title: Comparison of the CLSI guideline and ISO/IDF standard for antimicrobial susceptibility testing of Lactobacilli.
abstract: Lactobacilli play a crucial role as probiotics and as starter cultures in the production of fermented foods. Although lactobacilli are a technologically useful and beneficial group of bacteria, a few members of them have been rarely correlated with bacterial infections. Correspondingly, clinicians are interested in the antimicrobial susceptibility of lactobacilli. In addition, antimicrobial susceptibility testing (AST) is also relevant for commercially applied lactobacilli as bacterial strains harboring transferable antibiotic resistance genes should not be used in fermented and probiotic foods. Therefore, two methods were developed by different organizations, which were compared within this study. For this purpose, 22 Lactobacillus-type strains were tested for their antimicrobial susceptibility to 16 antibiotics following the procedures of the Clinical and Laboratory Standards Institute (CLSI) and the International Organization of Standardization (ISO)/International Dairy Federation (IDF). Crucial discrepancies between both procedures were detected mainly due to the different AST media. Hence, half of the strains tested did not consistently grow in the CLSI medium, whereas all showed evaluable growth in the ISO/IDF medium. However, some antibiotics were influenced by the latter medium. In particular, low levels of essential agreement between both methods were obtained with seven antibiotics. Accordingly, different interpretative criteria are needed for both procedures to distinguish resistant from susceptible strains.
authors.affiliation: Institute of Food Science, Department of Food Science and Technology, BOKU-University of Natural Resources and Life Sciences , Vienna, Austria .
authors.forename: Sigrid
authors.initials: S
authors.lastname: Mayrhofer
authors.forename: Ulrike
authors.initials: U
authors.lastname: Zitz
authors.forename: Firew H
authors.initials: FH
authors.lastname: Birru
authors.forename: Dagmar
authors.initials: D
authors.lastname: Gollan
authors.forename: Aleksandra K
authors.initials: AK
authors.lastname: Gołoś
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Kneifel
authors.forename: Konrad J
authors.initials: KJ
authors.lastname: Domig
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004352:Drug Resistance, Microbial / Q000187:drug effects*; D016908:Gram-Positive Bacterial Infections / Q000188:drug therapy; D007778:Lactobacillus / Q000187:drug effects*; D008826:Microbial Sensitivity Tests / Q000379:methods
chemical_list: D000900:Anti-Bacterial Agents