Trueperella pyogenes

Trueperella pyogenes is a species of bacteria that are nonmotile, facultatively anaerobic, and gram-positive. The cells typically measure 0.5 by 2.0 μm. They appear as pleomorphic or coccoid rods. They tend to be grouped singly, or in short chains. Sometimes, they are grouped into V-shaped pairs.[2]

T. pyogenes is found in the urogenital, gastrointestinal, and upper respiratory tracts of cattle, goats, horses, musk deer, pigs, and sheep, in which it may cause abscesses, mastitis, metritis, and pneumonia.[2][3] It can thrive in either anaerobic or aerobic environments, but is ideally suited to one with high (about 7%) levels of carbon dioxide.[3]

The species was originally classified as Corynebacterium pyogenes then Actinomyces pyogenes,[4] then Arcanobacterium pyogenes,[4] now Trueperella pyogenes.[5] When the genus Arcanobacterium was split into two (Arcanobacterium and Trueperella gen. nov.),[5] the new genus name was chosen in honor of the German microbiologist Hans G. Trüper.[2] The specific name pyogenes is used in various bacterial genera and was derived from the Greek word puon or Latin word pyum, and the suffix -genes, yielding pyogenes, meaning "pus-producing".[1]

Although it can infect a wide variety of tissues, Trueperella pyogenes is the most common cause of "Summer mastitis" in cattle, and the most common cause of pyometra in dogs.