Dear Enterococcus research site;
Two questions: 1) Is Enterococcus a genus
completely separate from Streptococcus? In the past it was called S. faecalis
or Group D Streptococcus.
2) Bergey's Manual of Determinative
Bacteriology has stated that the some enterococci posses polar flagella. Is this
1) Yes, Enterococcus became a separate genus in 1984. See: Chapter
18 in Manual of Clinical Microbiology, ASM Press, 7th Ed. 1999; Int J Syst
Bacteriol, 1984, 34:31-34
2) Motility has been reported for two species (see: Manual of
Clinical Microbiology). E. casseliflavus and E. gallinarum can show motility in
some cases. All other enterococci are not motile, especially not the most
common species faecalis and faecium.
Were these two species ever considered as
taxonomically or phylogenetically related to the Streptococci?
Yes, they belonged to the genus streptococcus before 1984.The
problem is as follows: much of the work has been done at a time when
Enterococcus was still part of the Streptococcus genus, and when the two
species mentioned were still considered variants of other species of
Enterococcus / Streptococcus. However, there are several papers that talk about
flagella in streptococcus (enterococcus ?). Work in more recent times has been
published in Russian or the exact species has not been identified. Considering
that Bergey states that they may have flagella, and since this is the usual
form of bacterial motility, it is safe to say that some isolates of E.
gallinarum or E. casseliflavus can have flagella.
Were these two species ever found in human clinical
specimens? If so what was the nature of their pathogenicity or lack
Yes, but not very often. (e.g. 8 of 632 enterococcal isolates were
E. gallinarum or E. casseliflavus in one study done in the US) There is not
much known about it (pathogenicity). Most studies look only at antibiotic
resistance. There are only very few virulence factors known for the major
players, E. faecalis and E. faecium. In general, the bacteria are very
resistant to harsh environments and they inhabit many different ecological
niches, including humans.
If you don't have access to the journals, you can do searches and
view abstracts on MedLine
Information courtesy of the Enterococcus research website.