Detection of CTX-M-Type Extended Spectrum Beta-Lactamase Producing Salmonella Typhimurium in Commercial Poultry Farms in Copperbelt Province, Zambia

Authors: Naomi Kaonga, Bernard. M. Hang’ombe, Athumani. M. Lupindu, Abubakar. S. Hoza

Ger. J. Vet. Res 2021. vol. 1, Iss. 2 pp:27-34


In Zambia, poultry is a rapidly increasing sector contributing 4.8% of the Agricultural Gross Domestic Product (GDP), thus providing a significant income-generating activity. Worldwide, poultry is a major reservoir of Salmonella with an increasing incidence of extended-spectrum beta-lactamase (ESBL) producing strains. ESBLs are enzymes produced by bacteria and are capable of inactivating a wide range of beta-lactam antibiotics. Salmonella enterica serovars Enteritidis and Typhimurium are the most important foodborne serotypes in many countries, infecting both humans and animals and are transmitted to humans through the food supply chain. CTX-M ESBLs have been described in Salmonella Typhimurium isolates with resistant genes located on transferable plasmids. This study aimed to detect S. Typhimurium, their antimicrobial resistance, and CTX-M-type ESBL Producing strains in commercial poultry farms in Copperbelt Province, Zambia. Five districts were considered for this study, where one poultry farm per district was randomly selected for sampling. An overall number of 384 fecal samples were analyzed using microbiological and molecular methods. S. Typhimurium was detected at 17.7% (CI: 14.2%-21.8%) in commercial poultry farms in Copperbelt Province, of which 12.8% (CI: 9.8%-16.5%) were found harboring the CTX-M-Type ESBL genes. S. Typhimurium isolates showed 88.2% resistance to at least one antimicrobial compound. All the isolates showed 100% resistance to tetracycline, followed by ampicillin and amoxicillin at 91.2%. These isolates also showed 58.8% resistance to cefotaxime and 54.4% to ceftazidime. Detection of CTX-M ESBL producing Salmonella Typhimurium suggests the contamination of chicken food chain at farm level and calls for public health protection measures.


Salmonella Typhimurium; CTX-M Extended Spectrum Beta-Lactamase; Copperbelt; Poultry


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