The epidemiology of bacterial resistance to quinolones

The new fluoroquinolones have been in use for nearly 10 years in the treatment of community- and nosocomially-acquired infections. Resistant clones may be selected during therapy and disseminate if favourable epidemiological conditions prevail. Resistance to the fluoroquinolones is still rare in common pathogens with 97 to 100% of strains remaining susceptible. Resistance has been reported in methicillin-susceptible Staphylococcus aureus, Campylobacter jejuni/coli, Salmonella, Shigella and Escherichia coli. Among nosocomial pathogens, the incidence of fluoroquinolone resistance varies between bacterial species, countries and periods of study, and is dependent on local epidemiological factors and antibiotic policies. The highest incidence of resistance is observed in Serratia and Acinetobacter spp., and particularly in methicillin-resistant S. aureus. Surveillance programmes are needed to follow up trends in resistance to the fluoroquinolones and their possible association with clinical failures.