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Phase variation in pneumococcal populations during carriage in the human nasopharynx

De Ste Croix, Megan, Mitsi, Elena ORCID:, Morozov, Andrew, Glenn, Sarah, Andrew, Peter, Ferreira, Daniela ORCID: and Oggioni, Marco (2020) 'Phase variation in pneumococcal populations during carriage in the human nasopharynx'. Scientific Reports, Vol 10, Issue 1803.

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Streptococcus pneumoniae is one of the world’s leading bacterial pathogens, responsible for pneumonia, septicaemia and meningitis. Asymptomatic colonisation of the nasopharynx is considered to be a prerequisite for these severe infections, however little is understood about the biological changes that permit the pneumococcus to switch from asymptomatic coloniser to invasive pathogen. A phase variable type I restriction-modification (R-M) system (SpnIII) has been linked to a change in capsule expression and to the ability to successfully colonise the murine nasopharynx. Using our laboratory data, we have developed a Markov change model that allows prediction of the expected level of phase variation within a population, and as a result measures when populations deviate from those expected at random. Using this model, we have analysed samples from the Experimental Human Pneumococcal Carriage (EHPC) project. Here we show, through mathematical modelling, that the patterns of dominant SpnIII alleles expressed in the human nasopharynx are significantly different than those predicted by stochastic switching alone. Our inter-disciplinary work demonstrates that the expression of alternative methylation patterns should be an important consideration in studies of pneumococcal colonisation.

Item Type: Article
Subjects: QW Microbiology and Immunology > Immunotherapy and Hypersensitivity > QW 806 Vaccination
WC Communicable Diseases > Infection. Bacterial Infections > Bacterial Infections > WC 217 Pneumococcal infections
WC Communicable Diseases > Virus Diseases > Viral Respiratory Tract Infections. Respirovirus Infections > WC 515 Human influenza
WV Otolaryngology > Pharyngeal Region > WV 400 General works
Faculty: Department: Clinical Sciences & International Health > Clinical Sciences Department
Digital Object Identifer (DOI):
Depositing User: Catherine Molloy
Date Deposited: 20 Feb 2020 16:58
Last Modified: 06 Mar 2020 12:10


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