title: Antibiotic susceptibility profile of bifidobacteria as affected by oxgall, acid, and hydrogen peroxide stress.
abstract: The effects of acid, oxgall, and H(2)O(2) on susceptibilities to antibiotics and nisin were examined for 13 strains of bifidobacteria. Susceptibilities to ampicillin, cloxacillin, penicillin, vancomycin, kanamycin, neomycin, paramomycin, streptomycin, chloramphenicol, erythromycin, tetracycline, and nisin A were assayed by a microdilution broth method. Acid-, oxgall- and H(2)O(2)-stressed variants were produced and assayed. Exposure to a pH of 2.0 for 60 min reduced susceptibilities to cloxacillin and nisin A but increased susceptibilities to ampicillin, vancomycin, aminoglycosides, chloramphenicol, and erythromycin in a strain-dependent manner. Exposure to oxgall (0.3%) for 90 min increased susceptibilities to cell wall-directed antibiotics and aminoglycosides but increased resistances to tetracycline and nisin A. Oxidative stress increased the susceptibilities of 70% of the strains to ampicillin and chloramphenicol, of 50% of the strains to cloxacillin and tetracycline, and of 40% of the strains to erythromycin but did not affect susceptibilities to vancomycin, kanamycin, and nisin A. This study shows that exposure of bifidobacteria to stressful conditions resembling those in the gastrointestinal tract may substantially modify their susceptibilities to antibiotics and may thus affect their probiotic capacities, especially when they are used for the management of intestinal infections and antibiotic-associated diarrhea.
authors.affiliation: Nutraceuticals and Functional Foods Institute (INAF), Université Laval, Québec, PQ, Canada, G1K 7P4.
authors.forename: E
authors.initials: E
authors.lastname: Kheadr
authors.forename: N
authors.initials: N
authors.lastname: Dabour
authors.forename: C
authors.initials: C
authors.lastname: Le Lay
authors.forename: C
authors.initials: C
authors.lastname: Lacroix
authors.forename: I
authors.initials: I
authors.lastname: Fliss
mesh_terms: D000143:Acids / Q000494:pharmacology*; D000667:Ampicillin / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001644:Bifidobacterium / Q000145:classification / Q000187:drug effects*; D002701:Chloramphenicol / Q000494:pharmacology; D003023:Cloxacillin / Q000494:pharmacology; D003470:Culture Media / Q000494:pharmacology; D024881:Drug Resistance, Bacterial; D004917:Erythromycin / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D009561:Nisin / Q000494:pharmacology; D010406:Penicillins / Q000494:pharmacology; D013045:Species Specificity; D013754:Tetracyclines / Q000494:pharmacology; D014640:Vancomycin / Q000494:pharmacology
chemical_list: D000143:Acids; D000900:Anti-Bacterial Agents; D003470:Culture Media; D010406:Penicillins; D013754:Tetracyclines; D009561:Nisin; D004917:Erythromycin; D002701:Chloramphenicol; D014640:Vancomycin; D000667:Ampicillin; D006861:Hydrogen Peroxide; D003023:Cloxacillin