title: Clarithromycin Resistance Mechanisms of Epidemic β-Lactamase-Nonproducing Ampicillin-Resistant Haemophilus influenzae Strains in Japan.
abstract: The aim of this study was to clarify the clarithromycin resistance mechanisms of β-lactamase-nonproducing ampicillin-resistant Haemophilus influenzae strains. In all clarithromycin-resistant strains, the transcript level of acrB was significantly elevated, and these strains had a frameshift mutation in acrR Introduction of the acrR mutation into H. influenzae Rd generated a clarithromycin-resistant transformant with the same MIC as the donor strain. Our results indicate that the acrR mutation confers clarithromycin resistance by the increasing the transcription of acrB.
authors.affiliation: Department of Microbiology, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan.
authors.forename: Shoji
authors.initials: S
authors.lastname: Seyama
authors.affiliation: Department of Microbiology, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan.
authors.forename: Takeaki
authors.initials: T
authors.lastname: Wajima
authors.affiliation: Department of Microbiology, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan.
authors.forename: Hidemasa
authors.initials: H
authors.lastname: Nakaminami
authors.affiliation: Department of Microbiology, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan noguchin@toyaku.ac.jp.
authors.forename: Norihisa
authors.initials: N
authors.lastname: Noguchi
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D017291:Clarithromycin / Q000494:pharmacology*; D006193:Haemophilus influenzae / Q000187:drug effects* / Q000201:enzymology*; D007564:Japan; D008826:Microbial Sensitivity Tests; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D001618:beta-Lactamases; D017291:Clarithromycin