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
Authors: Epson EE, Pisney LM, Wendt JM, Maccannell DR, Janelle SJ, Kitchel B, Rasheed JK, Limbago BM, Gould CV, Kallen AJ, Barron MA, Bamberg WM
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.
PMID: 24602944 [PubMed - in process]