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Modeling Transmission of Methicillin-Resistant Staphylococcus Aureus Among Patients Admitted to a Hospital

Published online by Cambridge University Press:  21 June 2016

Janet Raboud*
Affiliation:
Department of Public Health Sciences, University of Toronto, and University Health Network, Toronto, Ontario, Canada Prosserman Centre for Health Research, Samuel Lunenfeld Research Institute, Toronto, Ontario, Canada
Refik Saskin
Affiliation:
Prosserman Centre for Health Research, Samuel Lunenfeld Research Institute, Toronto, Ontario, Canada
Andrew Simor
Affiliation:
Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada Sunnybrook and Women's College Health Sciences Centre, Toronto, Ontario, Canada
Mark Loeb
Affiliation:
McMaster University, Hamilton, Ontario, Canada
Karen Green
Affiliation:
Department of Microbiology, Mount Sinai Hospital, Toronto, Ontario, Canada
Don E. Low
Affiliation:
Department of Microbiology, Mount Sinai Hospital, Toronto, Ontario, Canada Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
Allison McGeer
Affiliation:
Department of Microbiology, Mount Sinai Hospital, Toronto, Ontario, Canada
*
Prosserman Centre for Health Research, Samuel Lunenfeld Research Institute, 60 Murray Street (Room 5-244), Toronto, Ontario, Canada, M5G 1X5., raboud@mshri.on.ca

Abstract

Objective:

To determine the impact of the screening test, nursing workload, handwashing rates, and dependence of handwashing on risk level of patient visit on methicillin-resistant Staphylococcus aureus (MRSA) transmission among hospitalized patients.

Setting:

General medical ward.

Methods:

Monte Carlo simulation was used to model MRSA transmission (median rate per 1,000 patient-days). Visits by healthcare workers (HCWs) to patients were simulated, and MRSA was assumed to be transmitted among patients via HCWs.

Results:

The transmission rate was reduced from 0.89 to 0.56 by the combination of increasing the sensitivity of the screening test from 80% to 99% and being able to report results in 1 day instead of 4 days. Reducing the patient-to-nurse ratio from 4.3 in the day and 6.8 at night to 3.8 and 5.7, respectively, reduced the number of nosocomial infections from 0.89 to 0.85; reducing the ratio to 1 and 1, respectively, further reduced the number of nosocomial infections to 0.32. Increases in handwashing rates by 0%, 10%, and 20% for high-risk visits yielded reductions in nosocomial infections similar to those yielded by increases in handwashing rates for all visits (0.89, 0.36, and 0.24, respectively). Screening all patients for MRSA at admission reduced the transmission rate to 0.81 per 1,000 patient-days from 1.37 if no patients were screened.

Conclusion:

Within the ranges of parameters studied, the most effective strategies for reducing the rate of MRSA transmission were increasing the handwashing rates for visits involving contact with skin or bodily fluid and screening patients for MRSA at admission. (Infect Control Hosp Epidemiol 2005;26:607- 615)

Type
Original Articles
Copyright
Copyright © The Society for Healthcare Epidemiology of America 2005

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