Decadal trends in antimicrobial susceptibility of Escherichia coli and Salmonella spp. in chicken from small-scale farm shops in Kandy district, Sri Lanka

E. coli and Salmonella spp. are two important foodborne pathogens that rapidly develop antimicrobial resistance (AMR) and frequently contaminate animal products, particularly chicken meat. In Sri Lankan small-scale poultry operations, substandard hygienic practices are common. The current study reports and compares two consecutive studies conducted in 2010-2011 and 2020-2021, which investigated AMR E. coli and Salmonella spp. contamination in chicken meat sold at small-scale farm shops in the Kandy district, Sri Lanka. The first study included 72 chicken meat samples collected from 10 out of the 20 divisional secretariat divisions (DSDs), while the second study included 37 meat samples from the same DSDs, collected 10 years later. Salmonella spp. and E. coli were isolated and identified, and AMR profiles were obtained using disc diffusion assay and CLSI guidelines. The first study reported 100% E. coli contamination in chicken meat, but a decade later, the percentage had significantly decreased to 70.3%. In both studies, E. coli isolates demonstrated resistance to more antimicrobials than Salmonella isolates, and the proportion of multidrug-resistant (MDR) E. coli isolates (defined as resistance to five or more antimicrobials) was higher than that of the Salmonella spp. isolates. Significantly lower MDR E. coli isolates were detected in the recent study. However, tetracycline resistance among E. coli isolates was higher compared to the previous study. Despite these improvements, the contamination level of chicken meat in small-scale retail shops remains concerning. Therefore, it is crucial to promote prudent antimicrobial use and ensure proper food processing practices at all levels of production in Sri Lanka.