Antibiotic spectrum of characterized Lactic Acid Bacteria obtained fromdomestic Dahi samples

From forty lactic acid bacterial isolates obtained from fifteen domestic dahi samples of dahi, thirteen were found to possess probiotic characteristics such as acid and bile tolerance . These acid and bile tolerant lactobacilli isolates further, were identified phenotypically and genotypically as Lb.rhamnosus (5 Nos). Lb. fermentum (3 Nos), Lb. plantarum (3 Nos) and Lb. delbrueckii ssp. bulgaricus (2 Nos). The identified cultures were subjected for the antibiotic test using the disc diffusion technique against Penicillin (10µg), Gentamycin (10µg), Streptomycin (10µg), Chloramphinicol (10µg), Kanamycin (30µg) Erythtomycin (15µg) and Bacitracin (10 µg). All the five strains of Lb.rhamnosus strains were susceptible to all the seven antibiotics tested as they showed more than 10 mm diameter inhibitory zone. Similarly all the three strains of Lb.plantarum, Lb.fermentum and Lb.delbruckii ssp. bulgaricus were susceptible to all the antibiotics to varying degrees. In this study the results clearly demonstrate the susceptible nature of the probiotic Lactobacilli isolates against the commonly used antibiotics.