Question

You remove pus from a wound and try to identify the pathogen multiple ways. The multi-locus gene tree showed your organism was most closely related to Streptococcus pyogenes but the 16S tree said it was most closely related to Streptococcus pneumoniae. Describe why this might be the case and other ways you should try to identify this organism.

Answer 1

It occurs because phylogenetic analyses based on the 16S rRNA gene sequences may have insufficient resolution for distinguishing between closely related species

Another genomic method for streptococcal identification is whole-genome analysis (WGS)

Step-by-step explanation:

The phylogenetic analysis of the highly conserved 16S rRNA gene sequences has recently been used to distinguish between prokaryotic species. However, this gene sometimes may show low resolution to distinguish between closely related species, and it has been suggested potential horizontal transference of rRNA genes. Moreover, multi-locus sequence analysis (MLSA) has also been used to identify species. MLSA analysis consists of analyzing simultaneously different genes and this technique has shown to have a high capacity for establishing relationships between species within a genus or genera within a family. Finally, whole-genome analysis (WGS) is the most powerful tool for distinguishing between closely species. WGS is a technique that provides a very high resolution which is based on the analysis of large-scale genome sequencing data generated by next sequencing generation (NGS) technologies.