Research Article | Open Access
Warsha Chaudhary1 , Nirmal Kumar Jeph1, Sandeep Kumar Sharma2, Alka Bharia1, Saksham Mandawat1, Akanksha Choudhary1, Jyoti Bishnoi3 and Anupriya4
1Department of Veterinary Medicine, Post Graduate Institute of Veterinary Education and Research, Jaipur, Rajasthan, India.
2Department of Veterinary Microbiology, Post Graduate Institute of Veterinary Education and Research, Jaipur, Rajasthan, India.
3Centre for Diagnosis, Surveillance and Response of Zoonotic Diseases (CDSRZ), Post Graduate Institute of Veterinary Education and Research, Jaipur, Rajasthan, India.
4Department of Veterinary Public Health and Epidemiology, Post Graduate Institute of Veterinary Education and Research, Jaipur, Rajasthan, India.
Article Number: 10662 | © The Author(s). 2026
J Pure Appl Microbiol. 2026;20(3):2136-2145. https://doi.org/10.22207/JPAM.20.3.05
Received: 05 June 2025 | Accepted: 18 June 2026 | Published online: 16 July 2026
Issue online: September 2026
Abstract

Colibacillosis is an infectious disease in animals, which is caused by Escherichia coli, leading to economic losses. The current investigation was conducted to evaluate the molecular typing of colibacillosis-associated Escherichia coli for determination of O157:H7 serotype and virulence factors. Overall, 100 faecal samples were screened between November 2023 to February 2024 from in and around Jaipur district of Rajasthan. Sample screening was done for isolating E. coli in which 77 isolates were recovered from 100 diarrhoeic cattle and its serological identification indicated presence of the most frequent serotype, encompassing O76 (5), O3 (4), O7 (4), O16 (4), O50 (4), O111 (3), O113 (2), O125 (2), O135 (2), O2 (1), O4 (1), O9 (1), O19 (1), O27 (1), O66 (1), O85 (1), O109 (1), O114 (1) and  O156 (1). Finally, Molecular characterization of the recovered isolates was conducted using PCR for detecting presence of fliCH7, rfbO157, stx1, stx2, EhlyA along with eaeA genes associated with E. coli. Among 77 E. coli isolates, none were recognized as O157:H7 serotypes. Among total E. coli isolates, 40 comprised Shiga toxin-producing E. coli (STEC) genes. The stx2 gene was the most prevalent (32.5%), followed by stx1 (17.5%), while combinations involving stx1, stx2 and EhlyA were detected in 10%-12.5% of isolates. The eaeA gene was rare, occurring in only 2.5% of the virulence-positive isolates. Results suggest that conventional culture methods, along with serological and molecular assays, are key techniques for isolating and characterizing STEC from fecal samples of diarrheic cattle.

Keywords

Colibacillosis, Escherichia coli, STEC, Serotype, Virulotype

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© The Author(s) 2026. Open Access. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License which permits unrestricted use, sharing, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.