Skip to main content Accessibility help

Staphylococcus aureus Nasal Colonization and Subsequent Infection in Intensive Care Unit Patients: Does Methicillin Resistance Matter?

  • Hitoshi Honda (a1), Melissa J. Krauss (a2), Craig M. Coopersmith (a3), Marin H. Kollef (a4), Amy M. Richmond (a5), Victoria J. Fraser (a1) and David K. Warren (a1) (a5)...



Staphylococcus aureus is an important cause of infection in intensive care unit (ICU) patients. Colonization with methicillin-resistant S. aureus (MRSA) is a risk factor for subsequent S. aureus infection. However, MRSA-colonized patients may have more comorbidities than methicillin-susceptible S. aureus (MSSA)-colonized or noncolonized patients and therefore may be more susceptible to infection on that basis.


To determine whether MRSA-colonized patients who are admitted to medical and surgical ICUs are more likely to develop any S. aureus infection in the ICU, compared with patients colonized with MSSA or not colonized with S. aureus, independent of predisposing patient risk factors.


Prospective cohort study.


A 24-bed surgical ICU and a 19-bed medical ICU of a 1,252-bed, academic hospital.


A total of 9,523 patients for whom nasal swab samples were cultured for S. aureus at ICU admission during the period from December 2002 through August 2007.


Patients in the ICU for more than 48 hours were examined for an ICU-acquired S. aureus infection, defined as development of S. aureus infection more than 48 hours after ICU admission.


S. aureus colonization was present at admission for 1,433 (27.8%) of 5,161 patients (674 [47.0%] with MRSA and 759 [53.0%] with MSSA). An ICU-acquired S. aureus infection developed in 113 (2.19%) patients, of whom 75 (66.4%) had an infection due to MRSA. Risk factors associated with an ICU-acquired S. aureus infection included MRSA colonization at admission (adjusted hazard ratio, 4.70 [95% confidence interval, 3.07-7.21]) and MSSA colonization at admission (adjusted hazard ratio, 2.47 [95% confidence interval, 1.52-4.01]).


ICU patients colonized with S. aureus were at greater risk of developing a S. aureus infection in the ICU. Even after adjusting for patient-specific risk factors, MRSA-colonized patients were more likely to develop S. aureus infection, compared with MSSA-colonized or noncolonized patients.


Corresponding author

Washington University School of Medicine, Division of Infectious Diseases, 660 South Euclid Avenue, Campus Box 8051, St Louis, MO 63110, (


