Cefepime

The BAL fluid from each subject was divided into 2 samples. The first sample was sent to the routine diagnostic laboratory. Antibiotic susceptibilities results were classified as susceptible, intermediate, and resistant by the Phoenix automated microbiology system (BD Diagnostics, le Pont de Claix, France) according to The European Committee on Antimicrobial Susceptibility Testing recommendations. The second BAL sample (10 mL) was sent to our laboratory, where it was subjected to centrifugation (4,000g for 4 min). Once the supernatant was carefully removed, a 1.5-mL aliquot was used to inoculate 2 Mu ¨ller-Hinton and 1 blood agar plates. A set of 9 different E-test strips, including amoxicillin, amoxicillin plus clavulanate, cefotaxime, cefepime, piperacillin, piperacillin-tazobactam, ertapenem, doripenem, and colimycin (BioMe ´rieux, Marcy-L'e ´toile, France), was directly applied to the Mu ¨ller-Hinton agar plates. Vancomycin and cefoxitin E-test strips were applied onto the blood agar plate (Fig. 1). The Mu ¨ller-Hinton agar plates were incubated at 37°C, whereas the blood agar plates were in a 5% CO 2 incubator at 37°C.

From June 2010 to June 2013, 140 CRE isolates were identified in a teaching hospital in Shanghai. In a retrospective review, we screened for several carbapenemase genes (bla KPC , bla IMP , bla VIM , bla OXA-48 , bla NDM , bla NMC , bla IMI , and bla SME ) according to primers used in previous studies (Nordmann et al., 2011; Queenan and Bush, 2007) . Two IMI-positive isolates, the IMI-3-producing Raoultella ornithinolytica RJ46C and the IMI-2-producing Escherichia coli RJ18, were identified and retained for additional study. The minimum inhibitory concentrations (MICs) of amikacin, ciprofloxacin, imipenem, ertapenem, meropenem, ceftriaxone, ceftazidime, cefepime, polymyxin B (bioMérieux, France), and tigecycline (Liofilchem, Italy) were determined by Etests and were interpreted according to Clinical and Laboratory Standards Institute guidelines (M100-S25).