Antibiotic Resistance in 'Lactobacillus Reuteri' and 'Lactobacillus Plantarum'

摘要

Lactic acid bacteria (LAB) may act as reservoirs of antibiotic resistance genes that can be transferred via the food chain or within the gastrointestinal tract to pathogenic bacteria. This thesis provides data required for assessing the potential risk of using antibiotic resistant strains of the LAB species Lactobacillus reuteri and Lactobacillus plantarum as food processing aids or probiotics. Knowledge of the distributions of antibiiotic minimum inhibitory concentrations (MICs) for a species is needed when using a phenotypic method to differentiate strains with acquired resistance from susceptible strains or strains with intrinsic resistance. Controlled and standardised conditions are required for antibiotic susceptibility testing of LAB, as demonstrated here during evaluation of the Etest and broth microdilution MIC determination methods used. Inoculum size and incubation time were varied during broth microdilution testing of the susceptibilities of 35 LAB strains to six antibiotics. An increase in either parameter resulted in elevated MICs for all species.