Performance of the GeneXpert® MRSA/SA SSTI test in periprosthetic joint infections: rate of failure, outcomes and risk factors - 10/10/25
, Marie Titécat b, d, e, Theo Martin a, b, e, Julien Dartus a, b, e, Sophie Putman a, b, e, f, Pierre Martinot a, b, e, François Demaeght b, d, Caroline Loïez b, d, g, Philippe-Alexandre Faure a, b, e, Gilles Pasquier a, b, e, Julien Girard a, b, e, Alain Duhamel f, Eric Senneville b, e, g, Henri Migaud a, b, gAbstract |
Background |
The GeneXpert® MRSA/SA SSTI test allows early detection of methicillin-resistant staphylococci in intraoperative samples of prosthetic joint infections (PJI) in order to stop early broad-spectrum antibiotics.
Questions/Purpose |
(1) What is the rate of false-negative GeneXpert® MRSA/SA SSTI test results? (2) Does a false-negative GeneXpert® MRSA/SA SSTI test result increase the risk of treatment failure for the patient with a PJI? (3) What are the risk factors of a false-negative result?
Method |
A retrospective study was carried out to compare all GeneXpert® assays to conventional cultures in prosthetic joint infections from April 1st, 2012 to October 1st, 2016. False-negative (FN) results (absence of methicillin-resistant staphylococci (MRS) with GeneXpert® test, but presence in the culture) were identified. We compared the rate of treatment failure between FN results and other test results and we established the risk factors of having a FN result.
Results |
Among the 612 GeneXpert® results, the rate of FN results was 3.6 % (22/612). We found a significant increase in treatment failures for prosthetic joint infection with a FN result with 14 treatment failures (14/22) compared to 198 treatment failures (198/590) in the other test results (OR, 2.1; 95 % CI, 1.3−3.4, p = 0.0019). Not considering suppressive antibiotics as a treatment failure, we found no significant difference in the rate of treatment failures between the false-negative tests and the other tests (OR, 1.36; 95 % CI, 0.66–2.81, p = 0.41). Tobacco use (OR, 3.8; 95 % CI, 1.4−10.3, p = 0.004), ASA classification (OR, 2,4; 95 % CI, 0.9−6.9, p = 0.064), history of infection in the joint (OR, 3.2; 95 % CI, 1.2−9.6, p = 0.007), chronic infections (OR, 3.2; 95 % CI, 0.8−17.5, p = 0.01) and polymicrobial infections (OR, 3.2; 95 % CI, 1.1−9.2, p < 0.0001) were risk factors for a FN result.
Conclusion |
GeneXpert® tests in prosthetic joint infections showed a low rate of FN results. An increased risk of treatment failures was observed in FN results only when long-term use of suppressive antibiotics was considered as treatment failure.
Level of evidence |
III; Diagnostic retrospective case control study.
Le texte complet de cet article est disponible en PDF.Keywords : Prosthetic joint infection, GeneXpert MRSA/SA SSTI assay, Methicillin-Resistant staphylococci, Infection diagnosis test
Plan
Vol 111 - N° 6
Article 104032- octobre 2025 Retour au numéro
Article précédent
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- Adrien Pascal, Pierre-Jean Lambrey, Benjamin Valentin, Henri Migaud, Sophie Putman, Philippe-Alexandre Faure, Julien Dartus, Caroline Loiez, Benoîtde Saint Vincent, Eric Senneville
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