The day after admission we learned that his joint fluid was growing
Staphylococcus lugdunensis. We originally started vancomycin and rifampin. We drew cultures from his permcath and from peripheral blood. The permcath cultures quickly turned positive, but the peripheral cultures were negative.
Orthopedics drained his knee and removed pus. The organism is sensitive to almost all gram positive antibiotics. Now what?
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Echo. Gotta get an echo–S.lugdunensis likes heart valves… And I'd be talking to vascular or IR about new access.
Staph lugdunensis has been popping up a lot lately, usually in the ICUs. I'm surprised it was so sensitive.
I asked around for criteria in removing permcaths. The consensus is that they should be removed in severe infections where seeding is likely (endocarditis, osteomyelitis, septic arthritis) or if there is an obvious tunnel infection. Times when it's okay to try to treat through a permcath infection include a simple bacteremia not from enterococcus or fungus. I believe the theory behind it has to do with the difference between a bacterial collection on the catheter (vegetation) vs infected fibrin on the catheter. The infected fibrin can be cured with Abx, but a vegetation may cause more potential harm with seeding other sites and may not be easily treated.
In this case the catheter should be removed and a vascath placed for dialysis until cultures clear and a new permcath can be placed. I would still use Vanc to treat this patient because of the ease of dosing with dialysis and better outpatient monitoring by HD units.
I agree that vancomycin dosing around dialysis is convenient, but it may not be the best option for the patient. S. lugdunensis shares vancomycin and oxacillin breakpoints with S. aureus. (Most coagulase-negative staphylococci require testing for the absence of the mecA gene encoding for PBP-2a to confirm oxacillin susceptiblity.) It also shares S. aureus's virulent behavior. We know that patients with MSSA endocarditis do worse when receiving vancomycin instead of a beta-lactam. If at all possible, I would strongly consider using oxacillin (since it's metabolized by the liver) as therapy instead of vancomycin. Daptomycin would be a reasonable alternative for its once-daily dosing, but oxacillin by continuous infusion would give your patient the best odds. Consider speaking with your local ID service if you haven't yet.