Microbiology 12 : wound, bone and joint infections Flashcards
major pathogens causing surgical site infections (SSIs
S.aureus
E.coli
Pseudomonas aeruginosa
three levels of SSIs
Superficail incisional - skin + subset
Deep incisional - fascia and muscle
organ/space infection - any part of anatomy other than the incision
Rheumatoid arthritis patients are at risk of surgical site infections. What steps are taken to prevent SSIs in these patients?
Stop DMARDs 4 weeks before and 8 weeks after op
why is obesity a risk factor for SSI?
Adipose tissue is poorly vascularised –> poor access to immune system
what is the most powerful risk factor for SSI following cardiothoracic surgery?
S.aureus carriage in the nose –> offer nasal decontamination
type of ventilation in theatre
positive pressure so air flows from within theatre to outside
How does temperature in surgery affect risk of acquiring SSI?
Low temp –> vasoconstriction –> less oxygenation –> increased risk of SSI
main risk factor for septic arthritis
rheumatoid arthritis
top 2 organisms in septic arthritis
Staph
Strep
which strain of staph can cause fulminant septic arthritis
S.aureus producing cytotoxin PVL
How does S aureus cause septic arthritis? i.e. how does it do its damage
Has fibronectin binding protein and PVL toxin
mx of septic arthritis
IV Abx 4-6 weeks OP + drainage of the joint
number 1 organism in osteomyelitis
S.aureus
best imaging modality for osteomyelitis?
MRI
Vertebral osteomyelitis - which part is most commonly affected?
Lumbar spine
