title: Antimicrobial activity of gatifloxacin tested against 1676 strains of ciprofloxacin-resistant gram-positive cocci isolated from patient infections in North and South America.
abstract: Gatifloxacin (formerly AM-115) is a new 8-methoxy fluoroquinolone with an expanded spectrum against Gram-positive cocci and some anaerobes. To assess this new agent's activity, a collection of 1,676 Gram-positive cocci were selected for resistance to ciprofloxacin (> or = 4 micrograms/mL) and tested against gatifloxacin and 18 other compounds by reference broth microdilution methods. The strains (approximately 23,000 total isolates from the SENTRY Antimicrobial Surveillance Program) were from significant blood stream, respiratory tract, wound, and urinary tract infections in patients in North (38 hospitals) and South (10 hospitals) America. Against Enterococcus faecalis and E. faecium, gatifloxacin inhibited only 16% and 10% of strains compared with 12% and 5% for recently released trovafloxacin, respectively. Among Staphylococcus aureus (90% oxacillin-resistant) strains, gatifloxacin was more active (67% susceptible at < or = 4 micrograms/mL) than trovafloxacin (59%) or sparfloxacin (4%). Gatifloxacin had a wider spectrum than trovafloxacin against coagulase-negative staphylococci especially S. epidermidis, 2% versus 58% resistance. The glycopeptides, chloramphenicol and rifampin were most active. Against all genus/species groups with more than 100 sample strains (1,566), high-level resistance to gatifloxacin and trovafloxacin (> 4 micrograms/mL) was not significantly different (41.7% versus 39.1%; p > 0.05). Emerging resistance to the fluoroquinolones remains a clinical problem among Gram-positive species, and gatifloxacin seems to be active in vitro against many of these contemporary strains isolated in the Americas.
authors.affiliation: Department of Pathology, University of Iowa College of Medicine, Iowa City 52242, USA.
authors.forename: R N
authors.initials: RN
authors.lastname: Jones
authors.forename: M L
authors.initials: ML
authors.lastname: Beach
authors.forename: M A
authors.initials: MA
authors.lastname: Pfaller
authors.forename: G V
authors.initials: GV
authors.lastname: Doern
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology*; D000995:Antitubercular Agents / Q000494:pharmacology; D001431:Bacteriological Techniques; D002939:Ciprofloxacin / Q000494:pharmacology*; D004352:Drug Resistance, Microbial; D024841:Fluoroquinolones; D000077734:Gatifloxacin; D016908:Gram-Positive Bacterial Infections / Q000188:drug therapy / Q000382:microbiology*; D006095:Gram-Positive Cocci / Q000187:drug effects*; D006801:Humans; D008826:Microbial Sensitivity Tests; D009287:Naphthyridines / Q000494:pharmacology; D009656:North America; D015363:Quinolones / Q000494:pharmacology; D013020:South America
chemical_list: D000890:Anti-Infective Agents; D000995:Antitubercular Agents; D024841:Fluoroquinolones; D009287:Naphthyridines; D015363:Quinolones; D002939:Ciprofloxacin; C080163:trovafloxacin; D000077734:Gatifloxacin; C061363:sparfloxacin