Antibiotic Susceptibility and Intestinal Epithelial Cell Adhesion Pattern of Homo Fermenting Lactic Acid Bacteria (LAB) Isolated from Kunu-Zaki, a Spontaneously Fermenting Nigerian Cereal Beverage

Aim: To determine the antibiotic reaction and adhesion pattern of antimicrobial homo-fermenting LAB strains in the fermenting slurries of kunu zaki.

Study Design: ANOVA. Inhibition of indicator lawn used ≥10mm inhibition as antibiotic susceptible. Adhesion was measured by staining and quantifying recorded as percentage and index values.

Place and Duration of Study: Department of Microbiology, Federal University of Technology Akure and Biotechnology Unit, Federal Institute of Industrial Research, Oshodi, Nigeria between June, 2012 and December, 2012.

Methodology: Kunu-zaki drinks were produced using spontaneously fermenting cereal grains of Digitaria exilis (acha), Sorghum bicolour (sorghum) and Pennisetum americanum (millet) in composite and non-composite proportions. LAB isolates were obtained on MRS agar. Homo-fermenting isolates were identified to species level using the API 50 CHL test kit. Antibiotic sensitivity testing on the identified isolates followed the modified standard Kirby-Bauer procedure on MRS agar (pH 7.4) using the disc diffusion technique with selected antibiotics. For quality control of the antibiotics, sensitive reference strains S. aureus ATCC 25923 and E. coli ATCC 25922 obtained from the Nigeria Institute of Medical Research were used. Adhesion and antimicrobial properties were determined using standard method.

Results: Antimicrobial substances produced by the eight LAB isolates inhibited the growth of four selected human pathogens in vitro. All eight LAB isolates were resistant to amoxicillin, gentamycin and ciprofloxacin. L. plantarum126, L. paracasei subsp paracasei339 and Pediococcus damnosus32 were resistant to erythromycin whilst all others were susceptible. L. plantarum126 and L. paracasei subsp paracasei339 were resistant to all antibiotics tested. All LAB isolates demonstrated high in-vitro intestinal epithelial cell adhesion potential.

Conclusion: LAB antimicrobial activity may not be affected if kunu zaki is consumed simultaneously with these antibiotic therapies. However, if these LAB strains are intended for use as kunu-zaki starter cultures, it is important that they should be further carefully examined for inability to transfer antibiotic resistance genes to food pathogens