II. Epidemiology

  1. MRSA colonized patients
    1. Higher risk of infection
    2. Higher risk of death due to Antibiotic Resistance

III. Risk Factors: Community acquired MRSA (unique from hospital acquired cases)

  1. Athletes (Contact Sports with frequent abrasions)
  2. Crowded living conditions
  3. Military recruits
  4. Pacific Island residents
  5. Natives of Alaska
  6. Native Americans
  7. Prison Inmates
  8. Men who have Sex with Men

IV. Risk Factors: Comorbidy or medical environment exposure

  1. Recent hospitalization (especially if antibiotics administered during hospitalization)
  2. Nursing facility residents
  3. Recent Corticosteroid therapy
  4. Injection drug use (Intravenous drug use)
  5. HIV positive patients (especially if CD4<500 cells/mm3)
  6. Hemodialysis patients
  7. Diabetes Mellitus
  8. Pressure Ulcer history
  9. Prior MRSA history
  10. Close contact with MRSA colonized person

V. Evaluation

  1. Base treatment on culture and sensitivity

VI. Characteristics

  1. Typically involves Skin and Soft Tissue Infections
    1. Now MRSA appears to be most common organism
  2. Consider as superinfection following Influenza

VII. Labs

  1. Rapid MRSA assay (e.g. nasal PCR for MRSA)

VIII. Management: Outpatient

  1. Avoid antibiotics for abscess <5 cm without signs of Cellulitis
  2. Precautions
    1. Avoid beta lactam antibiotics (not effective)
    2. Dicloxacillin and Cephalexin are not effective for MRSA
    3. Avoid Fluoroquinolones due to resistance
  3. Topical Antibiotics with efficacy against MRSA (Impetigo, Folliculitis)
    1. Mupirocin 2% (Bactroban) Apply three times daily for 5 days
    2. Retapmulin 1% (Atabax) Apply twice daily for 5 days
  4. Oral antibiotics with efficacy against MRSA
    1. Trimethoprim Sulfamethoxazole (Bactrim, Septra)
      1. Adult: 1-2 DS tabs orally twice daily
        1. Use double the standard dose for MRSA (two DS tabs twice daily)
      2. Child: 8-12 mg/kg of trimethoprim divided bid
    2. Doxycycline
      1. Adults: 100 mg orally twice daily
    3. Clindamycin (Cleocin)
      1. Resistance rates in MRSA Infection has risen in U.S. (Septra and Doxycycline are preferred)
      2. Risk of induced resistance (identified with the D-Zone Test)
      3. Adult: 300-450 mg orally every 6 hours (or IV 600 mg every 8 hours)
      4. Child: 10-20 mg/kg orally every 8 hours (or IV 24-40 mg/kg divided q8 hours)
    4. Linezolid (Zyvox)
      1. Adult: 600 mg orally or IV every 12 hours
      2. Child: 10 mg/kg orally or IV every 12 hours
      3. Very expensive, and not first-line
      4. Serious Drug Interactions with MAO inhibitors and SSRIs
      5. Bioavailability is same for oral and IV
    5. Rifampin (risk of induced resistance)
      1. Used in combination with above agents or with Vancomycin to increase efficacy
      2. Tremblay (2013) Ann Pharmacother 47:1045-54 [PubMed]

IX. Management: Inpatient

  1. Vancomycin
    1. Preferred agent for inpatient treatment
    2. Adult: 15 mg/kg IV every 12 hours
    3. Child: 40 mg/kg IV divided every 6 hours
    4. Adjust for Chronic Kidney Disease
    5. Increasing Vancomycin resistant Staphylococcus aureus
      1. Try other antibiotics above prior to Vancomycin (Decreases Vancomycin resistance risk)
      2. Vancomycin intermediate Staphylococcus aureus (1 mcg/ml or more)
      3. Vancomycin resistant Staphylococcus aureus (MIC 16 mcg/ml or more)
  2. New agents with MRSA activity (only for severe cases or in Vancomycin resistance)
    1. Synercid (Quinupristin-Dalfopristin)
    2. Cyclic Lipopeptide: Cubicin (Daptomycin)
      1. Adult: 4 mg/kg IV every 24 hours
      2. Complicated Skin and Soft Tissue Infections
      3. Do not use for Pneumonia
      4. Associated with Myopathy and signficant gastrointestinal symptoms
    3. Zyvox (Linezolid)
      1. See Dosing above
      2. Complicated Skin and Soft Tissue Infections
      3. Complicated Pneumonia
      4. May be preferred over Vancomycin (toxin suppression, no nephrotoxicity) in Skin and Soft Tissue Infections
        1. Yue (2013) Cochrane Database Syst Rev (1):CD008056 [PubMed]
    4. Tygacil (Tigecycline)
      1. Adult: 100 mg IV load, then 50 mg IV every 12 hours
    5. Teflaro (Ceftaroline)
      1. Adult: 600 mg IV every 12 hours (lower dosing for Renal Insufficiency)
  3. First-line antibiotics
    1. Vancomycin is only first-line agent in many cases
    2. Linezolid is also first-line for MRSA, complicated Pneumonia
  4. Alternative antibiotics
    1. Linezolid
    2. Daptomycin (do not use in Pneumonia)

