Bacteriological assessment of water quality in Barishal, Bangladesh: potability testing and antibiogram profiling

Abstract

Water hygiene is a critical public health issue, particularly in developing countries like Bangladesh. Therefore, this study aimed to evaluate the bacteriological quality and antimicrobial resistance (AMR) patterns of bacterial isolates in drinking water sources commonly used by the public across Barishal district of Bangladesh. A total of 30 water samples were collected from six sources - household reserved tanks, ponds, rivers, hotels, farms, and street food vendor vans - between July 2022 and June 2023. Bacterial contamination was assessed using total viable count, most probable number (MPN), and selective culture methods, while antibiotic susceptibility testing (AST) was conducted to evaluate antimicrobial resistance (AMR) patterns. Results indicated substantial contamination, with the highest bacterial load observed in household reserved tank water (5.6 × 10⁵ CFU/mL). Predominant bacterial isolates included Escherichia coli and Staphylococcus spp., suggesting fecal contamination and potential health risks. AMR profiling revealed resistance to beta-lactam antibiotics such as amoxicillin and penicillin, with multidrug resistance observed in E. coli, Staphylococcus spp., and non-lactose fermenting bacteria. However, susceptibility to colistin and levofloxacin was noted in some isolates. These findings underscore the urgent need for routine water quality monitoring, effective disinfection strategies, and public awareness initiatives to mitigate health risks and curb the spread of AMR in environmental water sources.

Keywords: Bangladesh; antibiotic resistance; bacterial isolation; fecal contamination; water hygiene.