Characterization of group A beta-haemolytic streptococcus with mucoid phenotype isolated in a tertiary hospital

Abstract

Introduction: The objective of this study is to characterize Streptococcus pyogenes isolates with a mucoid phenotype and to compare them with non-mucoid isolates obtained between April and August 2016.

Material and methods: Identification and antimicrobial susceptibility were performed in all isolates. The emm type and exotoxin genes speA, speB, speC, speF, speG, speH, speJ, speZ and ssa were analyzed. Clinical and demographic data were collected.

Results: From 96 isolates analyzed, 47% had a mucoid phenotype and 95.5% of them presented speA-speB-speF-speG-ssa genes and emm3 genotype. The main clinical manifestation was pharyngotonsillitis (77.1%) evolving to scarlet fever in 67.5% of the cases.

Conclusion: This study describes the circulation of a mucoid phenotype strain with a speA-speB-speF-speG-ssa toxin profile and emm3.1 genotype considered one of the most frequent and virulent of SGA.

Keywords: Escarlatina; Mucoid; Mucoide; Scarlet fever; Serotipo emm3; Serotype emm3; Streptococcus pyogenes.