CHINET 2009 surveillance of bacterial resistance in China

Objective To investigate the resistance of clinical isolates from hospitals in several regions of China.Methods Twelve general hospitals and two children s hospitals were involved in this program.Bacterial susceptibility testing was carried out according to a unified protocol using Kirby-Bauer method.Results were analyzed according to CLSI 2010 breakpoints.Results A total of 47 850 clinical isolates were collected from January to December 2010,of which gram negative organisms and gram positive cocci accounted for 71.6%and 28.4%respectively.Methicillin-resistant strains accounted for an average of 51.7%in S.aureus(MRSA) and 71.6%in coagulase negative Staphylococcus(MRCNS).The resistance rates of MR strains toβ-lactams and other antimicrobial agents were much higher than those of MS strains.However, 73.9%and 63.2%of MRSA strains were still susceptible to sulfamethoxazole-trimethoprim and fosfomycin,while 87.8%and 68.7%of MRCNS strains were susceptible to rifampin and fosfomycin.No staphylococcal strains were found resistant to vancomycin, teicoplanin or linezolid.But for the first time,a few coagulase-negative staphylococcal strains were found intermediate to linezolid,mainly Staphylococcus haemolyticus.The resistance rates of E.faecalis strains to most tested drugs including nitrofurantoin, fosfomycin and ampicillin were much lower than those of E.faecium.Some strains of both species were resistant to vancomycin.Vancomycin resistant strains of E.faecalis and E.faecium were mainly Van-A type based on their phenotype. Regarding non-meningitis S.pneumoniae strains,the number of PSSP strains isolated from adults were less than those isolated in 2009,but the prevalence of PRSP strains increased.The prevalence of ESBLs producing strains was 56.2%in E. coli and 43.6%in Klebsiella spp.(K.pneumoniae and K.oxytoca) isolates on average.ESBLs-producing Enterobacteriaceae strains were more resistant than non-ESBLs-producing strains in terms of antibiotic resistance rates.The strains of Enterobacteriaceae were still highly susceptible to carbapenems.Overall less than 6%of these strains were resistant to carbapenems.About 57.1%and 58.3%of Acinetobacter spp.(A.baumannii accounts for 86.8%) strains were resistant to imipenem and meropenem.Compared with the data of year 2009,pan-drug resistant strains in K.pneumoniae and A.baumannii increased significantly.Conclusions The antibiotic resistance of clinical bacterial isolates is growing in 2010.It poses a serious threat to clinical practice and implies the importance of strengthening infection control.