[Investigation of acquired drug-resistant genes and strains relationship in Pseudomonas aeruginosa isolated from burn patients]

Abstract

Objective: To investigate the acquired drug-resistant genes and strains relationship in 40 strains of Pseudomonas aeruginosa isolated from burn patients. Methods: Forty strains of Pseudomonas aeruginosa isolated from burn patients hospitalized in our burn department from January 2014 to December 2015 were selected, with 20 strains from each year. Kirby-Bauer paper disk diffusion method was used to detect sensitivity of the isolated Pseudomonas aeruginosa to 9 kinds of antibiotics of cefotaxime, ceftazidime, cefepime, imipenem, meropenem, gentamicin, amikacin, ciprofloxacin, and levofloxacin. Polymerase chain reaction was applied to detect 9 kinds of acquired β-lactamase antibiotics-resistant genes, outer membrane porin protein oprD2 genes, 12 kinds of acquired aminoglycosides antibiotics-resistant genes, and 6 kinds of acquired disinfectant-resistant genes and genetic marker genes of mobile genetic elements. Among the above genes, positive expression genes were verified by DNA sequencing and comparison. Sequences of twenty-eight acquired drug-resistant genes of the above 40 Pseudomonas aeruginosa strains were analyzed by unweighted pair-group method with arithmetic means cluster analysis. Results: Forty strains of Pseudomonas aeruginosa were resistant to the above 9 kinds of antibiotics. Two kinds of acquired β-lactamase antibiotics-resistant genes of bla(TEM), bla(CARB), 5 kinds of acquired aminoglycosides antibiotics-resistant genes of aac(6')-Ⅰb, aac(6')-Ⅱ, ant(2″)-Ⅰ, ant(3″)-Ⅰ, and rmtB, and 3 kinds of acquired disinfectant-resistant genes and genetic marker genes of mobile genetic elements of qacE△1-sul1, merA, and intⅠ1were detected in 40 strains of Pseudomonas aeruginosa with oprD2 gene deficiency. Forty strains aggregated obviously, with a total of 7 gene modes and 3 clones. Drug-resistant gene sequences of strains of number 2 to 4, 6 to 9, 11, 14, and 17 to 39 were similar and with close relationship. Drug-resistant gene sequences of number 12 and 13 strains were similar and with close relationship. Drug-resistant sequences of number 10 and 16 strains were similar and with close relationship. Conclusions: Genes of bla(TEM), bla(CARB), aac(6')-Ⅰb, aac(6')-Ⅱ, ant(2″)-Ⅰ, rmtB, qacE△1-sul1, merA, and intⅠ1 were prevalent in these strains of Pseudomonas aeruginosa with oprD2 gene deficiency isolated from burn patients, which may play key roles in resistance of Pseudomonas aeruginosa to β-lactamase, aminoglycoside, and quinolone antibiotics, and the drug-resistant phenotypes were in good coincidence with genotypes. Pseudomonas aeruginosa strains isolated from burn patients were with similar acquired drug-resistant genes and close relationship.

Keywords: Cluster analysis; Drug resistance; Genes; Pseudomonas aeruginosa.