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Outbreak of spontaneous staphylococcal arthritis and osteitis in mice
T Bremell1, S Lange, L Svensson
1Department of Rheumatology, University of Göteborg, Sweden.
Abstract:
Staphylococcus aureus is the most common bacterial species found in association with nongonococcal bacterial arthritis in humans. We present here the first description of spontaneous bacterial arthritis and osteitis in mice. Clinically, the most obvious findings were swelling and/or ankylosis of hindpaws and nodose changes of the tail. The prevalence of arthritis and osteitis ranged from 0% to greater than 50% of the mice studied, depending on the mouse strain. The most prominent histopathologic feature of the arthritis was hypertrophy of the synovial tissue and destruction of cartilage and underlying bone. Most of the S aureus-infected mice displayed an identical phage type, which was also the only S aureus phage type found in skin isolates from clinically healthy mice. However, a few S aureus isolates were not typeable, indicating that an additional strain(s) might cause bacterial arthritis in mice.
Insights
This study describes spontaneous bacterial arthritis and osteitis in mice caused by Staphylococcus aureus. Different mouse strains showed varying prevalence, with key findings including joint swelling and bone destruction.
Area of Science:
- Veterinary Pathology
- Microbiology
- Immunology
Background:
- Staphylococcus aureus is a common cause of human nongonococcal bacterial arthritis.
- Spontaneous bacterial arthritis and osteitis have not been previously described in mice.
Purpose of the Study:
- To describe the first instance of spontaneous bacterial arthritis and osteitis in a mouse model.
- To investigate the clinical and histopathological features of this condition.
- To identify the causative Staphylococcus aureus strains and their prevalence.
Main Methods:
- Induction of bacterial arthritis and osteitis in various mouse strains.
- Clinical examination for signs of arthritis and osteitis (swelling, ankylosis, tail lesions).
- Histopathological analysis of affected joints, focusing on synovial tissue, cartilage, and bone.
- Phage typing of Staphylococcus aureus isolates from infected mice and healthy controls.
Main Results:
- Arthritis and osteitis prevalence varied significantly (0% to >50%) across different mouse strains.
- Clinical signs included hindpaw swelling/ankylosis and nodose tail changes.
- Histopathology revealed synovial hypertrophy and destruction of cartilage and bone.
- Most infected mice harbored an identical Staphylococcus aureus phage type, also found in healthy mice.
- Some untypeable S. aureus isolates suggest additional strains may be involved.
Conclusions:
- Spontaneous bacterial arthritis and osteitis can occur in mice, mimicking human disease.
- Mouse strain is a critical factor influencing disease susceptibility.
- A specific Staphylococcus aureus phage type is frequently associated with the condition, but other strains may also contribute.