Contributed Talk 3: The role of metabolic and immunological competition in structuring pneumococcal populations and the effects of vaccination

Duration: 17 mins 36 secs
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Description: Watkins, ER (University of Oxford)
Tuesday 28 October 2014, 12:00-12:15
 
Created: 2014-10-29 17:24
Collection: Understanding Microbial Communities; Function, Structure and Dynamics
Publisher: Isaac Newton Institute
Copyright: Watkins, ER
Language: eng (English)
Distribution: World     (downloadable)
Explicit content: No
Aspect Ratio: 16:9
Screencast: No
Bumper: UCS Default
Trailer: UCS Default
 
Abstract: Streptococcus pneumoniae (the pneumococcus) is a major cause of bacterial pneumonia, septicemia and meningitis worldwide. Traditional serotyping methods have demonstrated that pneumococcal populations are highly diverse, with over 90 capsular serotypes. More recently, whole genome sequencing has revealed extensive diversity among the metabolic genes, and that metabolic alleles tend to segregate in non-overlapping associations with the antigenic serotype. Here, we use a multilocus model in which strains are composed of metabolic, antigenic and virulence components to explain these patterns of structuring through ecological and immunological competition in the host.

Currently, pneumococcal protein conjugate vaccines target only a small subset of its >90 known capsular serotypes. We use our model to show that a strain-targeted vaccination strategy could alter the genomic profile of non-vaccine strains, potentially leading to an increase in their transmissibility and virulence. The results are consistent with data on the changes in the population structure of the pneumococcus following vaccination, including support at the whole genome level in a collection of 600 pneumococcal genomes.

Similar non-overlapping associations among metabolic and antigenic alleles have been observed in a number of other bacterial pathogens, suggesting that metabolic and immunological competition may play important roles in the maintenance of pathogen population structure more generally. Our vaccination findings also have implications for strain-targeted vaccination in a range of bacterial and viral systems.
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