title: High frequency of integrons related to drug-resistance in clinical isolates of Acinetobacter baumannii.
abstract: OBJECTIVE
  As an opportunistic pathogen, Acinetobacter baumannii causes various nosocomial infections. In recent years, the increasing cumulative infection outbreaks involving A. baumannii have appeared worldwide. In addition, a perplexing trouble for clinical treatment is a severe drug-resistance problem with A. baumannii. In this study, we investigated the drug-resistance rates and integrons' distribution in A. baumannii clinical strains in East China. Furthermore, we explored the relationship between integrons and drug resistance.
  
  
  METHODS
  Strains were identified using non-fermenting bacteria identification cards by Vitek-32 system. Disk-diffusion method (Kirby-Bauer) was used to judge antimicrobial sensitivity. Integrons and the gene cassettes of integrons were identified by PCR, restriction enzyme digestion and DNA sequencing.
  
  
  RESULTS
  Except imipenem and cefoperazone/sulbactam, the drug-resistance rates of the A. baumannii clinical isolates to other 15 kinds of antibacterials, all surpassed 30%. Of 96 A. baumannii clinical isolates, 66 strains carried class 1 integrons (no class 2 or 3 integrons were found). Overall, the drug-resistance rates in integrons-positive A. baumannii to 14 kinds of antibacterials were higher than those in integrons-negative A. baumannii. Gene sequencing showed that 9 of 12 integrons contained seven different gene cassettes (aacA4, catB3, dfrA1, blam-1, orfX, aadA1, and sat2). The cassette arrays aacA4-catB3-dfrA1 was found in five detected integrons.
  
  
  CONCLUSIONS
  High resistances in A. baumannii clinical strains to most common antimicrobial agents have appeared in East China, which was closely related with high frequencies class 1 integrons. A. baumannii integrons cassettes carried multi-drug-resistant gene codes. We believe that integrons cassettes gene could be taken as a marker of prognosticating A. baumannii antimicrobial resistance, but only reveal partial drug resistance profiles.
authors.affiliation: Department of Laboratory Medicine, Changzhou Tumor Hospital Soochow University, Changzhou 213001, China.
authors.forename: Z
authors.initials: Z
authors.lastname: Chang-Tai
authors.forename: L
authors.initials: L
authors.lastname: Yang
authors.forename: H
authors.initials: H
authors.lastname: Zhong-Yi
authors.forename: Z
authors.initials: Z
authors.lastname: Chang-Song
authors.forename: K
authors.initials: K
authors.lastname: Yin-Ze
authors.forename: L
authors.initials: L
authors.lastname: Yong-Ping
authors.forename: D
authors.initials: D
authors.lastname: Chun-Lei
mesh_terms: D000151:Acinetobacter Infections / Q000382:microbiology*; D040981:Acinetobacter baumannii / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002681:China; D003428:Cross Infection / Q000382:microbiology; D004269:DNA, Bacterial / Q000235:genetics*; D024881:Drug Resistance, Bacterial; D006801:Humans; D032023:Integrons; D008826:Microbial Sensitivity Tests / Q000379:methods; D016133:Polymerase Chain Reaction / Q000379:methods
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial