Enhancing diagnostic accuracy for periprosthetic joint infections with an alternative homogenization approach.

PURPOSE

In this study, we assessed the use of two commercial bead mills, ProbeAX (PBX) and ProbeAX Evolution (PBX-E, AxonLab). Additionally, we investigated the application of PBX in routine procedures and evaluated whether extended incubation in enrichment media, such as thioglycolate broths (THIO) and blood culture bottles (BCB), could enhance the microbiological diagnosis of periprosthetic infections (PJI) and fracture-related infections (FRI).

METHODS

The PBX and PBX-E were evaluated on the quantitative recovery of multiple microorganisms from spiked samples. For the comparison of the three methods, tissue samples from 87 individuals suspected of having PJI or FRI and requiring surgery were included in the study.

RESULTS

The added value of BCB and THIO, next to conventional culture (CC), was assessed by comparing the sensitivities of each technique, being 87.1% for CC, 96.8% for BCB, and 80.6% for THIO. The contamination rate of THIO (59.8% (52/87)) was significantly higher compared to CC (21.8% (19/87)) and BCB (17.2% (15/87)), resulting in the lowest specificity for THIO (20.0%), followed by CC (67.8%) and BCB (75.4%). The mean time-to-positivity (TTP) for BCB was 2.3 days, for CC 2.5 days, and 7.3 days for THIO (p <.001). Nonetheless, extended incubation was necessary to confirm all infections, particularly those caused by anaerobic bacteria.

CONCLUSION

This study demonstrates that culturing tissue samples in BCB improves the diagnosis of PJI/FRI. Extended incubation for more than 5 days is only essential for detecting slow-growing bacteria, such as Cutibacterium acnes. Regarding the stability of different bacteria, the novel PBX-E demonstrated superior results. Time until inoculation, however, is critical to ensure optimal recovery.