Affiliation:
1. Department of Pathology, Hershey Medical Center, Hershey, Pennsylvania 17033,1 and
2. Department of Pathology, Case Western Reserve University, Cleveland, Ohio 441062
Abstract
ABSTRACT
MICs, time-kills, and postantibiotic effects (PAEs) of ABT-773 (a new ketolide) and 10 other agents were determined against 226 pneumococci. Against 78
ermB
- and 44
mefE
-containing strains, ABT-773 MICs at which 50% of the isolates tested were inhibited (MIC
50
s) and MIC
90
s were 0.016 to 0.03 and 0.125 μg/ml, respectively. Clindamycin was active only against macrolide-resistant strains containing
mefE
(MIC
50
, 0.06 μg/ml; MIC
90
, 0.125 μg/ml). Activities of pristinamycin (MIC
90
, 0.5 μg/ml) and vancomycin (MIC
90
, 0.25 μg/ml) were unaffected by macrolide or penicillin resistance, while β-lactam MICs rose with those of penicillin G. Against 19 strains with L4 ribosomal protein mutations and two strains with mutations in domain V of 23S rRNA, ABT-773 MICs were 0.03 to 0.25 μg/ml, while macrolide and azalide MICs were all ≥16.0 μg/ml. ABT-773 was bactericidal at twice the MIC after 24 h for 8 of 12 strains (including three strains with erythromycin MICs greater than or equal to 64.0 μg/ml). Kill kinetics of erythromycin, azithromycin, clarithromycin, and roxithromycin against macrolide-susceptible strains were slower than those of ABT-773. ABT-773 had longer PAEs than macrolides, azithromycin, clindamycin, or β-lactams, including against
ermB
-containing strains. ABT-773, therefore, shows promising in vitro activity against macrolide-susceptible as well as -resistant pneumococci.
Publisher
American Society for Microbiology
Subject
Infectious Diseases,Pharmacology (medical),Pharmacology
Cited by
42 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