Characterization of Streptococcus pneumoniae serotype 19F-variants occurring in Brazil uncovers a predominant lineage...

Streptococcus pneumoniae (S. pneumoniae) of serogroup 19 are mainly represented by serotypes 19A and 19F, which are associated with antimicrobial resistance and disease. The wzy gene, a component of the pneumococcal capsular locus, is the target to differentiate serotypes 19A and 19F by PCR-based capsular typing. In the last decade, allelic variants of the wzy^19F gene have been described, leading to misinterpretation of capsular typing results.

A collection of 154 serotype 19F S. pneumoniae strains recovered from carriage and disease in Brazil was evaluated to identify and characterize wzy^19F variant isolates.

Eleven (7%) wzy^19F variant isolates were detected and identified as belonging to ST810 (n = 10) or ST13673 (n = 1; single-locus variant of ST810). They were mostly recovered from diseased patients, susceptible to the antimicrobial agents tested (except for one multidrug-resistant strain) and did not harbor pili genes. Sequences of the wzy^19F gene of these variants were identical to each other and to those previously described in Brazil, but slightly different from wzy^19F variants identified in other countries.

This study indicated that wzy^19F variants present a geographically driven distribution and was the first to uncover phenotypic and genetic features of a wzy^19F variant lineage occurring in Brazil since 1989.