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Novel Diagnostics in Revision Arthroplasty: Implant Sonication and Multiplex Polymerase Chain Reaction
Published on: December 3, 2017
Polymicrobial Late-Onset Knee Prosthetic Joint Infection Involving Parvimonas micra: A Case Report and Genomic
Mauro Jose Salles1,2,3, Daniel Litardi Pereira2, Ícaro Santos Oliveira2,3
1Laboratório Especial de Microbiologia Clínica (LEMC), Division of Infectious Diseases, Department of Internal Medicine, Universidade Federal de São Paulo-UNIFESP, São Paulo CEP 04025-010, Brazil.
Abstract:
We report a rare case of polymicrobial late-onset knee prosthetic joint infection (PJI) caused by Parvimonas micra and Staphylococcus aureus. An 80-year-old woman with multiple comorbidities presented, five years after total knee arthroplasty, with progressive pain and radiographic signs of prosthetic loosening. Synovial fluid analysis revealed marked neutrophilic inflammation, and intraoperative tissue cultures, including sonication fluid yielded both pathogens. Identification was confirmed by MALDI-TOF MS and whole-genome sequencing (WGS). The P. micra strain showed 97.2% identity to reference strain SAMN29629855, and carried virulence genes such as groEL, tufA, clpP, ctrD, srtC4, and gaIE, associated with oxidative stress response, adhesion, immune evasion, and biofilm formation. Resistance genes vanW, vanT, and vanY from the van operon were also detected, though vanA and vanB were absent. The patient underwent a two-stage revision surgery and a 12-week course of pathogen-targeted antimicrobial therapy, with complete resolution of symptoms and no recurrence after 12 months. This case highlights the overlooked pathogenicity of P. micra in chronic PJIs, especially in polymicrobial biofilm-related infections. The integration of WGS provided valuable insights into possible genetic characteristics of virulence determinants of this rare cause of PJI.
Insights
This case study details a rare polymicrobial prosthetic joint infection in a knee replacement caused by Parvimonas micra and Staphylococcus aureus. Whole-genome sequencing revealed P. micra
Area of Science:
- Infectious Diseases
- Orthopedic Surgery
- Microbiology
- Genomics
Background:
- Late-onset prosthetic joint infections (PJIs) pose significant challenges in orthopedic surgery.
- Polymicrobial infections are less common but can complicate treatment strategies.
- Parvimonas micra is an emerging pathogen in chronic infections, often overlooked.
Purpose of the Study:
- To report a rare case of polymicrobial late-onset knee PJI.
- To characterize the virulence and resistance genes of the involved pathogens, particularly P. micra.
- To highlight the role of P. micra in chronic biofilm-related PJIs.
Main Methods:
- Case presentation of an 80-year-old female with a five-year-old total knee arthroplasty.
- Synovial fluid analysis and intraoperative tissue and sonication fluid cultures.
- Pathogen identification using MALDI-TOF MS and whole-genome sequencing (WGS).
- Analysis of virulence and antibiotic resistance genes in P. micra.
Main Results:
- Polymicrobial infection identified: Parvimonas micra and Staphylococcus aureus.
- P. micra strain possessed virulence genes (groEL, tufA, clpP, ctrD, srtC4, gaIE) and vanW, vanT, vanY resistance genes.
- Successful treatment with two-stage revision surgery and targeted antimicrobial therapy.
- No recurrence observed at 12-month follow-up.
Conclusions:
- Parvimonas micra can be a significant pathogen in chronic, polymicrobial prosthetic joint infections.
- Whole-genome sequencing provides crucial insights into the genetic basis of virulence and resistance in rare PJI pathogens.
- Early identification and targeted therapy are essential for successful management of complex PJIs.
