Phenotypic resistance and virulence gene profiles of non-typhoidal Salmonella in retail poultry products in Arusha, Tanzania: A One Health perspective

Vet World Vol.18 October-2025 Article - 6

Research Article

Veterinary World, 18(10): 2991-3001

https://doi.org/10.14202/vetworld.2025.2991-3001

Salum Ahmed^1,2,3, Ali Ali¹, Beatus Lyimo⁴, and Esther Gwae Kimaro⁴

1. Department of Biomedical Research and Clinical Trial, Ifakara Health Institute (IHI), P.O. Box 74, Bagamoyo, Tanzania.

2. School of Life Science and Bioengineering (LiSBE), The Nelson Mandela African Institution of Science, Technology (NM-AIST), P.O. Box 447, Arusha, Tanzania.

3. Livestock Training Agency (LITA), The Ministry of Livestock and Fisheries, P.O. Box 3101, Arusha, Tanzania.

4. School of Life Science and Bioengineering (LiSBE), The Nelson Mandela African Institution of Science, Technology (NM-AIST), P.O. Box 447, Arusha, Tanzania.

Background and Aim: Non-typhoidal Salmonella (NTS) is a leading cause of foodborne illness, with poultry products serving as major transmission routes. In sub-Saharan Africa, surveillance of antimicrobial resistance (AMR) and virulence determinants remains limited. This study investigated the prevalence, AMR, and virulence gene profiles of NTS isolated from poultry products retailed in Arusha, Tanzania.

Materials and Methods: A cross-sectional study was conducted between August and October 2023. A total of 240 samples (layer eggs and broiler meat) were collected from two wards in Arusha City using systematic random sampling. NTS isolates were confirmed by polymerase chain reaction (PCR) and tested for susceptibility to 11 antimicrobial agents using the Kirby–Bauer method. Virulence (invA and stn) and resistance genes (tetA, tetB, blaTEM, blaCTXM, and blaSHV) were screened by PCR. Statistical associations were analyzed using odds ratios (OR) and 95% confidence intervals (CI).

Results: The overall prevalence of NTS was 23.3% (56/240). Layer eggs showed significantly higher contamination (20%) compared with broiler meat (3.3%) (OR = 10.0, 95% CI: 4.4–22.6, p < 0.001). Salmonella Typhimurium was the predominant serotype. All isolates carried invA and stn genes. Alarmingly, 100% of isolates were resistant to imipenem (IMI), while resistance to ampicillin (58.9%) and tetracycline (41.1%) was also common. Multidrug resistance patterns were frequent, although resistance genes were detected at a low prevalence (tetA, 5.3%; blaTEM, 3.5%).

Conclusion: The findings demonstrate a high prevalence of virulent and IMI-resistant S. Typhimurium in retail poultry products in Arusha, particularly in eggs. These results highlight critical gaps in food safety regulation and antimicrobial stewardship within the Tanzanian One Health framework. Further genomic studies are warranted to elucidate underlying resistance mechanisms and inform effective surveillance strategies.

Keywords: antimicrobial resistance, non-typhoidal Salmonella, One Health, poultry, Tanzania, virulence genes.

How to cite this article: Ahmed S, Ali A, Lyimo B, and Kimaro EG (2025) Phenotypic resistance and virulence gene profiles of non-typhoidal Salmonella in retail poultry products in Arusha, Tanzania: A One Health perspective, Veterinary World, 18(10): 2991-3001.

Received: 04-06-2025 Accepted: 04-09-2025 Published online: 08-10-2025

Corresponding author: Salum Ahmed E-mail: chiambasalum@gmail.com

DOI: 10.14202/vetworld.2025.2991-3001

Copyright: Ahmed, et al. This article is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, 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. The Creative Commons Public Domain Dedication waiver (http:// creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.