Prevalence and Multidrug-Resistant Pattern of Salmonella from the Eggs and Egg-Storing Trays of Retail Markets of Bangladesh

Aim: Salmonellosis is one of the most common and widely distributed foodborne illnesses in human, and multidrugresistance of Salmonella spp. has increased in developing countries with the indiscriminate use of antibiotics in the poultry production system. A cross-sectional study was conducted on randomly selected retail markets of Chittagong City Corporation to determine the prevalence and antimicrobial resistance pattern of Salmonella isolated from commercial layer eggs, eggshell surface, and egg-storing trays.

Materials and Methods: Chicken eggs, egg surface, and egg-storing trays samples from the retail markets were collected for isolating Salmonella spp. (bacteriological culture methods) followed by antimicrobial susceptibility testing (disc diffusion method) against Salmonella isolates during the period from July to December 2013.

Results: Out of the 310 layer eggs, egg surface, and egg-storing trays samples, the highest prevalence of Salmonella spp. was found in eggs trays (57.15%) and the lowest (13.33%) in eggs and the prevalence differed significantly (p<0.01). On the other hand, the prevalence was higher (45%) in samples of Pahartali bazar and lower (31.43%) in samples of Bohderhat bazar but the variation among the sites was not varied significantly (p>0.05). Isolated Salmonella was tested for resistance to eight different antimicrobial agents, using disc diffusion method. Among eight antimicrobial tested (n=111), 100% resistance were found to ampicillin and amoxicillin followed by erythromycin (60-100%), tetracycline (72-93%), ciprofloxacin (22-66%), colistin (27-66%), enrofloxacin (42-54%), and pefloxacin 23.07% across the study sites. Ciprofloxacin remained sensitive in 40.9% cases and, pefloxacin and colistin appeared to be almost sensitive (61-72%) against Salmonella isolates at studied areas. Salmonella isolates showed multidrug-resistance pattern up to five of the eight antimicrobials tested.

Conclusion: It can be said that the rational use of antibiotics needs to be adopted in commercial poultry farming system of Bangladesh to prevent the emergence of drug-resistance Salmonella to protect the public health consequences.