Epidemiology and risk factors of rectal colonization of carbapenemase-producing Enterobacteriaceae among high-risk patients from ICU and HSCT wards in a university hospital

Abstract

Background: Nosocomial infections caused by carbapenemase-producing Enterobacterieceae (CPE) constitute a major global health concern and are associated with increased morbidity and mortality. Rectal colonization with CPE is a risk factor for bacterial translocation leading to subsequent endogenous CPE infections. This prospective observational study was aimed to investigate the prevalence and epidemiology of rectal colonization of CPE, 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 in a university hospital in China. Methods: In a prospective cohort study, 150 fecal samples from rectal swabs were consecutively obtained for inpatients from the ICU and HSCT wards from November 2018 to May 2019, and screening test for CPE was conducted by using home-made trypsin soybean broth (TSB) selective media and MacConkey agar. Antimicrobial susceptibility was determined by the broth microdilution method and carbapenemase genes were characterized by both the GeneXpert Carba-R and PCR for blaKPC, blaNDM, blaIMP, blaVIM and blaOXA. In order to further investigate the risk factors and clinical outcomes of CPE colonization, a prospective case-control study was also performed.Results: 26 suspected CPE strains, including 17 Klebsiella pneumoniae, 6 Escherichia coli, 1 Citrobacter freundii, 1 Enterobacter Kobe, and 1 Raoultella ornithinolytica, were identified in 25 non-duplicated fecal samples from 25 patients, with a carriage rate of 16.67% (25/150). Through GeneXpert Carba-R and subsequent PCR and sequencing, all the suspected CPE isolates were identified to be positive for the carbapenemase genes, of which 17 were blaKPC-carriers, and another 9 were blaNDM-producers. Multivariate analysis indicated that urinary system diseases, operation of bronchoscopy, and combined use of antibiotics were independent risk factors for acquiring CPE colonization in high-risk patients from the ICU and HSCT wards. Conclusions: This study revealed a high prevalence of rectal CPE colonization in high-risk patients from ICU and HSCT wards, and a predominant colonization of the KPC-producing K. pneumoniae strains. Stricter infection control measures are urgently needed to limit the dissemination of CPE strains, especially in patients who were afflicted by urinary system diseases, have underwent bronchoscopy, and were previously exposed to combined antibiotic use.

Effectiveness of surveillance cultures for high priority multidrug-resistant bacteria in hematopoietic stem cell transplant units

“…In this study, the collection site varied according to the pathogen tested ( Table 2 ). Our data corroborate the fact that rectal swabs were more sensitive than fecal cultures 20 , 21 , especially regarding VRE and CRE. Despite this, rectal swabs should be used with care in patients undergoing HSCT to prevent skin or mucosal injuries during severe neutropenia.…”

Usefulness of surveillance Cultures for Carbapenem-resistant Enterobacteriaceae, Carbapenem-resistant Pseudomonas aeruginosa and Vancomycin-resistant Enterococci in Hematopoietic Stem Cell Transplant Unit

“…Our data corroborate the fact that the rectal swab is more sensitive than the culture of feces [18,19], especially regarding VRE and CRE. Despite this, the use of rectal swab in HSCT patients should be used with care, to avoid skin or mucosal breakdown during severe neutropenia.…”

Identification and infection control of carbapenem-resistant Enterobacterales in intensive care units

“…A study comprising active screening of CRE infections in hematology units in China reported that the CRE colonization rate in patients was 16.46% [27]. In a prospective cohort study of inpatients from the ICU and hematopoietic stem cell transplantation wards, the CRE colonization rate was 16.67% and KPC-producing K. pneumoniae was dominant [28]. National surveillance of CRE strains in China showed that KPC-2 and NDM were responsible for phenotypic resistance in 90% of CRE strains [29].…”