Streptococcus pyogenes infection in paediatrics: from pharyngotonsillitis to invasive infections

Background: Streptococcus pyogenes or Group A Streptococci (GAS) cause many infections in infancy. Changes in its epidemiology have been described in recent years, including an increase in invasive infections (iGAS). Methods: A retrospective-descriptive study was conducted on children less than 15 years old, with GAS infections, in particular iGAS, and their complications from February 2004-April 2014. Results: A total of 2,192 positive cultures were obtained of which 92.7% were pharyngeal cultures. Twenty-nine patients were admitted to hospital: 4 with suppurative complications, 7 post-infective, 14 iGAS, and 4 probable iGAS cases. There were no differences in the frequency of GAS isolations/year. Non-invasive isolates were more frequent in winter and spring (P < .001), and 68.3% were in patients younger than 5 years. The incidence of iGAS was 2.1/100,000 children/year. There was no seasonality, and it was more frequent in younger children (P = .039). The most common diagnosis was pneumonia (6/14). Eight patients required intensive care. They were treated empirically with second or third-generation cephalosporin or with intravenous penicillin, and pneumonia required longer treatment times (P = .016). All GAS isolates were sensitive to penicillin, and 10.6% were resistant to erythromycin. The time spent in hospital was longer for iGAS than other cases (P = .028). No patients died. Conclusions: Pharyngotonsillitis caused by GAS is common in childhood, and its incidence is increasing in children younger than 5 years. At the moment, post-infectious complications are rare. Invasive infections are the most severe forms of presentation, and are more common in younger children. (C) 2016 Asociacion Espanola de Pediatria. Published by Elsevier Espana, S.L.U. All rights reserved.