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Severe infections caused by Propionibacterium acnes: an underestimated pathogen in late postoperative infections
1Department of Medical Microbiology, University of Zurich, Switzerland.
Abstract:
Propionibacterium acnes belongs to the cutaneous flora of humans and is rarely considered a pathogen in human diseases. It is a frequent contaminant in blood cultures; however, in some patients it has been identified as the causative agent of life-threatening infections. Within the last years we have observed an abrupt increase in severe P. acnes infections which prompted us to study in detail the clinical and microbiological features, risk factors, and outcomes of these cases. In a retrospective review of microbiological records of 905 Propionibacterium isolates from a five-year period (1990-95), 70 were identified from 20 patients with clinical and microbiological evidence of a P. acnes infection. The clinical syndromes included endocarditis (7 patients), post-craniotomy infections (6 patients), arthritis and spondylodiscitis (4 patients), endophthalmitis (2 patients) and pansinusitis (1 patient). The predominant predisposing conditions were previous surgery preceding the infection from 2 weeks to 4 years and implantation of foreign bodies such as prosthetic heart valves, intraocular lenses and ventriculo-peritoneal shunts. Therapy consisted of intravenous antibiotics in all cases and surgical procedures to remove infected tissue in eighteen patients. The outcome was favorable in sixteen patients (80 percent) who had a complete recovery. These data confirm the pathogenic potential of P. acnes in late post-surgical infections, in particular after implantation of a foreign body, and suggest a combined therapeutic approach with intravenous antibiotics and surgical removal of the infected tissue.
Insights
Propionibacterium acnes, a common skin bacterium, can cause severe infections, especially after surgery or with foreign body implantation. Early diagnosis and combined antibiotic and surgical treatment lead to favorable outcomes in most patients.
Area of Science:
- Infectious Diseases
- Microbiology
- Clinical Medicine
Background:
- Propionibacterium acnes (P. acnes) is typically considered part of human skin flora.
- While rare, P. acnes can be a causative agent of severe, life-threatening infections.
- An observed increase in severe P. acnes infections necessitated a detailed study.
Purpose of the Study:
- To investigate the clinical and microbiological features of severe P. acnes infections.
- To identify risk factors associated with these infections.
- To evaluate the outcomes and therapeutic approaches for P. acnes infections.
Main Methods:
- Retrospective review of microbiological records from 1990-1995.
- Analysis of 70 P. acnes isolates from 20 patients with confirmed infections.
- Examination of clinical syndromes, predisposing conditions, treatments, and patient outcomes.
Main Results:
- Twenty patients presented with P. acnes infections, including endocarditis, post-craniotomy infections, arthritis, spondylodiscitis, endophthalmitis, and pansinusitis.
- Common predisposing factors included recent surgery and implanted foreign bodies (prosthetic valves, shunts, lenses).
- Sixteen out of twenty patients (80%) achieved a complete recovery with combined antibiotic and surgical therapy.
Conclusions:
- P. acnes demonstrates significant pathogenic potential in late post-surgical infections, particularly those involving foreign body implantation.
- A combined therapeutic strategy involving intravenous antibiotics and surgical intervention is recommended.
- Prompt diagnosis and appropriate treatment are crucial for favorable outcomes in severe P. acnes infections.