A Plasmidic Class 1 Integron from Five Pseudomonas aeruginosa Clinical Strains Harbored aacA4 and Nonsense-mutated cmlA1 Gene Cassettes

Abstract

Five strains of multidrug-resistant Pseudomonas aeruginosa (P. aeruginosa) were isolated from inpatients at a local hospital in China. The most frequent resistance was to cefoperazone, ciprofloxacin, ceftriaxone, cefotaxime, gentamicin, piperacillin, trimethoprim sulfamethoxazole, and tobramycin. These strains were found to contain the class 1 integron, in which the 2360-bp gene cassettes were flanked by 5 -and 3 -conserved segments. Sequence analysis revealed that the gene cassettes contained aacA4 and cmlA1 genes; however, the latter gene had a nonsense mutation resulting in the production of a truncated protein. To the best of our knowledge, this is the first report of a nonsense mutation in the cmlA1 gene. Moreover, the P. aeruginosa strains showed identical profiles in pulsed-field gel electrophoresis, suggesting that they were derived from the same clone. These results emphasize the importance of controlling the spread of multidrug-resistant pathogens in hospitals.

Prevalence of Antibiotic Resistance and Class 1 Integrons in Clinical and Environmental Isolates ofPseudomonas aeruginosa

“…Yan et al conducted another study on the presence of integron genes in 118 bacterial strains including both Gram-positive and -negative ones; moreover, they assessed antibiotic resistances among these strains and the association between the presence of resistant genes and antibiotic resistance (20). The results of their study demonstrated that 100 out of 118 strains (84.7%) were resistant to more than 3 antibiotics, and then, categorized as multidrug re- (16) sistance.…”

Screening of Class 1 and Class 2 Integrons in Clinical Isolates of Pseudomonas aeruginosa Collected from Seven Hospitals in Turkey: A Multicenter Study

“…While 5' conserved region of class 1 integron includes class 1 integrase gene encoding a site-specific integrase (intI) and recombination site, 3' conserved region includes sulI and qacEΔ1 genes [18]. Class 1 integrons have been reported in P. aeruginosa isolates [8,[19][20][21][22][23][24][25][26][27]. Organization of class 2 integrons is similar to the class 1 integrons and they are inserted in the Tn7 transposons family.…”