Bloodstream Infections in Southwestern China: 2012 Whire Union Report on Bacterial Susceptibility toAntibiotics

Objective To test the susceptibility of blood culture isolates to antibiotics in a sample of hospitals in Southwestern China in 2012. Methods Blood culture samples were taken and tested from the patients under the Whire Union surveillance in three tertiary hospitals in Southwestern China in 2012. We performed antimicrobial susceptibility analyses on the blood culture isolates using WHONET5.5 and SPSS19.0．Results A total of 1 745 isolates were identified: 877 Gram-positive (50.26％); 868 Gram-negative (49.74％). Coagulase-negative Staphylococcius (CNS，541 strains，31.00％)，Escherichia coli (ECO,379 strains，21.72％)，Klebsiella spp. (170 strains，9.74％)，Enterococcus spp. (143 strains，8.20％) and Staphylococcus aureus (SAU, 128 strains，7.34％) comprised the majority of isolates．Methicillin-resistant was found in 37.5％ of S.aureus and 85.4％ of CNS，respectively．Zero and 6．3％ resistance to vancomycin were found for Enterococcus faecalis and E．faecium, respectively，compared with a 1.4％and 7.9％ resistance to linezolid, respectively. Imipenem-resistance occurred in 0.7% E.coli, 3.6% Klebsiella spp., and 11.1% Enterobacter spp.. Nonfermenters were highly resistant to carbapenems，with an imipenem resistance rate of 25.0% in P.aeruginosa and 79.1% in Acinetobacter baumannii. Antimicrobial usage and critical-care units were identified as risk factors for MRSA and multi-drug-resistant A. baumannii infections. Patients undergoing tracheotomy/endotracheal intubation were likely to develop multi-drug-resistant A. baumannii infections than others. Conclusion CNS， E．coli，Klebsiella spp.，Enterococcus spp. and S．aureuswere the predominant organisms in bloodstream infections in Southwestern China. Low methicillin-resistant rate was found in Staphylococcus aureus But vancomycin-resistant rate was high in E．faecium. Imipenem-resistant rates varied in Enterobacteriaceae: higher in non-fermenting bacteria especially in Acinetobacter spp.. Use of abtimicrobial drugs and invasive procedures can lead to development of antimicrobial drugs-resistance．