title: [Antimicrobial resistance of Gram-negative bacilli isolated from 13 teaching hospitals across China].
abstract: OBJECTIVE
  To explore the antimicrobial resistance of nosocomial Gram-negative bacilli across China.
  
  
  METHODS
  A total of 1247 consecutive and non-repetitive Gram-negative bacilli were isolated from 13 Chinese teaching hospitals from March to August 2012. All isolates were sent to a central laboratory for reidentification and susceptibility testing. The minimal inhibitory concentration (MICs) of meropenem and other antibacterial agents were determined by agar dilution method. And the data were analyzed with WHONET-5.6 software.
  
  
  RESULTS
  The activity of antimicrobial agents against Enterobacteriaceae was in the following descending order of susceptibility rate: meropenem (97.5%, 849/871) , amikacin (94.5%, 823/871) , imipenem (93.6%, 815/871) , ertapenem (92.9%, 809/871) , piperacillin/tazobactam (89.9%, 783/871) , cefoperazone/sulbactam (83.5%, 727/871) , cefepime (78.1%, 680/871) , polymyxin B (77.0%, 670/871) , cefiazidime (69.6%, 606/871) , levofloxacin (69.2%, 603/871) , ciprofloxacin (63.6%, 554/871) , minocyline (63.1%, 550/871) , ceftriaxone (55.7%, 485/871) , cefotaxime (54.2%, 472/871) and cefoxitin (51.4%, 448/871) . The prevalence of extended-spectrum beta-lactamase (ESBL) was 64.3% (117/182) in Escherichia coli (E. coli) and 32.1% (60/187) in Klebsiella pneumonia (K. pneumoniae) . The sensitivities of E. coli to meropenem and imipenem were 100%. And over 90% of E. coli was sensitive to ertapenem, amikacin, piperacillin/tazobactam and polymyxin B. However, over 60% of E. coli was resistant to ciprofloxacin, levofloxacin, ceftriaxone and cefotaxime. The susceptibility of K. pneumoniae to meropenem, imipenem, amikacin and polymyxin B maintained at over 90%. The activities of antimicrobial agents against E. cloacae, E. aerogenes and Citrobacter freundii were in the following descending order of susceptibility rate: meropenem (96.0%-100%) , imipenem (96.0%-100%) , polymyxin B (95.8%-100%) , amikacin (92.2%-100%) , ertapenem (85.6%-93.3%) , cefepime (77.8%-93.3%) , cefoperazone/sulbactam (78.4%-90.0%) and piperacillin/tazobactam (65.0%-89.8%) . The most susceptible agent against Acinetobacter baumannii (A. baumannii) was polymyxin B (100%) . The susceptibilities of A.baumannii to imipenem, meropenem and minocyline were 37.8% (65/172) , 36.0% (62/172) and 62.8% (108/172) respectively. The most active agents against Pseudomonas aeruginosa (P. aeruginosa) were polymyxin B (97.2%, 173/178) , followed by amikacin (89.3%, 159/178) and cefiazidime (83.7%, 149/178) . Clinical and Laboratory Standards Institute revised P.aeruginosa susceptibility standard in 2012. The sensitivity of piperacillin/tazobactam changed from 83.7% (149/178) to 77.5% (138/178) . The sensitivity of meropenem decreased from 78.1% ( 139/178 ) to 71.3% ( 127/178 ) while that of imipenem declined from 69.7% (124/178) to 59.6% (106/178) . The prevalence of multi-drug resistant A. baumannii and P. aeruginosa were 65.7% (113/172) and 9.0% (16/178) respectively.
  
  
  CONCLUSIONS
  Carbapenems remain highly active against Enterobacteriaceae. Increasing resistance of A. baumannii to all antimicrobial agents is noted. New breakpoint to P.aeruginosa has obvious effects on antimicrobial sensitivity.
authors.affiliation: Department of Clinical Laboratory, Peking University People's Hospital, Beijing, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Wang
authors.forename: Chun-jiang
authors.initials: CJ
authors.lastname: Zhao
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.forename: Yun-song
authors.initials: YS
authors.lastname: Yu
authors.forename: Zhen-hong
authors.initials: ZH
authors.lastname: Zhu
authors.forename: Yun-zhuo
authors.initials: YZ
authors.lastname: Chu
authors.forename: Zi-yong
authors.initials: ZY
authors.lastname: Sun
authors.forename: Zhi-dong
authors.initials: ZD
authors.lastname: Hu
authors.forename: Xiu-li
authors.initials: XL
authors.lastname: Xu
authors.forename: Kang
authors.initials: K
authors.lastname: Liao
authors.forename: Ying-chun
authors.initials: YC
authors.lastname: Xu
authors.forename: Li-yan
authors.initials: LY
authors.lastname: Zhang
authors.forename: Ya-ning
authors.initials: YN
authors.lastname: Mei
authors.forename: Bin
authors.initials: B
authors.lastname: Yang
authors.forename: Yu-xing
authors.initials: YX
authors.lastname: Ni
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology*; D002681:China; D024881:Drug Resistance, Bacterial / Q000187:drug effects*; D006090:Gram-Negative Bacteria / Q000187:drug effects* / Q000302:isolation & purification; D006784:Hospitals, Teaching; D006801:Humans; D008826:Microbial Sensitivity Tests
chemical_list: D000890:Anti-Infective Agents