Surveillance of antimicrobial resistance in clinical isolates from Wuhan Tongji Hospital during 2010

Objective To investigate the antibiotic resistance in the clinical strains isolated from Tongji Hospital to the antimicrobial agents commonly used in 2010.Methods Antimicrobial susceptibility was tested by Kirby-Bauer method.The minimum inhibitory concentrations(MICs) of penicillin and ceftriaxone for S.pneumoniae and vancomycin for Staphylococcus spp.were determined by E-test.All data were analyzed by WHONET5.4 software.Results A total of 5 287 strains were isolated during 2010,including gram-positive cocci(1 476,27.9%),gram-negative bacilli(3 149,59.6%),and fungus(662,12.5%).The top five pathogenic bacteria isolated from outpatients were Escherichia coli,Pseudomonas aeruginosa,Klebsiella pneumoniae,Staphylococcus aureus and Haemophilus influenzae,while the top five pathogens isolated from inpatients were Escherichia coli,Staphylococcus aureus,Pseudomonas aeruginosa,Acinetobacter baumannii and Klebsiella pneumoniae.The prevalence of MRSA and MRCNS was 63.3% and 74.7%,respectively.The prevalence of ESBLs-producing Escherichia coli and Klebsiella pneumoniae was 80.1% and 55.6%,respectively.ESBLs-producing strains were more resistant than non-ESBLs-producing strains.Vancomycin resistance(VanA type) was identified by PCR in 11 strains of Enterococcus.The percentage of antibiotic-resistant E.faecium strains was significantly higher than that of E.faecalis(P 0.05).The prevalence of penicillin nonsusceptible Streptococcus pneumoniae(PNSSP) was 33.0%(non-meningitis strains).The percentage of Pseudomonas aeruginosa strains resistant to imipenem and meropenem was 18.5% and 14.3%,respectively.The percentage of Acinetobacter baumannii strains resistant to imipenem and meropenem was higher than 50%.More than 75% of Haemophilus influenzae isolates were susceptible to most antibiotics except ampicillin and trimethoprim-sulfamethoxazole.The prevalence of β-lactamases was 31.9% in these Haemophilus influenzae isolates.Conclusions Most isolates collected in our hospital during 2010 were gram-negative bacilli.The prevalence of multi-drug resistant strains is increasing compared to previous years,especially the increase of vancomycin-resistant Enterococcus and multi-drug resistant gram-negative bacilli.