Evaluation of Microbial Pathogens in Biofilms of Deteriorating Fish in Ogun State, South-Western Nigeria

Abstract

The experiment was carried out to identify bacteria pathogens that causes fish spoilage and consequently reduces their shelf-life in the environment and invariably found out basis for controlling and preventing their activity. Thirty fish samples comprising of fifteen Titus (Scomber scombrus) and fifteen Kote (Trachurus trachurus) were collected from five major markets in Ogun state, Nigeria. Samples were cultured and processed using the pour plate and streak plate technique. Samples from the skin scrapings were cultured in five media consisting of four selective media and a basal media; Maconkey agar, Eosin Methylene Blue agar, Mannitol Salt agar, Salmonella Shigella agar and Nutrient agar. Differentiation and isolation of various isolates were based on gram-staining technique and biochemical reactions using OXOID MICROBACT^TM identification kits. On examination, in vitro assay showed the presence of six bacteria species in the surface biofilms namely; Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, Salmonella typhi, Proteus vulgaris and Proteus stuartii. Prevalence of the various isolates in the culture were found to be 25.2%, 20.6%,18.7%, 14.9%, 11.2% and 9.3% respectively. The highest colony count (140) was obtained from samples obtained from Ijebu-Ode while the lowest colony count was obtained from Sagamu. The mean bacteria load of the isolates was 7x10⁶ CFU ml^-1. The high microbial load in biofilms of the samples obtained from the market especially those of enteric bacteria showed the need for enforcement of high hygiene standards for food handlers and food storage companies.