Continuing Medical Education
Community-acquired methicillin-resistant Staphylococcus aureus

https://doi.org/10.1016/j.jaad.2006.04.018Get rights and content

Published data confirm that community-acquired methicillin-resistant Staphylococcus aureus (MRSA) infections are increasing in incidence in both urban and rural settings. The statistical risk is higher for athletes, military personnel, prison inmates, intravenous drug abusers, the homeless, children in daycare, and certain Native American groups, but the infections are by no means restricted to these populations. Roughly 85% of the infections involve the skin and subcutaneous tissue, with the most common presentations being an abscess or folliculitis. The typical associated gene cassette is quite small and codes only for methicillin resistance. Abscesses generally respond to drainage.

Learning objective

At the conclusion of this learning activity, participants should recognize groups at high risk for community-acquired MSRA infections and manage these infections appropriately.

Section snippets

Key points

  • Community-acquired methicillin-resistant Staphylococcus aureus (MRSA) has existed for more than a decade but recently has emerged as an important worldwide pathogen.

  • Genes for resistance are typically carried by staphylococcal chromosomal cassette mec type IVa.

  • This small gene cassette codes only for methicillin resistance (rather than multiple antibiotic resistance).

  • Clones with multiple antibiotic resistance are emerging in Asia.

  • Outbreaks in the United States occur in both rural and urban

Key points

  • Community-acquired MRSA clones are genetically distinct from classic health care–associated clones.

  • Community-acquired MRSA has now crossed over from the community into health care settings.

  • It may be best to refer to “community-type strains” and “health care–type strains,” regardless of where the infection is actually acquired.

  • In the hospital setting, community-acquired MRSA tends to produce cutaneous and joint infections, just as it does in the community.

The distinction between

Key points

  • Outcomes for hospitalized patients with MRSA are worse than for those with methicillin-sensitive Staphylococcus aureus (MSSA).

  • Community-acquired MRSA colonization is much more likely to progress to clinical infection than is MSSA colonization.

  • The resulting community-acquired MRSA infection is likely to be a cutaneous abscess or folliculitis.

  • Panton-Valentine leukocidin is the major virulence factor among community-acquired MRSA strains.

  • The community-acquired MRSA pulmonary syndrome is a distinct

Key points

  • The primary treatment for a community-acquired MRSA abscess is drainage (Fig 1).

  • Many patients have responsed to drainage alone.

  • Failure to drain the abscess may have catastrophic consequences, even if an effective antibiotic is prescribed.

Population-based surveillance data from Baltimore and Atlanta and hospital laboratory–based sentinel surveillance of 12 hospitals in Minnesota between 2001 and 2002 included 1,647 cases of community-acquired MRSA infection, representing between 8% and 20% of

Key points

  • Surgical drainage, rather than antibiotic therapy, is the single most important intervention for a community-acquired MRSA abscess.

  • When an antibiotic is required, trimethoprim-sulfamethoxazole remains an inexpensive and effective choice for the majority of patients.

  • Tetracyclines are effective for many strains.

  • Overall, inducible lincosamide resistance is becoming more prevalent, although a reverse trend has been noted in one Dallas hospital.

  • Although many community-acquired MRSA strains remain

Key points

  • Community-acquired MRSA skin infections recur at a high rate.

  • Skin surface and fomite colonization appear to be at least as important as nasal colonization.

  • Alcohol-based disinfectants may be superior to detergent-based formulations.

Recurrence of community-acquired MRSA infections is related to untreated colonization. Close contacts of those with MRSA infection often become colonized or infected. Both nasal and skin surface colonization must be addressed to reduce the risk to the patient and

Key points

  • Seriously ill patients should be hospitalized.

  • Most infections in clinically well patients are appropriately treated on an outpatient basis with oral antibiotics.

  • Pus-containing lesions, especially in recognized risk groups, suggest community-acquired MRSA infection.

  • The primary treatment for an abscess remains drainage.

  • Sulfa drugs are an appropriate choice for most community-acquired MRSA infections that require antibiotic therapy.

  • The first-line empiric therapy for most other skin infections

Conclusions

Community-acquired MRSA strains are increasing in prevalence and can be highly virulent. Most infections present as skin and soft-tissue abscesses, which may respond to drainage alone. A severe syndrome of lung and septic joint involvement often affects children and may be fatal.

Sulfa drugs represent the most valuable class of antibiotics for the treatment of cutaneous community-acquired MRSA infections. Tetracyclines and clindamycin have also been used successfully, although concerns about

References (133)

  • F.B. Marangon et al.

