Wednesday, March 9, 2016

Staph Aureus Bacteremia

We discussed a case of non-specific abdominal pain and the diagnosis was found to be a staphylococcus aureus epidural abscess!

Just to recap, here are a few key points about staphylococcus aureus bacteremia:
  • Always take a finding of staph aureus in the blood seriously. This infection is associated with high mortality and morbidity. Staph aureus can spread rapidly and lead to abscesses. Remember that staph loves the spine (among other organs) and is a common cause of endocarditis.  Treatment consists of antibiotics and source control (just like every infectious disease). Vancomycin a good choice for empiric treatment to cover MRSA until the culture sensitivity can guide further management. If you find out that the organism is MSSA then a 4-6 week course of cloxacillin is generally sufficient. Also – ID consultation has been shown to reduce mortality in staph aureus bacteremia so make sure to involve your ID colleague early!
  • Look for a source. Keep in mind that the chances of finding a source are quite good if the patient acquires the bacteremia in hospital; however, we only identify a source in about 50% of patients who present from the community. Make sure to do a detailed history, physical and appropriate investigations to assess for sources like prosthetic material, septic joint, skin and soft tissue infections, endocarditis, endovascular lines and spinal/epidural abscesses. This includes a TTE to rule out endocarditis. However, keep in mind that TTE is not perfect at picking up endocarditis so you need to do a TEE if you are concerned.
  • Assess for complications. If and when you find a source of the infection, take some time to assess for complications associated with staph aureus bacteremia. Remember that staph aureus has the ability to metastasize to almost anywhere in the body so once you find a source, look carefully to rule out any other foci of infection. Pay attention to findings like new back pain (even if very mild), joint pain,  or even subtle physical findings of endocarditis. Renal and pulmonary sites of spread should also be considered.
  • Staph in the urine can be a marker for staph in the blood. Staph aureus in the urine is weird! It is not a typical organism we think about when considering UTI. So, this finding should prompt you to send blood cultures which may reveal staph aureus bacteremia.

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