MRSA decolonisation

Around one in fifty people carries MRSA harmlessly, usually in the nose, and also in the throat, armpits, groin and on damaged skin. Carriage causes no symptoms, but it is the reservoir from which infection starts — and the reason a treated boil returns weeks later. Decolonisation aims to reduce that reservoir at the moments when it matters most.

• Nasal mupirocin 2% — a match-head amount into each nostril twice daily for five days. See Bactroban (mupirocin).
• Chlorhexidine washing — 4% skin cleanser used as a daily body wash for five days, or 2% impregnated cloths in hospital. See chlorhexidine.
• Chlorhexidine mouthwash — added for ventilated and some surgical patients.
• Laundry and environment — clean towels and bedding daily during the course, hot wash, and cleaning of frequently touched surfaces.

Cycles may be repeated monthly for several months in people with recurrent infection. Some centres add oral antibiotics such as co-trimoxazole with rifampicin for stubborn carriage, but only under specialist advice because resistance develops readily.

Screening and decolonising MRSA carriers before joint replacement, cardiac and vascular surgery reduces surgical site infection. Chlorhexidine showering on the day before and the day of surgery is combined with an MRSA-active prophylactic antibiotic — usually a glycopeptide such as teicoplanin or vancomycin in known carriers. More detail is on the hospitals and surgery page.

Decolonisation is not a cure for carriage. Many people are recolonised within six to twelve months, particularly if a household member also carries MRSA. Prolonged or repeated mupirocin use selects for mupirocin-resistant strains, and reduced chlorhexidine susceptibility has been reported, so courses are kept short and targeted rather than open-ended. Why recurrence happens is covered on why MRSA keeps coming back.