Antibiotic susceptibility situation of environmental Legionella pneumophila isolates in Southern Germany.

Antimicrobial resistance is an emerging problem in hospitals and long-term healthcare facilities. Early detection of susceptibility pattern changes in pathogenic bacteria can prevent treatment failures. Therefore, this study chose to investigate the antibiotic susceptibility situation of Legionella pneumophila isolates from hospitals and long-term healthcare facilities in Southern Germany. Serogroups and minimal inhibitory concentrations (MICs) of nine antibiotics were determined from 41 L. pneumophila strains. In total, 28% of the collected strains belonged to the more pathogenic serogroup 1, whereas 72% belonged to serogroups 2-14. Among the tested antibiotics, rifampicin had the lowest MIC₉₀ value. The MIC₉₀ values can be summarized in the following order: rifampicin < levofloxacin < moxifloxacin < ciprofloxacin < clarithromycin < azithromycin < erythromycin < doxycycline < tigecycline.