ANTIBIOGRAM, ANTIBIOTIC AND DISINFECTANT RESISTANCE GENES, BIOFILM-PRODUCING AND -ASSOCIATED GENES, AND GENOTYPE OF METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS CLINICAL ISOLATES FROM NORTHERN THAILAND

Methicillin-resistant Staphylococcus aureus (MRSA) causes a variety of infectious diseases in both hospital and community. The study determined prevalence of antibiotic resistance and associated genes, biofilm-producing phenotype and associated genes, SCCmec types, and clonal subtype ST239 of MRSA clinical isolates obtained from three hospitals in northern Thailand during January 2013 to October 2015. Some 95% of MRSA isolates were multidrug resistant, with 82%, 60% and 47% harboring ermA, ermB and qacAB, respectively. Although all MRSA isolates were positive for slime (biofilm) production on Congo red agar, quantitative measurement of biofilm generation using microliter plate assay (MTP) indicated 60% were low biofilm producers, with prevalence of biofilm-associated genes, bab, cna, fnbA, and icaAD, ranging from 50% to 100%. MRSA SCCmec type III was predominant, but the presence of SCCmec type IV and type V (albeit at low frequency) indicated acquisition of community-acquired infection. Clonal subtype ST239 was detected in 29% of MRSA isolates in hospitals located in the lower and upper northern regions. The information provided by this study should be useful for future active surveillance of MRSA and in the development of the strategies to lower prevalence and to control the spread of this virulent staphylococcal infection in hospitals and the community at large.