Increase in Invasive Group A Streptococcal Disease and Emergence of Mucoid Strains in a Pediatric Population: February–June 2017

Abstract

Background Infection with group A Streptococcus (GAS) can cause severe systemic and locally invasive disease. Invasive group A streptococcal (iGAS) disease incidence varies both seasonally and year-to-year, and it may exhibit clustered outbreaks. We observed an upswing in iGAS cases at a tertiary care Children’s Hospital, prompting further characterization of local iGAS disease. Methods Cases of iGAS disease were abstracted from the medical record by manual chart review of all positive screening tests and cultures for GAS over a 4-year span. Incidence rates per 1000 hospital admissions and per 100 positive GAS tests were calculated and compared. Selected isolates were further characterized by whole-genome sequencing. Results Significant year-to-year differences in per-admission iGAS incidence rate were observed in February and June, although per-positive test incidence rates were not significantly different. Whole-genome sequencing revealed 2 dominant serotypes—emm3 and emm6—with high rates of mucoid phenotype and systemic bacteremia. Conclusions We document a significant but transient increase in iGAS disease incidence in 2 months of 2017. Genome sequencing revealed 2 dominant serotypes associated with mucoid phenotypes and severe disease, highlighting the dynamic nature of iGAS disease pattern.

Epidemiological and Microbiological Aspects of the Peritonsillar Abscess

“…In group I (0-18 age group) Staphylococcus aureus has the highest incidence in the summer, the lowest in the autumn (p = 0.0192). In agreement with the literature [1,2,6,23,38,39], we consider the findings regarding the seasonality of the individual microbial agents interesting from an epidemiological point of view. From a clinical point of view, the treatment strategy remains the same.…”

“…Differences in the PTA incidence in individual periods of the year (spring, summer, autumn, and winter) are not significant in our group (p = 0.4396), nor were they significant in studies from Denmark, England, or the USA [13,23,37]. Other studies have reported significant differences in the seasonal incidence of PTA in a group of pediatric patients with the highest incidence in the spring or summer [6,38,39]. In our work, a detailed analysis revealed that the incidence of PTA in boys in group I (0-18 years) is statistically significantly higher during the summer and, conversely, is at its lowest in the autumn (p = 0.0023).…”