SMIEJA M, MAHONY JB, GOLDSMITH CH, CHONG S, PETRICH A, CHERNESKY M; Interscience Conference on Antimicrobial Agents and Chemotherapy.
Abstr Intersci Conf Antimicrob Agents Chemother Intersci Conf Antimicrob Agents Chemother. 2000 Sep 17-20; 40: 146.
McMaster Univ., Hamilton, ON, Canada
BACKGROUND: PCR has variable sensitivity for detecting C. pneumoniae in clinical specimens. We examined whether repeated testing of a sample increased sensitivity and enabled semi-quantitation.METHODS: Initially, nested (Tong and Sillis, nPCR) and non-nested (Campbell, nnPCR) assays were compared using 10 replicates of 16 serial dilutions of culture-grown C. pneumoniae VR 1310. The relationship of PCR positivity to C. pneumoniae concentration was analyzed by probit analysis (SPSS). To validate the model, we tested 10 replicates of 24 previously PCR-positive patients: nasopharyngeal swabs (NPS) from patients with respiratory symptoms (14), and peripheral blood mononuclear cell (PBMC) specimens from patients with atherosclerotic heart disease (10).RESULTS: In the model, the number of PCR positive replicates was proportional to the concentration of C. pneumoniae. Above five inclusion forming units (IFU)/mL, both assays were >90% sensitive. At 0.1 IFU/mL, per-run assay sensitivities were 22% (nPCR) and 11 % (nnPCR). The probit model predicted better sensitivity for the nPCR (P=0.04). For the patient specimens, ten nPCR replicates were superior to nnPCR replicates (14/24 vs. 1/24, P<0.001), with between 1 and 9 nPCR replicates positive (mean 2.2, median 1). By interpolation from the nPCR probit curve, median C. pneumoniae concentration was estimated: PBMC, 0.06 IFU/mL (95% CI=0.03 to 0.11); adult NPS, 0.04 IFU/mL (95% CI=0.02 to 0.08); and pediatric NPS, < 0.02 IFU/mL.CONCLUSIONS: For detecting and semi-quantitating low concentrations of C. pneumoniae in clinical specimens, a 10-replicate PCR considerably increased PCR sensitivity.KEYWORDS: Chlamydia pneumoniae; Diagnosis; Polymerase
Publication Types:
Keywords:
- Adult
- Child
- Chlamydophila pneumoniae
- Humans
- Polymerase Chain Reaction
- Reproducibility of Results
- Research
- Research Design
- Sensitivity and Specificity
- psychology
Other ID:
UI: 102248044
From Meeting Abstracts