Skip to main content Accessibility help

Methicillin-Resistant Staphylococcus aureus: Site of Acquisition and Strain Variation in High-Risk Nursing Home Residents with Indwelling Devices

  • Kristen E. Gibson (a1), Sara E. McNamara (a2), Marco Cassone (a2), Mary Beth Perri (a3), Marcus Zervos (a3) (a4), Lona Mody (a2) (a5) and on behalf of the Targeted Infection Prevention (TIP) Study Team, Ann Arbor, Michigan (a5)...



Characterize the clinical and molecular epidemiology of new methicillin-resistant Staphylococcus aureus (MRSA) acquisitions at nasal and extranasal sites among high-risk nursing home (NH) residents.


Multicenter prospective observational study.


Six NHs in southeast Michigan.


A total of 120 NH residents with an indwelling device (feeding tube and/or urinary catheter).


Active surveillance cultures from the nares, oropharynx, groin, perianal area, wounds (if present), and device insertion site(s) were collected upon enrollment, at day 14, and monthly thereafter. Pulsed-field gel electrophoresis and polymerase chain reaction for SCCmec, agr, and Panton-Valentine leukocidin were performed.


Of 120 participants observed for 16,290 device-days, 50 acquired MRSA (78% transiently, 22% persistently). New MRSA acquisitions were common in extranasal sites, particularly at device insertion, groin, and perianal areas (27%, 23%, and 17.6% of all acquisitions, respectively). Screening extranasal sites greatly increases the detection of MRSA colonization (100% of persistent carriers and 97.4% of transient carriers detected with nares, groin, perianal, and device site sampling vs 54.5% and 25.6%, respectively, for nares samples alone). Colonization at suprapubic urinary catheter sites generally persisted. Healthcare-associated MRSA (USA100 and USA100 variants) were the dominant strains (79.3% of all new acquisition isolates). Strain diversity was more common in transient carriers, including acquisition of USA500 and USA300 strains.


Indwelling device insertion sites as well as the groin and perianal area are important sites of new MRSA acquisitions in NH residents and play a role in the persistency of MRSA carriage. Clonal types differ among persistent and transient colonizers.


Corresponding author

University of Michigan Medical School Division of Geriatric and Palliative Care Medicine, 300 North Ingalls Road, Room 905, Ann Arbor, MI 48109 (


