Reply to Matthys.

1. “According to the National Institute for Health and Care Excellence (NICE) guidelines, reflexive culture with throat swabs have a poor sensitivity (73%– 80%) . and there is an asymptomatic carriage range from 6% to 40%. ” We question the basis for the assertion that throat cultures have only 73%–80% sensitivity. Sensitivity is dependent on the method employed, but throat culture is generally considered to be the gold standard for detection of group A streptococci and is comparable even to molecular methods [1]. In our study, rapid antigen testing had an estimated sensitivity of only 76% compared to throat culture [2]. The fact that asymptomatic colonization with group A streptococci can occur is not relevant to our study, as we recommend that diagnostic testing be limited to patients with moderate to severe symptoms. Such an approach directs testing and antibiotic treatment to those patients most likely to benefit. Furthermore, studies suggest that group A streptococcal colonization of the pharynx is unusual in adults. Two prospective studies involving >400 adults found a carriage rate of only 0%–2%, without seasonal variation [3, 4]. 2. “A prospective RCT [randomized controlled trial] showed more peritonsillar abscesses in the group treated with antibiotics. ” The Decision rule for severe Symptoms and Complications of Acute Red Throat in Everyday practice (DESCARTE) study cited by Dr Matthys was an observational cohort study, not a randomized clinical trial, and actually showed a lower risk of suppurative complications in patients prescribed immediate or delayed antibiotics compared to those prescribed no antibiotics, once the analysis controlled for significant baseline differences between the treatment and control groups [5]. This, along with earlier studies [6–8], suggests that antibiotics do in fact reduce the risk of suppurative complications including peritonsillar abscesses. Moreover, the DESCARTE study included patients with sore throat from any cause, the vast majority of whom did not harbor group A streptococci, so the potential benefit of antibiotic treatment in patients with streptococcal infection may have been underestimated. 3. “Antigen test used according to a clinical score provided . no clear advantage over a clinical score alone. ” On the contrary, reliance on clinical scores has been shown to result in antibiotic overuse in comparison to laboratoryguided management [9]. 4. “Delaying antibiotics by . 48 hours or more would overshoot . their time of greatest benefit for symptoms. ” Multiple studies have shown that the clinical benefit of antibiotics in patients with streptococcal pharyngitis is not dependent on the duration of symptoms [6, 7]. Moreover, even when delayed up to 9 days, treatment can reduce the likelihood of rheumatic fever [10]. 5. “A no antibiotics strategy . may reduce the problem of antibiotic resistance. ” There is no evidence to support this assertion in the setting of streptococcal pharyngitis. Despite >70 years of penicillin use, clinical isolates of penicillin-resistant group A streptococci have not been described. This is apparently because the organisms are intolerant to mutations that reduce the affinity of penicillinbinding proteins [11].