EVIDENCE-BASED ANSWER
The jury is out as to whether you should treat asymptomatic carriers of group A streptococci (GAS), because no studies specifically address the issue. In addition, many patients are unlikely to care about their carrier status, although they probably care about symptoms and treatment side effects. Nonetheless, you may want to consider treating GAS carriers under the following circumstances (strength of recommendation [SOR]: C, expert opinion):
- recurrent pharyngitis without cough or congestion
- acute rheumatic fever or poststreptococcal glomerulonephritis outbreaks
- GAS pharyngitis outbreaks in a closed community
- family history of acute rheumatic fever
- multiple documented GAS pharyngitis episodes within a family over several weeks despite therapy
- excessive patient/family anxiety about GAS
- all treatment options, except tonsillectomy, have been exhausted.
Oral clindamycin for 10 days is probably the most effective treatment for carriers. A single dose of intramuscular penicillin plus 4 days of oral rifampin is also effective (SOR: C, 2 randomized controlled trials [RCTs]).
Clinical commentary
A case I won’t soon forget
Meredith A. Goodwin, MD
Florida State University College of Medicine, Tallahassee
My most memorable encounter with GAS carriage involved a family of 5 when I was practicing in a small town. The youngest child, about 6 years of age, had recurrent, culture-positive GAS pharyngitis. I tested the family twice, but all cultures remained stubbornly negative. When the mother complained to the family veterinarian the next week about her son’s recurrent infections, the vet decided to culture the dog. The dog was positive, was treated, and the infections stopped!
Be sure to culture all household contacts before prescribing antibiotics. Patients (and parents) want to break the cycle and avoid future infections, so they are motivated to make sure that everyone is cultured. Providers and staff must be flexible in order to accomplish this.
Evidence summary
As many as 25% of patients with GAS pharyngitis remain culture-positive after an adequate regimen of antibiotic therapy and are deemed GAS carriers.1 Appropriate screening and management of asymptomatic carriers continues to cause confusion.
Routine treatment is usually unnecessary
The Infectious Diseases Society of America (IDSA) considers GAS carriers at low risk for developing complications and spreading infection to close contacts.2 The 2002 IDSA practice guidelines recommend against routine screening for and treatment of GAS carriage except under the circumstances (2 through 7) outlined in the evidence-based answer.2 It may be reasonable to treat patients whose carrier status is unknown when they have a second case of pharyngitis. For known GAS-positive patients, however, repeated episodes of pharyngitis over months or years should raise suspicion of intercurrent viral pharyngitis rather than true GAS pharyngitis.
When you should consider routine treatment
Some experts practicing in areas with a high prevalence of acute rheumatic fever take a different position: They favor routine treatment of patients with active pharyngitis and a positive throat culture, even if the patient is a known GAS carrier.3