Density and duration of experimental human pneumococcal carriage

The density and duration of pneumococcal carriage are considered to affect the likelihood of transmission and invasive disease. Because of its importance in both spreading and causing disease, carriage has been suggested as an endpoint in future vaccine studies. Culture is the current gold standard...

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Main Authors:	Gritzfeld, J F, Cremers, A J H, Ferwerda, G, Ferreira, D M, Kadioglu, A, Hermans, P W M, Gordon, S B
Format:	Online
Language:	English
Published:	Blackwell Publishing Ltd 2014
Online Access:	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4313687/

id	pubmed-4313687
recordtype	oai_dc
spelling	pubmed-43136872015-02-10 Density and duration of experimental human pneumococcal carriage Gritzfeld, J F Cremers, A J H Ferwerda, G Ferreira, D M Kadioglu, A Hermans, P W M Gordon, S B Epidemiology The density and duration of pneumococcal carriage are considered to affect the likelihood of transmission and invasive disease. Because of its importance in both spreading and causing disease, carriage has been suggested as an endpoint in future vaccine studies. Culture is the current gold standard for detection, but may not be sensitive enough to detect changes at low density. Healthy adult volunteers received an intranasal inoculation of Streptococcus pneumoniae serotype 6B. Pneumococcal density in nasal washes collected at six time-points post-inoculation was determined by culture and quantitative PCR (qPCR). Natural pneumococcal carriers detected at initial screening were followed in parallel. In 331 nasal washes from 79 volunteers, the sensitivity and specificity of pneumococcal detection by qPCR, as compared with culture, were 92.3% and 75.9%. The estimation of pneumococcal density by culture and qPCR was highly correlated (rs = 0.73, p <0.0001), although qPCR had a lower detection limit. Pneumococcal density fluctuated within a carriage episode, and occasionally fell below the detection limit of both methods. The duration of carriage episodes was underestimated when only one method was used. Similar fluctuations in density were observed in natural carriers. Pneumococcal carriage is a dynamic event. Culture and qPCR are complementary for surveying the density and duration of pneumococcal carriage episodes. Blackwell Publishing Ltd 2014-12 2014-07-04 /pmc/articles/PMC4313687/ /pubmed/24995531 http://dx.doi.org/10.1111/1469-0691.12752 Text en © 2014 The Authors Clinical Microbiology and Infection © 2014 European Society of Clinical Microbiology and Infectious Diseases
repository_type	Open Access Journal
institution_category	Foreign Institution
institution	US National Center for Biotechnology Information
building	NCBI PubMed
collection	Online Access
language	English
format	Online
author	Gritzfeld, J F Cremers, A J H Ferwerda, G Ferreira, D M Kadioglu, A Hermans, P W M Gordon, S B
spellingShingle	Gritzfeld, J F Cremers, A J H Ferwerda, G Ferreira, D M Kadioglu, A Hermans, P W M Gordon, S B Density and duration of experimental human pneumococcal carriage
author_facet	Gritzfeld, J F Cremers, A J H Ferwerda, G Ferreira, D M Kadioglu, A Hermans, P W M Gordon, S B
author_sort	Gritzfeld, J F
title	Density and duration of experimental human pneumococcal carriage
title_short	Density and duration of experimental human pneumococcal carriage
title_full	Density and duration of experimental human pneumococcal carriage
title_fullStr	Density and duration of experimental human pneumococcal carriage
title_full_unstemmed	Density and duration of experimental human pneumococcal carriage
title_sort	density and duration of experimental human pneumococcal carriage
description	The density and duration of pneumococcal carriage are considered to affect the likelihood of transmission and invasive disease. Because of its importance in both spreading and causing disease, carriage has been suggested as an endpoint in future vaccine studies. Culture is the current gold standard for detection, but may not be sensitive enough to detect changes at low density. Healthy adult volunteers received an intranasal inoculation of Streptococcus pneumoniae serotype 6B. Pneumococcal density in nasal washes collected at six time-points post-inoculation was determined by culture and quantitative PCR (qPCR). Natural pneumococcal carriers detected at initial screening were followed in parallel. In 331 nasal washes from 79 volunteers, the sensitivity and specificity of pneumococcal detection by qPCR, as compared with culture, were 92.3% and 75.9%. The estimation of pneumococcal density by culture and qPCR was highly correlated (rs = 0.73, p <0.0001), although qPCR had a lower detection limit. Pneumococcal density fluctuated within a carriage episode, and occasionally fell below the detection limit of both methods. The duration of carriage episodes was underestimated when only one method was used. Similar fluctuations in density were observed in natural carriers. Pneumococcal carriage is a dynamic event. Culture and qPCR are complementary for surveying the density and duration of pneumococcal carriage episodes.
publisher	Blackwell Publishing Ltd
publishDate	2014
url	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4313687/
_version_	1613183166625873920

Density and duration of experimental human pneumococcal carriage

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