Hide All
1. Centers for Medicare and Medicaid Services. Nursing Home Data Compendium 2012. Accessed September 10, 2013.
2. Bradley, SF, Terpenning, MS, Ramsey, MA, et al. Methicillin-resistant Staphylococcus aureus: colonization and infection in a long-term care facility. Ann Intern Med 1991;115:417422.
3. O’Sullivan, NP, Keane, CT. Risk factors for colonization with methicillin-resistant Staphylococcus aureus among nursing home residents. J Hosp Infect 2000;45:206210.
4. Muder, RR, Brennen, C, Wagener, MM, et al. Methicillin-resistant staphylococcal colonization and infection in a long-term care facility. Ann Intern Med 1991;114:107112.
5. Mody, L, Maheshwari, S, Galecki, A, Kauffman, CA, Bradley, SF. Indwelling device use and antibiotic resistance in nursing homes: identifying a high-risk group. J Am Geriatr Soc 2007;55:19211926.
6. Dommeti, P, Wang, L, Flannery, EL, Symons, K, Mody, L. Patterns of ciprofloxacin-resistant gram-negative bacteria colonization in nursing home residents. Infect Control Hosp Epidemiol 2011;32:177180.
7. Kluytmans, J, van Belkum, A, Verbrugh, H. Nasal carriage of Staphylococcus aureus: epidemiology, underlying mechanisms, and associated risks. Clin Microbiol Rev 1997;10:505520.
8. Vandenbergh, MF, Yzerman, EP, van Belkum, A, et al. Follow-up of Staphylococcus aureus nasal carriage after 8 years: redefining the persistent carrier state. J Clin Microbiol 1999;37:31333140.
9. Mody, L, Bradley, SF, Galecki, A, et al. Conceptual model for reducing infections and antimicrobial resistance in skilled nursing facilities: focusing on residents with indwelling devices. Clin Infect Dis 2011;52:654661.
10. McDougal, LK, Steward, CD, Killgore, GE, Chaitram, JM, McAllister, SK, Tenover, FC. Pulsed-field gel electrophoresis typing of oxacillin-resistant Staphylococcus aureus isolates from the United States: establishing a national database. J Clin Microbiol 2003;41:51135120.
11. Lina, G, Piemont, Y, Godail-Gamot, F, et al. Involvement of Panton-Valentine leukocidin-producing Staphylococcus aureus in primary skin infections and pneumonia. Clin Infect Dis 1999;29:11281132.
12. Okuma, K, Iwakawa, K, Turnidge, JD, et al. Dissemination of new methicillin-resistant Staphylococcus aureus clones in the community. J Clin Microbiol 2002;40:42894294.
13. Kondo, Y, Ito, T, Ma, XX, et al. Combination of multiplex PCRs for staphylococcal cassette chromosome mec type assignment: rapid identification system for mec, ccr, and major differences in junkyard regions. Antimicrob Agents Chemother 2007;51:264274.
14. Witte, W, Enright, M, Schmitz, FJ, Cuny, C, Braulke, C, Heuck, D. Characteristics of a new epidemic MRSA in Germany ancestral to United Kingdom EMRSA 15. Int J Med Microbiol 2001;290:677682.
15. Strommenger, B, Cuny, C, Werner, G, Witte, W. Obvious lack of association between dynamics of epidemic methicillin-resistant Staphylococcus aureus in Central Europe and agr specificity groups. Eur J Clin Microbiol Infect Dis 2004;23:1519.
16. Zhang, K, McClure, J, Elsayed, S, Louie, T, Conly, JM. Novel multiplex PCR assay for characterization and concomitant subtyping of staphylococcal cassette chromosome mec types I to V in methicillin-resistant Staphylococcus aureus. J Clin Microbiol 2005;43:50265033.
17. Tenover, FC, McDougal, LK, Goering, RV, et al. Characterization of a strain of community-associated methicillin-resistant Staphylococcus aureus widely disseminated in the United States. J Clin Microbiol 2006;44:108111.
18. Cohen, AL, Calfee, D, Fridkin, SK, et al. Recommendations for metrics for multidrug-resistant organisms in healthcare settings: SHEA/HICPAC position paper. Infect Control Hosp Epidemiol 2008;29:901913.
19. Martinez-Capolino, C, Reyes, K, Johnson, L, et al. Impact of active surveillance on meticillin-resistant Staphylococcus aureus transmission and hospital resource utilization. J Hosp Infect 2010;74:232237.
20. Wang, L, Lansing, B, Symons, K, et al. Infection rate and colonization with antibiotic-resistant organisms in skilled nursing facility residents with indwelling devices. Eur J Clin Microbiol Infect Dis 2012;31(8):17971804.
21. Fisch, J, Lansing, B, Wang, L, et al. New acquisitions of antibiotic-resistant organisms in skilled nursing facilities. J Clin Microbiol 2012;50(5):16981703.
22. Kluytmans, JA, Wertheim, HF. Nasal carriage of Staphylococcus aureus and prevention of nosocomial infections. Infection 2005;33:38.
23. McKinnell, JA, Huang, SS, Eells, SJ, Cui, E, Miller, LG. Quantifying the impact of extra-nasal testing body sites for MRSA colonization at the time of hospital or intensive care unit admission. Infect Control Hosp Epidemiol 2013;34:161170.
24. Mody, L, Kauffman, CA, Donabedian, S, Zervos, M, Bradley, SF. Patterns of nasal and extra-nasal colonization with S. aureus in nursing homes. Clin Infect Dis 2008;46:13681373.
25. Nouwen, J, Boelens, H, van Belkum, A, Verbrugh, H. Human factor in Staphylococcus aureus nasal carriage. Infect Immun 2004;72:66856688.
26. Nouwen, JL, Ott, A, Kluytmans-Vandenbergh, MF, et al. Predicting the Staphylococcus aureus nasal carrier state: derivation and validation of a “culture rule.” Clin Infect Dis 2004;39:806811.
27. Hudson, LO, Reynolds, C, Spratt, BG, et al. Diversity of methicillin-resistant Staphylococcus aureus strains isolated from residents of 26 nursing homes in Orange County, California. J Clin Microbiol 2013;51:37883795.
28. Yang, ES, Tan, J, Eells, S, Rieg, G, Tagudar, G, Miller, LG. Body site colonization in patients with community-associated methicillin-resistant Staphylococcus aureus and other types of S. aureus skin infections. Clin Microbiol Infect 2010;16:425431.
29. Stone, ND, Lewis, DR, Lowery, HK, et al. Importance of bacterial burden among methicillin-resistant Staphylococcus aureus carriers in a long-term care facility. Infect Control Hosp Epidemiol 2008;29:143148.
30. Lederer, SR, Riedelsdorf, G, Schiffl, H. Nasal carriage of methicillin-resistant Staphylococcus aureus: the prevalence, patients at risk and the effect of elimination on outcomes among outclinic haemodialysis patients. Eur J Med Res 2007;12:284288.
31. Stone, ND, Lewis, DR, Johnson, TM, et al. Methicillin-resistant Staphylococcus aureus (MRSA) nasal carriage in residents of Veterans Affairs long-term care facilities: role of antimicrobial exposure and MRSA acquisition. Infect Control Hosp Epidemiol 2012;33:551557.


Altmetric attention score

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed