Surveillance of bacterial resistance in Peking Union Medical College Hospital during 2014 / 中国感染与化疗杂志

ABSTRACT

Objective To investigate the antimicrobial resistance proifle in the clinical bacterial strains isolated from Peking Union Medical College Hospital during 2014.Methods A total of 8 295 nonduplicate clinical isolates were collected. Disc diffusion test (Kirby-Bauer method) and automated systems were employed to study the antimicrobial susceptibility. The data were analyzed by using WHONET 5.6 software according to CLSI 2014 breakpoints.Results Of the 8 295 isolates, 67.4% were gram-negative, and 32.6% were gram-positive. The top 10 most frequently isolated bacteria wereE. coli(18.1%),P. aeruginosa (10.8%),K. pneumoniae (10.2%),S. aureus (9.8%), A. baumannii(9.2%),E. faecalis (6.3%),E. faecium (4.1%), coagulase-negativeStaphylococcus (4.1%),E. cloacae (3.1%) andS. maltophilia (2.9%). Methicillin resistant strains inS. aureus (MRSA) and coagulase negativeStaphylococcus (MRCNS) accounted for average of 28.4% and 66.5%, respectively. The resistance rates of MR strains to β-lactams and other antimicrobial agents were much higher than those MS strains. Overall, 81.3% of MRSA strains were still susceptible to trimethoprim-sulfamethoxazole, while 81.1% of MRCNS strains were susceptible to rifampin. No staphylococcal strains were resistant to vancomycin, teicoplanin or linezolid. The resistance rate ofE. faecalis strains to most of the drugs tested (except chloramphenicol) was much lower than those ofE. faecium. Several strains of bothE. faecium andE. faecalis were found resistant to vancomycin and teicoplanin, which were Van-A and Van-B types based on their phenotype. No linezolid resistant enterococcal strains were found. Data showed that 90.8% ofβ-hemolyticStreptococcus strains were susceptible to penicillin. ESBLs-producing strains accounted for 54.2%, 31.0% and 28.9% inE. coli,Klebsiella spp (K. pneumoniae andK. oxytoca) andP. mirabilis, respectively.Enterobacteriaceae isolates were still highly susceptible to carbapenems. Overall, no more than 3.3% of these strains were resistant to carbapenems. A few extensively drug-resistant strains ofK. pneumoniae (1.3%, 11/842) were identiifed. The resistance rates ofP. aeruginosa to imipenem and meropenem were 17.5% and 11.8%, respectively.P. aeruginosa isolates showed the lowest resistance rate (5.9%) to amikacin. And 69.0% and 67.4% ofA. baumanniiisolates were resistant to imipenem and meropenem.A. baumannii isolates showed the lowest resistance rates to cefoperazone-sulbactam and minocycline (47.8% and 28.7%), respectively. The prevalence of extensively drug-resistant strains was 32.3% inA. baumannii and 1.8% inP. aeruginosa. The prevalence of β-lactamase inH. inlfuenzae was 33.7%. More than 93.0% ofS. pneumoniae strains were resistant to erythromycin and clindamycin.Conelusions Bacterial resistance is still increasing in this hospital, especially carbapenem resistantEnterobacteriaceae. It is necessary to take effective hospital infection control measures and use antibiotics rationally.