Diversity of pneumococcal surface protein A (PspA) among prevalent clones in Spain

Abstract

Background: PspA is recognized as a major pneumococcal virulence factor and a possible vaccine candidate. The aim of this study was to analyze the PspA family and clade distribution among 112 Spanish pneumococci representatives of dominant clones among patients with invasive disease (n = 66) and nasopharyngeal healthy carriage in children (n = 46). Results: PspA family 2 was predominant among invasive (63.6%) and carriage (54.3%) pneumococcal isolates. No PspA family 3 isolates were detected and only one strain was PspA negative. Although four clonal complexes contained strains of different clades, a clear association between clade and multi locus sequence typing results was found. Clades 1, 3 and 4 were associated with a wide variety of sequence types (ST) related to multiresistant and antibiotic-susceptible worldwide-disseminated clones. Clade 1 was associated with Spain6B-ST90, Spain14-ST18, Colombia5-ST289, Sweden1-ST306, Denmark14-ST230 and Sweden1-ST304 clones. Clade 3 was associated with Spain23F-ST81, Spain9V-ST156, Tennessee14-ST67, Netherlands3-ST180 and Netherlands7F-ST191 clones. Clade 4 was related to Sweden15A-ST63, Netherlands18C-ST113 and Greece21-ST193 clones. In contrast, PspA clade was not related to serotype, age or clinical origin of the isolates. Conclusion: PspA clades were associated with genotypes. PspA family 2 and family 1 were dominant among major Spanish pneumococcal clones isolated from patients with invasive disease and nasopharyngeal carriage in children.