title: Quantitative evaluation of periprosthetic infection by real-time polymerase chain reaction: a comparison with conventional methods.
abstract: Several recent studies have demonstrated the limited accuracy of conventional culture methods for diagnosing periprosthetic infections. We have applied real-time polymerase chain reaction (PCR) assays for the rapid identification of bacteria around implants and reported its utility. However, the capability of quantification is also a useful feature of this type of assay. The aim of our study was to validate the usefulness of quantitative analyses using real-time PCR of cases with clinical periprosthetic infections in comparison with more established tests, such as C-reactive protein (CRP) levels, microbiologic cultures, and histopathology. Fifty-six joints with suspected infections were reviewed retrospectively. A universal PCR assay was used to perform the quantitative analyses. The differences in the threshold cycles between clinical samples and a negative control (∆Ct) in each case were calculated. The results of the quantitative PCR assay were compared with CRP levels, microbiologic cultures, and histopathology. There was a significant correlation found between the CRP and ∆Ct values. There were also significant differences found in the ∆Ct values according to CRP levels, with higher CRP levels showing higher ∆Ct values. Similarly, there were significant differences in the ∆Ct measurements in our culture results and among our pathologic evaluations. We confirmed that quantification by universal PCR based on the ∆Ct correlated with preoperative CRP levels and was associated with the microbiologic culture results and pathologic severity. This quantification method may be valuable for assessing infection severity.
authors: Department of Orthopaedic Surgery, Yokohama City University, School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, Japan. yushimiyamae@yahoo.co.jp
authors: Yushi
authors: Y
authors: Miyamae
authors: Yutaka
authors: Y
authors: Inaba
authors: Naomi
authors: N
authors: Kobayashi
authors: Hyonmin
authors: H
authors: Choe
authors: Hiroyuki
authors: H
authors: Ike
authors: Takako
authors: T
authors: Momose
authors: Shusuke
authors: S
authors: Fujiwara
authors: Tomoyuki
authors: T
authors: Saito
mesh_terms: D001419:Bacteria / Q000235:genetics / Q000302:isolation & purification*; D001424:Bacterial Infections / Q000175:diagnosis* / Q000382:microbiology; D058491:Bacterial Load / Q000379:methods*; D006801:Humans; D016459:Prosthesis-Related Infections / Q000175:diagnosis* / Q000382:microbiology; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods*; D012189:Retrospective Studies