Detection and characterization of Salmonella enterica in the gut and liver of Clarias gariepinus obtained from main fish market in Ilorin, Kwara State, Nigeria

Document Type : Original Article


1 Department of Aquaculture and Fisheries, Faculty of Agriculture, University of Ilorin, Ilorin, Nigeria

2 Department of Veterinary Microbiology, Faculty of Veterinary Medicine, University of Ilorin, Ilorin, Nigeria

3 Department Aquaculture and Fisheries, Faculty of Agriculture, University of Ilorin, Ilorin, Nigeria

4 Department of Aquaculture and Fisheries Management, Faculty of Renewable Natural Resources, University of Ibadan, Ibadan, Nigeria


Background:  Salmonella is an important foodborne pathogen prevalent in human and aquatic environments. However, identifying its source has been challenging, particularly in developing countries. This study aimed to detect the presence of Salmonella in fish sold at Ilorin's primary fish market in Kwara State, Nigeria. Methods: A total of 60 gut samples were collected from 60 Clarias gariepinus specimens at the major fish markets in Ilorin. Standard bacteriological procedures were employed to isolate and identify Salmonella. The isolates were subsequently confirmed genotypically through partial genome sequencing of the 16S rRNA gene. A phylogenetic tree was constructed using the sequences of the isolates and reference strains from the gene bank. Results: Among the collected samples, 11 were presumptively positive for Salmonella, but molecular confirmation revealed that 6 of them were indeed Salmonella enterica, resulting in a detection rate of 10 %. The remaining presumptive isolates were molecularly confirmed as Lysinibacillus macrolides, Proteus terrae, Enterobacter hormaechei, and Alcaligenes faecalis; most of which belong to the Enterobacteriaceae family, similar to Salmonella. Conclusion: The detection of Salmonella in the fish specimens sold at the market poses a substantial risk to public health. Therefore, implementing targeted interventions to control its prevalence is highly recommended.


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