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Modeling the Spread of Methicillin-Resistant Staphylococcus aureus (MRSA) Outbreaks throughout the Hospitals in Orange County, California

  • Bruce Y. Lee (a1), Sarah M. McGlone (a1), Kim F. Wong (a1), S. Levent Yilmaz (a1), Taliser R. Avery (a2), Yeohan Song (a1), Richard Christie (a1), Stephen Eubank (a3), Shawn T. Brown (a1) (a4), Joshua M. Epstein (a5), Jon I. Parker (a5), Donald S. Burke (a1), Richard Platt (a2) and Susan S. Huang (a6)...



Since hospitals in a region often share patients, an outbreak of methicillin-resistant Staphylococcus aureus (MRSA) infection in one hospital could affect other hospitals.


Using extensive data collected from Orange County (OC), California, we developed a detailed agent-based model to represent patient movement among all OC hospitals. Experiments simulated MRSA outbreaks in various wards, institutions, and regions. Sensitivity analysis varied lengths of stay, intraward transmission coefficients (β), MRSA loss rate, probability of patient transfer or readmission, and time to readmission.


Each simulated outbreak eventually affected all of the hospitals in the network, with effects depending on the outbreak size and location. Increasing MRSA prevalence at a single hospital (from 5% to 15%) resulted in a 2.9% average increase in relative prevalence at all other hospitals (ranging from no effect to 46.4%). Single-hospital intensive care unit outbreaks (modeled increase from 5% to 15%) caused a 1.4% average relative increase in all other OC hospitals (ranging from no effect to 12.7%).


MRSA outbreaks may rarely be confined to a single hospital but instead may affect all of the hospitals in a region. This suggests that prevention and control strategies and policies should account for the interconnectedness of health care facilities.


