title: Prevalence and Characterization of Integrons in Multidrug Resistant Acinetobacter baumannii in Eastern China: A Multiple-Hospital Study.
abstract: OBJECTIVE
  The aim of this multiple-hospital study was to investigate the prevalence of integrons in multidrug-resistant Acinetobacter baumannii (MDRAB) in Eastern China, and characterize the integron-integrase genes, so as to provide evidence for the management and appropriate antibiotic use of MDRAB infections.
  
  
  METHODS
  A total of 425 clinical isolates of A. baumannii were collected from 16 tertiary hospitals in 11 cities of four provinces (Fujian, Jiangsu, Zhejiang and Shandong) from January 2009 to June 2012. The susceptibility of A. baumannii isolates to ampicillin/sulbactam, piperacillin/tazobactam, ceftazidime, ceftriaxone, cefepime, aztreonam, meropenem, amikacin, gentamicin, tobramycin, ciprofloxacin, levofloxacin, sulfamethoxazole/trimenthoprim, minocycline and imipenem was tested, and integrons and their gene cassettes were characterized in these isolates using PCR assay. In addition, integron-positive A. baumannii isolates were genotyped using pulsed-field gel electrophoresis (PFGE) assay, and intI1 gene cassette was sequenced.
  
  
  RESULTS
  intI1 gene was carried in 69.6% of total A. baumannii isolates, while intI2 and intI3 genes were not detected. The prevalence of resistance to ampicillin/sulbactam, piperacillin/tazobactam, ceftazidime, ceftriaxone, cefepime, aztreonam, imipenem, meropenem, amikacin, gentamicin, tobramycin, ciprofloxacin, levofloxacin and sulfamethoxazole/trimenthoprim was significantly higher in integron-positive A. baumannii isolates than in negative isolates (all p values <0.05), while no significant difference was observed in the prevalence of minocycline resistance (p > 0.05). PFGE assay revealed 27 PFGE genotypes and 4 predominant genotypes, P1, P4, P7 and P19. The PFGE genotype P1 contained 13 extensive-drug resistant and 89 non-extensive-drug resistant A. baumannii isolates, while the genotype P4 contained 34 extensive-drug resistant and 67 non-extensive-drug resistant isolates, appearing a significant antimicrobial resistance pattern (both p values <0.05). Sequencing analysis revealed two gene cassette assays of aacA4-catB8-aadA1 and dfrXII-orfF-aadA2 in MDRAB isolates.
  
  
  CONCLUSIONS
  The results of this study demonstrate a high prevalence of class 1 integrons in MDRAB in Eastern China, and a greater prevalence of antimicrobial resistance in intI1 gene-positive MDRAB isolates than in negative isolates. Four predominant PFGE genotypes are identified in intI1 gene-positive MDRAB isolates, in which P4 is an epidemic PFGE genotype in Fujian Province, and it has a high proportion of extensive drug resistant A. baumannii. The gene cassette dfrXII-orfF-aadA2 is reported, for the first time, in A. baumannii strains isolated from Fujian Province, Eastern China.
authors: Fujian Medical University Union Hospital, No. 29 Xinquan Road, Fuzhou 350001, China. jingchen389@126.com.|School of Public Health, Fujian Medical University, No.1 Xueyuan Road, Shangjie Town, Minhou County, Fuzhou 350108, China. jingchen389@126.com.
authors: Jing
authors: J
authors: Chen
authors: Department of Pharmaceuticals, Fujian Health College, No. 366 Guankou Road, Jingxi Town, Minhou County, Fuzhou 350101, China. kinglh2002@126.com.
authors: Hong
authors: H
authors: Li
authors: Fujian Center for Disease Control and Prevention, 76 Jintai Road, Fuzhou 350001, China. yangjinsong2001@sina.com.
authors: Jinsong
authors: J
authors: Yang
authors: Fujian Medical University Union Hospital, No. 29 Xinquan Road, Fuzhou 350001, China. deanzhanrong@aliyun.com.
authors: Rong
authors: R
authors: Zhan
authors: Fujian Center for Disease Control and Prevention, 76 Jintai Road, Fuzhou 350001, China. cap2006@live.cn.
authors: Aiping
authors: A
authors: Chen
authors: School of Public Health, Fujian Medical University, No.1 Xueyuan Road, Shangjie Town, Minhou County, Fuzhou 350108, China. yysh@fjcdc.com.cn.|Fujian Center for Disease Control and Prevention, 76 Jintai Road, Fuzhou 350001, China. yysh@fjcdc.com.cn.
authors: Yansheng
authors: Y
authors: Yan
mesh_terms: D000151:Acinetobacter Infections / Q000453:epidemiology* / Q000382:microbiology; D040981:Acinetobacter baumannii / Q000187:drug effects* / Q000235:genetics* / Q000378:metabolism; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002681:China / Q000453:epidemiology; D004269:DNA, Bacterial / Q000235:genetics* / Q000378:metabolism; D024901:Drug Resistance, Multiple, Bacterial; D006761:Hospitals; D032023:Integrons; D015995:Prevalence
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial
keywords: Acinetobacter baumannii; antimicrobial resistance; eastern China; integron; multidrug resistance