In the last issue of Pediatric Views, we asked clinicians to
send in questions they'd like answered by a Children's
Hospital Boston expert. The response has been excellent. Below is the first in an ongoing Q&A series between
Pediatric Views readers and experts.
Answer: No clinical group A strep isolate resistant to
penicillin has been documented to date. Ampicillin or
amoxicillin is often used instead of penicillin, but these
agents offer no advantage.
For penicillin-allergic patients, erythromycin or another
macrolide is the usual treatment, except when there is known to be a high prevalence of erythromycin resistance.
In treating patients for recurrent of group A strep (GAS) infection, a challenge is distinguishing between infection and colonization. Persistent or recurrent GAS pharyngitis can
represent noncompliance with therapy, a new infection acquired from a close contact, or, less likely, treatment failure. In these patients, an additional course of penicillin or other agent is indicated. Throat culture with erythromycin or
clindamycin sensitivity testing may be indicated if treatment with one of these agents fails.
For many patients who have recurrent symptoms of
pharyngitis with positive GAS throat cultures or rapid antigen tests, the likely explanation is GAS colonization in the face of intermittent viral infections. While repeat throat culture or rapid antigen testing is not routinely recommended after treatment, retesting between pharyngitis episodes may be useful in diagnosing GAS colonization. Persistent positive tests in the absence of symptoms suggest that the patient is colonized. Patients with long-term GAS colonization do not have an increased risk for rheumatic fever, nor are they likely to be contagious, so treatment is not routinely recommended. When eradication of colonization is desired, clindamycin
or penicillin plus rifampin may be more successful than
penicillin alone.
—Catherine Lachenauer, MD
Assistant in Medicine, Division of Infectious Diseases
www.childrenshospital.org/infectious
