Impact of Experimental Human Pneumococcal Carriage on Nasopharyngeal Bacterial Densities in Healthy Adults

Shak, Joshua R., Cremers, Amelieke J. H., Gritzfeld, Jenna, de Jonge, Marien I., Hermans, Peter W. M., Vidal, Jorge E., Klugman, Keith P. and Gordon, Stephen ORCID: https://orcid.org/0000-0001-6576-1116 (2014) 'Impact of Experimental Human Pneumococcal Carriage on Nasopharyngeal Bacterial Densities in Healthy Adults'. PLoS ONE, Vol 9, Issue 6, e98829.

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Abstract

Colonization of the nasopharynx by Streptococcus pneumoniae is a necessary precursor to pneumococcal diseases that result in morbidity and mortality worldwide. The nasopharynx is also host to other bacterial species, including the common pathogens Staphylococcus aureus, Haemophilus influenzae, and Moraxella catarrhalis. To better understand how these bacteria change in relation to pneumococcal colonization, we used species-specific quantitative PCR to examine bacterial densities in 52 subjects 7 days before, and 2, 7, and 14 days after controlled inoculation of healthy human adults with S. pneumoniae serotype 6B. Overall, 33 (63%) of subjects carried S. pneumoniae post-inoculation. The baseline presence and density of S. aureus, H. influenzae, and M. catarrhalis were not statistically associated with likelihood of successful pneumococcal colonization at this study’s sample size, although a lower rate of pneumococcal colonization in the presence of S. aureus (7/14) was seen compared to that in the presence of H. influenzae (12/16). Among subjects colonized with pneumococci, the number also carrying either H. influenzae or S. aureus fell during the study and at 14 days post-inoculation, the proportion carrying S. aureus was significantly lower among those who were colonized with S. pneumoniae (p = 0.008) compared to non-colonized subjects. These data on bacterial associations are the first to be reported surrounding experimental human pneumococcal colonization and show that co-colonizing effects are likely subtle rather than absolute.

Item Type:	Article
Subjects:	QW Microbiology and Immunology > Immunotherapy and Hypersensitivity > QW 805 Vaccines. Antitoxins. Toxoids WA Public Health > Preventive Medicine > WA 110 Prevention and control of communicable diseases. Transmission of infectious diseases WC Communicable Diseases > Infection. Bacterial Infections > Bacterial Infections > WC 210 Streptococcal infections (General or not elsewhere classified) WC Communicable Diseases > Infection. Bacterial Infections > Bacterial Infections > WC 217 Pneumococcal infections WV Otolaryngology > Pharyngeal Region > WV 400 General works
Faculty: Department:	Clinical Sciences & International Health > Clinical Sciences Department
Digital Object Identifer (DOI):	https://doi.org/10.1371/journal.pone.0098829
Depositing User:	Lynn Roberts-Maloney
Date Deposited:	15 Apr 2015 08:55
Last Modified:	07 Oct 2019 08:24
URI:	https://archive.lstmed.ac.uk/id/eprint/5079

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