Staphylococcus aureus in the community - Information for clinicians

Last updated: 17 December 2008

What is Staphylococcus aureus (staph) in the community?

Many healthy people carry staphylococcal bacteria on their skin or in the anterior nares of the nose. Some strains of staph are resistant to the antibiotic methicillin and other antibiotics; these are known as methicillin resistant Staphylococcus aureus (MRSA). There are some strains of MRSA referred to as Community acquired MRSA (CaMRSA) which tend to spread in community settings. CaMRSA strains are often quite different to MRSA strains associated with hospitals and can cause disease in otherwise healthy people. CaMRSA usually manifests as skin infections such as pimples and boils, impetigo or cellulitis, and more serious infections including osteomyelitis, bacteraemia and pneumonia.

Who is at risk of infection in the community?

Crowding and frequent skin to skin contact can increase the risk of infection so outbreaks tend to occur in schools, dormitories, military barracks, correctional facilities, and child care centers. People with co-morbidities such as diabetes, with broken skin or dermatitis, or with immune suppression, are also at risk of infection.

When should specimens be collected?

CaMRSA should be considered in the differential diagnosis of serious or recurrent skin and soft tissue infections such as skin abscesses and boils. Collect a specimen for culture and antimicrobial susceptibility from patients with boils, wounds, or other sites of infection that warrant antibiotic therapy particularly severe local infections or when in connection with a cluster or outbreak of infection. It is not necessary to collect nasal cultures in patients with suspected CaMRSA infection.

How are skin infections treated?

Incision and drainage remains the primary treatment for boils and abscesses. Patients should be told of the importance of keeping wounds clean and covered following incision. Empiric antibiotic therapy may be used in addition according to the severity and progression of infection, presence of systemic illness, patient co-morbidities, inability to drain abscess, or lack of response to initial treatment with incision and drainage alone. The following treatment is recommended by the Therapeutic guidelines: antibiotic.

For Large or multiple skin infections or with systemic symptoms (while awaiting culture results) use: Di(flu)cloxacillin
For patients who are hypersensitive to penicillin (excluding immediate hypersensitivity), use: cephalexin
For patients with immediate penicillin hypersensitivity, use:clindamycin
 
For CaMRSA skin infections - probable, confirmed, severe or recurring

• guided by culture sensitivities
• clindamycin (check susceptible to erythromycin) or
• cotrimoxazole, or
• doxycycline (adults)

1. In non-remote community settings, remove crusts 8-hourly using saline or soap and water, or aluminium acetate solution or potassium permanganate solution, and apply a topical cream such as mupirocin 2% topically, 8-hourly for 7 days.
2. In remote communities where Streptococcus pyogenes is confirmed, or suspected; remove crusts 12-hourly using saline or soap and water, aluminium acetate solution or potassium permanganate solution. Give benzathine penicillin IM as a single dose.

What about recurrent cases and their contacts?

Some people can have repeated skin infections, and members of the same household can be affected due to contact with skin or contaminated objects or surfaces. Routinely ask patients with staph infections about other cases of skin and soft tissue infections in household members or other close contacts. It is important to counsel the patient (and provide them with a fact sheet) about prevention measures and good hygiene practices. Encourage the patient to share the fact sheet with their contacts.

Current evidence does not support the routine use of agents to eliminate colonisation. However, it may be reasonable to try and eliminate staph carriage if:

1. an individual patient has multiple documented recurrences of MRSA infection, or
2. ongoing MRSA transmission occurs in a well-defined, closely-associated group (eg household or sporting group).

Decolonisation should be considered only where standard prevention measures have proven unsuccessful at interrupting transmission. Key points for a decolonisation procedure include:

• All household members with skin and soft tissue infections should be treated at the same time
• Use an antiseptic wash or soap containing triclosan 1% or chlorhexidine 2% daily for bathing/showering for at least 5 days. If boils are occurring on the scalp, use a shampoo or soap containing an antiseptic.
• Do not share clothing, towels, or other linen that comes in contact with the skin
• Regularly clean the household environment with a standard household detergent
• Avoid sports/games that involve contact and cause sweating and friction with clothes during this period
• Use a topical nasal cream such as mupirocin 2% or chlorhexidine 0.3% nasal cream, applied intranasally with a cotton bud stick, three times daily for 10 days. The widespread use of mupirocin often causes resistance, and should be used after skin infections are controlled

What is the public health response?

CaMRSA is not notifiable in NSW, however, the public health unit should be contacted if a potential outbreak or cluster of infections is identified. A cluster may be considered as two or more cases occurring in a defined group (such as a household or sporting group).

Management of individuals with skin and soft tissue infections

Management of individuals with skin and soft tissue infections - download form

• Management of individuals with skin and soft tissue infections - download form  /resources/publichealth/infectious/diseases/images/gp_flowchart.gif