Intra-cellular Staphylococcus aureus alone causes infection in vivo

Area of Science:

• Microbiology
• Infectious Diseases
• Orthopedics

Background:

• Chronic and recurrent bone infections are common but poorly understood.
• Staphylococcus aureus (S. aureus) is frequently implicated in these persistent infections.
• S. aureus's ability to survive inside host cells may contribute to its evasion of immune responses and antibiotics.

Purpose of the Study:

• To investigate if intracellular S. aureus within host cells can induce bone infections in vivo.
• To provide evidence for the role of intracellular S. aureus in the pathogenesis of chronic and recurrent bone infections.

Main Methods:

• Osteoblasts were infected with S. aureus.
• Extracellular S. aureus was eliminated.
• Infected osteoblasts were inoculated into an open fracture rat model.
• Bone infections were assessed via bacterial cultures and radiography at 21 days post-operation.

Main Results:

• Inoculation with intracellular S. aureus within osteoblasts successfully induced local bone infections in the rat model.
• As few as 102 colony-forming units of intracellular S. aureus were sufficient to cause severe bone infections.
• Radiographic and culture data confirmed infection development.

Conclusions:

• Intracellular S. aureus is sufficient to induce bone infections in vivo.
• Intracellular S. aureus may persist within host cells during asymptomatic periods, leading to recurrence.
• This intracellular mechanism is a potential driver for chronic and recurrent Staphylococcus aureus bone infections.