ASPEN, COLO. — Can patients with repeated Staphylococcus aureus infections be decolonized to prevent recurrences?
The evidence supporting this approach is not very good. But, it is always worth a try, Dr. Sarah K. Parker said at a meeting on pediatric infectious diseases sponsored by the Children's Hospital, Denver.
Community-acquired staphylococcal infections are on the rise, even in normal, healthy children. Now, many of the organisms seen in the community—as well as in the hospital—are methicillin resistant.
Two or three times a week, she sees a child with a small, pustular lesion (often on the buttocks) that the child's primary-care physician has called a bug bite, but which turns out to be a S. aureus infection instead, said Dr. Parker of the pediatric infectious diseases department at the hospital.
That's a very common misdiagnosis of these infections. It is one that has been noted by other infectious disease specialists, and it illustrates not just how common the misdiagnosis has become, but also how common the infections now are, Dr. Parker said.
Some individuals do have recurrences that may be the result of incomplete treatment, but it also appears that some individuals just may be prone to repeated infections.
The Cochrane Collaboration recently reviewed evidence on methods for decolonizing patients with antibiotic treatment, Dr. Parker noted. It concluded that the practice of treating patients prophylactically with antibiotics or mupirocin to reduce nasal carriage of S. aureus is not supported by enough good evidence.
The exception may be for the use of mupirocin, which has been the subject of various studies. In general, that research shows that, if patients are treated twice daily for 5–7 days, 85% of them will be culture negative at about 14 days. However, 25% of those will be recolonized by 30 days, and 50%–70% will be recolonized by 6 months, Dr. Parker said.
Moreover, the nose isn't the entire story, she added. About 60% of individuals with staphylococcus in the nares also are colonized at other sites, and 20% of those colonized in sites other than the nose are not colonized in the nose.
One placebo-controlled study that used mupirocin in 32 normal individuals with recurrent infections for 5 days each month for 12 months reported that infections were reduced by about 50%, but not totally (Arch. Int. Med. 1996;65:109–13).
Also, in that study and others, resistance did develop. “This is a serious concern,” she said.
Therefore, given the questionable efficacy that prophylactic mupirocin treatment is likely to have and the resistance, Dr. Parker said she focuses on education for patients and families that have recurrent infections and resorts to a single, twice-daily course of mupirocin for 5 days only on occasion in those who have already been educated.
Among the measures she educates patients about include the following:
She tells parents to inspect the child carefully and often, since many times the sites of infections are in places covered by clothing.
Nails need to be kept clean and short to prevent scratches.
Bathing with an antimicrobial soap, such as hexachlorophene or chlorhexidine, can be 20%–50% effective at decolonizing extranasal sites in the short term.
Some recommend having patients bathe with bleach in the water, about 1 tablespoon per gallon, which is not much more than is found in a chlorinated swimming pool.
Towels and underwear need to be changed and washed often, Dr. Parker said.
For the physicians who see these infections, surgical treatment is most important.
“Incise these lesions and drain them very early, like as soon as you see a little head, get this thing open,” Dr. Parker said. “Scrub it, clean it, and even use a topical antistaph [treatment] on it.”