    Ciprofloxacin and levofloxacin resistance among methicillin-sensitive Staphylococcus aureus isolates from keratitis and conjunctivitis

    Am J Ophthalmol

    (2004)
  • T. Horii et al.

    Detection of mutations in quinolone resistance-determining regions in levofloxacin- and methicillin-resistant Staphylococcus aureus: effects of the mutations on fluoroquinolone MICs

    Diagn Microbiol Infect Dis

    (2003)
  • B.A. Cunha

    Methicillin-resistant Staphylococcus aureus: clinical manifestations and antimicrobial therapy

    Clin Microbiol Infect

    (2005)
  • P.R. Hsueh et al.

    Nosocomial infections due to methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci at a university hospital in Taiwan from 1991 to 2003: resistance trends, antibiotic usage and in vitro activities of newer antimicrobial agents

    Int J Antimicrob Agents

    (2005)
  • J.L. Munoz Bellido et al.

    In vitro activity of linezolid, synercid and telithromycin against genetically defined high level fluoroquinolone-resistant methicillin-resistant Staphylococcus aureus

    Int J Antimicrob Agents

    (2002)
  • H. Imamura et al.

    Dicationic dithiocarbamate carbapenems with anti-MRSA activity

    Bioorg Med Chem

    (2001)
  • Y. Kobayashi

    Study of the synergism between carbapenems and vancomycin or teicoplanin against MRSA, focusing on S-4661, a carbapenem newly developed in Japan

    J Infect Chemother

    (2005)
  • D.A. Robinson et al.

    Evolutionary models of the emergence of methicillin-resistant Staphylococcus aureus

    Antimicrob Agents Chemother

    (2003)
  • N. van der Mee-Marquet et al.

    Bloodstream Infection Study Group of the Relais d'Hygiene du Centre. Epidemiology and typing of Staphylococcus aureus strains isolated from bloodstream infections

    J Clin Microbiol

    (2004)
  • Centers for Disease Control and Prevention

    Outbreaks of community-associated methicillin-resistant Staphylococcus aureus skin infections—Los Angeles County, California, 2002–2003

    MMWR Mor Mortal Wkly Rep

    (2003)
  • T.J. Kowalski et al.

    Epidemiology, treatment, and prevention of community-acquired methicillin-resistant Staphylococcus aureus infections

    Mayo Clin Proc

    (2005)
  • B.A. Diep et al.

    Widespread skin and soft-tissue infections due to two methicillin-resistant Staphylococcus aureus strains harboring the genes for Panton-Valentine leucocidin

    J Clin Microbiol

    (2004)
  • T.S. Naimi et al.

    Comparison of community- and health care–associated methicillin-resistant Staphylococcus aureus infection

    JAMA

    (2003)
  • D. Lu et al.

    Community-acquired methicillin-resistant Staphylococcus aureus, a new player in sports medicine

    Curr Sports Med Rep

    (2005)
  • J.T. Weber

    Community-associated methicillin-resistant Staphylococcus aureus

    Clin Infect Dis

    (2005)
  • E.D. Charlebois et al.

    Origins of community strains of methicillin-resistant Staphylococcus aureus

    Clin Infect Dis

    (2004)
  • P.R. Cohen

    Cutaneous community-acquired methicillin-resistant Staphylococcus aureus infection in participants of athletic activities

    South Med J

    (2005)
  • W.C. Mathews et al.

    Incidence of and risk factors for clinically significant methicillin-resistant Staphylococcus aureus infection in a cohort of HIV-infected adults

    J Acquir Immune Defic Syndr

    (2005)
  • M. Tumbarello et al.

    Risk factors and predictors of mortality of methicillin-resistant Staphylococcus aureus (MRSA) bacteraemia in HIV-infected patients

    J Antimicrob Chemother

    (2002)
  • E.S. Pan et al.

    Population dynamics of nasal strains of methicillin-resistant Staphylococcus aureus—and their relation to community-associated disease activity

    J Infect Dis

    (2005)
  • H.A. Carleton et al.

    Perdreau-Remington F. Community-adapted methicillin-resistant Staphylococcus aureus (MRSA): population dynamics of an expanding community reservoir of MRSA

    J Infect Dis

    (2004)
  • S.C. Buckingham et al.

    Emergence of community-associated methicillin-resistant Staphylococcus aureus at a Memphis, Tennessee, Children's Hospital

    Pediatr Infect Dis J

    (2004)
  • K. Purcell et al.

