Background
The incidence of poststernotomy mediatinitis is 1-3% with mortality rate of 10-25%. Poststernotomy Mycoplasma hominis sternal wound infection is uncommon and difficult to diagnose and treat, as they are rarely cultured by conventional laboratory methods and exhibit a poor response to broad-spectrum antibiotics, which can lead a fatal outcome. Mycoplasma hominis frequently colonizes the human genital and respiratory tract.There are currently no guidelines to manage Mycoplasma hominis mediastinitis; thus, reporting of new cases is useful for sharing successful experiences.

Method and Materials
A 56-year old patient who underwent ascending aorta replacement postoperatively developed mediastinitis with atypical Mycoplasma hominis. Vacuum-assisted closure (VAC)® treatment for sternal wound infection has been common since 1996. The VAC system has recently been modified to allow for intermittent instillation of antiseptics, antibacterials, or saline into the wound bed (VAC-Instill®).

Result
We present the first successful treatment of Mycoplasma hominis mediastinitis after cardiac surgery with VAC-Instill® therapy combined with dilute antiseptic irrigation for bacterial eradication.

Conclusion
The adequate delivery of bactericidal agents to infected tissue can be difficult, especially in mediastinitis with Mycoplasma species. Closed continuous irrigation has the advantage of washing out bacteria, necrotic tissue, fibrin, and clots. The effective eradication of Mycoplasma hominis parallels intravenous antibiotic therapy and prepares the wound bed until sternal closure. Although this is only one case, the VAC-Instill® system for the treatment of this very difficult wound may have eliminated the need for high-risk replacement of the prosthetic graft.