title: Risk factors and mortality of patients with nosocomial carbapenem-resistant Acinetobacter baumannii pneumonia.
abstract: BACKGROUND
  Acinetobacter baumannii is characterized by strictly aerobic, gram-negative, nonmotile, nonlactose-fermenting, oxidase-negative, catalase-positive coccobacilli, and the combination of its environmental resilience and its rapid development of resistance to multiple classes of antimicrobials renders it a successful nosocomial pathogen.
  
  
  OBJECTIVE
  The aim of this study was to identify specific risk factors and outcome of nosocomial pneumonia because of carbapenem-resistant Acinetobacter baumannii (CRAB).
  
  
  METHODS
  The retrospective study, set in a 1,500-bed referral and tertiary care hospital, was conducted to analyze the clinical and microbiologic data of patients with nosocomial pneumonia because of Acinetobacter baumannii (A baumannii) from January 2006 to December 2011. Comparisons were made between patients with CRAB pneumonia and patients with carbapenem-susceptible A baumannii (CSAB) pneumonia. Only the first isolation of A baumannii was considered.
  
  
  RESULTS
  A total of 145 patients with CSAB pneumonia and 97 patients with CRAB pneumonia was included. Among these patients, the independent risk factors for acquiring CRAB pneumonia were Acute Physiology and Chronic Health Evaluation II (APACHE II) score (>20) at admission, systemic illnesses (chronic respiratory disease and cerebrovascular accident), presence of excess noninvasive or invasive devices (mechanical ventilation), and ever used antibiotics within 28 days (carbapenem and cefepime). The patients with CRAB pneumonia had higher mortality rate than CSAB pneumonia. Multivariate analysis showed that, among patients with A baumannii pneumonia, APACHE II score (>20) at pneumonia onset, infections with other microorganisms, and inappropriate therapy were independently associated with 28-day mortality.
  
  
  CONCLUSIONS
  Patients with CRAB pneumonia have a higher mortality rate than those with CSAB pneumonia. The nosocomial occurrence of CRAB pneumonia is strongly related to systemic illnesses, APACHE II score, mechanical ventilation, and ever used antibiotics within 28 days.
authors.affiliation: Department of Respiratory Diseases, the Affiliated Huai'an Hospital of Xuzhou Medical College, Huai'an, China.
authors.forename: Yu-long
authors.initials: YL
authors.lastname: Zheng
authors.forename: Yu-feng
authors.initials: YF
authors.lastname: Wan
authors.forename: Li-yang
authors.initials: LY
authors.lastname: Zhou
authors.forename: Mao-lin
authors.initials: ML
authors.lastname: Ye
authors.forename: Shu
authors.initials: S
authors.lastname: Liu
authors.forename: Chuan-qin
authors.initials: CQ
authors.lastname: Xu
authors.forename: Yuan-qiang
authors.initials: YQ
authors.lastname: He
authors.forename: Jian-hui
authors.initials: JH
authors.lastname: Chen
mesh_terms: D000151:Acinetobacter Infections / Q000188:drug therapy* / Q000401:mortality*; D040981:Acinetobacter baumannii / Q000187:drug effects*; D000368:Aged; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D015780:Carbapenems / Q000627:therapeutic use*; D000077723:Cefepime; D002511:Cephalosporins / Q000627:therapeutic use; D015331:Cohort Studies; D003428:Cross Infection / Q000517:prevention & control; D004198:Disease Susceptibility / Q000401:mortality; D024901:Drug Resistance, Multiple, Bacterial / Q000187:drug effects; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D011014:Pneumonia / Q000188:drug therapy* / Q000401:mortality*; D012189:Retrospective Studies; D012307:Risk Factors; D018440:beta-Lactam Resistance
chemical_list: D000900:Anti-Bacterial Agents; D015780:Carbapenems; D002511:Cephalosporins; D000077723:Cefepime