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- Erlandsson, Ann, 1968-, et al.
(författare)
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PCR assay or culture for diagnosis of Bordetella pertussis in the routine diagnostic laboratory?
- 1997
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Ingår i: Journal of Infection. - : Elsevier. - 0163-4453 .- 1532-2742. ; 35:3, s. 221-224
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Tidskriftsartikel (refereegranskat)abstract
- A nested PCR method was compared with culture for the detection of Bordetella pertussis in a routine clinical diagnostic laboratory. A total of 241 clinical nasopharyngeal aspirates were examined in parallel in the laboratory. Both methods were positive for 75 samples (31%), eight samples were positive by nested PCR only (3.3%), and one sample was positive by culture only (0.4%). The mean time actually required in the clinical laboratory (not operating with pertussis diagnosis during weekends) from the day of arrival to the diagnosis of a positive or negative sample by the nested PCR assay was 1.8 _+ 1.3 days (mean _+ SD), for positive culture 4.5 _+ 1.4 days and for negative culture 10.5 +_ 1.0 days. The hands-on time in the laboratory to perform the nested PCR was 2 h, for a positive culture 25 min, and for a negative culture 15 min. The cost analysis of the methods, when running one sample at a time, showed that the laboratory cost for PCR was six times higher than culture. When running four samples together the cost for PCR was three times higher than culture. In conclusion, the nested PCR is the more rapid and sensitive method compared to culture. With the present design, the PCR-protocol involves higher material expenditure and claims more bands-on time.
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| 2. |
- Erlandsson, Ann, 1968-, et al.
(författare)
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Quantification of Bordetella pertussis in clinical samples by colorimetric detection of competitive PCR products
- 1998
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Ingår i: Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS). - : John Wiley & Sons. - 0903-4641 .- 1600-0463. ; 106:7-12, s. 1041-1048
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Tidskriftsartikel (refereegranskat)abstract
- Quantification of microorganisms is an important part of the normal diagnostic work of a clinical microbiology laboratory. Traditionally the diagnosis of pertussis is subject to a yes or no approach with no quantitative dimension. This can, however, be of interest as a factor when judging the risk of a patient spreading the bacterium and as a research tool. The aim of the present study was to develop a PCR-based quantitative assay for Bordetella pertussis DNA in clinical nasopharyngeal aspirates by combining a quantitative PCR with a colorimetric detection principle, DIANA (detection of immobilised amplified nucleic acid). A competitor to the PCR target sequence in IS-481, containing a lac-operator, was constructed and calibrated, and a test protocol prepared. A total of 46 clinical nasopharyngeal aspirates, previously diagnosed using a standard nested PCR assay and quantified by culture, were analysed by the quantitative PCR. The method showed acceptable precision and accuracy considering that it estimates the total number of bacterial genomes while culture detects viable bacteria. Recognised advantages were the simple colorimetric detection, the inborn indication of a working PCR assay, and the possibility of obtaining results even when partial inhibition of the PCR assay was seen. In addition, the quantitative PCR result can be obtained within one day compared to 3–10 days for culture. The present results and the qualities of the quantitative PCR suggest that this assay will be a useful complement in routine diagnostics and in research.
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