Year of Publication



Public Health

Degree Name

Dr. of Public Health (Dr.P.H.)

Committee Chair

Dr. Wayne Sanderson

Committee Member

Dr. Derek Forster

Committee Member

Dr. Phillip Westgate

Committee Member

Dr. Kathleen Winter


Background: This study aimed to identify risk factors of carbapenem-resistant Enterobacteriaceae (CRE) acquisition among adult intensive care unit (ICU) patients at a Kentucky academic medical center and to evaluate sink drains as a possible environmental reservoir of carbapenem-resistant organism (CRO) transmission.

Methods: A retrospective cohort study was conducted from October 1, 2013 through October 31, 2016. Intensive care unit patients were screened for CRE at admission and weekly until discharge. Cases were defined as patients who tested positive for CRE on ICU admission day 3 or greater. Sink drains were sampled for CROs in selected units from January 2018 through August 2018. Whole-genome sequencing was conducted on a subset of sink drain and patient isolates to identify genetic relationships.

Results: The cohort consisted of 7026 patients with 7888 admissions. A total of 51 patients tested positive for CRE after day 3 of admission. Independent risk factors of CRE acquisition included morbid obesity (RR=2.10; 95% CI 1.12-3.95); admission to a medical ICU (RR=2.39; 95% CI 1.32-4.35); use of a carbapenem in the previous 90 days (RR=2.27; 95% CI 1.21-4.26); previous 90 day diagnoses of Clostridium difficile enterocolitis (3.51; 95% CI 1.27-9.68) and pressure ulcers (3.48; 95% CI 1.91-6.36); and having drainage tubes (RR=2.63; 95% CI 1.38-4.98), tube feeds (RR=4.46; 95% CI 1.74-11.43); and dialysis (RR=2.22; 95% CI 1.15-4.27) in the prior 90 days. The incidence rate of CRE acquisition was estimated at 6.52 (95% CI 4.81-8.64) per 10 000 ICU patient days. Sink drains were a common environmental reservoir of carbapenemase-producing organisms; however, their presence could not be directly linked to patient transmission.

Conclusions: This study revealed independent risk factors of CRE acquisition within ICUs of a Kentucky academic medical center. The majority of CRE risk factors are associated with invasive procedures and alteration of immune system and/or colon microbiota. Sink drains serve as an important environmental reservoir of CROs and should be considered in Infection Prevention processes. These results will assist in creating a more targeted CRE active surveillance system.

Available for download on Wednesday, December 20, 2023

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