Avoid Antibiotics Without Diagnosis

One Level I study addressed whether administration of antibiotic therapy prior to obtaining cultures from the joint affected the sensitivity of the cultures in diagnosing periprosthetic infections.¹⁰⁵ 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. Hence, there is a concern that antibiotics can interfere with isolation of the infecting organism leading to confusion regarding the diagnosis or inability to use organism specific antibiotics subsequently when infection is confirmed. Thus, administration of oral or intravenous antibiotics to patients with suspected diagnosis of periprosthetic joint infection is discouraged, until aspiration of the joint is performed or samples for culture are obtained.  
 
The finding of only one Level I study supporting this recommendation would be evaluated as moderate strength. However, because of the severity of the potential harm to the patient in getting a false negative culture result, the strength of the recommendation was elevated to strong.