DTT-based biofilm and conventional intraoperative cultures for the detection of prosthetic joint infections: a comparative study.

BACKGROUND

Accurate diagnosis of prosthetic joint infection (PJI) remains challenging. Biofilm culture by sonication has been included according to EBJIS criteria; however, this method is associated with technical difficulties. Dithiothreitol pretreatment (DTT-P) biofilm culture appears to be a promising alternative. The aim of this study was to compare the microbiological results from intraoperative tissue cultures (reference standard) with those obtained from DTT-P biofilm culture on explanted prosthesis, in order to explore the role of DTT-P in routine practice.

METHODS

We conducted a retrospective, single-center, observational study including consecutive adult patients who underwent hip, knee, or shoulder prosthetic revision, between May 2023 and November 2024. For each explanted prosthesis, microbiological analysis was performed using both conventional intraoperative tissue cultures and DTT-P biofilm culture.

RESULTS

Among 192 revision procedures, the overall concordant results between the two methods were 93.8% (180/192). Thirty-four procedures (17.7%) were managed as PJIs. Of these, 19 (70.6%) were identified by both methods, 6 (17.6%) fulfilled the EBJIS criteria by DTT-P biofilm culture with negative conventional tissue cultures, and 6 were exclusively diagnosed by conventional culture. Three cases were defined as "Likely" infections. Slow-growing Gram-positive bacteria and polymicrobial infections represented a diagnostic challenge. The EBJIS histopathological criterion (≥ 5 PMNs in ≥ 5 HPFs) was met in only 2 out of 154 cases (1.3%), indicating a very limited contribution of histopathology in detecting PJIs in our cohort.

CONCLUSIONS

Overall, these findings reflect the complexity of diagnosing PJI in clinical practice. Though DTT-P may provide complementary diagnostic information by identifying additional PJI cases, its results should be interpreted with caution. Larger prospective studies are needed to confirm these findings and evaluate the cost-effectiveness of this approach.