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Propionibacterium acnes endocarditis: a case series
J M Banzon1, S J Rehm1, S M Gordon1
1Department of Infectious Disease, Cleveland Clinic, Cleveland, OH, USA.
Objectives:
Propionibacterium acnes remains a rare cause of infective endocarditis (IE). It is challenging to diagnose due to the organism's fastidious nature and the indolent presentation of the disease. The purpose of this study was to describe the clinical presentation and management of P. acnes IE with an emphasis on the methods of diagnosis.
Methods:
We identified patients from the Cleveland Clinic Infective Endocarditis Registry who were admitted from 2007 to 2015 with definite IE by Duke Criteria. Propionibacterium acnes was defined as the causative pathogen if it was identified in at least two culture specimens, or identified with at least two different modalities: blood culture, valve culture, valve sequencing or histopathological demonstration of microorganisms.
Results:
We identified 24 cases of P. acnes IE, 23 (96%) of which were either prosthetic valve endocarditis or IE on an annuloplasty ring. Invasive disease (71%) and embolic complications (29%) were common. All but one patient underwent surgery. Propionibacterium acnes was identified in 12.5% of routine blood cultures, 75% of blood cultures with extended incubation, 55% of valve cultures, and 95% of valve sequencing specimens. In 11 of 24 patients (46%), no causative pathogen would have been identified without valve sequencing.
Conclusions:
Propionibacterium acnes almost exclusively causes prosthetic valve endocarditis and patients often present with advanced disease. The organism may not be readily cultured, and extended cultures appear to be necessary. In patients who have undergone surgery, valve sequencing is most reliable in establishing the diagnosis.
Insights
Propionibacterium acnes rarely causes infective endocarditis (IE), often affecting prosthetic valves. Valve sequencing is crucial for diagnosing this challenging infection when standard cultures fail.
Area of Science:
- Infectious Diseases
- Cardiology
- Microbiology
Background:
- Propionibacterium acnes is a rare cause of infective endocarditis (IE).
- Diagnosis is challenging due to the organism's fastidious nature and indolent disease presentation.
- IE caused by P. acnes predominantly affects prosthetic valves.
Purpose of the Study:
- To describe the clinical presentation of P. acnes IE.
- To outline management strategies for P. acnes IE.
- To emphasize diagnostic methods for P. acnes IE.
Main Methods:
- Patients with definite IE from 2007-2015 were identified from the Cleveland Clinic IE Registry.
- P. acnes was confirmed if isolated from ≥2 cultures or ≥2 modalities (blood, valve, sequencing, histology).
Main Results:
- 24 cases of P. acnes IE were identified; 96% involved prosthetic valves or annuloplasty rings.
- Invasive disease (71%) and embolic complications (29%) were common; 96% of patients underwent surgery.
- P. acnes was detected in 12.5% of routine blood cultures, 75% of extended blood cultures, 55% of valve cultures, and 95% of valve sequencing specimens.
- Valve sequencing identified the pathogen in 46% of cases where other methods failed.
Conclusions:
- P. acnes IE predominantly affects prosthetic valves and presents as advanced disease.
- Extended blood cultures and valve sequencing are essential for diagnosis.
- Valve sequencing is the most reliable method for diagnosing P. acnes IE in surgically treated patients.
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