Table 1

Parameter estimates for VRE transmission in the Cook County Hospital ICU

SymbolInterpretationValueUnits and notes
Study duration133Days
N p Number of beds16
X p Uncolonized patients116
Y p Colonized patients73
ΛAdmission rate1.36Patients/day
D p LOS (uncolonized)9.8Days
δIncrease in LOS55.1%
N h Number of HCWs10Average for 24 hr
n Nursing HCWs79.4%Average for 24 hr
D h Duration of contamination*1/24Days
a Per-capita contact rate1.38/HCW/patient/day
aN h Patient-HCW contact rate13.8Contacts/patient/day
aN p HCW-patient contact rate22.1Contacts/HCW/day
b p Colonization probability*6%/Contact
b p Contamination probability*40%/Contact
R(p, q)Effective reproductive number0.69
p Compliance with hand washing/barrier precautions50.1%
q Nursing contact cohort probability*80%
R 0 Basic reproductive number3.81
φAdmission colonization prevalence14.9%
y p Endemic colonization prevalence36.1%Model = 36.1%
  • * Estimated value.