Trueperella pyogenes is a species of nonmotile, facultatively anaerobic, Gram-positive bacteria.

[4] 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.

[4][5] Although it can thrive in either anaerobic or aerobic environments, it is ideally suited to one with high (about 7%) levels of carbon dioxide.

[4] The specific name pyogenes, used in various bacterial genera, was derived from the Greek puon or Latin pyum and suffix -genes, yielding pyogenes, meaning "pus-producing".

[2] Although it can infect a wide variety of tissues, Trueperella pyogenes is the most common cause of "summer mastitis" in cattle and pyometra in dogs [citation needed].