Research Article

Mathematical Model of the Impact of a Nonantibiotic Treatment for Clostridium difficile on the Endemic Prevalence of Vancomycin-Resistant Enterococci in a Hospital Setting

Table 1

Parameters used in modeling the effect of antibiotic versus nonantibiotic treatment of CDAD on VRE colonization.

ParameterPatientsValue

Npnumber of patients in the hospital400
ratio of patients to HCW4
CDAD−, uncolonized, off antibiotic: admission rate50.1 per day
CDAD−, uncolonized, off antibiotic: average length of stay5 days
CDAD−, uncolonized, on antibiotic: admission rate2.505 per day
CDAD−, uncolonized, on antibiotic: average length of stay14 days
CDAD−, colonized, off antibiotic: admission rate0.334 per day
CDAD−, colonized, off antibiotic: average length of stay28 days
CDAD−, colonized, on antibiotic: admission rate0.501 per day
CDAD−, colonized, on antibiotic: average length of stay28 days
CDAD−, uncolonized, on antibiotic: stop antibiotic15% per day
CDAD−, uncolonized, off antibiotic: start antibiotic15% per day
CDAD−, colonized, on antibiotic: stop antibiotic4% per day
CDAD−, colonized, off antibiotic: start antibiotic16% per day
fraction of CDAD+, on antibiotic: stop antibiotic0.5
average number of contacts between uncolonized8 per day
CDAD− patients on antibiotic and HCW
average number of contacts between uncolonized8 per day
CDAD+ patients on antibiotic and HCW
probability of colonization per contact between uncolonized0.024
CDAD+ patient on antibiotic and contaminated HCW
probability of colonization per contact between uncolonized0.06
CDAD− patient on antibiotic and contaminated HCW
CDAD−, uncolonized, on antibiotic: transit to CDAD+1.07% per day
CDAD−, colonized, on antibiotic: transit to CDAD+1.07% per day
CDAD+, colonized, on antibiotic: transit to CDAD−27% per day
CDAD+, colonized, off antibiotic: transit to CDAD−27% per day
CDAD+, uncolonized, on antibiotic: transit to CDAD−27% per day
CDAD+, uncolonized, off antibiotic: transit to CDAD−27% per day
fraction of AB patients that transit to CDAD+ and stop AB0.0 or 0.5

ParameterHealth care workersValue

average number of contacts between HCW and colonized CDAD+ patients10 per day
average number of contacts between HCW and colonized CDAD+ patients10 per day
probability of contamination per contact between uncontaminated0.4
HCW and colonized CDAD− patient on antibiotic
probability of contamination per contact between uncontaminated0.4
HCW and colonized CDAD− patient off antibiotic
probability of contamination per contact between uncontaminated0.16
HCW and colonized CDAD+ patient on antibiotic
probability of contamination per contact between uncontaminated0.16
HCW and colonized CDAD+ patient off antibiotic
average duration of HCW contamination48 minutes
hand-washing compliance factor between 0 and 10.6

CDAD = clostridium difficile-associated disease; VRE = vancomycin-resistant enterococci; HCW = health care worker; CDAD+ = clostridium difficile-associated disease positive; CDAD− = clostridium difficile-associated disease negative; AB = antibiotics.