Molecular identification of bacteria from aseptically loose implants.
Polymerase chain reaction (PCR) assays have been used to detect bacteria adherent to failed orthopaedic implants, but some PCR assays have had problems with probable false-positive results. We used a combination of a Staphylococcus species-specific PCR and a universal PCR followed by DNA sequencing to identify bacteria on implants retrieved from 52 patients (92 implants) at revision arthroplasty. We addressed two questions in this study: (1) Is this method able to show the existence of bacterial DNA on presumed aseptic loosed implants?; and (2) What proportion of presumed aseptic or culture-negative implants was positive for bacterial DNA by PCR? Fourteen implants (15%) were believed infected, whereas 74 implants (85%) were believed aseptic. Each implant was sonicated and the resulting solution was submitted for dual real-time PCR assay and culture. All implants believed aseptically loose were culture-negative, but nine of the 74 (12%) had bacterial DNA by PCR; two (2.7%) were PCR-positive and also showed histologic findings suggestive of infection. Uniquely developed PCR and bacterial sequencing assays showed bacterial DNA on 12% of implants removed for presumed aseptic loosening. Additional studies are needed to determine the clinical importance of bacterial DNA detected by PCR but not by conventional culture.


METHODS
Level III, diagnostic study.
Kobayashi
Naomi
N
Department of Anatomic Pathology, L25, The Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA.
Procop
Gary W
GW
Krebs
Viktor
V
Kobayashi
Hideo
H
Bauer
Thomas W
TW
D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects*; D020878:Device Removal; D006801:Humans; D007595:Joint Prosthesis / Q000382:microbiology; D016133:Polymerase Chain Reaction; D011475:Prosthesis Failure; D012086:Reoperation; D013203:Staphylococcal Infections / Q000175:diagnosis* / Q000209:etiology / Q000382:microbiology; D013210:Staphylococcus / Q000302:isolation & purification*