Molecular and phenotypic characteristics of methicillin-resistant Staphylococcus aureus isolated from hospitalized patients

Abstract

Introduction: Methicillin-resistant Staphylococcus aureus (MRSA) is one of the leading causes of infections acquired in both community and hospital settings. In this study, MRSA isolated from different sources of hospitalized patients was characterized by molecular and phenotypic methods. Methodology: A total of 123 S. aureus isolates were characterized according to their genetic relatedness by repetitive element sequence based-PCR (REP-PCR), in vitro antimicrobial susceptibility profile, SCCmec typing and presence of seven virulence factor-encoding genes. Results: REP-PCR fingerprinting showed low relatedness between the isolates, and the predominance of one specific lineage or clonal group was not observed. All isolates were susceptible to teicoplanin and linezolide. All isolates were resistant to cefoxitin and penicillin, and the majority were also resistant to one or more other antimicrobials. Fifty isolates (41.7%) were intermediately resistant to vancomycin. Most isolates harbored SCCmec type II (53.7%), followed by type I (22.8%), type IV (8.1%) and type III (1.6%). All isolates harbored at least two virulence factor-encoding genes, and the prevalence was as follows: coa, 100%; icaA, 100%; hla, 13.0%; hlb, 91.1%, hld, 91.1%; lukS-PV and lukF-PV, 2.4%; and tst, 34.1%. A positive association with the presence of hla and SCCmec type II, and tst and SCCmec type I was observed. Conclusion: This study showed the high virulence potential of multidrug-resistant MRSA circulating in a teaching hospital. A high prevalence of MRSA showing intermediate vancomycin resistance was also observed, indicating the urgent need to improve strategies for controlling the use of antimicrobials for appropriate management of S. aureus infections.

Differences in resistance profiles and virulence genes among methicillin-resistant and methicillin-susceptible Staphylococcus aureus of different lineages at a public tertiary hospital

“…The predominance of SCCmec type II (34/52, 65.4%) was also observed among the MRSA strains isolated from patients with bloodstream and respiratory tract infections during 2015-2016 in the University Hospital of Londrina in the Parana State, Brazil 20 . Interestingly, the predominance of MRSA strains harboring SCCmec II elements was also observed in a study during 2010 to 2013 in the same hospital 21 . These data suggest the shift in the MRSA population and emphasizes on the substitution of the strains harboring SCCmec III with those carrying SCCmec II that is becoming prevalent in some areas 19,20 .…”

Disseminated Clonal Complex 5 (CC5) methicillin-resistant Staphylococcus aureus SCCmec type II in a tertiary hospital of Southern Brazil

“… 14 ; b PVL: Panton Valentine Leukocidin encoding gene and tst-1 : Toxic Shock Syndrome Toxin encoding gene were detected as described in Oliveira et al . 16 ; c Antimicrobial resistance profile was determined by disk-diffusion assay according to the CLSI guidelines 8 - I: OXA; II: OXA, ERI, CLI, CIP; III: OXA, ERI, CLI, CIP, GN; OXA: Oxacillin, CLI: Clindamycin, ERI: Erithromycin, CIP: Ciprofloxacin; GN: Gentamicin; d Year of isolation; e Source of isolation, T: Tracheal secretion, B: Blood; f MIC vancomycin determined by E-test ; - Absence; + Presence.…”

Comparison of HRM analysis and three REP-PCR genomic fingerprint methods for rapid typing of MRSA at a Brazilian hospital

“…Although the Brazilian endemic clone (BEC) with SCCmec type III has been shown to be the clone that is spread in Brazil, this was not the SCCmec type found most frequently in our isolates; indeed, SCCmec type II was most prevalent, according to another study described by Oliveira et al [43]. Furthermore, the analysis of DNA polymorphism performed in our study showed a low genetic similarity (45%) of strain BEC9393 with most of the strains studied.…”