Surveillance of antibiotic resistance in clinical isolates from First Affiliated Hospital of Zhejiang University Medical College in 2005

Objective To investigate the antibiotic resistance in clinical isolates from First Affiliated Hospital of Zhejiang University Medical College in 2005.Methods Antimicrobial susceptibility testing was carried out by means of Kirby-Bauer(KB)technique.The data were analyzed by WHONET 5.3 software.Results Of the 4 551 clinical isolates collected,66.2% were gram-negative bacilli and 33.8% were gram-positive cocci.Nonfermentative gram negative strains accounted for 55.2% of all gram-positive isolates.About 68.6% of Staphylococcus aureus were methicillin-resistant(MRSA),and 86.8% of coagulase negative Staphylococcus isolates were methicillin-resistant(MRCNS).No vancomycin-or teicoplanin-resistant isolate was found in Staphylococcus,Enterococcus faecalis or Enterococcus faecium.The prevalence of extended-spectrum β-lactamases(ESBLs)was 55.8% in E.coli,43.5% in K.pneumoniae and 9.1% in Proteus mirabilis.Imipenem and meropenem were the most potent antimicrobial agents against Enterobacteriaceae(96%).About 35.7% of Acinetobacter baumannii isolates were resistant to cefoperazone-sulbactam,while more than 60% of the isolates were resistant to imipenem or meropenem.The resistance rate of P.aeruginosa was lowest to amikacin(14.7%),followed by ceftazidime,cefepime,cefoperazone-sulbactam and aztreonam(23%-29%).More strains were resistant to imipenem(33.4%)than to meropenem(25.2%).Minocycline showed good activity against Stenotrophomonas maltophilia,Chryseobacterium meningosepticum and Burkholderia cepacia(resistance in 10% of the strains).Conclusions Special attention should be paid to the serious antimicrobial resistance in nonfermenting gram-negative bacilli,especially A.baumannii.