Skin and soft tissue infections (SSTI) are the most common presentation of MRSA (meticillin-resistant Staph. Aureus) infection, although it can also cause severe, invasive disease. This guideline is for the treatment of uncomplicated skin and soft tissue infection (eg cellulitis, erysipelas, abscess) with MRSA.
It is not applicable to patients with evidence of systemic illness (such as sepsis), necrotising /deep tissue infections, superficial infections (such as pustules and papules), hidradenitis suppurativa, or immunocompromising conditions.

Staphylococcus aureus, including MRSA, is one of the most common pathogens that cause cellulitis/abscesses. MRSA is resistant to penicillin-related antibiotics such as flucloxacillin and most cephalosporins and may be resistant to other antibiotic classes. Lack of response to empiric antibiotics may be due to MRSA.

Note:

• Minor skin and soft tissue infections (SSTIs) (furunculosis, folliculitis, small boils without cellulitis) do not need systemic antibiotic treatment.

• Non-severe/uncomplicated cellulitis with no systemic illness may be treated with oral antibiotics but consider the need for iv antibiotics/admission for assessment if there are risk factors for treatment failure or poor outcome (cellulitis affecting face or perineum, frail/aged >80 , previous splenectomy, chronic renal or liver disease, immunocompromised, alcohol abuse, treatment failure in the community, diabetes mellitus, chronic venous insufficiency, morbid obesity).

• Abscesses - incision and drainage is the optimal management for abscesses.     

• Larger abscesses (> 5cm), multiple abscesses, systemic features of infection, surrounding cellulitis and immunocompromised patients should be treated with oral antibiotics in addition to drainage.
• small abscesses - consider additional use of antibiotics - discuss potential benefits and side-effects with the patient (antibiotics may reduce risk of treatment failure and recurrence but there is a risk of antibiotic-related side-effects)

Antibiotics
 If active infection with MRSA confirmed by lab results, and admission not warranted:

Use sensitivities on report to guide treatment; If no response to treatment, seek advice from Microbiology.

If active infection and patient has MRSA risk factors (see below), and admission not warranted:

• MRSA should be considered when choosing empirical (best guess) antimicrobial treatment regimens for infection
• The treatment options below are suitable empirical treatment for uncomplicated SSTI where MRSA is suspected - confirm sensitivities with cultures and adjust antibiotic treatment accordingly.

Risk factors for MRSA infection include:

• patients who are/have been colonised with MRSA (from screening swabs);
• patients who have had previous MRSA infections
• being a resident of a long-term care facility (care home, or any other long term residential facility)
• patients who have recently been in hospital

 Preferred Option

Alternative Option

Notes

Doxycycline initially 200 mg daily for 1 dose, then maintenance 100 mg once daily PO 5 days (may be extended up to 14 days depending on clinical response).
200mg od may be used for severe infections.

Co-trimoxazole (contains trimethoprim and sulfamethoxazole) (trimethoprim/sulfamethoxazole) 960mg twice daily PO 5 days (may be extended up to 14 days depending on clinical response) (see BNFc for dosing in children >6 weeks old)
Or
Clindamycin 300 qds PO 5 days (may be extended up to 14 days depending on clinical response).
(see BNFc for dosing in children)

Or
Clarithromycin 500mg bd PO 5 days
(Erythromycin 500mg qds in pregnancy)
(may be extended up to 14 days depending on clinical response).
(see BNFc for dosing in children)

Check the MRSA is susceptible - see culture sensitivity report.
Doxycycline contraindicated in pregnancy and <12years
Co-trimoxazole (contains trimethoprim and sulfamethoxazole) may slightly increase the risk of congenital malformations, including neural tube defects, when prescribed to pregnant women
Clindamycin is considered safe in pregnancy but has a higher risk of diarrhoea