Journal of Veterinary and Biomedical Sciences
(ISSN: 2659 – 0743)
Volume 8, No. 1, 2026
Pages 8-25
DOI: 10.36108/jvbs/6202.80.0120
Isolation, Antibiotic susceptibilty testing and Detection of Antibiotic resistant Genes of Salmonella gallinarum and pullorum Isolated from Plateau State, Nigeria
Moses, Gyang D.1, Chah, K.2 and Shoyinka, S.V.O2
1National Veterinary Research Institute, Vom Nigeria.
2.Faculty of Veterinary Medicine, University of Nigeria, Nsukka, Nigeria
ABSTRACT
The aim of this study was to determine the antibiotypes of Salmonella enterica var Gallinarum and Pullorum isolated from chickens in Plateau State, Nigeria. The study adopted a passive survey design. Diseased chicken carcasses from Plateau State submitted to the Diagnostic Department of the National Veterinary Research Institute, Vom, Plateau State for post mortem examination and laboratory diagnosis were used for the study. The study was conducted between January and December, 2017. Based on case history and post mortem findings of suspected cases of salmonellosis, samples (heart blood, sections of the liver and gall bladder, spleen, lungs, ovary, kidneys and intestinal segments) from 494 chickens were collected and processed for Salmonella isolation, antibiotic sensitivity tests and antibiotic resistant genes type detection. The bacteriology samples were collected aseptically and inoculated into peptone water and incubated at 37oC for 18 hours, then sub-cultured into Rappaport Vassiliadis broth and incubated at 42oC for 18 hours, and finally sub-cultured on MacConkey agar (MCA) and incubated at 37oC for 24 hours. Isolates were Gram stained and characterized phenotypically using standard biochemical tests such as citrate test, reaction on triple sugar iron agar, urease test, methyl red-Voges-Proskauer test, glucose and dulcitol fermentation and hanging drop motility test. Serotypes of the isolates were identified by slide agglutination test. Susceptibility of the isolates to 14 antimicrobial agents was carried out using the disc diffusion method. Antimicrobial resistance genes were assessed using polymerase chain reaction (PCR). Chi square was used to test association between resistance and the Salmonella serotypes. Significance was accepted at p < 0.05. Salmonella Gallinarum and Pullorum were isolated from 45(9.1%) and 5(1.0%) respectively of the chicken carcasses examined. Thirty-five (70%) of the 50 isolates exhibited resistance to at least one antimicrobial agent. Resistance to sulphamethoxazole/trimethoprim was the highest (58%), followed by ampicllin (46%) and enrofloxacin (40%) while the least resistance was to meropenem 3 (6%). Of the 35 resistant isolates, 26 (74.3%) were multidrug-resistant. Genes encoding aminoglycosides (aadA), quinolones (gyrA) and sulphamethoxazole (sul1) were detected in 1(3.3%), 26 (86.7%) and 28 (93.3%) respectively of the isolates analyzed.
Keywords: Isolation, Salmonella Gallinarum and Pullorum, Antibiotic sensitivity tests (AST) and antibiotic resistant genes detection.