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This Article Full Text (Papers in Press[PDF]) All Versions of this Article: jmm.0.009878-0v1 58/8/1023    most recent Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Google Scholar Articles by Fry, N. K Articles by Harrison, T. G PubMed PubMed Citation Articles by Fry, N. K Articles by Harrison, T. G Agricola Articles by Fry, N. K Articles by Harrison, T. G

The role of PCR in the diagnosis of pertussis infection in infants: five years experience of provision of a same-day real-time PCR service in England and Wales from 2002 to 2007

HPA Centre for Infections

¹ E-mail: norman.fry{at}hpa.org.uk

Received January 27, 2009
Accepted April 9, 2009

As part of an enhanced surveillance program for pertussis in England and Wales, a real-time PCR service for detection of Bordetella pertussis was introduced, for infants 6 months of age admitted to a paediatric intensive care unit or paediatric ward, with a respiratory illness compatible with pertussis. Two real-time fluorescent resonance energy transfer hybridization probe LightCycler (Roche Diagnostics) PCR assays were used, one (designed in-house) targeting the pertussis toxin S1 promoter (ptxA-pr), including an internal process control (IPC) to test for sample inhibition and reagent performance. The other (previously published) targeting the insertion element IS481. The analytical sensitivities of the assays were 100 fg and 10 fg per reaction for the ptxA-pr PCR and the IS481 PCR respectively. The ptxA-pr assay was specific for B. pertussis whilst the IS481 PCR also showed some cross-reactivity with B. holmesii and the type strain of B. parapertussis. From April 2002 to March 2007, 848 samples from 774 patients were received. Samples for testing were extracted with the QiaAmp DNA Mini Kit (Qiagen) or MagNaPure Compact Nucleic Acid Isolation Kit I using the MagNaPure Compact (Roche Diagnostics). Of all samples tested, 183 of 848 (21.6 %) samples had evidence of Bordetella infection (18.4 % ptxA-pr and IS481; 3.12 % IS481 only). Six hundred and twenty-one samples (73.2 %) were negative and 24 (2.8 %) were inhibitory. Within the targeted age group of 6 months, most patients (130 of 138) with evidence of Bordetella spp. by PCR were 3 months old. The overall percentage increase in laboratory confirmed cases due to PCR for the five year period described ranged from 9 % to 26 % per year (mean, 19 %). Real-time PCR is an invaluable tool both for the enhanced epidemiological surveillance and in the provision of a rapid diagnosis of pertussis where results can affect patient and contact management.