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 Ma t: October 1997 and October 1998 in 13 teaching hospitals. All non-repetiti ve isolates of P. aeruginosa collected were subject to serotypage and deter mination of the inhibiting minimal concentrations for ticarcillin, piperaci llin, piperacillin + tazobactam, ceftazidime, imipenem, amikacin, ciproflox acin and fosfomycin. Identification of the betalactamases and quantificatio n of the cephalosporinase were done for the strains intermediate or resista nt 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 t o antibiotics except for fosfomycin. Whatever the serotype, 76% of P. aerug inosa 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. In tegron encoding bla PSE-I could be implicated in susceptibility to fosfomyc in of P. aeruginosa strains. The associations fosfomycin + imipenem or fosf omycin + ceftazidime could be proposed in case of infections due to P. aeru ginosa O: 12. (C) 2001 Editions scientifiques et medicales Elsevier SAS.