EFFECT OF PROBIOTIC STRAINS OF LACTOBACILLUS SP. ON ENTEROPATHOGENIC ESCHERICHIA COLI O SEROGROUPS ISOLATED FROM CLINICAL SPECIMENS

Background and Aim:Enteropathogenic Escherichia coli (EPEC) are common intestinal pathogens of adults and young children. Many methods have been employed to control these bacteria, including the use of probiotic strains specially Lactobacillus species. The aim of this investigation was to evaluate the antagonistic influences of probiotic Lactobacillus species, including L. plantarum, L. acidophilus and L. casei on the enteropathogenic E.coli O serogroups.Methods:A total of 188 clinical specimens from E.coli bacteria were isolated from medical centers of Tehran and O serogroup profiles of each isolate were determined. The inhibitory influence of pure cultures and two pooled cultures supernatants of Lactobacillus strains on the growth of every serogroup of E.coli were assessed by the spot agar design and by monitoring turbidity.Results:The clinical specimens belonged to 11 serogroups of enteropathogenic E. coli including O18, O20, O26, O44, O86, O111, O112, O119, O125, O126 and O142. In non-neutralized culture, all of the strains and the pool of Lactobacillus strains were antagonistic towards serogroups O18, O20, O111, O125 and O126. Other microbial antagonism profiles were between 47% and 81%. The combination of Lactobacillus strains indicated greater inhibitory activity toward all E.coli serogroups than the individual media.Conclusion:All strains of Lactobacillus assessed in this study indicated bactericidal influences on enteropathogenic E.coli O serogroups. Thus, the strains of Lactobacillus studied could be employed as antibacterial supplements to control pathogenic bacteria such as enteropathogenic E.coli.

کلیدواژه ها:

Enteropathogenic E.coli ، Lactobacillus ، probiotic ، microbial antagonism