530. Sequential Screening of High-Risk Patients for Carbapenemase-Producing Enterobacteriaceae Colonization

BACKGROUND: Early identification of patients colonized with carbapenemase-producing Enterobacteriaceae (CPE) facilitates the implementation of appropriate infection control measures and reduces nosocomial transmission. Sequential screening for CPE colonization of close contacts of known cases to confirm initial negative results is recommended. Fraser Health (FH) expanded sequential screening to patients with recent exposure to other risk factors following the identification of CPE in patients who initially screened negative. METHODS: FH screens patients for CPE who report healthcare outside of Canada or travel to endemic countries within the previous 12 months. Patients remain on contact precautions and are re-screened 7 and 21 days after the last known exposure date. We reviewed CPE cases with foreign healthcare or travel to endemic countries who screened negative on admission but subsequently screened positive within 30 days. Patients without confirmation of colonization through a rectal screen or possible exposure to a current nosocomial source were excluded. Whole-genome sequencing results were examined to confirm foreign healthcare or travel as the likely source of acquisition. Medical records were reviewed to obtain patient history and clinical details. RESULTS: Between November 2015 and January 2019, 21 patients had a positive CPE screen within 30 days of a negative screen, with no known CPE exposures during that time. The median time between the last date of known exposure and positive CPE screen was 20 days (range: 7–77 days). Twelve (57%) cases were hospitalized outside of Canada, 8 (38%) reported other foreign healthcare encounters, and 1 (5%) had no reported healthcare outside of Canada but had traveled to an endemic country. Sixteen (71%) cases received antibiotics prior to the positive CPE screen. CONCLUSION: Patients with unrecognized CPE colonization are a source for nosocomial transmission. Patients screening negative for CPE with recent exposure to risk factors other than contact with a known case may screen positive at a later date. This may be due to higher colonization levels or antibiotic selection pressures. Consideration should be given to sequential CPE screening of high-risk patients based on the last day of exposure. DISCLOSURES: All authors: No reported disclosures.