Incidence of Carbapenem Resistant Enterobacteriaceae (CRE) Bacteremia in Patients Colonized with CRE

Background:

Carbapenemase Resistant Enterobacteriaceae (CRE) are an increasing challenge in the prevention and management of both community acquired and hospital acquired infections. Unfortunately, despite early detection of CRE carriers and infection control precautions CRE bacteremias have developed in our hospital. The primary objective of our study is to investigate the prevalence of CRE bacteremias among CRE positive carriers and identify patients at risk for developing a CRE bacteremia.

Methods:

Using our Laboratory Information System all CRE bacteremias and CRE rectal screens (Positive and Negative results) performed between January 2014 and January 2016 were identified. Growth on selective media was confirmed by modified Hodge test, colistin and temocillin E-tests, and sent to reference laboratory for additional testing. Sensitivities were performed by Vitek2 using EUCAST breakpoints and confirmed by reference laboratory. Demographic characteristics and infection control precautions taken were recorded.

Results:

During the two year period, 15042 Rectal screens were performed of which 504 were positive. There were 18 positive blood cultures taken from 13 patients. 7/13 (54%) were male, mean age 75.5 years (range 38-90). 9 patients have died, deaths occurred between 1-567 days post bacteremia, 5 deaths occurred within 30 days of bacteremia, 8 within 90 days. 7 patients had no rectal screening performed, a further 2 patients, had screening performed after the diagnosis of bacteraemia, of the remaining 4, only 2 had positive screens. In one patient, the rectal screen revealed a second CRE, Citrobacter amalonaticus. The majority of bacteremias were caused by Klebsiella pneumoniae (12), others were Serratia marcescens (4), Enterobacter aerogenes (1), Escherichia coli (1). All except one isolate were sensitive to aminoglycosides. One K. pneumoniae isolate was resistant to gentamicin and tobramycin but remained sensitive to amikacin. All isolates produced KPC enzyme.

Conclusion:

There is a low incidence of bacteremia in patients colonized with CRE. Almost half of the patients who developed bacteremia had not been screened, and may not have been recognized as being at risk. This suggests that screening and infection control measures may protect from the development of bacteremia in patients colonized with CRE.