Antibiogram of Biofilm Producing and Non-Producing Community Acquired-Methicillin Resistant Staphylococcus aureus Isolated from Potential Risk Population of Dharan, Nepal

Abstract

Background Staphylococcus aureus is one of the common cause of hospital acquired infection and community acquired infections. Nowadays these organisms became resistant towards variety of drugs. MRSA is the emerging antibiotic resistant bacteria that are resistant to methicillin antibiotic and known to be the infectious pathogen causing severe infection and a cause of fatal mortality.Materials and methodology Altogether 200 nasal swabs and 200 hand swabs were obtained from participants and transported to microbiology lab in cold chain. The samples were swabbed in mannitol salt agar (MSA) containing oxacillin powder of 6mg/L and incubated at 37°C for 24 hrs. Staphylococcus aureus colonies were identified based on growth characteristics on MSA plates (golden yellow colonies), Gram stain and positive results for coagulase tube test and catalase test. The pure isolated MRSA were subjected to antibiotic susceptibility tests and biofilm formation assays.Results From our study the overall prevalence of CA-MRSA was 61.5%. Higher frequency of multi-drug resistant MRSA was isolated. The biofilm producing CA-MRSA were 51.2% which showed high drug resistance and rest (48.7%) were non-biofilm producers. There was significant association in biofilm production with multi-drug resistance (p<0.05). Ciprofloxacin was most sensitive drug against the isolates which was statistically significant (p<0.05). The resistant pattern of biofilm producers reported high ability of multi-drug resistance compared to non-biofilm producers (p<0.05). Microtitre plate method was found to be gold standard over tube and congo red agar method for screening biofilm formation. Surprisingly the emergence of VISA and VRSA strains were significantly reported from our study. The prevalence of VISA and VRSA among CA-MRSA was found to be 49.5% and 40.6% respectively among the isolates which indicates the failure of Vancomycin drug in clinical therapy.Conclusions The prevalence of CA-MRSA was found more in barbers followed by beauticians and municipal waste workers in comparison to healthy controls. This study reported the higher carriage of CA-MRSA in potential risk population along with emergence of VISA and VRSA strains. Improvement in personal hygiene and formulation of appropriate health policy helps to prevent CA-MRSA infection. This study concludes that CA-MRSA is still emerging with multi-drug resistance.