Browsing by Subject "Weissella"

Lactic acid bacteria have a long history of use in food industry due to their favorable metabolic properties and health benefits for human health. Therefore, they are generally recognized as safe (GRAS) by FDA (U.S Food and Drug Administration) and have QPS (Qualified Presumption of Safety) status granted by EFSA (European Food Safety Authority). Nowadays, antimicrobial resistance (AMR) is a serious global risk and due to the increasing AMRs, more and more microbial infections have become more difficult to treat with antibiotics. AMR has mainly been of concern in relation to pathogenic microbes. However, since fermented foods are favorable environments for AMR gene transfer it should also be considered in the context of beneficial bacteria and their potential to spread AMR genes into pathogenic microbes. The aim of this study was to determine antibiotic susceptibilities of Lactobacillus plantarum, Lactobacillus rhamnosus, Leuconostoc sp. and Weissella sp. strains by E-test method and to detect selected specific antibiotic resistance genes by PCR. In addition, the goal was to define new cut-off values for Weissella strains since, so far, these have not been defined by EFSA. Antibiotic susceptibilities were determined against eight antibiotics: ampicillin, chloramphenicol, clindamycin, erythromycin, gentamicin, kanamycin, streptomycin and tetracycline. The detected AMR genes were blaZ, mecA, cat, lnuA, tetK and tetM. Most of the determined strains were observed to exhibit a notable resistance to kanamycin. Several Leuconostoc sp. and L. rhamnosus strains showed also resistance to chloramphenicol. Interestingly, one L. rhamnosus strain was observed to exhibit multiresistance to chloramphenicol and clindamycin. Moreover, 48% Leuconostoc strains had higher MIC value for streptomycin than the cut-off value defined by EFSA. Any of the selected AMR genes were not detected even though a notable resistance during the phenotypic testing was observed. However, this might be explained by the small amount of detected AMR genes. The results obtained in the present study provided more information about the antibiotic susceptibility and the safety of L. plantarum, L. rhamnosus, Leuconostoc sp. and Weissella sp. strains. Moreover, new cut-off values were proposed for Weissella sp. strains.