Methods: A nationally representative retrospective cohort study among adult patients admitted to any VA hospital from 2004 through 2014. Carbapenem resistance was defined by CLSI breakpoints in effect during a given year. Inclusion criteria were: i) hospital admission; ii) age ≥ 18 years; iii) ≥ 1 blood culture positive for an Enterobacteriaceae species demonstrating resistance to ≥ 1 carbapenem agent per 2015 CDC CRE definitions (including ertapenem). In recurrent CRE-BSI, only the first case was included. Incidence densities of CRE-BSI were compared year-by-year (overall and by CRE species category) using linear regression analysis.
Results: A total of 1,301 CRE-BSI cases were observed over the study period, corresponding to an overall incidence of 1.79 cases/10,000 hospitalizations. There was a profound increase in the incidence of CRE-BSI from 1.08 cases/10,000 hospitalizations in 2004 to 2.24 cases/10,000 hospitalizations in 2009. Following a decrease in incidence in 2010 (1.61 cases/10,000 hospitalizations), rates of CRE-BSI increased again by 2014 (1.90 cases/10,000 hospitalizations). The majority of CRE-BSI cases were due to Klebsiella pneumoniae (n=638; 49.0%), followed by Enterobacter species (n=188; 14.5%), Proteus species (n=148; 11.1%), and Escherichia coli (n=120; 9.2%). The incidence of CRE-BSI caused by Proteus species increased from 0.19 cases/10,000 hospitalizations in 2009 to 0.38 cases/10,000 hospitalizations in 2014. In contrast, the incidence of CRE-BSI caused by Escherichia coli decreased from 0.29 cases/10,000 hospitalizations in 2009 to 0.10 cases/10,000 hospitalizations in 2014.
Conclusion: In a national sample of hospitalized VA patients, marked changes in the incidence of CRE-BSI were observed from 2004-2014. Rates of CRE-BSI caused by Proteus species appear to be increasing and rates of CRE-BSI caused by Escherichia coli appear to be decreasing.
N. S. Britt,
Merck & Co., Inc.:
Gilead Sciences, Inc.: Grant Investigator , Consulting fee
Merck & Co., Inc.: Grant Investigator , Consulting fee
Theravance Biopharma US, Inc.: Board Member and Speaker's Bureau , Speaker honorarium
E. M. Potter, None
M. E. Steed, Merck & Co., Inc.: Grant Investigator , Research grant
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