title: Methicillin-resistant Staphylococcus aureus in hospitals and the community: stealth dynamics and control catastrophes.
abstract: Methicillin-resistant Staphylococcus aureus (MRSA) represents a serious threat to the health of hospitalized patients. Attempts to reduce the spread of MRSA have largely depended on hospital hygiene and patient isolation. These measures have met with mixed success: although some countries have almost eliminated MRSA or remained largely free of the organism, others have seen substantial increases despite rigorous control policies. We use a mathematical model to show how these increases can be explained by considering both hospital and community reservoirs of MRSA colonization. We show how the timing of the intervention, the level of resource provision, and chance combine to determine whether control measures succeed or fail. We find that even control measures able to repeatedly prevent sustained outbreaks in the short-term can result in long-term control failure resulting from gradual increases in the community reservoir. If resources do not scale with MRSA prevalence, isolation policies can fail "catastrophically."
authors.affiliation: Department of Medical Microbiology, Royal Free and University College Medical School, University of London, WC1E 7HU, United Kingdom. ben.cooper@hpa.org.uk
authors.forename: B S
authors.initials: BS
authors.lastname: Cooper
authors.forename: G F
authors.initials: GF
authors.lastname: Medley
authors.forename: S P
authors.initials: SP
authors.lastname: Stone
authors.forename: C C
authors.initials: CC
authors.lastname: Kibbler
authors.forename: B D
authors.initials: BD
authors.lastname: Cookson
authors.forename: J A
authors.initials: JA
authors.lastname: Roberts
authors.forename: G
authors.initials: G
authors.lastname: Duckworth
authors.forename: R
authors.initials: R
authors.lastname: Lai
authors.forename: S
authors.initials: S
authors.lastname: Ebrahim
mesh_terms: D017714:Community-Acquired Infections / Q000382:microbiology / Q000517:prevention & control*; D003428:Cross Infection / Q000382:microbiology / Q000517:prevention & control*; D006801:Humans; D008433:Mathematics; D016106:Methicillin Resistance; D010356:Patient Isolation; D013203:Staphylococcal Infections / Q000517:prevention & control* / Q000635:transmission; D013211:Staphylococcus aureus / Q000187:drug effects*; D013269:Stochastic Processes