    Epidemic of community-acquired methicillin-resistant Staphylococcus aureus infections: a 14-year study at Driscoll Children's Hospital

    Arch Pediatr Adolesc Med

    (2005)
  • M.E. Stemper et al.

    Emergence and spread of community-associated methicillin-resistant Staphylococcus aureus in rural Wisconsin, 1989 to 1999

    J Clin Microbiol

    (2004)
  • H.C. Baggett et al.

    An outbreak of community-onset methicillin-resistant Staphylococcus aureus skin infections in southwestern Alaska

    Infect Control Hosp Epidemiol

    (2003)
  • D.W. Dietrich et al.

    Community-acquired methicillin-resistant Staphylococcus aureus in southern New England children

    Pediatrics

    (2004)
  • B. Said-Salim et al.

    Community-acquired methicillin-resistant Staphylococcus aureus: an emerging pathogen

    Infect Control Hosp Epidemiol

    (2003)
  • M.V. Tirabassi et al.

    Geographic information system localization of community-acquired MRSA soft tissue abscesses

    J Pediatr Surg

    (2005)
  • S. Kitai et al.

    Characterization of methicillin-resistant Staphylococcus aureus isolated from retail raw chicken meat in Japan

    J Vet Med Sci

    (2005)
  • L. Saiman et al.

    Hospital transmission of community-acquired methicillin-resistant Staphylococcus aureus among postpartum women

    Clin Infect Dis

    (2003)
  • C. Eckhardt et al.

    Transmission of methicillin-resistant Staphylococcus aureus in the neonatal intensive care unit from a patient with community-acquired disease

    Infect Control Hosp Epidemiol

    (2003)
  • C.D. Salgado et al.

    Community-acquired methicillin-resistant Staphylococcus aureus: a meta-analysis of prevalence and risk factors

    Clin Infect Dis

    (2003)
  • Y.C. Huang et al.

    Nasal carriage of methicillin-resistant Staphylococcus aureus in school children without identifiable risk factors in northern Taiwan

    Pediatr Infect Dis J

    (2005)
  • J.A. Jernigan et al.

    Prevalence of and risk factors for colonization with methicillin-resistant Staphylococcus aureus at the time of hospital admission

    Infect Control Hosp Epidemiol

    (2003)
  • O. Lesens et al.

    Healthcare-associated Staphylococcus aureus bacteremia and the risk for methicillin resistance: is the Centers for Disease Control and Prevention definition for community-acquired bacteremia still appropriate?

    Infect Control Hosp Epidemiol

    (2005)
  • S.D. Reed et al.

    Costs and outcomes among hemodialysis-dependent patients with methicillin-resistant or methicillin-susceptible Staphylococcus aureus bacteremia

    Infect Control Hosp Epidemiol

    (2005)
  • D.P. Calfee et al.

    Spread of methicillin-resistant Staphylococcus aureus (MRSA) among household contacts of individuals with nosocomially acquired MRSA

    Infect Control Hosp Epidemiol

    (2003)
  • M.W. Ellis et al.

    Natural history of community-acquired methicillin-resistant Staphylococcus aureus colonization and infection in soldiers

    Clin Infect Dis

    (2004)
  • V.R. Laibl et al.

    Clinical presentation of community-acquired methicillin-resistant Staphylococcus aureus in pregnancy

    Obstet Gynecol

    (2005)
  • L.G. Miller et al.

    Necrotizing fasciitis caused by community-associated methicillin-resistant Staphylococcus aureus in Los Angeles

    N Engl J Med

    (2005)
  • Cited by (119)

    • Optimizing the structure of (salicylideneamino)benzoic acids: Towards selective antifungal and anti-staphylococcal agents

      2021, European Journal of Pharmaceutical Sciences
      Citation Excerpt :

      Thus, its occurrence has been associated with health care settings, including hospitals and other health care environments (Kale and Dhawan, 2016). Moreover, this pathogen has been emerged as a major cause of community-associated infections, as well (Elston, 2007). MRSA strains are instantly classified as a multidrug resistant strains called „superbugs“.

    • Can a UV-C box help the cinema industry by disinfecting video cameras?

      2023, Journal of Preventive Medicine and Hygiene
    View all citing articles on Scopus

    Funding sources: None.

    Disclosure: The author has been a consultant and speaker for Abbott Laboratories and Medicis. His work for them involved a cephalosporin inactive against methicillin-resistant Staphylococcus aureus.

    Reprints not available from the author.

    View full text