Resistance of Pseudomonas aeruginosa and genotyping of the main β-lactamases in China / 中华传染病杂志

ABSTRACT

Objective To investigate the resistance of Pseudomonas aeruginosa and genotyping of the main β-lactamases in China. Methods A total of 645 Pseudomonas aeruginosa isolates were collected from 28 hospitals in 16 cities in China from July 2006 to July 2007. The susceptibilities to 11 kinds of antimicrobial agents were detected by agar dilution or Kirby-Bauer disk diffusion method. The genotypes of β-lactamases including TEM, SHV, CTX-M and OXA of all the strains were detected by polymerase chain reaction (PCR) and sequence analysis. Results The resistance rates of 645 Pseudomonas aeruginosa isolates to antimicrobial agents were high, except those to amikacin and meropenem were lower than 30 %. Two hundred and seventy-five (42. 64 % ) strains were carbapenem and (or) meropenem-nonsusceptible Pseudomonas aeruginosa. Three hundred and sixty-eight (57.05 %) strains were multidrug-resistant Pseudomonas aeruginosa and 20 (3. 10%) strains were pandrug-resistant. The genotyping results of β-lactamases were as follows 51 stains produced OXA-10 group β-lactamases, 37 were CARB type, 36 were TEM, 35 were PER, 11 were CTX-M, 9 were VEB, 5 were SHV, 24 were metallo-β-lactamases positive and 1 was GES. None of genotypes of plasmidmediated AmpC enzyme and other carbapenemases were detected. CTX-M-13, CTX-M-14,CTX-M-15, CTX-M-3 of extended spetrum β-lactamese were detected in Pseudomonas aeruginosa.Conclusions The situation of Pseudomonas aeruginosa resistances is severe in China. OXA-10 and PSE-1 are the most common genotypes of β-lactamases. The β-lactamases genotyping is different between carbapenem-nonsusceptible and carbapenem-susceptible strains.