Detection of extended spectrum beta lactamase producing enterobacterales from diseased chickens and estimation of antimicrobial usage from antibiotics importation and sales data in Lusaka district, Zambia.
No Thumbnail Available
Date
2024
Authors
Chileshe, Chikwanda
Journal Title
Journal ISSN
Volume Title
Publisher
The University of Zambia
Abstract
Poultry products in Zambia form an integral part of the human diet in many households, as they are more affordable and easier to produce as compared to other sources of animal protein. However, the burden of poultry diseases has remained a major challenge, hindering the growing consumer demand for poultry products in Zambia. This has resulted in non-prudent antimicrobial use on farms, with the intent to prevent and treat poultry diseases for growth optimization and maximising profits. This study aimed to identify the different types of extended-spectrum -lactamase (ESBL) producing Gram negative bacteria (GNB) causing diseases in chickens in Lusaka and to asses possible association between antibiotic resistance
and antibiotic consumption. A cross-sectional study was conducted in Lusaka, which involved the collection of samples from diseased chickens at three different post-mortem facilities. Importation data was gathered from antimicrobial usage (AMU) data collection report from the Ministry of Fisheries and Livestock (MOFL) whilst sales data was collected from the largest outlet of veterinary pharmaceutical products in Zambia. A total of 215 samples were collected and screened for GNB. Of these samples, 103 tested positive for various clinically relevant Enterobacterales, including Enterobacter (43/103, 41.7%), Escherichia coli (20/103, 19.4%), Salmonella (10/103, 9.7%), and Shigella (8/103, 7.8%). Other isolated bacteria included Yersinia, Morganella, Proteus, and Klebsiella, which accounted for 21.4%. Only E. coli, Enterobacter, Salmonella, and Shigella were subjected to antimicrobial susceptibility testing (AST) using the Kirby-Bauer disc diffusion due to their public health significance. The AST results revealed that E. coli, Enterobacter and shigella were highly resistant to tetracycline, ampicillin, amoxicillin, and trimethoprim-sulfamethoxazole, while Salmonella showed complete susceptibility to all tested antibiotics. The observed resistance patterns correlated with antimicrobial usage estimated from the importation and sales data. The broth microdilution test was used to quantify for cefotaxime resistance. Results from this test showed that only fourteen (14/103, 13.5%) were resistant to cefotaxime. Eight of the fourteen isolates were Enterobacter whilst the remaining six were E. coli. The polymerase chain reaction (PCR) technique was then used to screen for the genes blaCTX-M, blaTEM, blaOXA and blaSHV. All Six (6/14, 42.9%) of the E. coli isolates carried the gene blaCTX-M whilst only four carried the gene blaTEM. On the other hand, all eight (8/14, 57.1%) of the Enterobacter isolates carried the gene blaTEM whilst only four of the isolates harboured the gene blaCTX-M. Sanger sequencing of the PCR products revealed that five (5/6,83.3%) of E. coli isolates carried the blaCTX-M-15 allele. These results suggest the presence of pathogenic ESBL-producing Enterobacteriaceae in poultry, threatening public health.
Description
Thesis of Master of Science in Veterinary Public Health.