Epidemiology of Carbapenem-Resistant Enterobacteriaceae at a Long-term Acute Care Hospital

Abstract

Background. Residents of long-term acute care hospitals (LTACHs) are considered important reservoirs of multidrug-resistant organisms, including Carbapenem-resistant Enterobacteriaceae (CRE). We conducted this study to define the characteristics of CRE-infected/colonized patients admitted to an LTACH and the molecular characteristics of the CRE isolates. Methods. This retrospective study was conducted to collect information on demographic and comorbid conditions in CREcolonized/ infected patients admitted to a 77-bed LTACH in Detroit between January 2011 and July 2012. Data pertaining to hospital- related exposures were collected for 30 days before positive CRE culture. Polymerase chain reaction (PCR) gene amplification, repetitive sequence-based PCR, and multilocus sequence typing (MLST) were performed on 8 of the CRE isolates. Results. The study cohort included 30 patients with CRE-positive cultures, 24 (80%) with infections, and 6 (20%) with colonization. The mean age of cohort was 69 ±12.41 years; 19 (63%) patients were ventilator-dependent, and 20 (67%) were treated with at least 1 antibiotic. Twenty-three (77%) patients had CRE detected following LTACH admission, and the median days from admission to CRE detection in these patients (interquartile range) was 25 (11-43). Seven more patients were already positive for CRE at the time of LTACH admission. Molecular genotyping and MLST of 8 CRE isolates demonstrated that all isolates belonged to the same strain type (ST258) and contained the blaKPC-3 sequence. Conclusions. The majority of patients with CRE presented several days to weeks after LTACH admission, indicating possible organism acquisition in the LTACH itself. The genetic similarity of the CRE isolates tested could further indicate the occurrence of horizontal transmission in the LTACH or simply be representative of the regionally dominant strain.