Hide All
1.Calfee, DP, Saigado, CD, Classen, D, et al.Strategies to prevent transmission of methicillin-resistant Staphylococcus aureus in acute care hospitals. Infect Control Hosp Epidemiol 2008;29(suppl 1):S62S80.
2.National Nosocomial Infections Surveillance (NNIS) system report, data summary from January 1992 through June 2004, issued October 2004. Am J Infect Control 2004;32(8:470485.
3.Jarvis, WR, Schlosser, J, Chinn, RY, Tweeten, S, Jackson, M. National prevalence of methicillin-resistant Staphylococcus aureus in inpatients at US health care facilities, 2006. Am J Infect Control 2007;35(10:631637.
4.Davis, KA, Stewart, JJ, Crouch, HK, Florez, CE, Hospenthal, DR. Methicillin-resistant Staphylococcus aureus (MRSA) nares colonization at hospital admission and its effect on subsequent MRSA infection. Clin Infect Dis 2004;39(6:776782.
5.Huang, SS, Platt, R. Risk of methicillin-resistant Staphylococcus aureus infection after previous infection or colonization. Clin Infect Dis 2003; 36(3):281285.
6.Blot, SI, Vandewoude, KH, Hoste, EA, Colardyn, FA. Outcome and attributable mortality in critically ill patients with bacteremia involving methicillin-susceptible and methicillin-resistant Staphylococcus aureus. Arch Intern Med 2002;162(19:22292235.
7.Cosgrove, SE, Sakoulas, G, Perencevich, EN, Schwaber, MJ, Karchmer, AW, Carmeli, Y. Comparison of mortality associated with methicillin-resistant and methicillin-susceptible Staphylococcus aureus bacteremia: a metaanalysis. Clin Infect Dis 2003;36(1):5359.
8.Soriano, A, Marco, F, Martinez, JA, et al.Influence of vancomycin minimum inhibitory concentration on the treatment of methicillin-resistant Staphylococcus aureus bacteremia. Clin Infect Dis 2008;46(2:193200.
9.Miller, LG, Diep, BA. Clinical practice: colonization, fomites, and virulence: rethinking the pathogenesis of community-associated methicillin-resistant Staphylococcus aureus infection. Clin Infect Dis 2008;46(5:752760.
10.Safdar, N, Maki, DG. The commonality of risk factors for nosocomial colonization and infection with antimicrobial-resistant Staphylococcus aureus, Enterococcus, gram-negative bacilli, Clostridium difficile, and Candida. Ann Intern Med 2002;136(11):834844.
11.Safdar, N, Bradley, EA. The risk of infection after nasal colonization with Staphylococcus aureus. Am J Med 2008;121(4:310315.
12.Horan, TC, Andrus, M, Dudeck, MA. CDC/NHSN surveillance definition of healthcare- associated infection and criteria for specific types of infections in the acute care setting. Am J Infect Control 2008;36(5:309332.
13.Kleinbaum, DG, Klein, M. Survival Analysis: A self-learning text. 2nd ed. New York, NY: Springer; 2005.
14.Schoenfeld, D. Partial residuals for the proportional hazards model. Bio-metrika 1982;69:5155.
15.Andersen, PK, Gill, RD. Cox regression model for counting processes: a large sample study. Ann Stat 1982;10:11001120.
16.Warren, DK, Guth, RM, Coopersmith, CM, Merz, LR, Zack, JE, Fraser, VJ. Epidemiology of methicillin-resistant Staphylococcus aureus colonization in a surgical intensive care unit. Infect Control Hosp Epidemiol 2006; 27(10):10321040.
17.Oztoprak, N, Cevik, MA, Akinci, E, et al.Risk factors for ICU-acquired methicillin-resistant Staphylococcus aureus infections. Am J Infect Control 2006;34(1):15.
18.Trouillet, JL, Chastre, J, Vuagnat, A, et al.Ventilator associated pneumonia caused by potentially drug-resistant bacteria. Am J Respir Crit Care Med 1998;157:531539.
19.Ellis, MW, Hospenthal, DR, Dooley, DP, Gray, PJ, Murray, CK. Natural history of community-acquired methicillin-resistant Staphylococcus aureus colonization and infection in soldiers. Clin Infect Dis 2004;39(7): 971979.
20.Wertheim, HF, Vos, MC, Ott, A, et al.Risk and outcome of nosocomial Staphylococcus aureus bacteraemia in nasal carriers versus non-carriers. Lancet 2004;364(9435:703705.
21.Garrouste-Orgeas, M, Timsit, JF, Kallel, H, et al.Colonization with methicillin-resistant Staphylococcus aureus in ICU patients: morbidity, mortality, and glycopeptide use. Infect Control Hosp Epidemiol 2001;22(11): 687692.
