title: In vitro activities of rifamycin derivatives ABI-1648 (Rifalazil, KRM-1648), ABI-1657, and ABI-1131 against Chlamydia trachomatis and recent clinical isolates of Chlamydia pneumoniae.
abstract: ABI-1648 (rifalazil) is a semisynthetic rifamycin with potent bactericidal activity against intracellular respiratory bacteria, including Mycobacterium tuberculosis, and a long half-life (approximately 60 h) and thus can be administered once weekly. We therefore tested the in vitro activities of ABI-1648, its derivatives ABI-1657 and ABI-1131, azithromycin, and levofloxacin against 10 strains of Chlamydia trachomatis and 10 recent clinical isolates of Chlamydia pneumoniae. The MICs at which 90% of the isolates were inhibited and the minimal bactericidal concentration at which 90% of the isolates were killed for ABI-1648, ABI-1657, and ABI-1131 were 0.0025 micro g/ml for C. trachomatis and 0.00125 to 0.0025 micro g/ml for C. pneumoniae. ABI-1648, ABI-1657, and ABI-1131 were 10- to 1,000-fold more active than azithromycin and levofloxacin.
authors.affiliation: Division of Infectious Diseases, Department of Pediatrics, State University of New York Downstate Medical Center, Brooklyn 11203-2098, USA.
authors.forename: Patricia M
authors.initials: PM
authors.lastname: Roblin
authors.forename: Tamara
authors.initials: T
authors.lastname: Reznik
authors.forename: Andrei
authors.initials: A
authors.lastname: Kutlin
authors.forename: Margaret R
authors.initials: MR
authors.lastname: Hammerschlag
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D000890:Anti-Infective Agents / Q000494:pharmacology; D000904:Antibiotics, Antitubercular / Q000494:pharmacology*; D017963:Azithromycin / Q000494:pharmacology; D002690:Chlamydia Infections / Q000382:microbiology; D002692:Chlamydia trachomatis / Q000187:drug effects*; D016993:Chlamydophila pneumoniae / Q000187:drug effects*; D006801:Humans; D064704:Levofloxacin; D008826:Microbial Sensitivity Tests; D015242:Ofloxacin / Q000494:pharmacology; D012294:Rifamycins / Q000494:pharmacology*
chemical_list: C476339:ABI 1131; C476338:ABI 1657; D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D000904:Antibiotics, Antitubercular; D012294:Rifamycins; C068980:KRM 1648; D064704:Levofloxacin; D017963:Azithromycin; D015242:Ofloxacin