Abstract：Objective To survey the distribution and changing pattern of susceptibility in blood culture isolates
in 10 hospitals across Western China in 2016—2017. Methods The isolates from blood cultures were routinely
identified. The antimicrobial susceptibility was determined by the Kirby-Bauer method in the participating institutions.
Results 10,504 bacterial isolates and their antibacterial susceptibility data were collected from all the 10 hospitals,
which included 4,412 (42%) Gram-negative bacteria isolates and 6,092 (58%) Gram-positive bacterial isolates. The
most frequent isolates were E. coli (28.9%), coagulase-negative Staphylococcus (CNS)(20.3%), Klebsiella (12.7%),
Enterococcus (7.4%), S. aureus (7.3%), Acinetobacter (3.7%), Enterobacter (3.2%), P. aeruginosa (3.1%), betahemolytic
Streptococcus (2.5%), and other Streptococcus (1.5%), taken together accounting for 90.6% of all blood
culture isolates. The prevalence of MRSA in S. aureus and MRCNS in coagulase-negative Staphylococcus was
32.9% and 74.9%, respectively. The percentage of gentamicin-or ampicillin-resisitant E. faecium was 46.6% and
6.9%, respectively, significantly higher than that of E. faecalis. The percentage of penicillin-resistant Streptococcus
pneumoniae and Streptococcus viridans was 3.4% and 8.9%. No strain was found resistant to vancomycin, teicoplanin
or linezolid in Staphylococcus, Streptococcus or S. pneumoniae. The prevalence of vancomycin-resistant strain was 2%
in E. faecium. The prevalence of linezolid-resistant strain was 1.6% in E. faecalis and 0.4% in E. faecium. Imipenem
or meropenem resistance was found in about 0.7%~13.3% of the isolates in the Enterobacteriaceae species, including
E. coli, Enterobacter, Serratia, Proteus and Phytrium. Nonfermenters were highly resistant to carbapenems, especially
Acinetobacter (68%). Carbapenems resistance rate was 20% of P. aeruginosa isolates. Conclusion Gram-negative
racilli plays an important role in blood stream infections. The resistance to the first line antibiotic is common among
all isolates. Antimicrobial agents should be used appropriately to reduce the selection pressure. Hospital infection
control measures should be strengthened to prevent the spread of resistant organisms.
