Antimicrobial resistance among nosocomial gram-negative bacilli: report from Chinese Meropenem Susceptibility Surveillance in 2008.

Objective To investigate antimicrobial resistance situation of nosocomial gram-negative bacilli in China in 2008.Methods A total of 1,057 consecutive and non-repetitive gram-negative bacilli strains were isolated from 10 hospitals during September,2008 to December,2008 in China.All isolates were sent to the central laboratory for reidentification and susceptibility tests.The minimal inhibitory concentration(MICs)of meropenem and other antibacterial agents were determined by agar dilution method.Results The activity of antibacterial agents against Enterobacteriaceae was in the following order:meropenem(susceptible rate,99.4%)imipenem(99.3%)amikacin(90.4%).The most potent agents against E.coli and K.pneumoniae included meropenem,imipenem(97.9%～100%),piperacillin/tazobactam(87.2%～97.9%),and amikacin(82.3%～92.9%).The most potent agents against E.cloacae,E.aerogenes,and Citrobacter freundii included meropenem,imipenem(97.4%~100%),amikacin(87.2%~91.9%),and cefepime(82.4%~93.5%).The most potent agents against Pseudomonas aeruginosa were amikacin(77.4%),followed by meropenem (76%),piperacillin/tazobactam(70.5%),and imipenem(70.5%).The most potent agents against Acinetobacter baumannii were imipenem(58.6%),meropenem(57%),and cefoperazone/sulbactam(49.2%).The most potent agents against Burkholderia cepacia were ceftazidime(77.4%),meropenme(75.5%),and piperacillin/tazobactam(69.8%).Conclusion Carbapenems remains very potent against Enterobacteriaceae.A.baumanni and P.aeruginosa,especially A.baumanni,have increased resistance to carbapenems.