Carbapenem-resistant Klebsiella pneumoniae producing New Delhi metallo-β-lactamase at an acute care hospital, Colorado, 2012

Infect Control Hosp Epidemiol. 2014 Apr;35(4):390-7. doi: 10.1086/675607.

Abstract

Objective: To investigate an outbreak of New Delhi metallo-β-lactamase (NDM)-producing carbapenem-resistant Enterobacteriaceae (CRE) and determine interventions to interrupt transmission.

Design, setting, and patients: Epidemiologic investigation of an outbreak of NDM-producing CRE among patients at a Colorado acute care hospital.

Methods: Case patients had NDM-producing CRE isolated from clinical or rectal surveillance cultures (SCs) collected during the period January 1, 2012, through October 20, 2012. Case patients were identified through microbiology records and 6 rounds of SCs in hospital units where they had resided. CRE isolates were tested by real-time polymerase chain reaction for blaNDM. Medical records were reviewed for epidemiologic links; relatedness of isolates was evaluated by pulsed-field gel electrophoresis (PFGE) and whole genome sequencing (WGS). Infection control (IC) was assessed through staff interviews and direct observations.

Results: Two patients were initially identified with NDM-producing CRE during July-August 2012. A third case patient, admitted in May, was identified through microbiology records review. SC identified 5 additional case patients. Patients had resided in 11 different units before identification. All isolates were highly related by PFGE. WGS suggested 3 clusters of CRE. Combining WGS with epidemiology identified 4 units as likely transmission sites. NDM-producing CRE positivity in certain patients was not explained by direct epidemiologic overlap, which suggests that undetected colonized patients were involved in transmission.

Conclusions: A 4-month outbreak of NDM-producing CRE occurred at a single hospital, highlighting the risk for spread of these organisms. Combined WGS and epidemiologic data suggested transmission primarily occurred on 4 units. Timely SC, combined with targeted IC measures, were likely responsible for controlling transmission.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Aged
  • Carbapenems / pharmacology
  • Carbapenems / therapeutic use*
  • Colorado
  • Cross Infection / epidemiology
  • Cross Infection / microbiology*
  • Cross Infection / prevention & control
  • Disease Outbreaks
  • Drug Resistance, Bacterial
  • Female
  • Hospitals
  • Humans
  • Klebsiella Infections / drug therapy*
  • Klebsiella Infections / epidemiology
  • Klebsiella pneumoniae* / drug effects
  • Klebsiella pneumoniae* / enzymology
  • Klebsiella pneumoniae* / genetics
  • Male
  • Microbial Sensitivity Tests
  • Middle Aged
  • Sequence Analysis, DNA
  • Young Adult
  • beta-Lactamases / biosynthesis*

Substances

  • Carbapenems
  • beta-Lactamases
  • beta-lactamase NDM-1