Categories of osteomyelitis
Hematogenous - Result from seeding of a bone related to a previous bacteremia
Direct implantation - Resulting from penetrating injury
Contiguous - Resulting from direct spread of bacteria from an overlying wound or pressure ulcer
Infection of Prosthetic Device - Resulting from infection of prosthetic material implanted in bone, with spread of organisms into the adjacent bone
Commonality of osteomyelitis categoreis by age
Children - Hematogenous more common
Adults - Contigious and prosthetic infections
Pathogens by category
- Hematogenous - Staph aureus, Strepto sp., gram-negatives, M. tuberculosis, Salmonella sp. (sickle-cell)
- Direct implantation - Pseudomonas aeruginosa (nail inj. with sneakers)
- Contiguous - S. aureus, gram-negatives, Strepto sp., anaerobes, Candida sp.
- Prosthetic Joint Infections - Coagulase negative staph, S. aureus, gram-negatives, Strep sp.
What is the duration of osteomyelitis infections?
Define the following:
- Sequestrum - Dead bone
- Involucrum - External bone formation
- Brodie's absecces - Localized abscesses
Diagnostics for osteomyelitis
X-rays may be negative in early infection, and in fact are not very sensitive for osteomyelitis
Bone/WBC scans or MRI imaging more effective
Bone biopsies or sometimes blood cultures for bacteri
Issues with culturing for osteomyelitis
Cultures of open ulcers overlying contigous osteomyelitis are unreliable
Sometimes biopsies cannot be done or the culture results may be negative, forcing empiric treatment
Difficulty of prosthetic osteomyelitis
Particularly difficult to treat, especially due to chance of biofilm generation
Prosthesis often needs to be removed for treatment to eradicate infection
What are biofilms?
What is special about their arrangement?
How do they compare to planktonic (suspended) organisms?
- Aggregations of microoranisms adhrent to a surface (e.g. bone or prosthetic)
- Embedded in a matrix they produce - slime or extracellular polymeric substance or glycocalyx
- Differences in biochemistry and physiology of biofilm organsm and more resistant to antibiotics
Resulting from seeding of bone related to a previous bacteremia.