An observational study on carbapenem-resistant Enterobacterales (CRE) colonisation and subsequent risk of infection in an adult intensive care unit (ICU) at a tertiary care hospital in India

BACKGROUND: Carbapenem-resistant Enterobacterales (CRE) are a global health problem with a growing prevalence. India has a high prevalence of CRE. CRE infections are difficult to treat, and are associated with significant morbidity and mortality. Colonisation is generally a prerequisite for infection and the prevention of CRE colonisation is key to the prevention of CRE infection. OBJECTIVES: To determine the prevalence of CRE colonisation and subsequent infections in an adult intensive care unit (ICU) in India. METHODS: We conducted a prospective observational study in which perirectal swabs were obtained along with relevant clinical details of consenting adult patients upon ICU admission between January 2019 and August 2020. Rectal screening was performed using MacConkey agar plates with ertapenem disks and further identification was performed using conventional microbiological techniques. Ertapenem minimum inhibitory concentration (MIC) was determined using an epsillometer (E) test. The modified carbapenem inactivation (mCIM) test and EDTA carbapenem inactivation test (eCIM) were performed to confirm carbapenem resistance using the Clinical Laboratory Standards Institute (CLSI) 2020 guidelines. RESULTS: 192 ICU patients were screened for CRE. 37 patients were found to be colonised with CRE. Klebsiella pneumoniae (N=25; 67.6%) was the most frequent CRE isolate, followed by Escherichia coli (N=11; 29.7%) and one Enterobacter species (N=1; 2.7%). 89.2% (33/37) patients developed CRE infection. Pneumonia was the most common CRE infection identified in 12/33 (36.4%) patients.during the hospital stay. The median duration of hospital stay was longer (17 days) for CRE colonised compared to CRE non-colonised patients (9 days) (P<0.001). Death occurred in 27 % (N=10/37) of CRE-colonised patients during the hospital admission. CONCLUSION: CRE colonisation is associated with high risk of subsequent CRE infection and longer ICU and hospital admission.