Long-lasting outbreak due to CTX-M-15-producing Klebsiella pneumoniae ST336 in a rehabilitation ward: report and literature review

Abstract

Background: Whereas Klebsiella species are the most frequently occurring agents in nosocomial outbreaks due to multidrug-resistant Gram-negative organisms, very few outbreaks have been reported from rehabilitation wards.

Aim: To describe a long-lasting outbreak due to extended-spectrum β-lactamase-producing (ESBL) Klebsiella pneumoniae in a rehabilitation ward.

Methods: ESBL K. pneumoniae from all in- and outpatients whose specimens were tested at a tertiary care university hospital between 2007 and 2012 were typed by pulsed-field gel electrophoresis and selected isolates were submitted to multi-locus sequence typing and ESBL genotyping. Outbreak characteristics and infection control interventions were summarized. The literature was searched for K. pneumoniae-related outbreaks in rehabilitation wards.

Findings: ESBL K. pneumoniae was detected in 69 out of 2478 K. pneumoniae-positive patients (2.8%) during the study period. Eight related outbreak clones from 35 patients, 25 of whom were in the rehabilitation ward, produced CTX-M-15 and belonged to ST336. The outbreak lasted for more than three years and was controlled by sequentially increasing measures culminating in review of all patient-related care, compulsory educational meetings for personnel, profession-specific guidelines and educational flyers for patients.

Conclusion: Half of ESBL K. pneumoniae-positive patients identified over six years at a tertiary care university hospital harboured related clones, and more than a third were hospitalized in a rehabilitation ward. Rehabilitation wards pose particular challenges for infection control because of patient dependency and an environment that encourages socializing. They are, however, rarely involved in K. pneumoniae-related outbreaks.

Keywords: CTX-M-15; Iceland; Klebsiella pneumoniae; Nosocomial; Outbreak; Rehabilitation.