Risk Factors and Epidemiology of Carbapenemase-Producing Enterobacteriaceae in High-Risk Patients

Illustration of Enterobacteriaceae bacteria. Individual bacterium are shown as pink rod shapes with multiple hair-like flagella used for motility. The Enterobacteriaceae family contains over a hundred species including Shigella, Klebsiella, Salmonella and Escherichia coli and can be found in animal guts, water and soil. Some Enterobacteriaceae members are animal and plant parasites.
Investigators assessed the risk factors, prevalence, and epidemiology of carbapenemase-producing Enterobacteriacea in high-risk patients from ICU and HSCT wards.

There is a high prevalence of rectal carbapenemase-producing Enterobacteriaceae (CPE) colonization in high-risk patients in the intensive care unit (ICU) and hematopoietic stem cell transplantation (HSCT) patients, according to data published in Antimicrobial Resistance and Infection Control.

Nosocomial CPE infections constitute a major global health concern. Rectal colonization with CPE is a risk factor for bacterial translocation and subsequent endogenous CPE infections. Investigators performed a prospective observational study at a university hospital in China to investigate the prevalence and epidemiology of rectal colonization, the carbapenemase genotypes, and to identify the independent risk factors for the acquisition of CPE colonization in high-risk patients from ICU and HSCT wards.

Twenty-six clinical CPE strains were identified in 25 non-duplicated rectal swabs from 25 patients (women, n=11; male, n=14) whose mean age was 63.48 (±22.81) years. The carriage rate was 16.67%. The identified strains included 17 Klebsiella pneumoniae, 6 Escherichia coli, 1 Citrobacter freundii, 1 Enterobacter Kobe, and 1 Raoultella ornithinolytica.

All of the suspected CPE isolates were positive for carbapenemase genes through GeneXpert Carba-R and subsequent PCR and sequencing. The most common gene found was blaKPC (17/26), detected in all 17 K. pneumonia isolates, followed by blaNDM (9/26), detected in the remaining isolates.

Multi-locus sequence typing further identified all the CPKP isolates as the ST11 clone. Multivariable analysis identified urinary system diseases, operation of bronchoscopy, and combined use of antibiotics as independent risk factors for acquiring CPE colonization in these patient groups.

Some limitations include a small sample size, so the results may not be applicable to other settings. Furthermore, they did not investigate the subsequent CPE infection rates in these colonized patients.

The study provided a detailed report of the prevalence of molecular epidemiology and risk factors for rectal CPE colonization in these high-risk patients from ICUs and HSCT wards. They conclude, “A bundle of infection control and prevention measures with an anti-infective stewardship program is urgently needed to reduce the rectal CPE colonization, especially in patients who were afflicted by urinary system diseases, have underwent bronchoscopy, and were previously exposed to combined antibiotic use.”


Yan L, Sun J, Xu X, Huang S. Epidemiology and risk factors of rectal colonization of carbapenemase-producing Enterobacteriaceae among high-risk patients from ICU and HSCT wards in a university hospital. Antimicrob Resist Infect Control. 2020; 9:155. doi:10.1186/s13756-020-00816-4.