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Diagnostic polymerase chain reaction
1Swedish Institute for Infections Disease Control, Stockholm, Sweden.
Abstract:
In this overview, the PCR sensitivities and specificities for diagnosis of B. pertussis in seven different pertussis vaccine studies are discussed. The performance sensitivity of the PCR methods ranged from < or = 1 to 10 cfu, and the diagnostic sensitivity from 73 to 100% when culture was used as a reference. The proportional increase in cases by positive PCR among culture-negatives ranged from 71 to 293% (four trials), whereas the gain was 6 to 11% among culture and serology-negatives (two trials). As the triggers for collecting nasopharyngeal samples, the selection of samples for PCR analysis, and the PCR protocols themselves differed between the trials, these figures must be interpreted with caution. However, the overall results indicate a considerable gain in sensitivity when PCR was added to culture, but a moderate gain in addition to serology.
Insights
Polymerase chain reaction (PCR) significantly improves Bordetella pertussis detection when combined with culture methods. While PCR offers a substantial sensitivity gain over culture alone, its added benefit is moderate when used alongside serology.
Area of Science:
- Microbiology
- Immunology
- Diagnostic Technologies
Background:
- Pertussis, caused by Bordetella pertussis, remains a significant public health concern, necessitating accurate diagnostic methods.
- Traditional diagnostic methods like culture have limitations in sensitivity.
- Polymerase chain reaction (PCR) has emerged as a sensitive molecular technique for pathogen detection.
Purpose of the Study:
- To evaluate the sensitivity and specificity of PCR for diagnosing B. pertussis across various pertussis vaccine studies.
- To compare the diagnostic yield of PCR when added to culture versus when added to both culture and serology.
Main Methods:
- Systematic review and analysis of PCR performance data from seven distinct pertussis vaccine studies.
- Assessment of PCR sensitivity using colony-forming units (cfu) and diagnostic sensitivity against culture as a reference standard.
- Calculation of the proportional increase in case detection by PCR among samples negative for culture and/or serology.
Main Results:
- PCR performance sensitivity ranged from < or = 1 to 10 cfu, with diagnostic sensitivity between 73% and 100% compared to culture.
- Positive PCR results in culture-negative samples increased case detection by 71% to 293% in four trials.
- The gain in detection was more moderate (6% to 11%) when PCR was added to both culture and serology-negative samples in two trials.
Conclusions:
- Adding PCR to culture significantly enhances the sensitivity for diagnosing B. pertussis.
- The incremental benefit of PCR is moderate when employed in conjunction with both culture and serology.
- Variations in sampling, sample selection, and PCR protocols across studies necessitate cautious interpretation of absolute figures.