I have recently been in the situation of dealing with a number of blood cultures which have grown the bacteria Enterococcus sp. Whilst not a particularly exciting bacteria, its presence in blood cultures should always be taken seriously. One particular patient had Enterococcus faecalis in 3 sets of blood cultures and was being treated for pneumonia on the basis of a fever and a few crackles in his chest. I went to the ward to review the patient and although a junior later commented that “you always come up with an amazing diagnosis!” it was “The Microbiology” which led to the correct answer, but I took the compliment anyway!
Vancomycin is a glycopeptide antibiotic commonly used to treat serious infections caused by Gram-positive bacteria, especially Staphylococcus aureus including MRSA.
The two biggest drawbacks to the use of Vancomycin are:
1) The narrow therapeutic window, i.e. a small range between efficacy and toxicity
2) The difficulty in getting a patient’s blood levels up to therapeutic levels quickly enough, especially when they are septic
The old regime was to use a dose of 1g BD for patients with normal renal function under 65 years old, and 1g OD if they were over 65 years old. Patients with renal failure were given 1g and then re-dosed when their levels were <15mg/L. In practice many microbiologists used to dose younger adults at much higher levels, often 1.25g BD or higher because these patients didn’t reach therapeutic levels on the old regime.
There is a scenario I come across on a fairly regular basis which drives me NUTS! It is the use of Teicoplanin to treat urinary tract infections especially pyelonephritis. It drives me nuts because Teicoplanin has no activity against Gram-negative bacteria and pyelonephritis is 99% of the time caused by these Gram-negative bacteria. Therefore the patient is essentially on no treatment at all. Pyelonephritis is the most common cause of Gram-negative sepsis and if not
treated with the appropriate antibiotics, sepsis has a mortality of 40% (see sepsis).
I was recently asked for advice about a patient who had severe community acquired pneumonia (CAP), the team looking after him were concerned as despite 5 days of IV Teicoplanin and Levofloxacin (he had a history of severe penicillin allergy) his blood inflammatory markers had not started to come down. Strange, I thought as this is normally a good combination for CAP.