Original Article

Widespread Emergence of Methicillin Resistance in Community-acquired Staphylococcus aureus Infections in Denver

Authors: Megan J. Clancy, MD, Amy Graepler, MT, Peter E. Breese, MSPH, Connie S. Price, MD, William J. Burman, MD


Background: Increasing rates of methicillin resistance among outpatient Staphylococcus aureus infections led us to assess the epidemiology and outcome of a local outbreak.

Methods: A retrospective cohort study of outpatient skin and soft tissue infections due to S aureus in 2003.

Results: From 2002 to mid-2004, the percentage of outpatient S aureus isolates resistant to methicillin increased from 6 to 45%. In multivariate analysis, only male sex and age greater than 18 years were associated with methicillin resistance. Methicillin resistance was common (>15%) among isolates from patients in nearly all subgroups evaluated. Pulsed field gel electrophoresis showed isolates related to USA 300, but methicillin-resistant strains had unusually high rates of quinolone resistance.

Conclusions: A single strain of methicillin-resistant S aureus is responsible for the increase in skin infections in outpatients without traditional risk factors for infection with an antibiotic-resistant strain. In areas with high rates of methicillin-resistant S aureus outpatient infections, we recommend non–β-lactam antibiotics for initial treatment of skin and soft tissue infections.

Key Points

* There is a rapid increase in community-acquired methicillin-resistant Staphylococcus aureus skin and soft tissue infections.

* These infections are widespread in the community, and we were unable to identify an at-risk group.

* These infections did not have worse outcomes than infections from methicillin-susceptible isolates.

* These infections were caused by a single pulsed field type that is responsible for outbreaks in other parts of the country.

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1. Crane LR, Levine DP, Zervos MJ, et al. Bacteremia in narcotic addicts at the Detroit Medical Center, I: microbiology, epidemiology, risk factors, and empiric therapy. Rev Infect Dis 1986;8:364–373.
2. Lewis E, Saravolatz LD. Comparison of methicillin-resistant and methicillin-sensitive Staphylococcus aureus bacteremia. Am J Infect Control 1985;13:109–114.
3. Centers for Disease Control and Prevention. Methicillin-resistant Staphylococcus aureus infections among competitive sports participants: Colorado, Indiana, Pennsylvania, and Los Angels County, 2000–2003. MMWR Morb Mortal Wkly Rep 2003;52:793–795.
4. Centers for Disease Control and Prevention. Methicillin-resistant Staphylococcus aureus skin and soft tissue infections in a state prison: Mississippi, 2000. MMWR Morb Mortal Wkly Rep 2001;50:919–922.
5. Baggett HC, Hennessy TW, Leman R, et al. An outbreak of community-onset methicillin-resistant Staphylococcus aureus skin infections in southwestern Alaska. Infect Control Hosp Epidemiol2003;24:397–402.
6. Sattler CA Jr, Mason EO, Kaplan SL. Prospective comparison of risk factors and demographic and clinical characteristics of community-acquired, methicillin-resistant versus methicillin-susceptible Staphylococcus aureus infection in children. Pediatr Infect Dis J 2002;21:910–917.
7. National Committee for Clinical Laboratory Standards. Performance Standards for Antimicrobial Disk Susceptibility Testing-Sixth Edition: Approved Standard M2-A6. 6th ed. Wayne, PA; 1998.
8. Tenover FC, Arbeit RD, Goering RV, et al. Interpreting chromosomal DNA restriction patterns produced by pulsed-field gel electrophoresis: criteria for bacterial strain typing. J Clin Microbiol1995;33:2233–2239.
9. 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;29:1128–1132.
10. Farizo K, Buehler J, Chamberland M, et al. Spectrum of disease in persons with human immunodeficiency virus infection in the United States. JAMA 1992;267:1798–1805.
11. Centers for Disease Control and Prevention. Four pediatric deaths from community-acquired methicillin-resistant Staphylococcus aureus: Minnesota and North Dakota, 1997–1999. MMWR Morb Mortal Wkly Rep 1999;48:707–710.
12. Mongkolrattanothai K, Boyle S, Kahana MD, et al. Severe Staphylococcus aureus infections caused by clonally related community-acquired methicillin-susceptible and methicillin-resistant isolates. Clin Infect Dis 2003;37:1050–1058.
13. Lucet JC, Chevret S, Durand-Zaleski I, et al. Prevalence and risk factors for carriage of methicillin-resistant Staphylococcus aureus at admission to the intensive care unit: results of a multicenter study.Arch Intern Med 2003;163:181–188.
14. Charlebois ED, Bangsberg DR, Moss NJ, et al. Population-based community prevalence of methicillin-resistant Staphylococcus aureus in the urban poor of San Francisco. Clin Infect Dis2002;34:425–433.
15. Shopsin B, Mathema B, Martinez J, et al. Prevalence of methicillin-resistant and methicillin-susceptible Staphylococcus aureus in the community. J Infect Dis 2000;182:359–362.
16. Baggett HC, Hennessy TW, Rudolph K, et al. Community-onset methicillin-resistant Staphylococcus aureus associated with antibiotic use and the cytotoxin Panton-Valentine leukocidin during a furunculosis outbreak in rural Alaska. J Infect Dis 2004;189:1565–1573.
17. Groom AV, Wolsey DH, Naimi TS, et al. Community-acquired methicillin-resistant Staphylococcus aureus in a rural American Indian community. JAMA 2001;286:1201–1205.
18. Baba T, Takeuchi F, Kuroda M, et al. Genome and virulence determinants of high virulence community-acquired MRSA. Lancet 2002;359:1819–1827.
19. Vandenesch F, Naimi T, Enright MC, et al. Community-acquired methicillin-resistant Staphylococcus aureus carrying Panton-Valentine leukocidin genes: worldwide emergence. Emerg Infect Dis 2003;9:978–984.
20. Gillet Y, Issartel B, Vanhems P, et al. Association between Staphylococcus aureus strains carrying gene for Panton-Valentine leukocidin and highly lethal necrotizing pneumonia in young immunocompetent patients. Lancet 2002;359:753–759.
21. Ellis MW, Hospenthal DR, Dooley DP, et al. Natural history of community-acquired methicillin-resistant Staphylococcus aureus colonization and infection in soldiers. Clin Infect Dis 2004;39:971–979.
22. Herold BC, Immergluck LC, Maranan MC, et al. Community-acquired methicillin-resistant Staphylococcus aureus in children with no identified predisposing risk. JAMA 1998;279:593–598.
23. Okuma K, Iwakawa K, Turnidge JD, et al. Dissemination of new methicillin-resistant Staphylococcus aureus clones in the community. J Clin Microbiol 2002;40:4289–4294.