Recovery of Methicillin Resistant Staphylococci from Public Vehicles in Kathmandu

Abstract

Objectives: The purpose of this study was to determine the extent of staphylococcal contamination in public vehicles in Kathmandu and to determine the antibiotic susceptibility pattern of the isolates.

Methods: This cross-sectional study was conducted from December 2022 to May 2023 in the Microbiological laboratory of Padma Kanya Multiple Campus, Kathmandu. A total of 120 swab (sterile cotton swab moistened with sterile normal saline) samples were collected by gently rubbing the surfaces from 19 different micro-buses during the time of heavy passenger flow (office time) and transported to the laboratory maintaining a cold chain. Staphylococcus aureus and Coagulase negative Staphylococci (CoNS) were identified by their characteristic yellow pigmented colonies on Mannitol Salt Agar (MSA) and the ability of S. aureus to produce coagulase enzyme. Kirby-Bauer disc diffusion method was employed to test the antibiotic susceptibility pattern of isolates. MRSA were identified on the basis of the zone of inhibition (<21 mm diameter) against Cefoxitin 30mcg disc.

Results: Out of 41 Staphylococcal isolates, 46.36% were S. aureus, among which 84.21% exhibited methicillin resistance (MRSA). All Coagulase Negative Staphylococci (CoNS) isolates (n=22) were resistant to methicillin (MRCoNS). MRSA and MRCoNS isolates were also resistant to antibiotics like Penicillin and Erythromycin.

Conclusion: This study reports relatively high occurrence of MRSA in environmental samples, predominantly in areas frequently touched by people indicating the possibility of easy spread of these organisms and subsequent opportunistic infections.