title: Emergence of extensively drug-resistant Acinetobacter baumannii complex over 10 years: nationwide data from the Taiwan Surveillance of Antimicrobial Resistance (TSAR) program.
abstract: BACKGROUND
  Acinetobacter baumannii complex (ABC) has emerged as an important pathogen causing a variety of infections. Longitudinal multicenter surveillance data on ABC from different sources in Taiwan have not been published. Using data from the Taiwan Surveillance of Antimicrobial Resistance (TSAR) conducted biennially, we investigated the secular change in resistance of 1640 ABC from 2002 to 2010 (TSAR period III to VII) to different antimicrobial agents and identified factors associated with imipenem-resistant and extensively drug-resistant ABC (IRABC and XDRABC).
  
  
  METHODS
  Isolates were collected by TSAR from the same 26 hospitals located in all 4 regions of Taiwan. Minimum inhibitory concentrations (MIC) were determined by reference broth microdilution method. Isolates nonsusceptible to all tested aminoglycosides, fluoroquinolones, β-lactam, β-lactam/β-lactam inhibitors, and carbapenems were defined as extensively drug-resistant (XDR). Multivariate logistic regression analysis was performed to assess the relationship between predictor variables among patients with resistant ABC and patients with non-resistant ABC.
  
  
  RESULTS
  The prevalence of IRABC increased from 3.4% in 2002 to 58.7% in 2010 (P < 0.001; odds ratio [OR], 2.138; 95% confidence interval [CI], 1.947 to 2.347) and that of XDRABC increased from 1.3% in 2002 to 41.0% in 2010 (P < 0.001; OR, 1.970; 95% CI, 1.773-2.189). The rates of non-susceptibility to other antimicrobial agents remained high (>55%) over the years with some fluctuations before and after TSAR V (2006) on some agents. Multivariate analysis revealed that recovery from elderly patients, origins other than blood, from ICU settings, or geographic regions are independent factors associated with IRABC and XDRABC. Although the prevalence of XDRABC increased in all four regions of Taiwan over the years, central Taiwan had higher prevalence of XDRABC starting in 2008. Susceptibility to polymyxin remained high (99.8%).
  
  
  CONCLUSIONS
  This longitudinal multicenter surveillance program revealed significant increase and nationwide emergence of IRABC and XDRABC in Taiwan over the years. This study also identified factors associated with IRABC and XDRABC to help guide empirical therapy and at-risk groups requiring more intense interventional infection control measures with focused surveillance efforts.
authors.affiliation: National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, No. 35 Keyan Road, Zhunan, Taiwan 35053.
authors.forename: Shu-Chen
authors.initials: SC
authors.lastname: Kuo
authors.forename: Shan-Chwen
authors.initials: SC
authors.lastname: Chang
authors.forename: Hui-Ying
authors.initials: HY
authors.lastname: Wang
authors.forename: Jui-Fen
authors.initials: JF
authors.lastname: Lai
authors.forename: Pei-Chen
authors.initials: PC
authors.lastname: Chen
authors.forename: Yih-Ru
authors.initials: YR
authors.lastname: Shiau
authors.forename: I-Wen
authors.initials: IW
authors.lastname: Huang
authors.forename: Tsai-Ling Yang
authors.initials: TL
authors.lastname: Lauderdale
mesh_terms: D000151:Acinetobacter Infections / Q000453:epidemiology* / Q000382:microbiology*; D040981:Acinetobacter baumannii / Q000187:drug effects* / Q000302:isolation & purification*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology; D024901:Drug Resistance, Multiple, Bacterial; D005260:Female; D006761:Hospitals; D006801:Humans; D015994:Incidence; D008137:Longitudinal Studies; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D013624:Taiwan / Q000453:epidemiology
chemical_list: D000900:Anti-Bacterial Agents