Table 1.

Parameter estimates for VRE transmission in the Cook County Hospital ICU

Symbol	Interpretation	Value	Units and notes
	Study duration	133	Days
Np	Number of beds	16
Xp	Uncolonized patients	116
Yp	Colonized patients	73
Λ	Admission rate	1.36	Patients/day
Dp	LOS (uncolonized)	9.8	Days
δ	Increase in LOS	55.1%
Nh	Number of HCWs	10	Average for 24 hr
n	Nursing HCWs	79.4%	Average for 24 hr
Dh	Duration of contamination*	1/24	Days
a	Per-capita contact rate	1.38	/HCW/patient/day
aNh	Patient-HCW contact rate	13.8	Contacts/patient/day
aNp	HCW-patient contact rate	22.1	Contacts/HCW/day
bp	Colonization probability*	6%	/Contact
bp	Contamination probability*	40%	/Contact
R(p, q)	Effective reproductive number	0.69
p	Compliance with hand washing/barrier precautions	50.1%
q	Nursing contact cohort probability*	80%
R0	Basic reproductive number	3.81
φ	Admission colonization prevalence	14.9%
yp	Endemic colonization prevalence	36.1%	Model = 36.1%

^*Estimated value.