A subacute presentation of Mycoplasma hominis prosthetic valve endocarditis

Area of Science:

• Infectious Diseases
• Cardiology
• Microbiology

Background:

• Prosthetic valve endocarditis (PVE) is a serious complication, often caused by common bacteria.
• Mycoplasma hominis is a rare but significant cause of PVE, presenting diagnostic challenges due to its fastidious growth requirements.
• Standard microbiological culture methods often fail to detect M. hominis in clinical samples.

Observation:

• A case of a subacute decline over 14 months in an immunocompetent elderly male with shortness of breath and splenic infarct.
• The patient had undergone a previous aortic valve replacement, suggesting prosthetic valve endocarditis.
• Initial diagnostic workup did not identify the causative agent using conventional methods.

Findings:

• Diagnosis of Mycoplasma hominis was achieved through 16S ribosomal RNA (rRNA) polymerase chain reaction (PCR) testing.
• The patient showed significant clinical improvement following redo aortic valve replacement and treatment with oral doxycycline.
• Long-term follow-up confirmed sustained recovery 2 years after antibiotic cessation.

Implications:

• 16S rRNA PCR is a valuable tool for the microbiological identification of difficult-to-culture pathogens like Mycoplasma hominis in PVE.
• Early and accurate diagnosis of M. hominis PVE can lead to effective targeted therapy and improved patient outcomes.
• This case highlights the importance of considering atypical organisms in prosthetic valve endocarditis, especially when standard cultures are negative.