Corresponding author

University of Pittsburgh, 200 Meyran Avenue, Suite 200, Pittsburgh, PA 15213 (


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1.McDonald, JR, Carriker, CM, Pien, BC, et al.Methicillin-resistant Staphylococcus aureus outbreak in an intensive care nursery: potential for interinstitutional spread. Pediatr Infect Dis J 2007;26(8):678683.
2.Widerstrom, M, Monsen, T, Karlsson, C, Wistrom, J. Molecular epidemiology of methicillin-resistant coagulase-negative staphylococci in a Swedish county hospital: evidence of intra- and interhospital clonal spread. J Hosp Infect 2006;64:177183.
3.Sanchez-Garcia, M, De la Torre, MA, Morales, G, et al.Clinical outbreak of linezolid-resistant Staphylococcus aureus in an intensive care unit. JAMA 2010;303(22):22602264.
4.Ludlam, HA, Swayne, RL, Kearns, AM, et al.Evidence from a UK teaching hospital that MRSA is primarily transmitted by the hands of healthcare workers. J Hosp Infect 2010;74(3):296299.
5.van Rijen, MM, Bosch, T, Heck, ME, Kluytman, JA. Methicillin-resistant Staphylococcus aureus epidemiology and transmission in a Dutch hospital. J Hosp Infect 2009;72(4):299306.
6.Wang, JT, Chang, SC, Ko, WJ, et al.A hospital-acquired outbreak of methicillin-resistant Staphylococcus aureus infection initiated by a surgeon carrier. J Hosp Infect 2001;47(2):104109.
7.Umoren, I, Nakamatsu, R, Sciortino, C, et al.An investigation of an outbreak: methicillin resistant Staphylococcus aureus colonization in an intensive cardiac unit. J Ky Med Assoc 2009;107(11):443449.
8.Williams, VR, Callery, S, Vearncombe, M, Simor, AE. The role of colonization pressure in nosocomial transmission of methicillin-resistant Staphylococcus aureus. Am J Infect Control 2009;37(2): 106110.
9.Monsen, T, Karlsson, C, Wistrom, J. Spread of clones of multidrug-resistant, coagulase-negative staphylococci within a university hospital. Infect Control Hosp Epidemiol 2005;26(1):7680.
10.Sader, HS, Pignatari, AC, Hollis, RJ, Jones, RN. Evaluation of interhospital spread of methicillin-resistant Staphylococcus aureus in Sao Paulo, Brazil, using pulsed-field gel electrophoresis of chromosomal DNA. Infect Control Hosp Epidemiol 1994;15(5): 320323.
11.Robotham, TV, Scarff, CA, Jenkins, DR, Medley, GF. Methicillin-resistant Staphylococcus aureus (MRSA) in hospitals and the community: model predictions based on the UK situation. J Hosp Infect 2007;65(S2):9399.
12.Huang, SS, Avery, TR, Song, Y, et al.Quantifying inter-hospital patient sharing as a mechanism for infectious disease spread. Infect Control Hosp Epidemiol 2010;31(11):11601169.
13.Lee, BY, McGlone, SM, Song, Y, et al.Social network analysis of patient sharing among hospitals in Orange County, California. Am J Pubi Health 2011;101(4):707713.
14.California Health and Human Services Agency. Office of Statewide Health Planning and Development, Sacramento, CA. Updated October 4, 2010.
15.Kuo, MN, Avery, TR, Nguyen, CM, et al, eds. Challenges to interhospital comparisons of methicillin-resistant Staphylococcus aureus (MRSA) rates in Orange County, California. In: Program and abstracts of the Fifth Decennial International Conference on Healthcare-Associated Infections; March 18-22, 2010; Atlanta, GA.
16.Avery, TR, Huang, SS. Impact of post-discharge events on hospital methicillin-resisitant Staphylococcus aureus (MRSA) rates. In: Program and abstracts of the Fifth Decennial International Conference on Healthcare-Associated Infections; March 18-22, 2010; Atlanta, GA.
17.Huang, SS, Rifas-Shiman, SL, Warren, DK, et al.Improving methicillin-resistant Staphylococcus aureus surveillance and reporting in intensive care units. J Infect Dis 2007;195:330338.
18.Robicsek, A, Beaumont, JL, Peterson, LR. Duration of colonization by methicillin-resistant Staphylococcus aureus after hospital discharge and risk. Clin Infect Dis 2009;48:910913.
19.Sanford, MD, Widmer, AF, Bale, MJ, Jones, RN, Wenzel, RP. Efficient detection and long-term persistence of the carriage for methicillin-resistant Staphylococcus aureus. Clin Infect Dis 1994;19(6):11231128.
20.Scanvic, A, Denie, L, Gaillon, S, Giry, P, Andremont, A, Lucet, JC. Duration of colonization by methicillin-resistant Staphylococcus aureus after hospital discharge and risk factors for prolonged carriage. Clin Infect Dis 2001;32(10):13931398.
21.Kluytman, J, van Belkum, A, Verbrugh, H. Nasal carriage of Staphylococcus aureus: epidemiology, underlying mechanisms, and associated risks. Clin Microbiol Rev 1997;10(3):505520.
22.Cooper, BS, Medley, GF, Stone, SP, et al.Methicillin-resistant Staphylococcus aureus in hospitals and the community: stealth dynamics and control catastrophes. Proc Natl Acad Sci USA 2004;101(27):1022310228.
23.Donker, T, Wallinga, J, Grundmann, H. Patient referral patterns and the spread of hospital-acquired infections through national health care networks. PLoS Comput Biol 2010;6(3):el000715.
24.Smith, DL, Dushoff, J, Perencevich, EN, Harris, AD, Levin, SA. Persistent colonization and the spread of antibiotic resistance in nosocomial pathogens: resistance is a regional problem. Proc Natl Acad Sci USA 2004;101(10):37093714.
25.Smith, DL, Levin, SA, Laxminarayan, R. Strategic interactions in multi-institutional epidemics of antibiotic resistance. Proc Natl Acad Sci USA 2005;102(8):31533158.


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