Detection of Biomaterial-Associated Infections in Orthopaedic Joint Implants

Abstract

Biomaterial-associated infection of orthopaedic joint replacements is the second most common cause of implant failure. Yet, the microbiologic detection rate of infection is relatively low, probably because routine hospital cultures are made only of swabs or small pieces of excised tissue and not of the surfaces of potentially infected implants. Joint replacements from patients in whom infection was suspected, after clinical, radiologic, and biochemical examinations, were used in this study. The aim of the current study was to compare the detection rate of infection in total joint replacements based on cultures of the excised tissue and scrapings from the biomaterial surface. Joint prostheses were retrieved from 22 patients requiring orthopaedic revision surgery because of suspected infection of their prostheses. Routine hospital culturing of tissue only showed bacterial growth in nine patients (41%). However, after prolonged culturing, bacterial growth was observed in 14 patients (64%), whereas extensive culturing of scrapings from the biomaterial surface indicated bacterial growth in 19 of the 22 patients (86%). In addition, confocal laser scanning microscopy enabled observation of biofilm bacteria on the surfaces of the explanted prostheses. Diagnosis in orthopaedic revision surgery should consider using a microbial or microscopic analysis of the surface of an explanted prosthesis, where the biofilm mode of growth firmly anchors and protects the infecting organisms. Improved detection of infection by analysis of the implant surface is expected to yield ameliorated therapy and a reduced need for revision surgery.

Is There a Role for Tissue Biopsy in the Diagnosis of Periprosthetic Infection?

“…Correct handling of the samples, immediate inoculation, and immediate transfer to the laboratory are mandatory to prevent contamination of the samples. Because bacteria that lead to a periprosthetic infection sometimes exist in low numbers and grow slowly [10,16,45], an adequate length of incubation is important. We chose to incubate our specimens for 14 days [21,25,28,60].…”

Do Genetic Susceptibility, Toll-like Receptors, and Pathogen-associated Molecular Patterns Modulate the Effects of Wear?

“…Moreover, peptidoglycan, a PAMP produced by both Gram-negative and Gram-positive bacteria, exists in synovial tissue from patients with osteoarthritis and rheumatoid arthritis [16,96] and, therefore, likely exists in periprosthetic tissue of patients with aseptic loosening. One potential source of PAMPs during aseptic loosening is the bacteria present in the biofilms found on many loose implants despite the absence of clinical signs of infection [21,47,54,74,76,107,109]. Patients with inflammatory arthritis, especially those receiving anti-TNF-a therapies, may be especially at risk for formation of these bacterial biofilms [95].…”

The comparison of pyrosequencing molecular Gram stain, culture, and conventional Gram stain for diagnosing orthopaedic infections

“…11,12,[23][24][25] The use of these tools is of particular interest in orthopedics, wherein the adhesion of bacteria within a biofilm on the surface of an implant may make the organism difficult to detect by conventional techniques. [15][16][17] Although some of these tools have been used to study orthopedic infections, much remains to be learned. 26 Pyrosequencing is a relatively new technology that is a fundamentally different way of sequencing DNA compared to the conventional Sanger sequencing.…”

“…13 We sought here to explore the utility of this assay for clinical orthopedic samples, recognizing several potential impediments such as the purity of extracted DNA, contamination, and the adhesion of bacteria in biofilm. [14][15][16][17] The purpose of this study was to compare the results of our assay with those obtained using conventional culture and direct Gram stain examination.…”