2011 CHINET surveillance of bacterial resistance in China

Objective To investigate the susceptibility and resistance of clinical bacterial isolates from hospitals in several regions of China.Methods Thirteen general hospitals and two children's hospitals were involved in this program. 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 2011.Results A total of 59 287 clinical isolates were collected from January to December 2011,of which gram negative organisms and gram positive cocci accounted for 71.5%(42 415/ 59 287) and 28.5%(16 872/59 287) respectively.The average prevalence of methicillin-resistant strains in S.aureus(MRSA) and coagulase negative staphylococcus(MRCNS) was 50.6%and 74.6%respectively.The resistance rates of MR strains toβ-lactams and other antimicrobial agents were much higher than those of MS strains.However,nearly 73.3%of MRSA strains were still susceptible to trimethoprim-sulfamethoxazole,while 88.2%of MRCNS strains were susceptible to rifampin. No staphylococcal strain was found resistant to vancomycin,teicoplanin or linezolid.In Enterococcus spp.,the resistance rates of E.faecalis strains to most tested drugs(except chloramphenicol) were much lower than those of E.faecium.Some strains of both species were resistant to vancomycin.Vancomycin resistant E.faecalis and E.faecium strains were mainly VanA type based on their phenotype.As for non-meningitis S.pneumoniae strains,the prevalence of PSSP strains isolated from both adults and children were higher than those isolated in 2010,but the prevalence of PRSP strains decreased.The prevalence of ESBLs producing strains was 50.7%in E.coli and 38.5%in Klebsiella spp.(K.pneumoniae and K.oxytoca) and 13.8%in Proteus mirabilis isolates on average.ESBLs-producing Enterobacteriaceae strains were more resistant than non-ESBLs-producing strains in terms of antibiotic resistance rate.The Enterobacteriaceae strains were still highly susceptible to carbapenems. Overall less than 6.1%of these strains were resistant to carbapenems.About 60.4%and 61.4%of Acinetobacter spp.(A. baumannii accounts for 88.6%) strains were resistant to imipenem and meropenem respectively.Compared with the data of year 2010,pan-drug resistant strains in K.pneumoniae and A.baumannii decreased.Conclusions The antibiotic resistance of clinical bacterial isolates is growing in 2011.The spread of multi-drug or pan-drug resistant strains in a specific region poses a serious threat to clinical practice and implies the importance of strengthening infection control.