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Prosthetic heart valve endocarditis caused by Bacillus circulans
1Department of Clinical Microbiology, Freeman Hospital, Newcastle-upon-Tyne, UK.
The Journal of Infection
|December 28, 1999
Summary
Prosthetic valve endocarditis caused by Bacillus circulans, a rare pathogen, presented late in a 56-year-old woman. The infection was diagnosed from the explanted valve, and the patient recovered with antibiotics.
Area of Science:
- Infectious Diseases
- Cardiology
- Microbiology
Background:
- Prosthetic valve endocarditis (PVE) is a serious complication following valve replacement surgery.
- Early PVE is typically caused by Staphylococcus species, while late PVE is often associated with Streptococcus or Enterococcus species.
Observation:
- A 56-year-old woman presented with symptoms of PVE 15 months after mechanical valve replacement.
- Pre-operative blood cultures were negative for any microbial growth.
- The causative organism, Bacillus circulans, was identified only upon culturing the explanted prosthetic valve.
Findings:
- Bacillus circulans, an unusual cause of PVE, can present as a late-onset infection.
- Diagnosis of PVE can be challenging when blood cultures are negative, necessitating examination of explanted devices.
- Successful treatment involved surgical intervention and a six-week course of trimethoprim and ciprofloxacin.
Implications:
- This case highlights the importance of considering atypical pathogens in late PVE.
- It underscores the diagnostic value of explanted valve cultures in refractory or culture-negative endocarditis.
- The findings suggest that Bacillus circulans, though uncommon, should be included in the differential diagnosis for PVE.