Rates of Fecal Transmission of Extended-Spectrum β-Lactamase-Producing and Carbapenem-Resistant Enterobacteriaceae Among Patients in Intensive Care Units in Korea

Background: We investigated the rates of fecal transmission of extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae (ESBL-E) and carbapenem-resistant Enterobacteriaceae (CRE) among patients admitted to intensive care units (ICUs). Methods: From June to August 2012, rectal cultures were acquired from all patients at ICU admission. For patients not carrying ESBL-E or ORE at admission, follow-up cultures were performed to detect acquisition. A chromogenic assay was used to screen for ESBL-E and ORE. Bacterial species identification and antibiotic susceptibility tests were performed using the Vitek 2 system (bioMerieux, France). ESBL genotypes were determined by PCR, and clonal relatedness of the isolates was assessed by pulsed-field gel electrophoresis. Results: Out of 347 ICU admissions, 98 patients were found to be carriers of ESBL-E (28.2%, 98/347). Follow-up cultures were acquired from 91 of the patients who tested negative for ESBL-E at admission; the acquisition rate in this group was 12.1% (11/91), although none was a nosocomial transmission. For ORE, the prevalence of fecal carriage was 0.3% (1/347), and the acquisition rate was 2.9% (4/140). None of the ORE isolates were carbapenemase-producers. Conclusions: The high prevalence of ESBL-E carriage on admission (28.2%), coupled with rare nosocomial transmission and the very low carriage rate of ORE (0.3%), challenge the routine use of active surveillance in non-epidemic settings. Nevertheless, passive surveillance measures, such as rapid and accurate screening of clinical specimens, will be critical for controlling the spread of CRE.