Molecular identification of bacteria from aseptically loose implants

Area of Science:

• Orthopaedic surgery
• Microbiology
• Molecular diagnostics

Background:

• Polymerase chain reaction (PCR) is used to detect bacteria on failed orthopaedic implants.
• Some PCR assays may yield false-positive results, complicating diagnosis.
• Identifying bacteria on implants is crucial for revision arthroplasty success.

Purpose of the Study:

• To determine if bacterial DNA exists on presumed aseptic loose implants using a refined PCR and sequencing method.
• To quantify the proportion of aseptic or culture-negative implants that test positive for bacterial DNA via PCR.
• To investigate the clinical relevance of PCR-detected bacterial DNA in the absence of positive cultures.

Main Methods:

• Utilized a combination of Staphylococcus species-specific PCR, universal PCR, and DNA sequencing.
• Analyzed 92 implants from 52 patients undergoing revision arthroplasty.
• Compared PCR results with conventional culture and histological findings.

Main Results:

• Bacterial DNA was detected by PCR in 12% (9 out of 74) of implants presumed to be aseptically loose.
• All aseptically loose implants were negative by conventional culture.
• Two implants (2.7%) were PCR-positive and showed histological signs of infection.

Conclusions:

• A novel PCR and sequencing approach identified bacterial DNA on 12% of implants removed for presumed aseptic loosening.
• The clinical significance of detecting bacterial DNA via PCR without positive cultures requires further investigation.
• This method offers a potential tool for identifying subclinical infections in revision arthroplasty.