title: Modeling spread of KPC-producing bacteria in long-term acute care hospitals in the Chicago region, USA.
abstract: OBJECTIVE
  Prevalence of bla KPC-encoding Enterobacteriaceae (KPC) in Chicago long-term acute care hospitals (LTACHs) rose rapidly after the first recognition in 2007. We studied the epidemiology and transmission capacity of KPC in LTACHs and the effect of patient cohorting.
  
  
  METHODS
  Data were available from 4 Chicago LTACHs from June 2012 to June 2013 during a period of bundled interventions. These consisted of screening for KPC rectal carriage, daily chlorhexidine bathing, medical staff education, and 3 cohort strategies: a pure cohort (all KPC-positive patients on 1 floor), single rooms for KPC-positive patients, and a mixed cohort (all KPC-positive patients on 1 floor, supplemented with KPC-negative patients). A data-augmented Markov chain Monte Carlo (MCMC) method was used to model the transmission process.
  
  
  RESULTS
  Average prevalence of KPC colonization was 29.3%. On admission, 18% of patients were colonized; the sensitivity of the screening process was 81%. The per admission reproduction number was 0.40. The number of acquisitions per 1,000 patient days was lowest in LTACHs with a pure cohort ward or single rooms for colonized patients compared with mixed-cohort wards, but 95% credible intervals overlapped.
  
  
  CONCLUSIONS
  Prevalence of KPC in LTACHs is high, primarily due to high admission prevalence and the resultant impact of high colonization pressure on cross transmission. In this setting, with an intervention in place, patient-to-patient transmission is insufficient to maintain endemicity. Inclusion of a pure cohort or single rooms for KPC-positive patients in an intervention bundle seemed to limit transmission compared to use of a mixed cohort.
authors.affiliation: 1Julius Center for Health Sciences and Primary Care,University Medical Center Utrecht,Utrecht,The Netherlands.
authors.forename: Manon R
authors.initials: MR
authors.lastname: Haverkate
authors.affiliation: 1Julius Center for Health Sciences and Primary Care,University Medical Center Utrecht,Utrecht,The Netherlands.
authors.forename: Martin C J
authors.initials: MC
authors.lastname: Bootsma
authors.affiliation: 2Department of Medicine,Division of Infectious Diseases,Rush University Medical Center,Chicago,Illinois,United States.
authors.forename: Shayna
authors.initials: S
authors.lastname: Weiner
authors.affiliation: 2Department of Medicine,Division of Infectious Diseases,Rush University Medical Center,Chicago,Illinois,United States.
authors.forename: Donald
authors.initials: D
authors.lastname: Blom
authors.affiliation: 2Department of Medicine,Division of Infectious Diseases,Rush University Medical Center,Chicago,Illinois,United States.
authors.forename: Michael Y
authors.initials: MY
authors.lastname: Lin
authors.affiliation: 4Department of Pathology,Rush University Medical Center,Chicago,Illinois,United States.
authors.forename: Karen
authors.initials: K
authors.lastname: Lolans
authors.affiliation: 5Department of Medical Laboratory Science,Rush University Medical Center,Chicago,Illinois,United States.
authors.forename: Nicholas M
authors.initials: NM
authors.lastname: Moore
authors.affiliation: 6Department of Medicine,Division of Infectious Diseases,Cook County Health and Hospital System,Chicago,Illinois,United States.
authors.forename: Rosie D
authors.initials: RD
authors.lastname: Lyles
authors.affiliation: 2Department of Medicine,Division of Infectious Diseases,Rush University Medical Center,Chicago,Illinois,United States.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Weinstein
authors.affiliation: 1Julius Center for Health Sciences and Primary Care,University Medical Center Utrecht,Utrecht,The Netherlands.
authors.forename: Marc J M
authors.initials: MJ
authors.lastname: Bonten
authors.affiliation: 2Department of Medicine,Division of Infectious Diseases,Rush University Medical Center,Chicago,Illinois,United States.
authors.forename: Mary K
authors.initials: MK
authors.lastname: Hayden
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000378:metabolism; D002641:Chicago / Q000453:epidemiology; D003428:Cross Infection / Q000175:diagnosis / Q000453:epidemiology* / Q000635:transmission; D004755:Enterobacteriaceae / Q000201:enzymology / Q000302:isolation & purification*; D004756:Enterobacteriaceae Infections / Q000175:diagnosis / Q000453:epidemiology* / Q000635:transmission; D005260:Female; D006761:Hospitals; D006801:Humans; D008134:Long-Term Care; D008297:Male; D008390:Markov Chains; D008875:Middle Aged; D015233:Models, Statistical; D009010:Monte Carlo Method; D015995:Prevalence; D012680:Sensitivity and Specificity; D001618:beta-Lactamases / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D001618:beta-Lactamases