Detection of Carbapenemase-Encoding Genes Among Clinical Isolates of Pseudomonas aeruginosa in a Chinese Burn Unit

Abstract

The carbapenemases have recently emerged as molecules implicated in one of the most feared bacterial resistance mechanisms because of their ability to hydrolyze virtually all lactamase agents and their highly mobile genes. This study aimed to investigate the prevalence of carbapenemase and antimicrobial susceptibilities of Pseudomonas aeruginosa isolated from burn patients in Chongqing, China. Antimicrobial susceptibility of 111 isolates was determined by the disc agar diffusion test and the agar dilution method. Random Amplification of Polymorphic DNA polymerase chain reaction analysis revealed 111 P. aeruginosa 42 genotypes. Carbapenemase genes were amplified by polymerase chain reaction and the sequence verified by blast. Ninety-three of 111 (83.8%) isolates were resistant to imipenem; all of them had developed multidrug resistance and exhibited higher resistant rates compared with the imipenem-susceptible Pseudomonas. Ciprofloxacin was the most effective antipseudomonal agent. Thirty-three of the isolates were identified to contain the metallo-β-lactamase blaIMP-4 gene and belong to different Random Amplification of Polymorphic DNA polymerase chain reactiongenotypes. In conclusion, the high prevalence of multidrug resistance (94.6%) and the production of blaIMP-4 genes in P. aeruginosa isolates in burn patients highlight the necessity of considering these issues in burn hospitals.