X. Prevention

  1. MRSA colonization in physicians is common
  2. Control of contagious spread
    1. Careful and frequent Hand Washing or Alcohol gels
    2. Proper handling of bodily secretions
    3. Isolate infected patients (cover wounds)
    4. Wash sheets, towels and clothing in hot water
    5. Remove colonized catheters
    6. Clean under Fingernails and keep nails short
    7. Do not share towels, razors, linens
    8. All contacts should frequently wash hands after touching patient's personal items (e.g. laundry)
    9. Consider disinfecting commonly touched surfaces (e.g. door knobs) twice weekly with bleach or lysol
  3. Identify source case of infection
    1. Swab nasopharynx of patients and staff near outbreak
  4. Decolonization Indications and Approach
    1. Indications
      1. Two MRSA Skin Infections at different sites over a six month period despite wound care, hygiene
      2. Decolonization of close contacts of these patients may be considered (e.g. household)
    2. Primary Strategy
      1. Bactroban applied twice daily to nares and wounds for 5-10 days
        1. Apply blueberry sized ointment in each nostril with cotton swab
        2. Press nostrils together with fingers and massage gently
    3. Other Methods
      1. Chlorhexidine (Hibiclens) showers for 5-14 days
      2. Dilute bleach baths (1/4 cup per 13 gallons water) for 15 minutes twice weekly for 3 months
  5. References
    1. (2016) Presc Lett 23(8)
    2. (2019) Presc Lett 26(1)

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Related Studies

Ontology: MRSA - Methicillin resistant Staphylococcus aureus infection (C0343401)

Concepts Disease or Syndrome (T047)
ICD10 A49.02
SnomedCT 266096002, 154316009, 186434000
Dutch infectie MRSA, MRSA, oxacillineresistente Staphylococcus aureus-infectie, meticillineresistente Staphylococcus aureus-infectie
French Infection à Staphylococcus aureus résistants à la méthicilline, SARM, Infection à Staphylococcus aureus oxacillino-résistant, Infection à Staphylococcus aureus méthicillino-résistant
German MRSA, Infektion MRSA, Oxacillinresistente Staphylococcus aureus-Infektion, Methicillinresistente Staphylococcus aureus-Infektion
Italian Stafilococco aureo meticillino-resistente, Infezione da stafilococco aureo meticillino-resistente, Infezione da Staphylococcus aureus meticillino-resistente, Infezione da Staphylococcus aureus oxacillino-resistente
Portuguese Estafilococo aureus meticilino-resistente, Infecção por estafilococo aureus meticilino-resistente, Infecção por Staphyloccocus aureus resistentes à meticilina, Infecção por Staphyloccocus aureus resistentes à oxacilina
Spanish SAMR, Infección por Staphylococcus aureus resistente a la oxacilina, Infección por Staphylococcus aureus resistente a meticilina, Infección por MRSA, infección por Staphylococcus aureus resistente a la meticilina (trastorno), infección por Staphylococcus aureus resistente a la meticilina
Japanese メチシリン耐性黄色ブドウ球菌感染, メチシリンタイセイオウショクブドウキュウキンカンセン, MRSAカンセン, MRSA, MRSA感染, MRSA, オキサシリンタイセイオウショクブドウキュウキンカンセン, オキサシリン耐性黄色ブドウ球菌感染
English Methicill-resis staph aur inf, MRSA-Methicill-resis staph aur, Methicillin-resistant staphylococcus aureus infection, MRSA - Methicillin-resistant staphylococcus aureus, Methicillin-resis staph aureus, Methicillin-resistant staphylococcus aureus, methicillin-resistant Staphylococcus aureus infection, methicillin-resistant Staphylococcus aureus infection (diagnosis), methicillin resistant Staphylococcus aureus infection, Infection MRSA, MRSA, oxacillin-resistant Staphylococcus aureus infection, oxacillin-resistant Staphylococcus aureus infection (diagnosis), methicillin-resistant staphylococcus aureus (MRSA) infection, mrsa infection, Methicillin resistant Staphylococcus aureus (MRSA) infection, Methicillin-resistant Staphylococcus aureus, Methicillin-resistant staphylococcus aureus infection (disorder), Methicillin resistant staphylococcus aureus, Oxacillin-resistant Staphylococcus aureus infection, Methicillin-resistant Staphylococcus aureus infection, MRSA - Methicillin resistant Staphylococcus aureus infection, Infection due to Methicillin resistant Staphylococcus aureus, MRSA infection, Methicillin resistant Staphylococcus aureus infection (disorder), Methicillin resistant Staphylococcus aureus infection
Czech MRSA, Infekce MRSA, Infekce způsobená kmeny Staphylococcus aureus rezistentními na oxacillin, Infekce způsobená meticilin rezistentními kmeny Staphylococcus aureus
Hungarian MRSA fertőzés, MRSA, Oxacillin-reszisztens Staphylococcus aureus fertőzés, Methicillin-rezisztens Staphylococcus aureus fertőzés

