Positivity Trends of Bacterial Cultures from Cases of Acute and Chronic Periprosthetic Joint Infections

Background: There is no clear distinction in the literature regarding the positivity trends of bacterial cultures in acute and chronic prosthetic joint infections. Methods: We prospectively included in this study all consecutive patients, aged over 18 years, that were hospitalized from September 2016 through December 2019, that underwent a joint arthroplasty revision surgery. Results: Forty patients were included in our analysis, 11 acute/acute hematogenous and 29 chronic PJIs. We were able to identify all strains of acute/acute hematogenous PJIs within 3 days, whereas this took 8 days for chronic PJIs. Sonication fluid cultures increased the positivity rate and helped in identifying rare pathogens such as Ralstonia pickettii from chronic PJIs, but also increased the number of identified strains from acute PJIs. Culturing synovial fluid in our study did not seem to have a clear benefit compared to sonication fluid and periprosthetic tissue cultures. Conclusion: There was a different positivity trend in bacterial cultures. Empiric broad-spectrum antibiotic therapy can be re-evaluated after 3 days for acute PJIs. A prolonged incubation time, especially in the case of chronic PJIs, is mandatory; however, extending the incubation period beyond 14 days would not further improve the ability to identify microorganisms.

Automated summary

This study found different positivity trends in bacterial cultures for acute and chronic prosthetic joint infections. Sonication fluid cultures improved the detection rate of rare pathogens in chronic infections, while culturing synovial fluid did not show clear benefits compared to sonication fluid and periprosthetic tissue cultures. Empiric broad-spectrum antibiotic therapy can be re-evaluated after 3 days for acute infections, and a prolonged incubation time is necessary for chronic infections, but extending the incubation period beyond 14 days does not further improve the ability to identify microorganisms.