Antibiotic resistance of Staphylococcus aureus in extra-hospital practice:a six-month period study in Aquitaine.

Antibiotic resistance of Staphylococous aureus has been surveyed by eight c ity laboratories of the Aquitaine area, during a six month-period (january to june 1998). Antibiotic susceptibility testing has been performed by the disk diffusion method, and the results have been collected and analysed usi ng the SIRscan system. After elimination of the redundant strains a total o f 747 isolates has been retained. They were mainly isolated from pus (64%) collected from patients of the community (40%) or hospitalized in 30 privat e clinics or nursing homes. The percentages of resistant strains (community /institutions) were: benzylpenicillin: 90% (87/92%), oxacillin: 39% (23/50% ), kanamycin: 37% (22/47%); gentamicin: 13% (8/16%), tobramycin: 37% (21/47 %), amikacin: 21% (13/27%); netilmicin: 6% (5/7%), erythromycin: 33% (30/35 %), spiramycin: 72% (77/69%), lincomycin: 24% (17/29%), pristinamycin: 2% ( 1/2%), tetracycline: 17% (14/19%); pefloxacin: 40% (25/50%), fosfomycin: 9% (6/12%), rifampicin: 10% (7/13%), fusidic acid: 14% (11/15%), cotrimoxazol e and vancomycin: 0%. Meticillin-susceptible strains of S. aureus were most ly sensitive to other antibiotics (less than or equal to 6% resistant strai ns, except for erythromycin: 22%). Among meticillin-resistant S. aureus, he terogeneous strains with a KT phenotype, and various resistance patterns to the remaining antibiotics were predominant (61%), compared to the homogene ous strains with a KTG phenotype and multiresistant to the other antibiotic s (32%). The frequencies of resistant strains were highly variable dependin g on the specimen, the laboratory and the health care institution, except f or cotrimoxazole and vancomycin which were always active. (C) 2001 Editions scientifiques et medicales Elsevier SAS.