Abstract
The taxonomic position of an actinomycete, strain 15‐116A
T
, isolated from a blood culture of a 31‐year‐old male from the United States was determined using polyphasic taxonomic analysis. Genome‐based phylogeny showed that the strain was closely related to
Streptomyces composti
,
Streptomyces thermocarboxydovorans
, and
Streptomyces thermospinosisporus
species. Digital DNA–DNA (dDDH) relatedness and average nucleotide identity (ANI) between the draft genome sequence of the strain and those of its closest phylogenomic neighbors listed above were between 35.9% and 37.3% (S. thermocarboxydovorans
JCM 10367
T
and
S. thermospinosisporus
JCM 11756
T
were 72.3% and 96.7%, respectively. These values are above the defined thresholds for prokaryotic species demarcation (70% dDDH and 95%–96.7% ANI) and fall within the dDDH range of 70%–79% for subspecies designation. Based on these findings and in accordance with the priority rule in nomenclature,
S. thermospinosisporus
is considered a later heterotypic synonym of
S. thermocarboxydovorans
and is classified as a subspecies of
S. thermocarboxydovorans
, for which the name
S. thermocarboxydovorans
subsp.
thermospinosisporus
subsp. nov. is proposed. Consequently,
S. thermocarboxydovorans
subsp.
thermocarboxydovorans
is created. Strain 15‐116A
T
was characterized by the presence of
LL
‐diaminopimelic acid in its peptidoglycan; diphosphatidylglycerol, phosphatidylethanolamine, and phosphatidylinositol as the major phospholipids; MK‐9(H
8
) and MK‐9(H
6
) as the predominant menaquinones (> 10%); and
iso-
C
15:0
,
anteiso
‐C
15:0
,
iso-
C
16:0
, and
anteiso-
C
17:0
as the major fatty acids (> 10%). Morphological, phenotypic, and genomic traits distinguished strain 15‐116A
T
from its closest phylogenetic neighbors and highlighted the assignment of strain 15‐116A
T
(= DSM 106436
T
= ATCC BAA‐2935
T
) to a novel species of the genus
Streptomyces
, for which the name
Streptomyces sanguinis
sp. nov. is proposed. Genome screening for virulence factor‐associated genes showed that the strain harbored a gene encoding isocitrate lyase, which is required for persistent infection of
Mycobacterium tuberculosis
(YP_177728), as well as gene clusters associated with phenazine biosynthesis (NP_252902), unlike its close relatives. Moreover, strain 15‐116A
T
possessed a gene encoding elongation factor Tu (WP_003028672), which plays an important role in the bacterium′s ability to adhere to host cells. However, further experimental studies are required to evaluate the pathogenic potential of this strain.