Taxonomy
Family: Peptostreptococcaceae
Formerly Peptostreptococcus micros

Natural habitats
Gram positive anaerobic cocci are part of the normal microbiota of the mouth, upper respiratory and gastrointestinal tracts, female genitourinary system and skin.

Gram positive anaerobic cocci constitute 1-15% of the normal oral micobiota.
P. micros is usually considered to be the predominant species of gram-positive anaerobic cocci in the oral micribiota and
P. anaerobius and Finegoldia magna are also present in the oral cavity.

Clinical significance
Most infections involving anaerobic cocci ar polymicrobial.

Isolation in pure culture is rare.