II. Risk Factors: Community acquired MRSA (unique from hospital acquired cases)
- Athletes (Contact Sports with frequent abrasions)
- Crowded living conditions
- Military recruits
- Pacific Island residents
- Natives of Alaska
- Native Americans
- Prison Inmates
- Men who have Sex with Men
III. Risk Factors: Comorbidy or medical environment exposure
- Recent hospitalization (especially if Antibiotics administered during hospitalization)
- Nursing facility residents
- Recent Corticosteroid therapy
- Injection drug use (Intravenous drug use)
- HIV positive patients (especially if CD4<500 cells/mm3)
- Hemodialysis patients
- Diabetes Mellitus
- Pressure Ulcer history
- Prior MRSA history
- Close contact with MRSA colonized person
IV. Evaluation
- Base treatment on culture and sensitivity
V. Characteristics
- Typically involves Skin and Soft Tissue Infections
- Consider in delayed Wound Healing or refractory Cellulitis
- Now MRSA appears to be most common organism
- Consider as respiratory superinfection following Influenza
VI. Labs
- Rapid MRSA assay (e.g. nasal PCR for MRSA)
VII. Management: Outpatient
- Avoid Antibiotics for abscess <5 cm without signs of Cellulitis
- Precautions
- Avoid beta lactam Antibiotics (not effective)
- Dicloxacillin and Cephalexin are not effective for MRSA
- Avoid Fluoroquinolones due to resistance
- Topical Antibiotics with efficacy against MRSA (Impetigo, Folliculitis)
- Oral Antibiotics with efficacy against MRSA
- Trimethoprim Sulfamethoxazole (Bactrim, Septra)
- Adult: 1 to 2 DS tabs orally twice daily
- May use double the standard dose for MRSA (two DS tabs twice daily)
- Child: 8 to 12 mg/kg of trimethoprim divided bid
- Adult: 1 to 2 DS tabs orally twice daily
- Doxycycline
- Adults: 100 mg orally twice daily
- Clindamycin (Cleocin)
- Resistance rates in MRSA Infection have risen in U.S. (Septra and Doxycycline are preferred)
- Risk of induced resistance (identified with the D-Zone Test)
- Adult: 300 to 450 mg orally every 6 hours (or IV 600 mg every 8 hours)
- Child: 10 to 20 mg/kg orally every 8 hours (or IV 24-40 mg/kg divided q8 hours)
- Linezolid (Zyvox)
- Adult: 600 mg orally or IV every 12 hours
- Child: 10 mg/kg orally or IV every 12 hours
- Very expensive, and not first-line
- Serious Drug Interactions with MAO Inhibitors and SSRIs
- Bioavailability is same for oral and IV
- Rifampin
- Risk of rapid development of induced resistance if used alone
- Used in combination with above agents or with Vancomycin to increase efficacy
- No additional benefit in MRSA bacteremia when added to MRSA effective agents
- Tremblay (2013) Ann Pharmacother 47:1045-54 [PubMed]
- Thwaites (2018) Lancet 391(10121): 668-78 [PubMed]
- Trimethoprim Sulfamethoxazole (Bactrim, Septra)
VIII. Management: Inpatient
-
Vancomycin
- Preferred agent for inpatient treatment
- Adult: 15 mg/kg IV every 12 hours
- Child: 40 mg/kg IV divided every 6 hours
- Adjust for Chronic Kidney Disease
- Increasing Vancomycin resistant Staphylococcus aureus
- Try other Antibiotics above prior to Vancomycin (Decreases Vancomycin resistance risk)
- Vancomycin intermediate Staphylococcus aureus (1 mcg/ml or more)
- Vancomycin resistant Staphylococcus aureus (MIC 16 mcg/ml or more)
- New agents with MRSA activity (only for severe cases or in Vancomycin resistance, e.g. Vancomycin MIC >1 mcg/ml)
- Synercid (Quinupristin-Dalfopristin)
- Cyclic Lipopeptide: Cubicin (Daptomycin)
- Adult: 4 mg/kg IV every 24 hours
- Complicated Skin and Soft Tissue Infections
- Do not use for Pneumonia
- Associated with Myopathy and signficant gastrointestinal symptoms
- Zyvox (Linezolid)
- See Dosing above
- Complicated Skin and Soft Tissue Infections
- Complicated Pneumonia
- May be preferred over Vancomycin (toxin suppression, no nephrotoxicity) in Skin and Soft Tissue Infections
- Tygacil (Tigecycline)
- Adult: 100 mg IV load, then 50 mg IV every 12 hours
- Teflaro (Ceftaroline)
- Adult: 600 mg IV every 12 hours (lower dosing for Renal Insufficiency)
- First-line Antibiotics
- Vancomycin is only first-line agent in many cases
- Linezolid is also first-line for MRSA, complicated Pneumonia
- Alternative Antibiotics
- Linezolid
- Daptomycin (do not use in Pneumonia)
- Clindamycin (risk of induced resistance)
IX. Complications
- MRSA colonized patients
- Higher risk of infection
- Higher risk of death due to Antibiotic Resistance
X. Prevention
- MRSA colonization in physicians is common
- Control of contagious spread
- Careful and frequent Hand Washing or Alcohol gels
- Proper handling of bodily secretions
- Isolate infected patients (cover wounds)
- Wash sheets, towels and clothing in hot water
- Remove colonized catheters
- Clean under Fingernails and keep nails short
- Do not share towels, razors, linens
- All contacts should frequently wash hands after touching patient's personal items (e.g. laundry)
- Consider disinfecting commonly touched surfaces (e.g. door knobs) twice weekly with bleach or lysol
- Identify source case of infection
- Swab nasopharynx of patients and staff near outbreak
- Decolonization Indications and Approach
- Indications
- Two MRSA Skin Infections at different sites over a six month period despite wound care, hygiene
- Decolonization of close contacts of these patients may be considered (e.g. household)
- Primary Strategy
- Bactroban applied twice daily to nares and wounds for 5-10 days
- Apply blueberry sized ointment in each nostril with cotton swab
- Press nostrils together with fingers and massage gently
- Bactroban applied twice daily to nares and wounds for 5-10 days
- Other Methods
- Chlorhexidine (Hibiclens) showers for 5-14 days
- Dilute bleach baths (1/4 cup per 13 gallons water) for 15 minutes twice weekly for 3 months
- Indications
- References
- (2016) Presc Lett 23(8)
- (2019) Presc Lett 26(1)
XI. References
- (2005) Lexi-comp Drug Database
- Carvey and Glauser (2023) Crit Dec Emerg Med 37(11): 23-9
- Glauser (2014) Crit Dec Emerg Med 28(11): 2-10
- Bamberger (2005) Am Fam Physician 72:2474-81 [PubMed]
- Breen (2010) Am Fam Physician 81(7): 893-9 [PubMed]
- Michel (1997) Lancet 349:1901-6 [PubMed]
- Kauffman (1993) Am J Med 94:371-8 [PubMed]
- Stevens (2009) Ann Intern Med 150(1): 11 [PubMed]
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Related Studies
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
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 |
Russian | METITSILLIN-REZISTENTNYI STAPHYLOCOCCUS AUREUS, MRSA, МЕТИЦИЛЛИН-РЕЗИСТЕНТНЫЙ СТАФИЛОКОКК ЗОЛОТИСТЫЙ, МЕТИЦИЛЛИН-РЕЗИСТЕНТНЫЙ STAPHYLOCOCCUS AUREUS, METITSILLIN-REZISTENTNYI STAFILOKOKK ZOLOTISTYI |
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 |