Surveillance of antimicrobial resistance in clinical isolates from Wuhan Tongji Hospital in 2009

Objective To investigate the antibiotic resistance of clinical strains isolated from Tongji Hospital to antimicrobial agents commonly used during 2009. Methods The minimum inhibitory concentrations (MICs) of penicillin,ceftriaxone for S. pneumoniae and vancomycin for Staphylococcus spp. were determined by E-test. Other antimicrobial susceptibility was tested by Kirby-Bauer method. Drug resistance was judged according to the Clinical and Laboratory Standards Institute (CLSI) 2008 M100-S18. Results A total of 5 791 bacterial strains were isolated in 2009. Gram-positive cocci,Gram-negative bacilli and Fungus accounted for 28.9% (1 676/5 791),59.8% (3 465/5 791) and 10.9% (630/5 791),respectively. For in-patients,the top 5 isolates were E. coli,Acinetobacter spp.,K. pneumoniae,S. aureus and P. aeruginosa. But for out-patients,E. coli,P. aeruginosa,K. pneumoniae,H. influenzae and S. aureus were the most common pathogens. The prevalence of MRSA and MRCNS were 62.9% (350/556) and 83.4% (399/478),respectively in 2009. Strains resistant to vancomycin and/or teicoplanin were found in Enterococcus (6 isolates). The prevalence of penicillin non-susceptible S. pneumoniae (PNSSP) was 30.1% (non-meningitis). All the 4 isolates from cerebrospinal fluid were penicillin-resistant S. pneumoniae (PRSP). Strains of Enterobacteriaceae were still highly susceptible to imipenem and meropenem. But we also identified a few resistant strains. The prevalence of ESBLs-producing E. coli and Klebsiella spp. was 78.3% (626/800) and 49.8% (311/625),respectively. The prevalence of carbapenems resistant Acinetobacter spp. was higher than 50%,while the prevalence of imipenem and meropenem resistant P. aeruginosa was 20.3% and 11.2%,respectively. X. maltophilia was highly susceptible to levofloxacin,sulfamethoxazole-trimethoprim and minocycline. About 77.3% to 92.4% of the isolates were susceptible to these 3 antibiotics. The sensitivity of H. influenzae isolates to sulfamethoxazole-trimethoprim was nearly 30%. Only 60% of H. influenzae strains were sensitive to ampicillin. Conclusions Most clinical isolates in 2009 were Gram-negative bacilli. Bacterial resistance is becoming more serious. The prevalence of multi-drug resistant strains is increasing,especially vancomycin-resistant Enterococcus and carbapenems-resistant Acinetobacter spp. It is necessary to identify these resistant strains timely for effective control of outbreak in hospital.