ISOLATION AND CHARACTERISATION OF STENOTROPHONOMAS SPECIES ASSOCIATED WITH FRESH FISH SOLD IN BENIN CITY

The increasing incidence of foodborne pathogens associated with fresh fish has raised public health concerns, particularly in developing regions where hygiene practices during fish handling and storage are often suboptimal. Stenotrophomonas species, known for their multidrug resistance and opportunistic pathogenicity, have been detected in various aquatic environments, but their prevalence in fresh fish markets in Benin City, Nigeria, remains understudied This study focused on the isolation and characterization of Stenotrophomonas species associated with fresh fish in, Benin City, Nigeria. Fresh fish samples were aseptically collected from various markets across Benin City using sterile techniques. Swabs were taken from the gills, skin, and intestines of the fish and cultured using nutrient media enriched with methionine. Preliminary identification of isolates was based on colonial morphology, Gram staining, and a series of biochemical tests such as catalase, oxidase, and citrate reactions. Colonies showing characteristic morphology of Stenotrophomonas were further subjected to Gram staining and biochemical tests including catalase, citrate, methyl red, motility, urease, and indole tests. The isolates were predominantly Gram-negative, catalase-positive, and motile rods. A total of 13 bacteria species isolated and presumptively identified then all the selected isolates were resistant to Imipenem. The presence of Stenotrophomonas species in fresh fish indicates potential spoilage and public health concerns. These bacteria can produce enzymes that degrade fish tissues, leading to quality deterioration. Furthermore, some Stenotrophomonas species are opportunistic pathogens and can cause infections in humans, particularly in immunocompromised individuals. The findings highlight the importance of implementing proper hygiene practices during fish handling, processing, and storage to minimize the risk of contamination and spoilage. Further research is needed to investigate the specific mechanisms of spoilage caused by these bacteria and to develop effective strategies for their control in the fish industry. The ecological, agricultural, public health and economic significance of these bacteria highlights the need for continued surveillance, particularly in regions like Nigeria where data is still limited. he presence of multidrug-resistant Stenotrophomonas spp. in fresh fish highlights potential risks to consumers, particularly immunocompromised individuals. Contamination likely arises from polluted water sources, unhygienic handling, or post-harvest storage conditions. These findings underscore the need for improved hygiene practices in fish markets and regular surveillance of antibiotic-resistant bacteria in food products. Further studies should investigate virulence genes and plasmid-mediated resistance mechanisms in these isolates to guide public health interventions.