Inhibition of Legionella pneumophila in guinea pig peritoneal macrophages by new quinolone, macrolide and other antimicrobial agents.
The effect of 14 antimicrobial agents, including new quinolones and a new macrolide, on the intracellular multiplication of Legionella pneumophila in cultured guinea pig peritoneal macrophages was examined. Gentamicin and beta-lactam antibiotics did not inhibit the intracellular growth of L. pneumophila. Minocycline, erythromycin and DR-3355 inhibited multiplication at concentrations of 1, 0.5 and 0.1 mg/l respectively. Rifampicin, the new macrolide roxithromycin, and the new quinolones ofloxacin, ciprofloxacin and AT-4140 all inhibited the intracellular growth of L. pneumophila at concentrations of less than 0.03 mg/l. The minimal extracellular concentration inhibiting intracellular multiplication (MIEC), compared with conventional MIC measurements, provides a better indication of antimicrobial efficacy against bacteria, such as L. pneumophila, which can multiply in phagocytes.
Kitsukawa
K
K
First Department of Internal Medicine, Faculty of Medicine, University of the Ryukyus, Okinawa, Japan.
Hara
J
J
Saito
A
A
D042462:4-Quinolones; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D000890:Anti-Infective Agents / Q000494:pharmacology*; D006168:Guinea Pigs; D007875:Legionella / Q000187:drug effects* / Q000254:growth & development; D018942:Macrolides; D008264:Macrophages / Q000382:microbiology*; D008826:Microbial Sensitivity Tests; D010537:Peritoneum
D042462:4-Quinolones; D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D018942:Macrolides