Staphylococcus aureusClinical Isolates: Antibiotic Susceptibility, Molecular Characteristics, and Ability to Form Biofilm

Abstract

Periodic monitoring ofStaphylococcus aureuscharacteristics in a locality is imperative as their drug-resistant variants cause treatment problem. In this study, antibiograms, prevalence of toxin genes (sea-see, seg-ser, seu, tsst-1, eta, etb, andetd), PFGE types, accessory gene regulator (agr) groups, and ability to form biofilm of 92S. aureusThailand clinical isolates were investigated. They were classified into 10 drug groups: groups 1–7 (56 isolates) were methicillin resistant (MRSA) and 8–10 (36 isolates) were methicillin sensitive (MSSA). One isolate did not have any toxin gene, 4 isolates carried one toxin gene (seq), and 87 isolates had two or more toxin genes. No isolate hadsee, etb, ortsst-1; six isolates hadetaoretd. Combinedseg-sei-sem-sen-seoof the highly prevalentegclocus was 26.1%. Theseb, sec, sel, seu, andetaassociated significantly with MSSA;sekwas more in MRSA. Thesek-seqassociation was 52.17% while combinedsed-sejwas not found. Twenty-three PFGE types were revealed, no association of toxin genes with PFGE types. All fouragrgroups were present;agrgroup 1 was predominant (58.70%) butagrgroup 2 strains carried more toxin genes and were more frequent toxin producers. Biofilm formation was found in 72.83% of the isolates but there was no association with antibiograms. This study provides insight information on molecular and phenotypic markers of ThailandS. aureusclinical isolates which should be useful for future active surveillance that aimed to control a spread of existing antimicrobial resistant bacteria and early recognition of a newly emerged variant.