Epidemiology and antimicrobial resistance profiles of Salmonella in chickens, sewage, and workers of broiler farms in selected areas of Bangladesh

Introduction: A cross-sectional study was conducted to determine the prevalence and AMR pattern of Salmonella isolated from broiler chickens, farm sewage, and farm workers. This study also aimed at identifying the risk factors for Salmonella infection in chickens. Methodology: Cloacal swabs (n = 50) from broiler chickens, farm sewage (n = 50), and hand washed water of farm workers (n = 50) were collected along with data on farm management and antimicrobial usage from 50 broiler farms of Mymensingh and Gazipur districts. All samples were analysed for the presence of Salmonella using selective media and PCR assay. Antimicrobial susceptibility test was done for ten antimicrobials by disk diffusion test. Risk factor analyses were carried out by multivariable logistic regression using SPSS. Results: The overall Salmonella prevalence was 66% (99/150). Salmonella prevalence were 82% and 72% in cloacal swabs and farm sewage samples, respectively. From hand washed water, 44% of the samples were positive for Salmonella. Salmonella infection in broiler chickens was significantly associated with farming experience (<= 5 years) and age of birds (>= 11 days). Similar pattern of antimicrobial resistance was observed in Salmonella isolated from three types of samples, and high resistances were observed to colistin, doxycycline, ciprofloxacin and ceftazidime. Moreover, isolates from all the three sources showed high percentage of multidrug-resistance (80.6% to 97.6%). Conclusions: The findings of this study reveal that antimicrobial-resistant Salmonella are prevailing at animal-human-environment interface, which needs an integrated approach to limit further spread of AMR.