A mathematical model of effects of environmental contamination and presence of volunteers on hospital infections in China

► We modeled the effects of environmental contamination and presence of volunteers on hospital infections. ► Free-living bacteria in the environment can promote transmission. ► Volunteers contribute substantially to MRSA transmission but they will be beneficial if well trained. ► Hand hygiene of volunteers and cleaning are the first two effective interventions. ► Isolation could be influential and dominant when the environment is sufficiently clean.