Activities of Lactobacillus brevis and Lactobacillus pentosus Isolated from the Liquor of Fermented Maize (Omidun) against Diarrheal Escherichia coli and Salmonella typhi

Aim: This study investigated the antimicrobial activities of Lactobacillus brevis and Lactobacillus pentosusisolated from the liquor (“Omidun”) of fermented maize against Escherichia coli and Salmonella typhi.

Place and Duration of Study: Lagos State University, Microbiology Department, Microbiology Laboratory, between 2015 – 2016.

Study Design: The study is an original experimental research paper.

Methods: Eight L. brevis and 6 L. pentosus strains were isolated from the liquor of 72 h fermented maize and identified using standard biochemical techniques including the Analytical Profile Index (API 50CHL). Cell – free extracts of the isolates were obtained by centrifugation at 9000 rpm for 25 minutes, followed by filtration using Millipore filter. Sensitivity of the test bacteria; E. coli and S. typhi to the cell – free extracts and selected antibiotics was determined using the agar diffusion technique.

Results: Cell – free extracts of the L. brevis and L. pentosus inhibited the growth of E. coli and S. typhi with zones of inhibition ranging from 21 – 24 mm and 16 – 25 mm respectively. The lactobacilli exerted greater inhibitory effect on S. typhi with greatest inhibition zones (IZ) of 25 (by L. pentosus CI1) and 24 mm (by L. brevis CI1) respectively than E. coli with greatest IZ of 18 (by L. pentosus CI1) and 22 mm (by L. brevis CI1) respectively. Both E. coli and S. typhi were susceptible to tetracycline with IZ of 20mm and 24mm respectively but resistant to co-trimoxazole, augmentin, nitrofurantoin and gentamicin and exhibited intermediate resistance to amoxicillin, pefloxacin, clotrimazole and ofloxacin. Escherichia coli exhibited intermediate resistance to ciprofloxacin (IZ = 16 mm) while S. typhi was resistant (IZ = 18 mm).

Conclusion: This study indicated that L. brevis and L. pentosus associated with liquor of fermented maize could be sources of antimicrobial metabolites which can be formulated into natural antidiarrheal products.