Abstract

Adenike A. O. Ogunshe and Olalekan P. Olabode

This study tries to evaluate the ability of L. fermentum LbFF4 isolated from Nigerian fermented food (fufu) and L. plantarum LbOG1 from a beverage (ogi), to inhibit some fish bacterial pathogens (Citrobacter, Enterobacter, Escherichia coli, Klebsiella, Proteus, Pseudomonas and Salmonella species) under in vitro conditions. Overall phenotypic antibiotic resistance of 124 Gram-negative bacterial isolates obtained from the gut contents of cat fish, Clarias gariepinus, using agar disc-diffusion method, indicated very high resistance to amoxicillin (88.8%), augmentin (85.1%), cotrimoxazole (80.6%), tetracycline (72.3%), gentamicin (61.9%) and nalidixic acid (57.5%). Multiple antibiotic resistance (MAR) of 37.5 - 87.5% were also recorded. None of the forty four Lactobacillus strains (L. brevis, L. delbruekii, L. fermentum, L. plantarum and L. reuterii) isolated from the gut contents of C. gariepinus was inhibitory in vitro towards the Gram-negative bacterial species. However, L. fermentum LbFF4 and L. plantarum LbOG1 exhibited in vitro antibacterial activities against 41.1 and 47.6% of the Gram- negative bacterial species respectively. The susceptibility patterns of the indicator pathogens using the probiotic candidates were significant. The potential probiotic candidates were able to survive relatively low pH (3.5 - 5.5) and the fish bile. This study therefore, signifies that lactobacilli-based probiotic candidates from Nigerian fermented foods and beverages can serve as adjunct, inhibitory food-supplements in the control of bacterial fish-borne pathogens of C. gariepinus.