Medical Microbiology and Infection

at a Glance

Fourth EditionStephen Gillespie and Kathleen Bamford

Case Studies

Case 21

A 25-year-old man is a long-standing patient of the renal unit, who are managing his end-stage renal failure. He has presented with evidence of recurrent line sepsis that has been treated with antibiotics. A succession of different bacteria have been cultured in the past 6 weeks. On this admission he presents with clouding of vision, which is diagnosed clinically as endophthalmitis.

  • 1. What is the underlying problem for this patient?

    Patients like this man depend on intravenous lines. The options for siting these lines become more difficult as time goes on so that recurrent line sepsis is often treated conservatively.

  • 2. What complications is he prone to?

    The patient is at risk of bacterial endocarditis seeded from an infected line tip. Another possibility, and the one most likely here, is that he has developed an endophthalmitis. Specialist advice from microbiologists and ophthalmologists will be required.

  • 3. What investigations would you recommend initially?

    It is important to establish the degree of inflammation so a full blood count and white cell count is required, together with a C-reactive protein. A set of three blood cultures is required.

  • 4. What more invasive investigation is probably necessary?

    A sample of vitreous humour. It is important to establish the aetiological diagnosis as this patient may have infection with a wide range of bacteria and penetration to the site of the infection is difficult.

  • 5. What action will you take at this time?

    The clinical story suggests that this line is infected and should be resited.

  • More info: A vitreous sample is taken and the culture reveals Staphylococcus aureus.
  • 6. What is the significance of this isolate?

    Given the history of line infection this is a likely pathogen in this circumstance.

  • 7. How will you manage the case now?

    Treatment should be based on the susceptibility pattern of the organisms. Antibiotics should be prescribed intravenously and subconjunctival injections may be required.

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