●Goals of antimicrobial therapy for eradication of group A Streptococcus (GAS) from the pharynx in the setting of acute streptococcal pharyngitis include:
•Reducing duration and severity of clinical signs and symptoms, including suppurative complications
•Reducing incidence of nonsuppurative complications (eg, acute rheumatic fever)
•Reducing transmission to close contacts by reducing infectivity．
We recommend initiating treatment with antimicrobial therapy for patients with symptomatic pharyngitis if the presence of group A streptococci in the pharynx is confirmed by culture or rapid antigen detection testing (RADT) (Grade 1A).
We suggest initiating treatment with antimicrobial therapy for patients whose clinical and/or epidemiologic factors point to a high index of suspicion for GAS pharyngitis while laboratory results are pending (Grade 2B).
Oral penicillin V is the agent of choice for treatment of GAS pharyngitis in many clinical settings given its proven efficacy, safety, narrow spectrum, and low cost. Amoxicillin is often used in place of oral penicillin in children, since the taste of the amoxicillin suspension is more palatable than that of penicillin. First-generation cephalosporins (such as cephalexin and cefadroxil) are acceptable alternatives to penicillin and amoxicillin, especially in the setting of treatment failure or beta-lactam hypersensitivity.
Although most patients improve clinically within the first few days of treatment, the conventional duration of oral antibiotic therapy is 10 days to achieve maximal pharyngeal GAS eradication rates. Intramuscular penicillin G benzathine may be administered to patients who cannot complete a 10-day course of oral therapy.
We suggest NOT treating with antibiotics for pharyngitis in the absence of positive diagnostic data (Grade 2C). We suggest erythromycin or azithromycin for treatment of pharyngitis due to Arcanobacterium haemolyticum (Grade 2C).
In general, test of cure is not necessary for asymptomatic patients or their close contacts following completion of a course of antimicrobial therapy, except in unique circumstances.
We suggest a repeat course of treatment for patients with a repeat episode of acute pharyngitis and positive repeat diagnostic testing (Grade 2C). Patients warranting a repeat course of treatment may receive an agent with greater beta-lactamase stability than the previous agent.
Patients who are long-term streptococcal carriers may develop multiple episodes of pharyngitis due to viral infection. In such cases, repeatedly positive cultures or rapid antigen tests for GAS may be misleading, and further treatment for streptococcal pharyngitis may not be warranted. Carriers are unlikely to spread the organism to close contacts and are at very low risk for developing suppurative complications or acute rheumatic fever. Moreover, eradication of GAS from the upper respiratory tract of carriers can be difficult and is not necessary.