[Comparative epidemiology of the resistance of enterobacteriaceae, Staphylococcus and Pseudomonas aeruginosa to fluoroquinolones in an outpatient study].

Since the clinical introduction of fluoroquinolones in general practice for the treatment of a wide range of infections, we have carried out an annual survey of the susceptibilities of Enterobacteriaceae, Staphylococcus and Pseudomonas aeruginosa isolated from domiciliary infections to quinolones (nalidixic acid and ofloxacin) as well as to amoxycillin, co-amoxyclav and co-trimoxazole.From 1990 to 1993, within the same three month period of the year, a total of 1750 strains were collected at three private clinical laboratories in greater Paris. The in vitro activities of antibiotics were evaluated using the standard disc-diffusion test. MICs of ofloxacin were determined for all intermediate and resistant strains.Resistance to quinolones remained unchanged during this four year period. Among Enterobacteriaceae, less than 3% of strains were resistant to fluoroquinolones. A regular decrease in the annual percentage of co-amoxyclav susceptible strains was noted: from 82.4% in 1990 to 68.1% in 1993 (p < 0.001). Resistance (intermediate plus resistant strains) was more frequent in patients more than 60 years old, in those who had received quinolones up to one month before specimen collection or in those who had been recently (within 3 months) hospitalised. Similar data were obtained for amoxycillin or co-amoxyclav.Our study, together with those performed by other European investigators, demonstrates that the prevalence of quinolone resistant strains in general practice remains low and stable despite high consumption of fluoroquinolones.