Prevention of Invasive Group A Streptococcal Infections

To the Editors: I read with great interest the multicenter study by Erlacher et al,1 which investigated whether invasive group A streptococcal (GAS) disease could have been prevented if patients had presented to a physician earlier and those with suspected GAS diseases had been treated with antibiotics. The study included 63 patients, 32 of whom had a preadmission physician visit before the development of invasive GAS disease. As shown in Table 2, the authors classified only 4 of these 32 patients (3 with scarlet fever and 1 with tonsillopharyngitis) as having a clinical presentation consistent with GAS, while the remaining patients were not considered to have a compatible clinical presentation. It is observed that 17 of the remaining 28 patients were diagnosed with pharyngitis, upper respiratory tract infection or otitis media during their preadmission visit. Only 4 of these patients received antibiotics. This leaves 13 patients who had a clinical presentation potentially consistent with a GAS infection but did not receive antibiotics. It is unclear why the authors assumed that these patients did not present with a clinical picture compatible with GAS. The signs and symptoms of streptococcal and nonstreptococcal pharyngitis overlap too broadly to make a diagnosis with the necessary precision based on clinical grounds alone.2 Concomitant cough, rhinorrhea, hoarseness, diarrhea and/or the presence of oropharyngeal vesicles strongly suggest a viral etiology.3 However, in the absence of such viral symptoms, the clinical diagnosis of GAS pharyngitis cannot be made with certainty, even by the most experienced physicians, and bacteriologic confirmation is required.2 Out of the patients diagnosed with pharyngitis or upper respiratory tract infection, only 2 were tested with a rapid antigen test for GAS, and none of the patients received a throat culture. It is also well known that negative rapid antigen tests should be confirmed with a throat culture.2 Given that throat cultures were not performed in any patient, how was it determined that the upper respiratory tract infections in these patients were not caused by GAS? Two patients were diagnosed with acute otitis media (AOM) at their preadmission visit, yet no antibiotics were prescribed. GAS is a recognized cause of otitis media in children, and compared to AOM caused by other pathogens, GAS-associated AOM is characterized by higher local aggressiveness.4 Therefore, it cannot be conclusively stated that these 2 patients did not have a clinical presentation consistent with GAS.