The frequency of BRO β-lactamase and its relationship to antimicrobial susceptibility and serum resistance in Moraxella catarrhalis.

We investigated the frequency of BRO β-lactamase and its relationship to antibiotic susceptibility profiles and serum susceptibility. Moraxella catarrhalis clinical isolates (n = 197) were collected from patients with respiratory tract infections in Tokyo between November 2004 and April 2005. Phenotypic and genotypic detection of β-lactamases was performed. The MICs of 6 antibiotics were determined by Etest, and the serum bactericidal assay was conducted by using the culture-and-spot test. Nearly all (192; 97%) of the clinical isolates were β-lactamase producers; of these, 182 (95%) were bro-1 and 10 (5%) were bro-2 positive. MIC50, MIC90, and geometric mean MICs of penicillin, amoxicillin, cefixime, and clarithromycin for BRO-1 isolates were significantly higher than for BRO-2 isolates. The frequency of intermediate and full serum resistance was significantly higher in BRO-1 isolates than in BRO-2 isolates (P = 0.0056), but not BRO-negative isolates (P = 0.1333). We provide the first evidence that the presence of BRO-1 in M. catarrhalis is associated with reduced susceptibility to clarithromycin and β-lactam antibiotics, as well as serum non-sensitive (intermediate and resistant). Copyright © 2013 Japanese Society of Chemotherapy and the Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Citation

Ryoichi Saito, Shotaro Nonaka, Yuji Fujinami, Shiho Matsuoka, Shinichi Nakajima, Hiroyuki Nishiyama, Noboru Okamura. The frequency of BRO β-lactamase and its relationship to antimicrobial susceptibility and serum resistance in Moraxella catarrhalis. Journal of infection and chemotherapy : official journal of the Japan Society of Chemotherapy. 2014 Jan;20(1):6-8

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PMID: 24462416

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