Susceptibility of ninety-eight clinical isolates of Legionella to macrolides and quinolones using the Etest.

Isolates of Legionella from 98 patients with Legionnaires' disease hospitalized in Columbus, Ohio, USA between 1991 through 1995 were tested for antimicrobial susceptibility to macrolides and quinolones using the Etest. Most (87%) isolates were Legionella pneumophila serogroup 1. All isolates tested remain susceptible to erythromycin, azithromycin, clarithromycin, ciprofloxacin, ofloxacin, and levofloxacin. In vitro susceptibility testing of Legionella to representative macrolides and quinolones should be considered to detect the emergence of resistant isolates.