Clearance of Carbapenemase-producing Enterobacteriaceae (CPE) Carriage: a Comparative Study of NDM-1 and KPC CPE

Objectives: The aim of this study was to compare clearance rates and related characteristics of patients carrying KPC-producing carbapenemase-producing Enterobacteriaceae (CPE) with those of patients carrying NDM-1-producing CPE.

Methods: From November 2010 to October 2016, consecutive patients whose clinical or surveillance cultures yielded CPE were prospectively identified and followed in a 2700-bed tertiary referral hospital. CPE control protocols included strict single-room isolation, contact precautions and weekly surveillance cultures. CPE clearance was defined as three or more consecutive CPE-negative cultures without relapse. We compared patients carrying NDM-1 CPE and KPC and those with and without clearance. The time to CPE clearance or discharge was assessed using the Kaplan-Meier method and NDM-1 CPE and KPC CPE groups were compared.

Results: A total of 147 patients carrying CPE, 106 with NDM-1 and 41 with KPC, were included in the study. At the time of hospital discharge, 12 of the 106 patients carrying NDM-1 CPE were clear of CPE, whereas none of the KPC CPE patients were (NDM-1, 11.3% (12/106) versus KPC, 0% (0/41), p 0.02). There was no significant association between CPE clearance and factors such as an immunocompromised condition, antibiotic usage, or species of colonizing organism. Among 40 patients who were readmitted, CPE non-clearance was significantly higher in patients carrying KPC CPE (NDM-1, 36.7% (11/30) versus KPC, 80.0% (8/10), p 0.03).

Conclusions: Compared with NDM-1 CPE patients, patients carrying KPC CPE had a significantly lower probability of clearance during hospitalization. Furthermore, KPC CPE carriage persisted for a substantial period of time following patient discharge.