The effects of positive blood cultures after surgery on the outcomes of total joint arthroplasty

Background The purpose of this study was to examine the results of arthroplasty in patients found to have blood cultures positive for the presence of bacteria during their postoperative course. Methods A retrospective review of all lower extremity total joint arthroplasties performed between 1997-2007 was conducted at a single medical center. Blood cultures were obtained in patients presenting with symptoms of infection at any time after surgery. Results A total of 12,160 patients were identified and cross-referenced with the microbiology records, identifying 87 implants with positive cultures in 78 patients. The most commonly identified organisms were coagulase-negative Staphylococcus aureus (21 of 78; 27%), E. coli (19 of 78; 24%), and methicillin-resistant Staphylococcus aureus (MRSA; six of 78; 8%). Deep periprosthetic infection was noted in four of the 87 implants (5%), all in three patients who had MRSA present in their blood cultures. Conclusions For blood cultures growing bacteria other than MRSA, antibiotic treatment alone appears to be sufficient in staving off deep infection. However, cultures containing MRSA may require more aggressive treatment.