2012 CHINET surveillance of bacterial resistance in China

Objective To investigate the susceptibility and resistance of clinical bacterial isolates from hospitals in several major regions of China.Methods Thirteen general hospitals and two children's hospitals were involved in this pro-gram.Antimicrobial susceptibility testing was carried out according to a unified protocol using Kirby-Bauer method or automated systems.Results were analyzed according to the breakpoints of CLSI 2012.Results A total of 72 397 clinical isolates were collected from January through December 2012,of which Gram negative organisms and Gram positive cocci accounted for 71.9%(52 043/72 397)and 28.1%(20 354/72 397)respectively.The average prevalence of methicillin-resistant strains in S. aureus(MRSA)and coagulase-negative Staphylococcus(MRCNS)was 47.9%and 77.1%,respectively.The resistance rates of MR strains to beta-lactams and other antimicrobial agents were much higher than those of MS strains.However,nearly 87.0%of MRSA strains were still susceptible to trimethoprim-sulfamethoxazole,while 89.1%of MRCNS strains were susceptible to rifampin.No stahylococcal strain was found resistant to vancomycin,teicoplanin or linezdid.Nearly0.4%of the MRCNS strains were found resistant to teicoplanin.In Enterococcus spp.,the resistance rates of E.fecalis strains to most antimicrobial agents tested(except chloramphenicol)were much lower than those of E.faecium.Some strains of both species were resistant to vancomycin,most of which were VanA type based on their phenotype.Some strains resistant to teicoplanin or linezolid were identified in both species.The prevalence of ESBLs producing strains was 55.3%in E.coli,33.9%in Klebsiella spp.(K.pneumoniae and K.oxytoca)and 20.7% in Proteus mirabilis on average.ESBLs producing Enterobacteriaceae strains were more resistant than non-ESBLs-producing strains to all the antimicrobial agents tested.Enterobacteriaceae strains were still highly susceptible to the three carbapenems tested,the overall resistance rates being 4.4%-6.3%.The resistance rates of Acinetobacterspp.(A.baumannii accounted for 89.6%)to imipenem and meropenem were up to 57.0%and 61.0%, respectively.Some carbapenem resistant strains were found in various Enterobacteriaceae spp.,especially in K.pneumoniae. Conclusions Bacterial resistance is still an important problem in clinical setting in China,especially the carbapenem resistant Enterobacteriaceae,which is of great concern.