Late onset prosthetic joint infection caused by Parvimonas micra.

Parvimonas micra (P.micra) is a difficult to culture gram positive anaerobic microorganism, typically found in the human microbiota, specially in the oral cavity. There are limited cases in literature reporting prosthetic joint infection due to this bacteria, although its isolation has been reported in different settings in later years. We present the case of a late onset knee prosthetic joint infection caused by Parvimonas micra in an 87 year old woman treated with antibiotics and two-step surgery with prosthetic material removal, antibiotic-loaded cement spacer placement and new prosthetic material replacement after 2 weeks of intravenous antimicrobial therapy followed by 6 weeks of oral therapy.