title: Microbiological Cutoff Values: A Critical Issue in Phenotypic Antibiotic Resistance Assessment of Lactobacilli and Bifidobacteria.
abstract: The purpose of this study was to assess the antimicrobial resistance profiles of several strains of Lactobacillus and Bifidobacterium spp. of probiotic interest. The International Organization for Standardization method was used to determine the minimal inhibitory concentrations of the antibiotics recommended by the European Food Safety Authority (EFSA). As a result, some of the tested microorganisms showed a visible growth up to the microbiological cutoff values indicated by EFSA guidelines in 2012. We were not able to categorize these strains as susceptible or resistant on the basis of antimicrobial resistance phenotypic testing as EFSA document does not explicitly deal with such a phenotypic condition where strains grow at antibiotic concentrations up to the established cutoff value. Although a few strains have been analyzed for this study, our findings highlight a potential challenge in accurately determining the antibiotic resistance in specific strains relevant for human and animal health.
authors.affiliation: Istituto di Microbiologia, Università Cattolica del Sacro Cuore , Piacenza, Italy .
authors.forename: Justyna
authors.initials: J
authors.lastname: Połka
authors.affiliation: Istituto di Microbiologia, Università Cattolica del Sacro Cuore , Piacenza, Italy .
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Morelli
authors.affiliation: Istituto di Microbiologia, Università Cattolica del Sacro Cuore , Piacenza, Italy .
authors.forename: Vania
authors.initials: V
authors.lastname: Patrone
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001644:Bifidobacterium / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development; D003470:Culture Media / Q000737:chemistry; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D005060:Europe; D015870:Gene Expression; D005798:Genes, Bacterial; D017408:Guidelines as Topic; D007612:Kanamycin / Q000494:pharmacology; D007778:Lactobacillus / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development; D008826:Microbial Sensitivity Tests; D019936:Probiotics; D013307:Streptomycin / Q000494:pharmacology; D013752:Tetracycline / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D003470:Culture Media; D007612:Kanamycin; D013752:Tetracycline; D013307:Streptomycin
keywords: Bifidobacterium; Lactobacillus; MIC; antimicrobial resistance; cutoff values; probiotic