Arcanobacterium

Arcanobacterium () is a genus of bacteria. They are gram-positive, non–acid fast, nonmotile, facultatively anaerobic, and non–endospore forming. They are widely distributed in nature in the microbiota of animals (including the human microbiota) and are mostly innocuous. Some can cause disease in humans and other animals (for example, "Arcanobacterium haemolyticum" infections). As with various species of a microbiota (including their cousins in the genera "Corynebacterium" and "Trueperella"), they usually are not pathogenic but can occasionally opportunistically capitalize on atypical access to tissues (via wounds) or weakened host defenses.
Taxonomy.
As explained by Yassin et al., the genus "Arcanobacterium" was first described by Collins et al. in 1982 to accommodate bacterial strains previously assigned to the genus "Corynebacterium" variously (and controversially) as "C. pyogenes hominis" and then "C. haemolyticum", thenceforth to be known as "Arcanobacterium haemolyticum". The name (from "arcanus" + "bacterium") means "secretive bacterium" or "enigmatic/mysterious bacterium". In 2011, Yassin et al., on the basis of 16S rRNA signature nucleotide comparisons, menaquinone and phospholipid compositions, and Christie–Atkins–Munch-Petersen (CAMP) tests, proposed that four species—"A. haemolyticum", "A. hippocoleae", "A. phocae", and "A. pluranimalium"—should continue to be affiliated with the genus "Arcanobacterium", whereas the species "A. abortisuis", "A. bernardiae", "A. bialowiezense", "A. bonasi", and "A. pyogenes" should be reclassified as members of a new genus, "Trueperella", as "Trueperella abortisuis" comb. nov., "Trueperella bernardiae" comb. nov., "Trueperella bialowiezensis" comb. nov., "Trueperella bonasi" comb. nov., and "Trueperella pyogenes" comb. nov. Therefore, they provided an emended description of the genus "Arcanobacterium".
In 2001, Lawson et al. reported that "A. pluranimalium" sp. nov. had been isolated from a harbour porpoise and a deer. In 2002, Hoyles et al. reported that "A. hippocoleae" sp. nov. had been isolated from a vaginal discharge of a horse.
In 2012, Hijazin et al. reported that "A. canis" sp. nov. had been isolated from otitis externa in a dog. In 2013 the same group (with Hijazin, Sammra, and others) reported that "A. phocisimile" sp. nov. had been isolated from harbor seals. In 2015, the same group (with Sammra and others) reported that "A. pinnipediorum" sp. nov. had also been isolated from a harbor seal.
Species.
"A. abortisuis" (now "Trueperella abortisuis")<br>
"A. bernardiae" (formerly "Actinomyces bernardiae"; now "Trueperella bernardiae")<br>
"A. bialowiezense" (now "Trueperella bialowiezense")<br>
"A. bonasi" (now "Trueperella bonasi")<br>
"A. canis"<br>
"A. haemolyticum"<br>
"A. hippocoleae"<br>
"A. phocae"<br>
"A. phocisimile"<br>
"A. pinnipediorum"<br>
"A. pluranimalium"<br>
"A. pyogenes" (formerly "Actinomyces pyogenes"; now "Trueperella pyogenes")