The distribution and structure of class I integron in the multidrug-reisistant Pseudomonas aeruginosa

Objective To investigate the antimicrobial susceptibility of Pseudomonas aeruginosa (P. aeruginosa) isolated from Zhenjiang area to 13 routinely used antibiotics and identify the structure and dissemination of class Ⅰ integron. Methods K-B test was used to determine the resistant rate of 71 strains of P. aeruginosa. DNA template was extracted by boiling method, PCR method was utilized to detect class Ⅰintegron, and subsequently gene cassettes were analyzed by sequencing. Results The resistant rates to 13 routinely used antibiotics were quite different from 18. 3 to 77.5% among 71 strains of P. aeruginosa. The prevalence of class Ⅰ integron was 38%. These integrons include 5 gene cassettes ( aadB, aac (6) - Ⅱ , PSE-Ⅰ , dfrA17 and aadAS), in which dfrA17 and aadA5 gene cassette were frequently found. Comparing with the negative strains of integron, the positive strains of integron has obviously higher resistance to ten the antibiotics including piporacillin, piperacillin-tazobactam, ceftriaxone, cefepime, ceftazidime, gentamicin,amikacin, tobmmycin, levofloxacin, and ciprofloxacin. Conclusions The resistant rates of P. aeruginosa to 13 drugs were different, and the resistant rates of integron positive strains were obviously higher than integron negative strains, which indicates that integron may play an important role in multidrug reisistance of P. aeruginoosa. Key words: Pseudomonas aeruginosa;  Drug-resistance,multiple, bacterial;  Integrons