Affiliation:
1. Department of Veterinary Microbiology, West Bengal University of Animal and Fishery Sciences
2. Kusuma School of Biological Sciences, Indian Institute of Technology Delhi
3. Department of Veterinary Public health, West Bengal University of Animal and Fishery Sciences
4. Department of Veterinary Microbiology, Central Agricultural University
5. Eastern Regional Station, ICAR-Indian Veterinary Research Institute
6. Evolutionary Ecology and Genetics Reasearch Group, Zoological Institute, Christian-Albrechts-Universität zu Kiel
Abstract
Abstract
Background
In commercial broiler farms, the dissemination of extended-spectrum beta-lactamase (ESBL)-producing E. coli presents a significant concern. These bacteria may spread vertically from parental stock or horizontally through contaminated feed, water, and infected companion birds. Understanding the transmission dynamics of ESBL-E. coli in small-scale poultry farms in rural settings is crucial.
Methods
We conducted a comprehensive study on a small-scale poultry farm in West Bengal, India. A total of 120 samples were collected at three different intervals (0th, 20th, and 40th day) of the production cycle, including cloacal swabs (n = 49), drinking water (n = 36), and feed (n = 35). All E. coli isolates were tested for resistance to eight antimicrobial agents. ESBL-producing E. coli was confirmed using the double-disc test. Furthermore, we conducted PCR to detect major ESBL genes, followed by sequencing of selected PCR products.
Results
We recovered a total of 173 E. coli isolates from the samples. These isolates exhibited varying degrees of resistance, with 100% resistance to cefixime, 83.3% to amoxicillin, 50% to tetracycline, and 33.3% to enrofloxacin. The occurrence of ESBL-E. coli initially decreased from day-old production to the 20th day but then increased in the subsequent 21st -40th day of the production cycle. Genotyping of ESBL revealed dynamic changes, with a progressive decrease in the occurrence of blaCTX-M and blaSHV in cloacal swabs and a corresponding increase in drinking water and feed. Notably, blaCTX-M-15 emerged as the predominant resistance determinant among antibiotic-resistant genes.
Conclusions
Our study sheds light on the probable vertical transmission of ESBL-E. coli from the parent flock to the studied birds, with a decrease observed up to the 20th day of the production cycle. Additionally, our findings highlight drinking water as a potential source of on-farm horizontal transmission of ESBL-E. coli. To prevent the spread of antimicrobial-resistant bacteria in birds and their products, it is essential for small-scale poultry farms to adopt strict biosecurity measures and maintain high hygiene standards. These insights have critical implications for poultry farming practices and public health.
Publisher
Research Square Platform LLC