Sensibilité aux antibiotiques de souches d' Escherichia coli isolées en 1998 et 1999: résultats d'une enquête multicentrique française
Objective Seven hospital lab departments were enrolled in this study in order to update and analyse data on E. coli susceptibility to antibiotics in 1998 and 1999. Material and methods 1,114 strains were randomly selected for analysis, a large number of which had been obtained from female (65,7%) and elderly patients, and essentially from urinary samples (56%) and blood cultures (23%). Results It was observed that resistance rates (R+I) were elevated for amoxicillin (44%), ticarcillin (42%), co-amoxiclav (31%) and cephalothin (36%), moderate for nalidixic acid (8%), ciprofloxacin (5%) and gentamicin (2%), and very low for ceftazidime (1%) and ceftriaxone (0.8%); 2 strains only (0.2%) were ESBL producers. Finally, it was noteworthy that pediatry units were providers of strains significantly more resistant to amoxicillin, co-amoxiclav, ticarcillin and cephalothin than strains from other units; no other risk-factor of resistance was detected. While the previous 1114 randomised strains presented MIC50 and 90 of 0.125 and 0.25 μg/mL for ceftazidime and 0,03 and 0,06 μg/mL for ceftriaxone, a complementary analysis carried out on a pool of 76 ESBL producers and 137 strains resistant (R+I) to ceftazidime and/or to cefotaxime/cetriaxone (but ESBL−) revealed that these value were increased of 7 to 9 dilutions for the 76 ESBL+ strains and of 5 to 6 for the 137 ESBL− strains in comparison with susceptible strains. Moreover these strains were observed to present elevated rates of co-resistance (R+I) to nalidixic acid, ciprofloxacin and gentamicin: 52%, 37% and 41% respectively for ESBL+ strains and 43%, 21% and 16% respectively for ESBL− strains.