Improving diagnosis of Bordetella pertussis to improve patient management

Abstract number: R2362

McCulloch E., Williams C.

Objectives: Bordetella pertussis is a serious potentially life threatening infection particularly in unimmunised infants. There has also been an increase in the number of people who, although fully vaccinated, loose their immunity over time. Due to the fragile nature of the organism and the prolonged time required to culture the organism it is significantly under reported. It was proposed that introducing real-time PCR as a clinical service to detect Bordetella pertussis and Bordetella parapertussis (a related less severe infection) would improve the management of patients with this infection.

Methods: Pernasal swabs or naso-pharyngeal aspirates from patients with a clinical suspicion of whooping cough were collected and cultured immediately as per routine laboratory protocol. In our real-time PCR assay, DNA is extracted using the EZ1 BioRobot (Qiagen) and a tissue extraction kit, then amplified and detected using an ABI Prism 7000 sequence detector and Taqman probes (Applied Biosystems). Each sample is performed in duplicate using a reaction which amplifies a specific B.pertussis or B.parapertussis gene target allowing detection amplified DNA.

Results: In the first year of introducing real-time PCR as a clinical service the turn-around time of sample processing improved from 5–7 days using standard culture methods to 24 hrs with a maximum of 3 days if a specimen was collected on a weekend. The sensitivity of the assay was also improved with 4 cases from a total of 13 positive patients that would not have been detected when culture was used alone. Clinicians were also more likely to take specimens for pertussis testing due to the improved service this resulted in cases of dual infection with RSV being detected were a positive virology result alone may have resulted in no further investigations.

Conclusion: The use of real-time PCR has allowed both a faster turn around time in processing patient samples, increased sensitivity and more appropriate isolation procedures for in-patients.

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Location: Barcelona, Spain
Presentation type:
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