18 19Purpose: Two phenotypic and three molecular methods were assessed for their ability 20 to identify viridans group streptococci (VGS) to the species level. 21Methods: A panel of 23 clinical isolates, comprising strains isolated from infective 22 endocarditis, blood cultures, pleural and peritoneal fluid, and 19 type/reference strains 23 were analyzed. Identification was performed using two conventional phenotypic 24 methods, API ® rapid ID 32 Strep and VITEK ® 2 system; and genotypic analysis of the 25 nucleotide sequence of the housekeeping gene sodA, restriction patterns generated by 26 restriction fragment length polymorphism (RFLP) of the 16S rRNA gene and multilocus 27 sequence analysis (MLSA) of 7 housekeeping genes. 28Results: The API ® rapid ID 32 Strep accurately speciated 79% of the strains assessed, 29 while the VITEK ® 2 generated a successful identification for 55%, presenting 30 limitations particularly with regard to species belonging to the mitis group. RFLP of the 31 16S rRNA gene correctly speciated 24% of the strains, having failed to allocate a 32 species for 36% of the isolates examined. In contrast, sequence analysis of the sodA 33 gene provided a correct identification for 95% of the strains assessed, while 34 identification using the MLSA technique was unsuccessful due to practical limitations. 35
Conclusions:The results generated herein indicate that no single methodology can be 36 used to provide an accurate identification to the species level of all VGS although, 37 nucleotide sequence analysis of the sodA gene proved to be useful in providing reliable 38 speciation. 39 40
The ability of viridans group streptococci to bind human plasminogen and its subsequent activation into plasmin may contribute to the pathogenesis of infective endocarditis (
The ability of viridans group streptococci (VGS) to bind human plasminogen and its subsequent activation into plasmin may contribute to the pathogenesis of streptococcal endocarditis. The increased proteolytic activity acquired through cell-bound plasmin may lead to a decreased stability of the streptococcal vegetation and possible embolisation. Twenty-two infective endocarditis isolates and 16 non-infective endocarditis isolates were screened for their ability to bind plasminogen through the quantification of its active form plasmin, using the colorimetric substrate D-Val-Leu-Lys p-nitroanilide. The species of the VGS assessed expressed a universal capability to bind human plasminogen, although they did so with differing affinities and independently of the site of isolation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.