Detection of periprosthetic joint infections in presumed aseptic patients

Title: Detection of periprosthetic joint infections in presumed aseptic patients
Yijuan Xu1, Jan Lorenzen1, Trine Rolighed Thomsen1,2, Kathrin Kluba3, Kathrin Chamaon3, Christoph Lohmann3
1. Danish Technological Institute, Aarhus, Denmark
2. Center for Microbial Communities, Department of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, Denmark
3. Department of Orthopaedics, Otto-von-Guericke University of Magdeburg, Germany
Aim: ”The HypOrth project (New approaches in the development of Hypoallergenic implant material in Orthopaedics: Steps to personalised medicine) aims to investigate adverse immune reactions to implant materials. For this project, it is of utmost importance to exclude patients with periprosthetic joint infections (PJIs). The aim of this study was to rule out PJIs in included patients using prolonged culture and next generation sequencing (NGS) based molecular analysis.”

Method: ”This study was approved with IRB approval No 150/12. Prior to surgery, the revision patients were examined and underwent joint fluid aspiration under sterile conditions. Only patients with negative joint aspirates after 14 days culturing were included. No antibiotics were administered prior to surgery and during surgery. Up to six tissue samples were collected for culture and one sample for pathological investigation. Joint fluid and one tissue biopsy were sampled for molecular analysis. The removed prostheses were sonicated and sonication fluid was used for molecular analysis. Prophylactic antibiotics (1.5g Cephalosporine, 2nd generation) were administrated after sampling. All tissue samples were cultured for 14 days. Final microbiological diagnosis was based on tissue cultures and pathological results.
For the molecular detection, DNA was extracted using MolYsis complete5 (Molzym, Germany). The V1-3 region of 16S rRNA gene was PCR amplified with bacterial primers 27F and 534R (30 cycles) and paired-end sequenced on Miseq DNA sequencer (v3 chemistry, 2 × 300 bp). The paired-end reads were trimmed using trimmomatic (v. 0.32) and then merged using FLASH (v. 1.2.11). The reads were screened for potential PhiX contamination using USEARCH (v. 7.0.1090), clustered into operational taxonomic units (sequence identity ≥ 97%) using USEARCH, and subsequently classified using the RDP classifier with the MiDAS database (v. 1.20).”

Results: “Out of 70 included patients five patients were considered infected: One solely by culture (Staphylococcus aureus), one solely by NGS (Staphylococcus sp.) and three with concordant data by both methods (no.1: S. epidermidis by both methods; no. 2: Staphylococcus capitis by culture, S. epidermidis by NGS; no3: S. epidermidis and Enterococcus faecalis by culture, E. faecalis by NGS).”

Conclusions: ”These five patients will become part of a separate infection group in the analysis of immune reaction of patients with prosthetic joints. The data emphasize the importance of thorough microbiological analysis and illustrates the value of both culture and NGS - both from a clinical point of view and for research purposes.”