Successful control of the first OXA-48 and/or NDM carbapenemase-producing Klebsiella pneumoniae outbreak in Slovenia 2014-2016

Abstract

Background: Carbapenemase-producing Enterobacteriaceae (CPE) occur only sporadically in Slovenia.

Aim: To describe the first Slovenian carbapenemase-producing (CP) Klebsiella pneumoniae and Escherichia coli outbreak which occurred at the tertiary teaching hospital University Medical Centre Ljubljana from October 2014 to April 2015.

Methods: A CPE-positive case was defined as any patient infected or colonized with CPE. A strict definition of a contact patient was adopted. Measures to prevent cross-transmission included cohorting of all CPE carriers with strict contact precautions and assignment of dedicated healthcare workers, cohorting of all contact patients until obtaining the result of screening cultures, systematic rectal screening of contact patients, and tagging of all CPE-positive cases and their contacts. Educational campaigns on CPEs were implemented. Clinical specimens were processed using standard procedures. Pulsed-field gel electrophoresis (PFGE) was used to determine relatedness. Multi-locus sequence typing was performed on CP K. pneumoniae isolates that belonged to different pulsotypes.

Findings: Before the outbreak was brought under control, 40 patients were colonized or infected with OXA-48 and/or New Delhi metallo-β-lactamase (NDM)-producing CPE; in 38 patients OXA-48 and/or NDM-producing K. pneumoniae was detected, in seven OXA-48 and/or NDM-producing E. coli was found together with K. pneumoniae, and in two patients only CP E. coli was isolated. The outbreak was oligoclonal with two major CP K. pneumoniae clusters belonging to ST437 and ST147 in epidemiologically linked patients.

Conclusion: Initial standard control measures failed to prevent the outbreak. Once the problem had been recognized, strict infection control measures and the education of healthcare workers contributed to the successful control of the outbreak.

Keywords: Carbapenemase outbreak; Hospitalization; Infection control; New Delhi metallo-β-lactamase; OXA-48; Patient transfer.