Bacteria isolated from late prosthetic joint infections: dental treatment and chemoprophylaxis.

The recommended administration of prophylactic antibiotics, before and during dental procedures, to persons with total joint prostheses is not without controversy. Hospital and dental charts of 2,693 patients in whom total prosthetic joints were placed at the Veterans Administration Hospitals of Ann Arbor and Allen Park, Michigan, as well as the University of Michigan Hospital, were analyzed. The identity of the micro-organism associated with the late (6 months after placement) infected prosthetic joint and the sensitivity of the organisms to specific antibiotics were recorded. Of the 30 (1.1%) late prosthetic joint infections, only one (0.04%) could be temporally associated with dental treatment. Fifty-three percent of the isolates were gram-positive staphylococci, the most common isolate being Staphylococcus epidermidis (36%). Pseudomonas aeruginosa was the most frequent gram-negative isolate cultured. Twenty-five of 34 isolates tested were resistant to penicillin, while only 3 of 36 isolates tested were resistant to a cephalosporin and 5 of 21 isolates tested were resistant to methicillin.