Analysis of pathogen spectrum and resistance of clinical common organisms causing bloodstream infections, hospital-acquired pneumonia and intra-abdominal infections from thirteen teaching hospitals in 2013

Abstract

To investigate the spectrum and antimicrobial resistance of major pathogensthat causing nosocomial infections in China, 2013. Nosocomial cases as well as pathogens causing bloodstream infections (BSI), hospital-acquired pneumonia (HAP) and intra-abdominal infections (IAI) from 13 teaching hospital around China were collected. The minimum inhibitory concentrations (MICs) were determined by the agar dilution method. The CLSI M100-S23 criteria were used for interpretation. Of all cases, 1 022 cases were from BSI, 683 from HAP and 674 from IAI.Escherichia coli and Klebsiella pneumoniae were the most prevalent pathogens causing BSI and IAI while Acinetobacter baumanii (34.6%) and Pseudomonas aeruginosa were dominated in HAP. Tigecycline, imipenem and meropenem exhibited high potency against Enterobacteriaceae and the susceptibilities rates were 95.6%, 94.2%and 95.2% respectively. Enterobacteriaceae demonstrated high resistance against cephalosporins (52.3%) and fluoroquinolones (38.9%) but were susceptible to β-lactam+inhibitor. Of all the Enterobacteriaceae, 30.5% were ESBLs positive and 4.3% were carbapenem resistant. Acinetobacter baumanii showed low susceptibilities to the microbial agents except for tigecycline (90.5%) and colistin (100%). The rate of carbapenem resistant Acinetobacter baumanii was 76.6%. Amikacin, ciprofloxacin, cefepime and piperacillin/tazobactam showed high antibacterial activity against Pseudomonas aeruginosa with susceptible rate 88.5%, 77.6%, 72.7% and 64.5% respectively. The resistant rate to imipenem and meropenem were 42.1% and 32.2%. All Staphylococcus aureus (166 strains) were susceptible to tigecycline, linezolid, daptomycin and glycopeptides. MRSA accounted for 46.9% of all the Staphylococcus aureus. The prevalence of MRSA in IAI (55.2%) and HAP (54.4%) were higher that that in BSI (35.0%). No Enterococcus strains were found resistant to tigecycline, linezolid and daptomycin. VRE was found in Enterococcus faecium, accounting for 1.9% of all Enterococcus faecium strains. Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii and Pseudomonas aeruginosa are the most common pathogens causing nosocomial infections. Nosocomial pathogens showed high susceptibilities against tigecycline. For ESBLs-producing Enterobacteriaceae strains, β-lactam+Inhibitor show high antibacterial activities. Vancomycin, teicoplanin and linezolid exhibit high potency to Staphylococcus aureus and Enterococcus.