Isolation, Identification and Antibiogram Assay of Escherichia coli from the Environment of Live Bird Markets in Bangladesh

Background: Live bird markets (LBMs) may facilitate the persistence and dissemination of Escherichia coli and antimicrobial resistant bacteria because of intensive bird handling, environmental contamination and inadequate sanitation. However, information on E. coli contamination and antimicrobial susceptibility in LBM environments in Rajshahi District, Bangladesh, remains limited. Objective: This study aimed to determine the prevalence, identify the cultural and biochemical characteristics, and assess the antimicrobial susceptibility pattern of E. coli isolated from water, soil and bird-dropping samples collected from LBMs in Rajshahi District. Methods: A total of 60 environmental samples, comprising 20 water, 20 soil and 20 bird dropping samples, were collected from LBMs across all ten upazillas of Rajshahi District between January and June 2023. E. coli was isolated and identified using cultural characteristics, Gram staining and biochemical tests. Antimicrobial susceptibility was determined by the Kirby Bauer disc diffusion method against seven antimicrobial agents using CLSI interpretive criteria. Results: E. coli was detected in 33 of 60 samples, giving an overall prevalence of 55.00%. Prevalence was highest in bird dropping samples (75.00%), followed by water (55.00%) and soil (35.00%). Among the 33 isolates, resistance was highest to oxytetracycline (78.79%) and amoxicillin (63.64%), followed by ciprofloxacin (48.48%), doxycycline (33.33%), levofloxacin (9.09%), erythromycin (9.09%) and neomycin (6.06%). Sensitivity was highest to neomycin (60.61%), followed by levofloxacin and erythromycin (51.51% each). Conclusion: The high prevalence of E. coli and substantial resistance to several commonly used antimicrobials indicate considerable microbiological and antimicrobial-resistance concerns in LBM environments. Improved sanitation, biosecurity, hygienic poultry handling and prudent antimicrobial use are warranted to reduce environmental contamination and potential transmission of resistant bacteria.