Detection of Extended-Spectrum Beta-Lactamase (ESBL)-Producing from Diseased Broiler Chickens in Lusaka District, Zambia.

Poultry products in Zambia form an integral part of the human diet in many households, as they are cheap and easy to produce. The burden of poultry diseases has, however, remained a major challenge. Growing consumer demand for poultry products in Zambia has resulted in non-prudent antimicrobial use on farms, intending to prevent and treat poultry diseases for growth optimisation and maximising profits. This cross-sectional study aimed to identify the different types of bacteria causing diseases in chickens in Lusaka and to detect the extended-spectrum lactamase (ESBL)-encoding genes. We collected 215 samples from 91 diseased chickens at three post-mortem facilities and screened them for Gram-negative bacteria. Of these samples, 103 tested positive for various clinically relevant , including (43/103, 41.7%), (20/103, 19.4%), (10/103, 9.7%), and (8/103, 7.8%). Other isolated bacteria included , , , and , which accounted for 21.4%. , , and were subjected to antimicrobial susceptibility testing. The results revealed that , , and were highly resistant to tetracycline, ampicillin, amoxicillin, and trimethoprim-sulfamethoxazole, while showed complete susceptibility to all tested antibiotics. The observed resistance patterns correlated with antimicrobial usage estimated from sales data from a large-scale wholesale and retail company. Six (6/14, 42.9%) isolates tested positive for , whilst eight (8/14, 57.1%) samples tested positive for . Interestingly, four (4/6, 66.7%) of the isolates carrying -positive strains were also positive for . Sanger sequencing of the PCR products revealed that five (5/6, 83.3%) of the abovementioned isolates possessed the allele. The results suggest the presence of potentially pathogenic ESBL-producing in poultry, threatening public health.