ASSESSMENT OF PHYSIOLOGICAL PROPERTIES OF SOME LACTIC ACID BACTERIA ISOLATED FROM THE INTESTINE OF CHICKENS USE AS PROBIOTICS AND ANTIMICROBIAL AGENTS AGAINST ENTEROPATHOGENIC BACTERIA

The aim of the present study was to isolate lactic acid bacteria able to produce antibacterial compounds from healthy chicken intestine against enteropathogenic bacteria. Isolates were characterized morphologically and biochemical tests were carried out for identification. The agar diffusion method was used to evaluate the antimicrobial activities. Growth with bile salts and resistance to acidic pH were tested in broth medium. Susceptibility to antibiotics was also tested. Fifteen strains were isolated and characterized. All the strains proved to tolerate bile salts at concentration of 0.4% and only three strains were resistant to pH 3.0. The antimicrobial test showed that all the lactic acid bacteria isolates provide an antimicrobial activity against Enterococcus faecalis, Escherichia coli, Salmonella arizonae, Enterococcus avium and Enterococcus casseliflavus. The isolates were resistant to trimethoprim, cefixim and erythromycin and susceptible to chloramphenicol, amoxicillin/clavulanic acid and tetracyclin. Among all the isolates, three strains Enterococcus faecium 1LC, Lactococcus cremoris NPL and Pediococcus spp. L4 were selected for several properties, tolerance to acid, bile salts and susceptibility to antibiotics. Selected strains were the most promising that may be useful as probiotic adjunct in poultry.