General information
P. anaerobius is only distantly related to other GPAC and is easily identified by a variety of techniques.

Taxonomy
Family: Peptostreptococcaceae

Natural habitats
P. anaerobius is part of the gastrointestinal flora and is commonly isolated from human clinical specimens, particularly from the abdominal cavity and genitourinary tract, but usually in heavily mixed growth; its place in the normal flora and infections of the mouth is less clear.

Clinical significance
It has been isolated from a wide variety of human clinical specimens, abscesses of the brain, jaw, pleural cavity, ear, pelvic, urogenital, and abdominal regions, as well as blood, spinal and joint fluid, and cases of osteomyelitis.

It has been recovered from specimens from periodontitis and intraoral sepsis and is one of the most common species of GPAC in infections of the abdominal cavity and the female genitourinary tract

Isolation in pure culture is rare.