Service de Bactériologie, Faculté de Médecine, Université d'Auvergne, 63001 Clermont-Ferrand, France. christophe.dechamps@u-clermont1.fr
In 2000, at the Université d'Auvergne teaching hospital in Clermont-Ferrand, France, 44 (6.2%) strains of Pseudomonas aeruginosa were found to be resistant to ceftazidime. After genotyping, 34 strains were selected. Nine had an additional beta-lactamase: OXA-21 (n = 6), PSE-1 (CARB-2) (n = 2), or PER-1 (n = 1). Ceftazidime resistance was related solely to the overproduction of the cephalosporinase in 30 strains. Sequencing of five bla(AmpC) genes encoding cephalosporinases with different pIs showed 99% identity with the ampC gene of P. aeruginosa PAO1.