Enhancement of antimicrobial activity of antibiotics by probiotics against Escherichia coli-An invitro study

Escherichia coli is the commonest organism responsible for urinary tract infection and diarrhoea specially in developing countries like India. Probiotic strains (Lactobacillus rhamnosus, Saccharomyces boulardii, Streptococcus faecalis and Lactobacillus acidophilus) are found to have antagonistic activity against E.coli (MTCC 443 and isolated human clinical strain). This study deals with enhancement of zone of antibiotics (Amoxicillin/clavulanate, Amikacin, Ceftazidime and Piperacillin/Tozobactum) by above mentioned Probiotic strains against E.coli Potentiation of antimicrobial activity of antibiotics by probiotic strains was investigated by using Kirby bauer disc diffusion method, keeping the antibiotic discs as positive control. Maximum zone enhancement was produced by Streptococcus faecalis in combination with Ceftazidime with the enhancement of zone by 24 mm and 18 mm against the MTCC and clinical strains of E.coli respectively. S.faecalis produced 14 mm enhancement in combination with Amoxicillin/Clavulanate against E.coli MTCC 443 followed by 10 mm by S.boulardii and L.rhamnosus in combination with Amoxicillin/Clavulanate against the E.coli (MTCC 443 and clinical strains). No enhancement was seen against probiotic strains and Piperacillin tozobactum combinations, while marginal enhancement was observed by Amoxicillin/Clavulanate in combination with the given probiotic strain. 75% tests showed enhancement of zone while in 21.87% tests zone diameter remained the same. Only 3.125% tests has shown decrease in zone diameter. The positive outcome of this study definitely indicates the therapeutic utility of the Probiotics.