. Although the incidence of S. aureus infections detected in the hospital increased in the study period, the frequency of MRSA isolates decreased from 33% to 18%. One hundred seventy-two MRSA isolates were resistant to three or more classes of antimicrobials, especially to fluoroquinolones. No relevant temporal trend in the distribution of antibiotic susceptibility was observed. The combination of the three typing schemes allowed the identification of 74 different clones, of which the combination ST125-t067-IV was the most abundant in the study (27 cases). Members of three clonal complexes, CC5, CC8, and CC22, comprised 91% of the isolates, and included 32 STs and 32 spa types. The emergence of low incidence strains throughout the study period and a large number of isolates resistant to different classes of antibiotics shows the need for epidemiological surveillance of this pathogen. Our study demonstrates that epidemiological and molecular surveillance is a powerful tool to detect the emergence of clinically important MRSA clones. more...