Incidence of a subsequent carbapenem-resistant Enterobacteriaceae infection after previous colonisation or infection: a prospective cohort study.

OBJECTIVES In patients with history of carbapenemase-producing carbapenem-resistant Enterobacteriaceae (CP-CRE), the need for CP-CRE targeted treatment in subsequent sepsis episodes is unclear. We aim to characterise the incidence of subsequent CP-CRE infective episode in individuals with prior CP-CRE colonisation and/or infection, and identify predictors for these subsequent CP-CRE infections. METHODS All adult inpatients with CP-CRE detected from any site between June 2012 and May 2014 at a tertiary-care hospital were prospectively followed for two years to assess for any subsequent CP-CRE infections. Potential factors to which patients were exposed during the follow-up period were collected from medical records and analysed. RESULTS A total of 171 patients were enrolled. Of 151 patients that entered the follow-up period, 16 (10.6%) developed a subsequent CP-CRE infection. The median time to a subsequent infective episode was 24.5 days (12 - 105 days). The type of carbapenemase was highly conserved within index and subsequent paired episodes (16 of 17 pairs). Patients with first CP-CRE isolated from intra-abdominal or respiratory sources were ≥7 times more likely to develop a subsequent infection, while most rectal carriers remain colonised. For carriers (n=133), Klebsiella spp (odds ratio [OR], 4.7) and OXA carbapenemase (OR, 9.4) were significant predictors for subsequent infection. In patients with initial infection (n=18), end-stage renal failure requiring dialysis (OR, 22.0) was the only predisposing factor. CONCLUSION The incidence of subsequent infections in patients with prior colonisation is low. Consideration for CP-CRE targeted therapy is recommended in patients on dialysis, and previous CP-CRE infections involving the bloodstream and/or respiratory tract.