Risk Factors for Recurrence of Carbapenem-Resistant Enterobacteriaceae Carriage: Case-Control Study

BACKGROUND The natural history of carbapenem-resistant Enterobacteriaceae(CRE) carriageand the timing and procedures required to safely presume a CRE-free status are unclear. OBJECTIVE To determine risk factors for recurrence of CRE among presumed CRE-free patients. METHODS Case-control study including CRE carriers in whom CRE carriagepresumably ended, following at least 2 negative screening samples on separate days. Recurrence of CRE carriagewas identified through clinical samples and repeated rectal screening in subsequent admissions to any healthcare facility in Israel. Patients with CRE recurrence (cases) were compared with recurrence-free patients (controls). The duration of follow-up was 1 year for all surviving patients. RESULTS Included were 276 prior CRE carriers who were declared CRE-free. Thirty-six persons (13%) experienced recurrence of CRE carriagewithin a year after presumed eradication. Factors significantly associated with CRE recurrence on multivariable analysis were the time in months between the last positive CRE sample and presumed eradication (odds ratio, 0.94 [95% CI, 0.89–0.99] per month), presence of foreign bodies at the time of presumed eradication (4.6 [1.64–12.85]), and recurrent admissions to healthcare facilities during follow-up (3.15 [1.05–9.47]). The rate of CRE recurrence was 25% (11/44) when the carrier status was presumed to be eradicated 6 months after the last known CRE-positive sample, compared with 7.5% (10/134) if presumed to be eradicated after 1 year. CONCLUSIONS We suggest that the CRE-carrier status be maintained for at least 1 year following the last positive sample. Screening of all prior CRE carriers regardless of current carriagestatus is advised. Infect. Control Hosp. Epidemiol. 2015;36(8):936–941