OBJECTIVE A surveillance study was performed for nosocomial infections in order to investigate the change in antimicrobial resistance of Klebsiella pneumoniae,especially the strains isolated from 1999 to 2004.METHODS K-B test was used for the antibiotics susceptibility test and the results were read based on National Committee for Clinical Laboratory Standards(NCCLS) of the USA.The situation of ESBLs-producing strains of K.pneumoniae was investigated.RESULTS Totally 326 K.pneumoniae strains showed the highest susceptibility to imipenem.Ceftazidime,cefepime,and cefoperazone/sulbactam also showed excellent activity against K.pneumoniae.The prevalence of ESBLs from 326 strains was 20.2%.CONCLUSIONS It is important to study the drug resistance in nosocomial infections by K.pneumoniae.

An ultra-high performance liquid chromatography-tandem mass spectrometry ( UHPLC-MS/MS ) method was developed and validated for the simultaneous determination of 9 kinds of trace endocrine disrupting chemicals in biological samples using ultrasonic-assisted extraction followed by purification with gel permeation chromatography ( GPC) and silica gel columns. The sample extracts were purified by Bio beads S-X3 GPC columns with cyclohexane/ethyl acetate (1:1, V/V) as mobile phase, and the target compounds were eluted in the fraction of 12-28 mL retention volume. Electrospray ionization source operated in positive mode and atmospheric pressure chemical ionization source operated in negative mode were used for mass spectrometric detection. Data acquisition was carried out in multiple reaction monitoring mode. Recoveries were predominately within 65 . 2%-118 . 0%. Method quantification limits were 0 . 1-9 . 7 ng/g dw ( dry weight ) . This method was successfully applied to the analysis of the target endocrine disrupting chemicals in carps collected from the Pearl River. with the exception of carbanilide and triclocarban, the rest analytes were detected in fish tissue samples, with the concentrations varied within the range of 0. 1-22. 6 ng/g dw.