Safety assessment of Lactic acid bacteria isolated from Iranian traditional fermented camel milk (Chal)

BACKGROUND AND OBJECTIVESFAO/WHO defines probiotics as live microorganisms, when administered in adequate amounts confer a health benefit on the host. There is a decade debate on the health benefits of probiotics but because of the history of use they are generally considered safe. However, there are concerns over infectious disease caused by lactobacilli in patients with underlying diseases and emergence of vancomycin resistant enterococci (VRE) which could cause infection in hospitalized patients. Recently, FAO/WHO has published a draft guideline for evaluations of probiotics which includes safety assessment and functional characterization. The working group suggested a few tests to consider the microorganisms as safe, the most important of which was determination of antibiotic resistance patterns. In this research, potential probiotic strains including lactobacilli, enterococci, leuconostoc and weissella isolated from Iranian traditional fermented camel milk (Chal) were assessed for the incidence of virulence determinants, antibiotic susceptibility, and virulence phenotypes.MATERIALS AND METHODSTotal DNA of the ۱۱ LAB strains was used to detect the presence of virulence genes, including gelE, efaAfm, efaAfs, ace, espfs, cylM, cylA andcylB using specific primers and PCR method. Antibiotic susceptibility was determined by commercially antibiotic-containing disks. Gelatinase, decarboxylase and hemolytic activities were determined using the phenotypic methods.RESULTS AND DISCUSSIONCylB, gelE and efaAfs were the most frequent genes identified in the strains. No β-hemolytic activity was observed while tyrosine decarboxylase activity and gelatinase production were observed in enterococcus and leuconostoc strains. Five out of ۱۱ strains were resistant to both kanamycin and vancomycin.CONCLUSIONThe results of this study suggested that according to the potential risk factors, traditional fermented foods need safety assessments in order to investigate their bacterial strains for harboring the virulence genes and transmissible resistance against antibiotics.