Moderate evidence supports avoiding administration of antimicrobials in patients suspected of having a periprosthetic joint infection until cultures have been obtained and a diagnosis has been established.

Rationale
One moderate strength study (Trampuz et al 2007) addressed whether administration of antibiotic therapy affected the sensitivity of cultures in diagnosing periprosthetic infection. The study found a false negative rate of 55% in patients receiving antibiotics within the previous 14 days, compared to 23% in patients not receiving antibiotics during the same time period. The difference was statistically significant. There is a concern that antibiotics can interfere with isolation of the infecting organism(s), leading to confusion regarding the diagnosis or inability to use organism-targeted antibiotics or antibiotics selected based on organism-specific susceptibility/resistance testing if infection is confirmed. In otherwise stable patients, antibiotic administration prior to definitive diagnosis of or surgical intervention for PJI is unlikely to be associated with benefit. Thus, administration of oral or intravenous antibiotics to patients with a suspected diagnosis of periprosthetic joint infection is discouraged until samples for culture are obtained. An exception, though rare, would be an acutely septic or potentially bacteremic patient, in whom appropriate cultures (e.g., blood, synovial fluid, as appropriate) should be promptly collected and antibiotics started based on clinical judgement. Also, in a patient in whom the infecting organism(s) have been well-defined prior to surgery (e.g. through synovial fluid cultures), the value of withholding antibiotics is lessened.

The finding of only one moderate strength study supporting this recommendation would be evaluated as limited evidence. However, because of the severity of the potential harm to the patient in getting a false negative culture result and the lack of harm in implementing the recommendation, the strength of the recommendation was elevated to moderate by the work group.

POSSIBLE HARMS OF IMPLEMENTATION
There may be scenarios where withholding antibiotic treatment may not be appropriate, such as in the case of sepsis. However, in a hemodynamically stable patient, there are no known associated risks or harms with this recommendation. It is important to note that there is not clear evidence as to the risk of delaying antibiotic treatment in the patient with suspected but undiagnosed periprosthetic infection which argues for expeditious evaluation to make the diagnosis. 

FUTURE RESEARCH
No indications for future research.
  1. Trampuz, A., Piper, K. E., Jacobson, M. J., Hanssen, A. D., Unni, K. K., Osmon, D. R., Mandrekar, J. N., Cockerill, F. R., Steckelberg, J. M., Greenleaf, J. F., Patel, R. Sonication of removed hip and knee prostheses for diagnosis of infection. N Engl J Med 2007; 7: 654-63