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Abiotrophia defectiva knee prosthesis infection: A case report
Nadim Cassir1, Jean-Charles Grillo, Jean-Noël Argenson
1Pôle des Maladies Infectieuses et Tropicales, Assistance Publique - Hôpitaux de Marseille et Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, UMR 6236, IRD 198, IFR48, Université de la Méditerranée, Marseille, France. michel.drancourt@univmed.fr.
Background:
Abiotrophia species have rarely been implicated in osteoarticular infections. We report one case of an A. defectiva knee prosthesis infection.
Case Presentation:
A 71-year-old man of Italian origin presented with pain and swelling of the knee four years after the implantation of a total knee replacement prosthesis. While standard culturing of the synovial fluid resulted in no isolation of microorganisms, the direct inoculation of the synovial fluid into a rich culture medium resulted in the identification of A. defectiva by polymerase chain reaction sequencing. Repeated attempts of culturing microorganisms from blood were negative, and echocardiograms and colonoscopies were unremarkable. High-dose amoxicillin for nine months and a two-stage replacement of the knee prosthesis led to full patient recovery by the time of the 12-month follow-up examination.
Conclusions:
Because Abiotrophia spp. are fastidious microorganisms, it is likely that cases of Abiotrophia orthopedic infection are misdiagnosed as culture-negative infections. Direct inoculation of synovial fluids into rich broth medium and further polymerase chain reaction-based detection of culture-negative synovial fluids are key tests for accurate documentation and detection of these infections.
Insights
Abiotrophia defectiva, a rare cause of bone infections, can be missed by standard tests. Advanced culturing and PCR of synovial fluid are crucial for diagnosing these difficult Abiotrophia orthopedic infections.
Area of Science:
- Microbiology
- Infectious Diseases
- Orthopedic Surgery
Background:
- Abiotrophia species are infrequently associated with osteoarticular infections.
- This case highlights a knee prosthesis infection caused by Abiotrophia defectiva.
Purpose of the Study:
- To report a case of Abiotrophia defectiva knee prosthesis infection.
- To emphasize diagnostic challenges and effective treatment strategies for rare microbial infections in orthopedic implants.
Main Methods:
- A patient with a knee prosthesis presented with infection symptoms.
- Synovial fluid analysis using standard cultures was negative.
- Direct inoculation into rich culture medium and PCR sequencing identified Abiotrophia defectiva.
Main Results:
- Standard synovial fluid cultures failed to detect the causative agent.
- Polymerase chain reaction sequencing confirmed Abiotrophia defectiva.
- The patient recovered after a nine-month antibiotic course and prosthesis replacement.
Conclusions:
- Abiotrophia species are fastidious and often lead to misdiagnosis as culture-negative infections.
- Direct inoculation into rich broth and PCR are vital for detecting these infections.
- Accurate diagnosis is essential for effective management of Abiotrophia orthopedic infections.
