Bactericidal activity of antibiotics against Legionella micdadei (Pittsburgh pneumonia agent).
The bactericidal activity of five antibiotics for Legionella micdadei was determined by the construction of time-kill curves. Erythromycin, rifampin, penicillin G, cephalothin, and gentamicin were bactericidal for L. micdadei at readily achievable concentrations. The minimal bactericidal concentrations, defined as those producing 99.9% killing within 24 h, were: erythromycin, 4.6; rifampin, 0.13; penicillin G, 0.25; cephalothin, 2.5; and gentamicin, 0.25 micrograms/ml. The ratios of the minimal bactericidal to minimal inhibitory concentrations for these antibiotics ranged from 1 to 8. Thus, the poor in vivo activity of beta-lactam and aminoglycoside antibiotics against L. micdadei cannot be ascribed to a lack of killing by these agents.
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002512:Cephalothin / Q000008:administration & dosage / Q000494:pharmacology; D004917:Erythromycin / Q000008:administration & dosage / Q000494:pharmacology; D005839:Gentamicins / Q000008:administration & dosage / Q000494:pharmacology; D007875:Legionella / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D010400:Penicillin G / Q000008:administration & dosage / Q000494:pharmacology; D010403:Penicillin Resistance; D012293:Rifampin / Q000008:administration & dosage / Q000494:pharmacology
D000900:Anti-Bacterial Agents; D005839:Gentamicins; D004917:Erythromycin; D010400:Penicillin G; D002512:Cephalothin; D012293:Rifampin