Abstract
BACKGROUND: Methicillin resistant Staphylococcus aureus (MRSA) is a human pathogen that can cause hospital and community acquired infections. Biofilm formation is a major virulence factor contributing to its pathogenicity. This study aimed to detect biofilm formation ability among methicillin resistant Staphylococcus aureus (MRSA) clinical isolates and determine SCCmec types. METHODS: A total of 115 S. aureus were isolated from various clinical samples collected at Nepal Armed Police Hospital from August 2022 to February 2023. The antibiotic susceptibility test was performed via a modified Kirby Bauer disc diffusion method following CLSI guidelines. Phenotypic detection of biofilm formation was performed by microtiter plate assay. Polymerase chain reaction was performed to detect mecA, icaA and SCCmec types. RESULTS: More than 90% of the isolates were resistant to cefixime and penicillin. Among the total isolates, 66% were multidrug resistant. The disc diffusion method detected 60% of the isolates as MRSA, with 15 isolates lacking the mecA gene. Different levels of biofilm biomass were observed among 86 (75%) of the isolates by microtiter plate method. PCR revealed the presence of the icaA gene in a low number of the isolates (16%). Compared with biofilm nonproducer isolates, biofilm producing S. aureus isolates presented a greater incidence of antibiotic resistance with multi drug resistance (MDR). SCCmec type V (21%) predominated, followed by type II (13%) and most of them were MDR and biofilm producers. CONCLUSIONS: Our results indicate a relatively high incidence of community acquired S. aureus circulating in the hospital setting. This study is the first to explore the associations between SCCmec types and biofilm formation among clinical isolates in Nepal. Monitoring the prevalence of biofilm producing S. aureus provides valuable insights into the evolving epidemiology of healthcare associated infections, facilitating the development of targeted infection control strategies.