Validation of 16S rRNA and Complete rpoB Gene Sequence Analysis for the Identification of Elizabethkingia Species.

Bacteria in the genus Elizabethkingia have emerged as a cause of life-threatening infections in humans. However, accurate species identification of these pathogens relies on molecular techniques. We aimed to evaluate the accuracy of 16S rRNA and complete RNA polymerase β-subunit ( rpoB ) gene sequences in identifying Elizabethkingia species. A total of 173 Elizabethkingia strains with whole-genome sequences in GenBank were included. The 16S rRNA gene and rpoB gene sequences from the same Elizabethkingia strains were examined. Of the 41 E. meningoseptica strains, all exhibited >99.5% 16S rRNA similarity to its type strain. Only 83% of the 99 E. anophelis strains shared >99.5% 16S rRNA gene similarity with its type strain. All strains of E. meningoseptica and E. anophelis formed a cluster distinct from the other Elizabethkingia species in the 16S rRNA and rpoB gene phylogenetic trees. The polymorphisms of 16S rRNA gene sequences are not sufficient for constructing a phylogenetic tree to discriminate species in the E. miricola cluster ( E. miricola , E. bruuniana , E. occulta , and E. ursingii ). The complete rpoB gene phylogenetic tree clearly delineates all strains of Elizabethkingia species. The complete rpoB gene sequencing could be a useful complementary phylogenetic marker for the accurate identification of Elizabethkingia species.