title: Emergence and rapid regional spread of Klebsiella pneumoniae carbapenemase-producing Enterobacteriaceae.
abstract: Exposure network analysis and molecular epidemiologic methods were used to analyze the emergence and regional spread of Klebsiella pneumoniae carbapenemase-producing Enterobacteriaceae over a 1-year period. Although 40 patients and 26 health care facilities were affected, 1 long-term acute care hospital played a critical role in the convergence of patients at high risk, amplification by cross-infection, and dissemination of these multidrug-resistant bacteria.
  
  
  BACKGROUND
  Klebsiella pneumoniae carbapenemase (KPC)-producing Enterobacteriaceae are an emerging antibiotic resistance threat with demonstrated epidemic potential.
  
  
  METHODS
  We conducted an outbreak investigation of KPC-producing Enterobacteriaceae among patients of acute and long-term acute care hospitals (LTACHs) in 4 adjacent counties in Indiana and Illinois from 1 January 2008 through 31 December 2008 (cases). The study used traditional and molecular epidemiologic methods and an adaptation of social network analysis ("exposure network analysis").
  
  
  RESULTS
  Clinical records for 40 (95%) of 42 patients were available. Patients were mostly older with multiple comorbid conditions. Eleven patients (27.5%) died during the index hospitalization or were discharged to hospice; 23 (57.5%) were discharged to a nursing home, and 4 (10.0%) were discharged to home. One LTACH (LTACH-A) was central to the regional outbreak: 24 (60%) of 40 cases were linked to LTACH-A, and at least 10 patients (25%) acquired KPC there. Of 16 cases not linked to LTACH-A, 12 (75%) were linked to 3 nursing homes. Only 4 patients (10%) definitely acquired KPC during an acute care hospital stay. Molecular typing revealed the 31 available KPC-positive K. pneumoniae isolates to be similar and to cluster with epidemic multilocus sequence type 258; 2 KPC-positive Escherichia coli isolates were unique.
  
  
  CONCLUSIONS
  We observed extensive transfer of KPC-positive patients throughout the exposure network of 14 acute care hospitals, 2 LTACHs, and 10 nursing homes. Although few cases were identified at most institutions, many facilities were affected. Successful control of KPC-producing Enterobacteriaceae will require a coordinated, regional effort among acute and long-term health care facilities and public health departments.
authors.affiliation: Hunter Holmes McGuire Veterans Affairs Medical Center, Virginia Commonwealth University, Division of Infectious Diseases, Richmond, Virginia, USA.
authors.forename: Sarah Y
authors.initials: SY
authors.lastname: Won
authors.forename: L Silvia
authors.initials: LS
authors.lastname: Munoz-Price
authors.forename: Karen
authors.initials: K
authors.lastname: Lolans
authors.forename: Bala
authors.initials: B
authors.lastname: Hota
authors.forename: Robert A
authors.initials: RA
authors.lastname: Weinstein
authors.forename: Mary K
authors.initials: MK
authors.lastname: Hayden
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001426:Bacterial Proteins / Q000096:biosynthesis*; D015373:Bacterial Typing Techniques; D016358:Contact Tracing; D003428:Cross Infection / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology* / Q000635:transmission; D004196:Disease Outbreaks; D024901:Drug Resistance, Multiple, Bacterial; D005260:Female; D006801:Humans; D007087:Illinois / Q000453:epidemiology; D007196:Indiana / Q000453:epidemiology; D007710:Klebsiella Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology* / Q000635:transmission; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification*; D008297:Male; D008875:Middle Aged; D017720:Molecular Epidemiology; D058885:Multilocus Sequence Typing; D001618:beta-Lactamases / Q000096:biosynthesis*
chemical_list: D001426:Bacterial Proteins; D001618:beta-Lactamases; C063912:carbapenemase