Fast and Sensitive Multiplex Real-Time Quantitative PCR to Detect Cutibacterium Periprosthetic Joint Infections.

Diagnosis of Cutibacterium periprosthetic joint infections (PJIs) is challenging due to a long cultivation time of up to 14 days. Faster culture-independent diagnosis would improve patient care with early and accurate treatment. Specific primers and probes were designed for Cutibacterium acnes, Cutibacterium avidum, and Cutibacterium granulosum and evaluated in a multiplex TaqMan real-time quantitative PCR (qPCR) format on 57 skin swabs and 20 culture-negative cerebrospinal fluid samples. The multiplex qPCR was tested in a PJI cohort of 41 sonication fluid samples from removed implants infected with different pathogens. All five culture-positive Cutibacterium PJIs were detected with the corresponding Cutibacterium-specific probe (100% positive percent agreement). The multiplex qPCR additionally detected C. avidum in two PJI sonication fluid samples that were diagnosed as Staphylococcus species infections according to culture (95% negative percent agreement). The new multiplex qPCR can provide a Cutibacterium PJI diagnosis within 1 day, allowing early and accurate antibiotic treatment. A prospective diagnostic trial in PJI with a high number of Cutibacterium species infections (shoulder PJI) is needed for further evaluation.