Ontology: Methicillin resistant Staphylococcus aureus (organism) (C1265292)

Definition (MSH) A strain of Staphylococcus aureus that is non-susceptible to the action of METHICILLIN. The mechanism of resistance usually involves modification of normal or the presence of acquired PENICILLIN BINDING PROTEINS.
Definition (MEDLINEPLUS)

MRSA stands for methicillin-resistant Staphylococcus aureus. It causes a staph infection (pronounced "staff infection") that is resistant to several common antibiotics. There are two types of infection. Hospital-associated MRSA happens to people in healthcare settings. Community-associated MRSA happens to people who have close skin-to-skin contact with others, such as athletes involved in football and wrestling.

Infection control is key to stopping MRSA in hospitals. To prevent community-associated MRSA

  • Practice good hygiene
  • Keep cuts and scrapes clean and covered with a bandage until healed
  • Avoid contact with other people's wounds or bandages
  • Avoid sharing personal items, such as towels, washcloths, razors, or clothes
  • Wash soiled sheets, towels, and clothes in hot water with bleach and dry in a hot dryer

If a wound appears to be infected, see a health care provider. Treatments may include draining the infection and antibiotics.

NIH: National Institute of Allergy and Infectious Diseases

Definition (CSP) type of bacteria that is resistant to certain antibiotics including methicillin and other more common antibiotics such as oxacillin, penicillin and amoxicillin; occurs most frequently among persons in hospitals and healthcare facilities (such as nursing homes and dialysis centers) who have weakened immune systems; infections in the community are usually manifested as skin infections, such as pimples and boils, and occur in otherwise healthy people.
Concepts Bacterium (T007)
MSH D055624
SnomedCT 115329001
LNC LP34425-6
English METHICILLIN RESISTANT STAPH AUREUS, MRSA, Methicillin-Resistant Staphylococcus aureus, Staphylococcus aureus.methicillin resistant, methicillin resistant staphylococcus aureus (MRSA), Methicillin Resistant Staphylococcus Aureus, Methicillin resistant Staphylococcus aureus, Methicillin resistant Staphylococcus aureus (organism), methicillin resistant Staphylococcus aureus
Spanish Staphylococcus aureus Resistente a Meticilina, SARM, MRSA, Staphylococcus aureus resistente a la meticilina (organismo), Staphylococcus aureus resistente a la meticilina
French Staphylocoque doré résistant à la méthicilline, S. aureus résistant à la méthicilline, S. aureus résistant à la méticilline, SARM, Staphylococcus aureus résistant à la méthicilline, Staphylococcus aureus résistant à la méticilline, Staphylocoque doré résistant à la méticilline
Italian Staphylococcus aureus meticillino resistente, Staphylococcus aureus meticillino-resistente, SAMR, Staphylococcus aureus meticillina resistente
German MRSA, Methicillin-resistenter Staphylococcus aureus
Portuguese Staphylococcus aureus Resistente à Meticilina, MRSA, SARM
Swedish Meticillinresistent Staphylococcus aureus
Czech MRSA, Staphylococcus aureus rezistentní na methicilin, methicilin-rezistentní Staphylococcus aureus, methicilin rezistentní Staphylococcus aureus, methicilin-rezistentní zlatý stafylokok
Polish Staphylococcus aureus oporny na metycylinę, Gronkowiec złocisty metycylinooporny, Gronkowiec złocisty oporny na metycylinę, Staphylococcus aureus metycylinooporny, MRSA
Japanese メチシリン耐性黄色ブドウ球菌