22.Corbella, X, Dominguez, MA, Pujol, M, et al.Staphylococcus aureus nasal carriage as a marker for subsequent staphylococcal infections in intensive care unit patients. Eur I Clin Microbiol Infect Dis 1997;16(5:351357.
23.Keene, A, Vavagiakis, P, Lee, MH, et al.Staphylococcus aureus colonization and the risk of infection in critically ill patients. Infect Control Hosp Epidemiol 2005;26(7:622628.
24.Robicsek, A, Beaumont, JL, Paule, SM, et al.Universal surveillance for methicillin-resistant Staphylococcus aureus in 3 affiliated hospitals. Ann Intern Med 2008;148(6:409418.
25.Harbarth, S, Huttner, B, Gervaz, P, et al.Risk factors for methicillin-resistant Staphylococcus aureus surgical site infection. Infect Control Hosp Epidemiol 2008;29(9:890893.
26.Roghmann, MC, Siddiqui, A, Plaisance, K, Standiford, H. MRSA coloni zation and the risk of MRSA bacteraemia in hospitalized patients with chronic ulcers. J Hosp Infect 2001;47(2:98103.
27.Kollef, MH, Morrow, LE, Niederman, MS, et al.Clinical characteristics and treatment patterns among patients with ventilator-associated pneumonia. Chest 2006;129(5:12101218.
28.Anderson, DJ, Chen, LF, Schmader, KE, et al.Poor functional status as a risk factor for surgical site infection due to methicillin-resistant Staphylococcus aureus. Infect Control Hosp Epidemiol 2008;29(9:832839.
29.Agbaht, K, Lisboa, T, Pobo, A, et al.Management of ventilator-associated pneumonia in a multidisciplinary intensive care unit: does trauma make a difference? Intensive Care Med 2007;33(8:13871395.
30.Perl, TM, Cullen, JJ, Wenzel, RP, et al.Intranasal mupirocin to prevent postoperative Staphybcoccus aureus infections. N Engl J Med 2002;346(24): 18711877.
31.Walsh, TJ, Standiford, HC, Reboli, AC, et al.Randomized double-blinded trial of rifampin with either novobiocin or trimethoprim-sulfamethoxazole against methicillin-resistant Staphylococcus aureus colonization: prevention of antimicrobial resistance and effect of host factors on outcome. Antimtcrob Agents Chemother 1993;37(6:13341342.
32.Wendt, C, Schinke, S, Wurttemberger, M, Oberdorfer, K, Bock-Hensley, O, von Baum, H. Value of whole-body washing with Chlorhexidine for the eradication of methicillin-resistant Staphylococcus aureus: a randomized, placebo-controlled, double-blind clinical trial. Infect Control Hosp Epidemiol 2007;28(9:10361043.
33.Simor, AE, Phillips, E, McGeer, A, et al.Randomized controlled trial of Chlorhexidine gluconate for washing, intranasal mupirocin, and rifampin and doxycycline versus no treatment for the eradication of methicillin-resistant Staphylococcus aureus colonization. Clin Infect Dis 2007;44(2): 178185.
34.Buehlmann, M, Frei, R, Fenner, L, Dangel, M, Fluckiger, U, Widmer, AF. Highly effective regimen for decolonization of methicillin-resistant Staphybcoccus aureus carriers. Infect Control Hosp Epidemiol 2008;29(6:510516.
35.Jones, JC, Rogers, TJ, Brookmeyer, P, et al.Mupirocin resistance in patients colonized with methicillin-resistant Staphylococcus aureus in a surgical intensive care unit. Clin Infect Dis 2007;45(5:541547.
36.Harbarth, S, Dharan, S, Liassine, N, Herrault, P, Auckenthaler, R, Pittet, D. Randomized, placebo-controlled, double-blind trial to evaluate the efficacy of mupirocin for eradicating carriage of methicillin-resistant Staphybcoccus aureus. Antimtcrob Agents Chemother 1999;43(6:14121416.
37.von Eiff, C, Becker, K, Machka, K, Stammer, H, Peters, G. Nasal carriage as a source of Staphybcoccus aureus bacteremia. N Engl J Med 2001;344(1): 1116.
38.Coello, R, Jimenez, J, Garcia, M, et al.Prospective study of infection, colonization and carriage of methicillin-resistant Staphylococcus aureus in an outbreak affecting 990 patients. Eur J Clin Microbiol Infect Dis 1994;13(1):7481.
39.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 2009;16:425.

Related content

Powered by UNSILO

Staphylococcus aureus Nasal Colonization and Subsequent Infection in Intensive Care Unit Patients: Does Methicillin Resistance Matter?

  • Hitoshi Honda (a1), Melissa J. Krauss (a2), Craig M. Coopersmith (a3), Marin H. Kollef (a4), Amy M. Richmond (a5), Victoria J. Fraser (a1) and David K. Warren (a1) (a5)...


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.