Correlation between the susceptibility to fosfomycin and bla PSE-1 in Pseudomonas aeruginosa.

A prospective survey was carried out during three three-weeks periods in Mat: October 1997 and October 1998 in 13 teaching hospitals. All non-repetitive isolates of P. aeruginosa collected were subject to serotypage and determination of the inhibiting minimal concentrations for ticarcillin, piperacillin, piperacillin + tazobactam, ceftazidime, imipenem, amikacin, ciprofloxacin and fosfomycin. Identification of the betalactamases and quantification of the cephalosporinase were done for the strains intermediate or resistant to ticarcillin. The most frequent serotypes were O : 6 (17%), O: 11 (13%), O : 1 (10%) and O : 12 (9%). Serotype O : 12 was the least susceptible to antibiotics except for fosfomycin. Whatever the serotype, 76% of P. aeruginosa strains with bla PSE-1 are susceptible to fosfomycin, when only 29.8% of non bla PSE-I producing strains were susceptible to this antibiotic. Integron encoding bla PSE-I could be implicated in susceptibility to fosfomycin of P. aeruginosa strains. The associations fosfomycin + imipenem or fosfomycin + ceftazidime could be proposed in case of infections due to P. aeruginosa O: 12. (C) 2001 Editions scientifiques et medicales Elsevier SAS.