Volume 16, Issue 1: 2026 - Article 222

Abstract
Colibacillosis is an acute, infectious and mostly systemic disease that has been reported to cause significant economic losses in poultry flocks worldwide. Rearing laying chickens, which is increasingly recognized for its economic potential in the poultry sector is greatly constrained by the occurrence of diseases, including colibacillosis. The present case report is on colibacillosis caused by multi-drug resistant Escherichia coli in nineteen‐weeks‐old layer chickens (n = 1,200) that were intensively managed on a battery cage system in Nsukka, Enugu State, Nigeria. The birds showed reduced feed intake, torticollis, staggering gait, well-formed greenish feces with white portions, weakness, poor body condition, huddling and 2% mortality. Necropsy of some of the dead chickens and euthanized living ones showed that the carcasses were emaciated, with fibrin deposits in the thoracic cavity, enlarged heart, congested liver, a focal region of congestion on the spleen and petechial hemorrhage on the intestines. Microscopically, there was nephrosis, hepatitis, erosion of the intestinal villi and depletion of lymphocytes in the spleen. Pure cultures of E. coli were isolated from the spleen, liver and heart (one dead bird) and liver (two live birds that were euthanized) and identified using both cultural and microscopic features as well as biochemical characteristics. The isolates exhibited multi-drug resistance to several antibiotics, including Tobramycin, Gentamicin, Ciprofloxacin, Trimetoprim-Sulphamethoxazole and Tetracycline but were susceptible to only Cefotaxime, which was used to successfully treat the flock. This case highlights the critical issue of antimicrobial resistance in animal husbandry. It reaffirms the need for better management practices in poultry production to mitigate transmission of pathogenic microorganisms, as well as the need to develop alternative strategies for controlling antibiotic-resistant bacterial organisms in avian species. This case further highlights the need for alternative treatments and strict antimicrobial stewardship to combat multidrug-resistant E. coli in poultry.

Keywords: Colibacillosis; Escherichia coli; Layer chickens; Antimicrobial resistance;
Multidrug resistance.

How to cite this article:
Ikenna-Ezeh NH, Ezema AS, Arungwa ME, Ogbue NJ, Eze IG, Onyeke CM, Nnadi MC
and Anyanwu MU (2026). Colibacillosis caused by multi-drug resistant Escherichia coli in
nineteen‐weeks‐old layer chicken flock at Nsukka, Enugu State, Nigeria: A case report.
Journal of Veterinary and Applied Sciences, 16(1): 1404 – 1415.

*Correspondence: E-mail:     arinzechukwu.ezema@unn.edu.ng     Phone: +2348068416301

Colibacillosis caused by multi-drug resistant Escherichia coli in nineteen‐weeks‐old layer chicken flock at Nsukka, Enugu State, Nigeria: A case report

Nkechi H. Ikenna-Ezeh ¹, Arinzechukwu S. Ezema ^{2 *}, Mmesoma E. Arungwa ¹, Ngozi J. Ogbue ¹, Ifeoma G. Eze ¹, Chidinma M. Onyeke¹, Muoneme C. Nnadi ¹ and Madubuike U. Anyanwu ¹
1 Department of Veterinary Microbiology and Immunology, Faculty of Veterinary Medicine, University of Nigeria, Nsukka, Enugu State, Nigeria.
² Department of Veterinary Pathology, Faculty of Veterinary Medicine, University of Nigeria, Nsukka, Enugu State, Nigeria.

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