Mark Crislip, MD, Infectious Diseases, 11:07PM Apr 19, 2011
The patient has had an artificial knee for about a year and it has worked flawlessly. Until the day of admission when it developed rubor, dolor, calor, and tumor.
Infected prosthetic knee. Not an unusual cause of consultation. Usually a staphylococcus or a streptococcus. This time? Gram negative rod. Hmm. Then it is identified as a Citrobacter koseri. Double Hmm. There are virtually no joint infectious with this organism, prosthetic or otherwise.
Citrobacters are a minor constituent of the bowel and a rare cause of human disease, usually UTI's. The patient has a long history of diverticulosis and -itis, so I am presuming for the time being it came from a leaky tic, although abdominal exam is normal.
But what to do? The literature is surprisingly optimistic on gram negative prosthetic joint infections.
Although this is not an early infection. It is an acute infection, which is probably a good prognostic sign
I am surprised they cured 1 in three. Taking a knee out in the elderly is not without significant morbidity, and with no co-morbidities I may have a reasonable shot at salvaging the knee.
The good news? Citrobacters complexes uranium.
Accumulate several times their own weight. I can do that with ice cream. Being just across the Pacific from a leaky nuclear reactor this may come in handy.
BTW: the name evidently has nothing to do with lemons. Citro intended to mean a citrate-utilizing rod.
Clin Microbiol Infect. 2010 Sep 3. Gram-negative prosthetic joint infection treated with debridement, prosthesis retention and antibiotic regimens including a fluoroquinolone. http://www.ncbi.nlm.nih.gov/pubmed/20825437
Clin Infect Dis. 2009 Oct 1;49(7):1036-43. Gram-negative prosthetic joint infections: risk factors and outcome of treatment. http://www.ncbi.nlm.nih.gov/pubmed/19691430
Uranium bioaccumulation by a Citrobacter sp. as a result of enzymically mediated growth of polycrystalline HUO2PO4 . Science 257 (5071): 782–784. http://www.ncbi.nlm.nih.gov/pubmed/1496397