Performance of the GeneXpert® MRSA/SA SSTI test in periprosthetic joint infections: rate of failure, outcomes and risk factors - 04/01/25

Doi : 10.1016/j.otsr.2024.104032

Jean-Thomas Leclerc ^a,^b,^c,⁎ , 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,^g
^a Department of Orthopaedic Surgery, University Hospital Center, Lille, France
^b University of Lille Nord de France, Lille, France
^c Department of Orthopaedic Surgery, University Hospital Center-Université Laval, Québec, Qc, Canada
^d Institute of Microbiology, University Hospital Center, Lille, France
^e Centre de Référence des Infections Ostéo-Articulaires Complexes Nord-Ouest (CRIOAC-NO), Lille–Tourcoing, France
^f Univ. Lille, CHU Lille, ULR2694 – METRICS: évaluation des Technologies de santé et des Pratiques Médicales, F-59000 Lille, France
^g Infectious Diseases Department, Dron Hospital, Tourcoing, France

^⁎Corresponding author.

Sous presse. Épreuves corrigées par l'auteur. Disponible en ligne depuis le Saturday 04 January 2025

Abstract

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.