Characterization of a CTX-M-15 Producing Klebsiella Pneumoniae Outbreak Strain Assigned to a Novel Sequence Type (1427)

Kai Zhou; Mariëtte Lokate; Ruud H Deurenberg; Jan Arends; Jerome Lo-Ten Foe; Hajo Grundmann; John W A Rossen; Alexander W Friedrich

doi:10.3389/fmicb.2015.01250

Characterization of a CTX-M-15 Producing Klebsiella Pneumoniae Outbreak Strain Assigned to a Novel Sequence Type (1427)

Front Microbiol. 2015 Nov 10:6:1250. doi: 10.3389/fmicb.2015.01250. eCollection 2015.

Authors

Kai Zhou¹, Mariëtte Lokate², Ruud H Deurenberg², Jan Arends², Jerome Lo-Ten Foe², Hajo Grundmann², John W A Rossen², Alexander W Friedrich²

Affiliations

¹ Department of Medical Microbiology, University Medical Center Groningen, University of Groningen Groningen, Netherlands ; State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University Hangzhou, China ; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases Hangzhou, China.
² Department of Medical Microbiology, University Medical Center Groningen, University of Groningen Groningen, Netherlands.

Abstract

Extended-spectrum -lactamase producing Klebsiella pneumoniae have emerged as one of the major nosocomial pathogens. Between July and September 2012, a CTX-M-15 producing K. pneumoniae caused an outbreak in a university hospital in the Netherlands. The outbreak isolates were characterized and assigned to a novel sequence type (ST1427). An epidemiological link between affected patients was supported by patient contact tracing and whole-genome phylogenetic analysis. Intra-strain polymorphism was detected among multiple isolates obtained from different body sites of the index patient, which may relate to antibiotic treatment and/or host adaptation. Environmental contamination caused by the outbreak clone was found in the patient rooms even on medical equipment. The novel clone was not closely related to any known endemic/epidemic clone, but carried a set of a plasmid-borne resistance genes [bla CTX-M-15, bla TEM-1, bla OXA-1, aac(6')-Ib-cr, qnrB1, tetA(A), aac(3)-II]. Analysis of its virulence factors revealed a previously uncharacterized capsular biosynthesis region and two uncharacterized fimbriae gene clusters, and suggested that the new clone was not hypervirulent. To our knowledge, this is the first outbreak report of K. pneumoniae ST1427, and our study could be of help to understand the features of this newly emerging clone.

Keywords: CTX-M-15; Klebsiella pneumoniae; extended-spectrum ß-lactamase; hospital outbreak; polymorphism; sequence type 1427; whole-genome sequencing.