Evaluation of quinolone resistance in gram negative bacilli isolated from community- and hospital-acquired infections.

Objective: Gram negative bacilli are among the most important microbial agents involved in both hospital- and community-acquired infections. The quinolones are preferred antibacterial agents for the treatment of both community- and hospital-acquired urinary tract infections caused by gram negative bacilli because of their strong antibacterial effects, and because they can be administered both orally and parenterally. In this study, it was aimed to determine the sensitivity of gram negative bacteria isolated from both hospital- and community-acquired infections, to quinolones.

Materials And Methods: Bacterial strains used in this study were isolated from pathologic samples of patients who were treated in different clinics or who were admitted to the polyclinics of Atatürk University Research Hospitals. Susceptibility to ciprofloxacin, levofloxacin, ofloxacin and norfloxacin was assessed for all strains included in the study via the Kirby-Bauer disk diffusion method according to CLSI criteria.

Results: Of the 205 strains tested, 116 (56.5%) were from community-acquired infections, and 89 (43.5%) were from hospital-acquired infections. Resistance rates of community-origin strains against ciprofloxacin, ofloxacin and levofloxacin were 25%, whereas they were 26.7% against norfloxacin. Ciprofloxacin was the most effective quinolone (65.2%) against hospital-origin strains. E. coli was the most commonly isolated etiological agent from both community- and hospital-acquired infections.

Conclusion: In this study, resistance to quinolones was observed for gram negative bacilli isolated from both hospital- and community-acquired infections, with the exception of community-acquired Salmonella and Shigella. Thus, these drugs should not be used empirically in the treatment of infections caused by gram negative bacilli, and susceptibility test results should be considered when planning therapy.