Mediastinitis caused by Mycoplasma hominis in immunocompetent patients: A case series report and literature review

Abstract

Background: Mycoplasma hominis, a commensal organism, is potentially pathogenic; its role in postoperative infections might be underestimated in cardiac surgery. Results: We reported two cases of postoperative M. hominis mediastinitis in immunocompetent patients with a DeBakey grade I aortic dissecting aneurysm and reviewed 10 other cases previously described. Among the 10 reviewed cases and our two cases, 11 patients were men (median age, 59 years; median onset of clinical symptoms time, 14.5 d after surgery; and mean peak of temperature, 38.5 ± 0.8 °C). In our reports, two patients underwent sternotomy site reopening and debridement before diagnosis was confirmed. Diagnosis was confirmed by prolonged culture and by performing metagenomic next-generation sequencing directly using the clinical samples. M. hominis was difficult to cover with initial empirical antibiotic therapy; the patient in this study showed complete improvement with long-term antimicrobial therapy. The targeted treatment duration for surviving patients among the reviewed cases ranged from three weeks to 16 months. Conclusions: The diagnosis of extragenital M. hominis infections is difficult. Therefore, the role of M. hominis as a cause of postoperative infections during cardiac surgery should be considered. Diagnosis requires molecular techniques to complement culture.

Keywords

• Mycoplasma hominis
• Mediastinitis
• Omadacycline
• Metagenomic next-generation sequencing