A bacteriological study of public bus and bus stop surfaces in Dhaka: identifying GLASS pathogens and analyzing their antibiotic resistance pattern

Abstract

Due to overcrowding, humid environment and unsanitary conditions, public buses of Dhaka city can be a probable reservoir for pathogenic and antimicrobial resistant bacteria. This study focuses on identifying the Global Antimicrobial Resistance and Use Surveillance System (GLASS) guidelines’ priority bacteria in common touch surfaces of buses and bus stops, and providing a proper insight on the antimicrobial resistance (AMR) pattern of these bacteria. Samples collected from seats, grab rails and bus stops were spread on different selective media. Based on colony morphology bacteria were presumptively selected, then polymerase chain reaction (PCR) was performed. Upon identification of target bacteria, the analysis of their AMR pattern was done using Kirby-Bauer disc diffusion method. Among the 30 samples, 60.0% were positive for Klebsiella pneumoniae, 36.7% for Vibrio species, 33.3% for Acinetobacter baumannii, 20% for Staphylococcus epidermidis, 16.7% for Enterococcus spp. and/or P. aeruginosa, and 10.0% for Staphylococcus aureus and/or Salmonella species. Samples taken from cloth surfaces had the highest bacterial count, while acrylic paint and steel surfaces had a relatively lower count. Among the nine bacteria, all bacteria except for A. baumannii, Salmonella species and P. aeruginosa showed an alarmingly high level of multidrug-resistance, with K. pneumoniae showing the highest resistance, 95%. The detection of multidrug-resistant bacteria in public buses, emphasise these transportation as being an important reservoir for clinically significant pathogens and the dissemination of antimicrobial resistance genes to the environmental microbiome. The findings of this study call for an urgent need for improving the overall conditions of buses and ensuring proper cleaning practices in public transports.