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

Objectives: In patients with a history of carbapenemase-producing, carbapenem-resistant Enterobacteriaceae (CP-CRE), the need for CP-CRE targeted treatment in subsequent sepsis episodes is unclear. This study aimed to characterise the incidence of subsequent CP-CRE infective episodes 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 who 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. (OR 4.7) and OXA carbapenemase (OR 9.4) were significant predictors of 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 was 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.