Affiliation:
1. College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University
2. Department of Clinical Pathology and Research Institute of Bacterial Resistance, Yonsei University College of Medicine
3. Department of Life Science, The University of Seoul Seoul
4. School of Life & Food Sciences, Handong Global University, Pohang, Korea
Abstract
ABSTRACT
We determined the macrolide resistance phenotypes of 241 clinical isolates of erythromycin-resistant enterococci (MICs, ≥1 μg/ml), including 147
Enterococcus faecalis
strains and 94
Enterococcus faecium
strains, collected from a hospital in Seoul, Korea, between 1999 and 2000. By the erythromycin (40 μg)-josamycin (100 μg) double-disk test, 93 strains were assigned to the constitutive macrolide, lincosamide, and streptogramin B (MLS
B
) resistance (cMLS
B
) phenotype, and the remaining 148 strains were assigned to the inducible MLS
B
resistance (iMLS
B
) phenotype. Of the strains with the iMLS
B
phenotype, 36 exhibited a reversibly inducible MLS
B
(riMLS
B
) phenotype, i.e., blunting of the erythromycin zone of inhibition, which indicates that the 16-membered-ring macrolide josamycin is a more effective inducer than the 14-membered-ring macrolide erythromycin. Sequence analysis of the regulatory regions of the
erm
(B) genes from all of the strains exhibiting the riMLS
B
phenotype revealed not only
erm
(Bv) [where v represents variant; previously
erm
(AMR)] (
n
= 13), as reported previously, but also three kinds of
erm
(B) variants, which were designated
erm
(Bv1) (
n
= 17),
erm
(Bv2) (
n
= 3), and
erm
(Bv3) (
n
= 3), respectively. In
lacZ
reporter gene assays of these variants, the 16-membered-ring macrolide tylosin had stronger inducibility than erythromycin at ≥0.1 μg/ml. These findings highlight the versatility of
erm
(B) in induction specificity.
Publisher
American Society for Microbiology
Subject
Infectious Diseases,Pharmacology (medical),Pharmacology
Cited by
29 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献