title: Genetic analyses of the antibiotic resistance of Bifidobacterium bifidum strain Yakult YIT 4007.
abstract: Bifidobacterium bifidum strain Yakult YIT 4007 (abbreviated as B. bifidum YIT 4007) is a commercial strain and resistant to erythromycin, neomycin, and streptomycin. Resistances to these antibiotics were endowed by sequential isolation of resistant mutants from its susceptible progenitor strain YIT 4001. Comparison of nucleotide sequences of various candidate genes of both strains led us to find that B. bifidum YIT 4007 had mutations on three copies of 23S ribosomal RNA genes, an 8 bp deletion of the rluD gene for pseudouridine synthase, and a mutation on the rpsL gene for ribosomal protein S12. The responsibility of these mutations to antibiotic resistances was supported by analyses of newly isolated mutants resistant to these antibiotics. The antibiotic resistances of B. bifidum YIT 4007 were evidently acquired by mutations of the structural genes on the chromosome and not associated with mobile genetic elements like insertion sequences, phages, and plasmids.
authors.affiliation: Yakult Central Institute for Microbiological Research, 1796 Yaho, Kunitachi, Tokyo 186-8650, Japan. takashi-sato@yakult.co.jp
authors.forename: Takashi
authors.initials: T
authors.lastname: Sato
authors.forename: Tohru
authors.initials: T
authors.lastname: Iino
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics; D001644:Bifidobacterium / Q000187:drug effects* / Q000235:genetics; D004252:DNA Mutational Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D024881:Drug Resistance, Bacterial; D004917:Erythromycin / Q000494:pharmacology*; D020459:Genes, rRNA; D019751:Intramolecular Transferases / Q000235:genetics; D008969:Molecular Sequence Data; D009355:Neomycin / Q000494:pharmacology*; D017354:Point Mutation; D012269:Ribosomal Proteins / Q000235:genetics; D017422:Sequence Analysis, DNA; D017384:Sequence Deletion; D013307:Streptomycin / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D012269:Ribosomal Proteins; C034212:ribosomal protein S12; D004917:Erythromycin; D019751:Intramolecular Transferases; C096995:pseudouridine synthases; D009355:Neomycin; D013307:Streptomycin