Comparison of established diagnostic methodologies and a novel bacterialsmpbreal-time pcr assay for specific detection of haemophilus influenzae isolates associated with respiratory tract infections
Reddington, Kate Schwenk, Stefan Tuite, Nina Platt, Gareth Davar, Danesh Coughlan, Helena Personne, Yoann Gant, Vanya Enne, Virve I. Zumla, Alimuddin
Reddington, Kate
Schwenk, Stefan
Tuite, Nina
Platt, Gareth
Davar, Danesh
Coughlan, Helena
Personne, Yoann
Gant, Vanya
Enne, Virve I.
Zumla, Alimuddin
Publication Date
2015-06-24
Type
Article
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Citation
Reddington, Kate; Schwenk, Stefan; Tuite, Nina; Platt, Gareth; Davar, Danesh; Coughlan, Helena; Personne, Yoann; Gant, Vanya; Enne, Virve I. Zumla, Alimuddin; Barry, Thomas (2015). Comparison of established diagnostic methodologies and a novel bacterialsmpbreal-time pcr assay for specific detection of haemophilus influenzae isolates associated with respiratory tract infections. Journal of Clinical Microbiology 53 (9), 2854-2860
Abstract
Haemophilus influenzae is a significant causative agent of respiratory tract infections (RTI) worldwide. The development of a rapid H. influenzae diagnostic assay that would allow for the implementation of infection control measures and also improve antimicrobial stewardship for patients is required. A number of nucleic acid diagnostics approaches that detect H. influenzae in RTIs have been described in the literature; however, there are reported specificity and sensitivity limitations for these assays. In this study, a novel real-time PCR diagnostic assay targeting the smpB gene was designed to detect all serogroups of H. influenzae. The assay was validated using a panel of well-characterized Haemophilus spp. Subsequently, 44 Haemophilus clinical isolates were collected, and 36 isolates were identified as H. influenzae using a gold standard methodology that combined the results of matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and a fucK diagnostic assay. Using the novel smpB diagnostic assay, 100% concordance was observed with the gold standard, demonstrating a sensitivity of 100% (95% confidence interval [CI], 90.26% to 100.00%) and a specificity of 100% (95% CI, 63.06% to 100.00%) when used on clinical isolates. To demonstrate the clinical utility of the diagnostic assay presented, a panel of lower RTI samples (n = 98) were blindly tested with the gold standard and smpB diagnostic assays. The results generated were concordant for 94/98 samples tested, demonstrating a sensitivity of 90.91% (95% CI, 78.33% to 97.47%) and a specificity of 100% (95% CI, 93.40% to 100.00%) for the novel smpB assay when used directly on respiratory specimens.
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Publisher
American Society for Microbiology
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Attribution-NonCommercial-NoDerivs 3.0 Ireland