Table 1. Default model parameters of the model.

Parameter Name	Explanation	Default Value
T	Observation period over which results are averaged	30*365 d
EH	Number of beds of one hospital	10–500
EC	Size of community	300*Total Hospital Size#
βH	transmission rate in hospital	0.4 d−1/Number of Beds
βC	transmission rate in community	0.005 d−1/Size of community
s	cost of drug resistance	10% –30% [28], [29], [30]
μ	Mutation rate	10−3 d−1
rTurn	Turn-over rate of patients in hospital (i.e. discharge rate)	1/7 d−1 ##
rBaseline	Baseline clearance rate	1/300 d−1 [32]
uH	Frequency of antibiotic use in hospital	0.005–0.5 [33]
uC	Frequency of antibiotic use in the community	10−4–0.02 [34]
Extension with environmental transmission in the hospital
cE	Colonization rate of environment	1/10
rTurn,E	Turn-over rate of environment	1/30 [22]
βE	Transmission rate from environment	βH* rTurn,E/cE
Extension with inter-ward transfer
w	Inter-ward transfer rate	0.01–0.1/patient day [23]

# Global average number of hospital beds per inhabitant, as retrieved from the WHO database http://apps.who.int/ghodata/.

## The average length of stay is 8 days in Switzerland (http://www.obsandaten.ch/indikatoren/5_4_1/2005/d/541.pdf, data from 2005) and 5 days in the US (http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5427a6.htm).