title: Intraphagocytic killing of gram-positive bacteria by ciprofloxacin.
abstract: The intraphagocytic killing of Staphylococcus aureus, Streptococcus pyogenes, and Corynebacterium group D2 by ciprofloxacin (0.1, 1 and 5 mg/L) within human neutrophils was determined. The organisms showed different susceptibility to neutrophil killing mechanisms. The neutrophils with intact and impaired (by phenylbutazone treatment) O2-dependent killing mechanisms were studied. The minimum concentrations of ciprofloxacin to kill 90% of phagocytosed bacteria within untreated neutrophils after 2 h were 1 mg/L for S. aureus and Corynebacterium group D2, and 0.1 mg/L for S. pyogenes. In contrast, exposure for 3 h was required to achieve similar cidal effects within phenylbutazone treated neutrophils. Synergic interaction between ciprofloxacin and the O2-dependent mechanisms of phagocytes was found. The reactive oxygen metabolites produced in the respiratory burst did not affect the intraphagocytic activity of ciprofloxacin. Phenylbutazone treatment of phagocytes would be a good experimental model to study intraphagocytic killing by drugs in situations where the oxidative mechanisms of neutrophils are impaired (for example AIDS and chronic granulomatous disease).
authors.affiliation: Servicio de Microbiologia, Hospital Universitario La Fe, Valencia, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Pemán
authors.forename: E
authors.initials: E
authors.lastname: Cantón
authors.forename: M T
authors.initials: MT
authors.lastname: Hernández
authors.forename: M
authors.initials: M
authors.lastname: Gobernado
mesh_terms: D016923:Cell Death / Q000187:drug effects; D002939:Ciprofloxacin / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D006094:Gram-Positive Bacteria / Q000187:drug effects* / Q000276:immunology; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000706:statistics & numerical data; D009504:Neutrophils / Q000187:drug effects / Q000378:metabolism / Q000382:microbiology; D010586:Phagocytes / Q000378:metabolism / Q000382:microbiology; D010587:Phagocytosis / Q000187:drug effects*; D010653:Phenylbutazone / Q000494:pharmacology
chemical_list: D002939:Ciprofloxacin; D010653:Phenylbutazone