ORIGINAL RESEARCH article

Front. Vet. Sci.

Sec. Veterinary Infectious Diseases

Volume 12 - 2025 | doi: 10.3389/fvets.2025.1612542

Detection and risk factor analysis of avian colibacillosis associated with colistin-resistant Escherichia coli and Klebsiella pneumoniae

Provisionally accepted
  • 1University of Veterinary and Animal Sciences, Lahore, Punjab, Pakistan
  • 2Institut für bakterielle Infektionen und Zoonosen, Friedrich Loeffler Institut, Jena, Germany

The final, formatted version of the article will be published soon.

Colibacillosis associated with colistin-resistant avian pathogenic Escherichia coli poses a threat to both food security and public health. The potential horizontal transmission of mobilized colistin-resistant (mcr) genes facilitates the co-emergence of Klebsiella pneumoniae. This study aimed to determine the prevalence, molecular detection, analyze the antibiogram and identify associated risk factors for colistin-resistant Escherichia coli and Klebsiella pneumoniae isolated from broiler chicken in three districts of Punjab province, Pakistan.In total, 230 visceral organ samples were collected from 13 different chicken farms located in Sargodha, Jhang and Toba Tek Singh in Pakistan. Following isolation, broth microdilution test was used to confirm phenotypic colistin resistance. Polymerase chain reaction was used to detect mcr-1 and mcr-2 genes associated with colistin resistance. Antimicrobial susceptibility test against 11 antibiotics was performed by using Kirby-Bauer disk diffusion method. Risk factors associated with colistinresistant bacteria, including host attributes, farm management practices, environmental and agent characteristics were analyzed.The prevalence of colistin-resistant E. coli and K. pneumoniae was 24.78% (95% CI, 19.6%-30.7%) and 3.04% (95% CI, 1.5%-6.1%), respectively. The prevalence of colistin-resistant E. coli varied between cities as 42%, 23.61% and 5.55% for Jhang, Sargodha and Toba Tek Singh, respectively. The detection frequency of mcr-1 gene 42.1% (24/57) was significantly (p < 0.01) higher than mcr-2 gene, 14.03% (8/57). Phylogenetic analysis of lipid A phosphoethanolamine transferase sequences revealed greater similarity with mcr-1.5 variant. Isolates were found resistant to amoxycillin-clavulanic acid (84.21%), cefotaxime (70.17%) and trimethoprim-sulfamethoxazole (73.68%). The multivariate logistic regression predicted preceding viral infection of respiratory tract as a significant association (OR = 4.808, p < 0.01), whereas daily removal/culling of dead/diseased chicken (OR = 0.308, p = 0.01) as a protective factor against the emergence of colistin-resistant strains.These findings indicate that emergence of the colistin-resistant strains deteriorates colibacillosis control efforts in poultry and serve as a possible reservoir for zoonotic infections.

Keywords: Escherichia coli, Klebsiella pneumoniae, MCR, Risk factors, Avian colibacillosis

Received: 15 Apr 2025; Accepted: 08 Jul 2025.

Copyright: © 2025 Saeed, Asif, Ehtisham-ul-Haque, Khan, Rehman, Rehman, Kamran Rafique, Ahmed, Qamar, Tomaso and El-Adawy. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence:
Muhammad Adnan Saeed, University of Veterinary and Animal Sciences, Lahore, 54000, Punjab, Pakistan
Hosny El-Adawy, Institut für bakterielle Infektionen und Zoonosen, Friedrich Loeffler Institut, Jena, Germany

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