title: [An analysis of resistance of nosocomial infection pathogens isolated from 13 teaching hospitals in 2011].
abstract: OBJECTIVE
  To investigate the pathogen profile of nosocomial infection in China, and to survey the susceptibility rates of these pathogens to the clinical common antibiotics.
  
  
  METHODS
  The non-repetitive nosocomial pathogens isolated from bloodstream infection (BSI), hospital acquired pneumonia (HAP) and intra-abdominal infection (IAI) and the case data were collected from 13 teaching hospitals in different areas of China and sent to a central laboratory for re-identification and susceptibility testing. The levels of minimal inhibitory concentration (MIC) of the common antibiotics were determined by agar dilution method. The data were analyzed by WHONET 5.6 software.
  
  
  RESULTS
  A total of 2103 clinical isolates were collected from January to December 2011, of which gram positive cocci and gram negative organisms accounted for 23.2% and 76.8% respectively. The top three pathogens of BSI were E. coli (31.0%, 243/784), K. pneumoniae (14.8%, 116/784) and S. aureus (10.6%, 83/784). The top three pathogens of HAP were A. baumannii (24.2%, 158/652), P. aeruginosa (23.0%, 150/652) and K. pneumoniae (16.4%, 107/652). The top three pathogens of IAI were E. coli (34.3%, 229/667), E. faecium (13.3%, 89/667) and K. pneumoniae (9.6%, 64/667). Methicillin-resistant S. aureus (MRSA) and coagulase negative Staphylococcus (MRCNS) accounted for 64.4% and 78.1% respectively. The susceptibility rates of Staphylococcus species to tigecycline, vancomycin, teicoplanin and linezolid were all 100%. The prevalence of MRSA in HAP was significantly higher than that in BSI or IAI. The susceptibility rates of Enterococcus species to tigecycline, teicoplanin and linezolid were all 100%. The prevalence of extended-spectrum β-lactamases (ESBL) was 64.3% in E. coli and 38.3% in K. pneumonia. Against Enterobacteriaceae, the most active agents were as following in order: tigecycline (92.3% - 100%) [except P.mirabilis], meropenem (87.5% - 100%), imipenem (87.5% - 100%) [except M. morganii], amikacin (87.5% - 100%), polymyxin B (75% - 100%) [except S. marcescens, P. mirabilis and M morganii], cefepime (67.8% - 100%), cefoperazone-sulbactam (66.6% - 100%), piperacillin-tazobactam (61.5% - 100%). Carbapenem-resistance Enterobacteriaceae strains emerged. The susceptibility rates of P. aeruginosa to imipenem and meropenem were 66.2% and 72.2%, respectively. The susceptibility rates of A. baumannii to imipenem and meropenem were 27.7% and 25.9%, respectively. The most active agents against A. baumannii were polymyxin B (100%), followed by tigecycline (79.8%) and minocycline (50.4%). The susceptibility rates of P.aeruginosa to antibiotics in BSI were higher than those in HAP and IAI. Susceptibility rates of S. maltophilia to trimethoprim-sulfamethoxazole, minocycline and levofloxacin were about 90% or above. Susceptibility rates of B. cepacia to trimethoprim-sulfamethoxazole, ceftazidime and meropenem were all 100%. Several P.aeruginosa and A. baumannii strains were resistant to all tested antibiotics except polymyxin B.
  
  
  CONCLUSIONS
  The pathogen profile is different in different types of infection. The prevalence of multi-drug resistant A. baumannii is high, which is still a key problem of nosocomial infection. Tigecycline remains relatively high activity against gram-positive cocci and gram-negative bacteria (except P. aeruginosa and P. mirabilis) in vitro.
authors.affiliation: Department of Clinical Laboratory, Peking University People's Hospital, Beijing 100044, China.
authors.forename: Hong-bin
authors.initials: HB
authors.lastname: Chen
authors.forename: Chun-jiang
authors.initials: CJ
authors.lastname: Zhao
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.forename: Bin
authors.initials: B
authors.lastname: Cao
authors.forename: Xiu-li
authors.initials: XL
authors.lastname: Xu
authors.forename: Yun-zhuo
authors.initials: YZ
authors.lastname: Chu
authors.forename: Zhi-dong
authors.initials: ZD
authors.lastname: Hu
authors.forename: Chao
authors.initials: C
authors.lastname: Zhuo
authors.forename: Bi-jie
authors.initials: BJ
authors.lastname: Hu
authors.forename: Wen-en
authors.initials: WE
authors.lastname: Liu
authors.forename: Kang
authors.initials: K
authors.lastname: Liao
authors.forename: Rong
authors.initials: R
authors.lastname: Zhang
authors.forename: Ji
authors.initials: J
authors.lastname: Zeng
authors.forename: Yong
authors.initials: Y
authors.lastname: Wang
authors.forename: Yan-ping
authors.initials: YP
authors.lastname: Luo
authors.forename: Zhan-wei
authors.initials: ZW
authors.lastname: Wang
authors.forename: Ying-mei
authors.initials: YM
authors.lastname: Liu
authors.forename: Xiao
authors.initials: X
authors.lastname: Chen
authors.forename: Bin
authors.initials: B
authors.lastname: Tian
authors.forename: Dan-hong
authors.initials: DH
authors.lastname: Su
authors.forename: Chun-mei
authors.initials: CM
authors.lastname: Zhou
authors.forename: Ming-xiang
authors.initials: MX
authors.lastname: Zou
authors.forename: Peng-hao
authors.initials: PH
authors.lastname: Guo
authors.forename: Hong-wei
authors.initials: HW
authors.lastname: Zhou
authors.forename: Yan
authors.initials: Y
authors.lastname: Jin
mesh_terms: D002681:China; D003428:Cross Infection / Q000382:microbiology*; D024881:Drug Resistance, Bacterial; D006784:Hospitals, Teaching; D006801:Humans