Influence of bacterial strains on bone infection
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J Cordero1, L Munuera, M D Folgueira
1Department of Orthopaedic Surgery, Hospital La Paz, Madrid, Spain.
Abstract:
Experiments were performed on 120 rabbits to compare the probability of infection after bone surgery without an implant, with polymethylmethacrylate, and with autografts. Staphylococcus aureus phage type 94/96, isolated from a human osteomyelitis, was instilled into the intramedullar cavity after reaming of the femoral canal and before insertion of the implant. The different 50% infective doses were determined for each of the groups for comparative purposes. The bacterial concentrations required to produce infection in femora without an implant were two times less than those necessary in femora implanted with polymethylmethacrylate. The bone graft required bacterial concentrations nine times less than those necessary to infect femora containing polymethylmethacrylate and four times less than those required to infect femora without an implant. The results presented here confirm that the susceptibility to infection in orthopaedic surgery is not only material dependent but also bacteria dependent.
Insights
Bone graft and polymethylmethacrylate implants affect infection risk in rabbits. Autografts showed higher susceptibility to Staphylococcus aureus infection compared to polymethylmethacrylate and no implant groups.
Area of Science:
- Orthopedic Surgery
- Infectious Disease
- Biomaterials Science
Background:
- Post-operative orthopedic infections pose a significant clinical challenge.
- Understanding the influence of implant materials and host factors on infection susceptibility is crucial for patient outcomes.
Purpose of the Study:
- To compare the probability of infection following bone surgery with different implant materials: polymethylmethacrylate (PMMA) and autografts.
- To determine the bacterial concentrations required to cause infection in the presence of these materials versus no implant.
Main Methods:
- Experiments were conducted on 120 rabbits.
- Staphylococcus aureus was instilled into the reamed femoral canal before implant insertion.
- The 50% infective dose (ID50) was determined for three groups: no implant, PMMA implant, and autograft.
Main Results:
- Femora without implants required half the bacterial concentration for infection compared to PMMA implants.
- Autografts required nine times less bacterial concentration than PMMA and four times less than no implant to cause infection.
- Infection susceptibility varied significantly based on the material used and bacterial challenge.
Conclusions:
- Orthopedic surgery infection risk is influenced by both the implant material and the specific bacteria involved.
- Autografts appear to increase susceptibility to Staphylococcus aureus infection compared to PMMA and native bone.
- Further research into material-bacteria interactions is warranted to mitigate infection risks.