A Longitudinal Study of Group A Streptococcal Colonization and Pharyngitis in US Children

Abstract

Background: Group A streptococci (GAS) are a major cause of pharyngitis in children. Recently, there were severe GAS outbreaks. The aims of this study were to assess pharyngeal colonization prevalence in healthy children, to assess different diagnostic definitions for GAS pharyngitis and to estimate incidence rates for these infections. Methods: A 2-year longitudinal study was conducted in healthy children in the United States. Pharyngeal swabs were cultured every 3 months for GAS colonization. Serum antistreptolysin O, antideoxyribonuclease B (DNaseB) and antistreptococcal C5a peptidase (SCP) antibody titers were assessed at baseline. When participants developed a sore throat, pharyngeal swabs were collected for rapid antigen detection test (RADT) and culture, and antibody titers were determined in serum samples. A range of case definitions were used for GAS pharyngitis. Results: A total of 422 children 3–12 years old were enrolled (140, 141 and 141 were 3–5, 6–9 and 10–12 years of age, respectively). The overall prevalence of GAS colonization during the study was 48%. Baseline antistreptolysin O, anti-DNaseB and anti-SCP antibody titers were higher for children older than 5 years. The incidence of GAS pharyngitis per 100 person-years was 15.9 for RADT/culture-proven and 4.6 for serologically confirmed pharyngitis. Conclusions: GAS throat colonization and pharyngitis were frequent in children 3–12 years old. The case definition employed impacted the measured incidence of GAS pharyngitis, with higher rates detected using RADT/culture-based definitions. These data suggest that case definition is important and that young children are exposed to GAS, which may inform plans for vaccine development and implementation.

Spatiotemporal Trends in Group A Streptococcal Pharyngitis in the United States

“…5 Some of the drivers for those pathogens, such as climatic factors, may also contribute to the trends in GAS pharyngitis. Alternatively, and more speculatively, the extent of asymptomatic carriage of GAS (nearly 50% in children ages 3-12 4 ) may result in false positive RADTs in the context of viral pharyngitis in hosts carrying GAS, such that the trends of viral infections may contribute to the observed trends of GAS pharyngitis.…”

“…1 According to the Centers for Disease Control and Prevention (CDC), GAS accounts for 20-30% of pharyngitis cases in children and 5-15% of pharyngitis cases in adults. 2 GAS pharyngitis is more common in the winter and spring months, 2–4 but its seasonality and geography in the U.S. remains poorly characterized.…”

The phage protein paratox is a multifunctional metabolic regulator ofStreptococcus

“…Streptococcus pyogenes (Group A Streptococcus or GAS) is a Gram-positive bacteria that is both a human commensal and pathogen [1][2][3] . The bacteria colonize the throat and skin in 1 to 5% of healthy adults and up to 20% of children 2,4 . GAS causes pharyngitis (strep throat), toxic shock syndrome, rheumatic fever, scarlet fever, and is the leading cause of flesh-eating disease world-wide 3,5 .…”