Identification and characterization of class 1 integrons among Pseudomonas aeruginosa isolates from patients in Zhenjiang, China
Received 6 July 2008; received in revised form 22 September 2008; accepted 26 November 2008. published online 09 February 2009.
Summary
Objectives
The role of integrons in the spread of antibiotic resistance has been well established. The aim of this study was to investigate the resistance profiles of Pseudomonas aeruginosa isolated from patients in Zhenjiang to 13 antibiotics, and to identify the structure and dissemination of class 1 integrons.
Methods
The Kirby–Bauer disk diffusion assay was used to determine the rate of P. aeruginosa resistance. Class 1 integrons from multidrug-resistant isolates were amplified by PCR, and their PCR products were sequenced. We also analyzed the integron structures containing the same gene cassettes by restriction fragment length polymorphism (RFLP). Isolates were genotyped by pulsed-field gel electrophoresis (PFGE).
Results
The resistance rates were between 29.6% and 90.1%. The prevalence of class 1 integrons was 38.0%. These integrons included five gene cassettes (aadB, aac6-II, blaPSE-1, dfrA17, and aadA5). The dfrA17 and aadA5 gene cassettes were found most often.
Conclusions
Class 1 integrons were found to be widespread in P. aeruginosa isolated from clinical samples in the Zhenjiang area of China. The antibiotic resistance rates in class 1 integron-positive strains of P. aeruginosa were noticeably higher than those in class 1 integron-negative strains. PFGE showed that particular clones were circulating among patients.
Corresponding Editor: J. Peter Donnelly, Nijmegen, The Netherlands
aClinical Laboratory, the Affiliated People's Hospital of Jiangsu University, Zhenjiang, Jiangsu Province, China
bDepartment of Microbiology and Immunology, Institute of Clinical Laboratory Medicine, Jiangsu University, Xuefu Road 301, Zhenjiang, Jiangsu Province, 212013 China
ABSTRACT