Multivalent pneumococcal vaccines can increase the transmissibility and virulence of non-vaccine strains Eleanor Watkins , Caroline Buckee, Bridget Penman, Martin Maiden, Sunetra Gupta Methods for Mathematical and Empirical Analysis of Microbial Communities Isaac Newton Institute for Mathematical Sciences, Cambridge 28 th October 2014
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Multivalent pneumococcal vaccines can increase the transmissibility and virulence of non-vaccine strains Eleanor Watkins, Caroline Buckee, Bridget Penman,
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Multivalent pneumococcal vaccines can increase the transmissibility and virulence of non-vaccine strains
Eleanor Watkins, Caroline Buckee, Bridget Penman, Martin Maiden, Sunetra Gupta
Methods for Mathematical and Empirical Analysis of Microbial Communities Isaac Newton Institute for Mathematical Sciences, Cambridge
Miller et al. (2011) Herd immunity and serotype replacement 4 years after seven-valent pneumococcal conjugate vaccination inEngland and Wales: an observational cohort study. Lancet Infect Dis.
Bruggemann et al. (2003). Clonal Relationships between Invasive and Carriage Streptococcus pneumoniae and Serotype- and Clone-Specific Differences in Invasive Disease Potential. JID. 187:1424.
• Non-overlapping combinations of antigenic and metabolic types
• Only a minority of strains cause invasive disease, associated with the fittest metabolic types.
Metabolic Analysis of Pneumococcal Genomes• 616 pneumococcal genomes from Massachussetts• Identified all loci involved with metabolism and transport (890 in total)• Analysed allelic diversity of each metabolic/transport locus (Genome Comparator)
Locus 1
IsolatesAllele numbers
Locus 2Locus 3Locus 4
Croucher et al. (2013). Population genomics of post-vaccine changes in pneumococcal epidemiology. Nature Genetics.
www.pubmlst.orgJolley & Maiden (2010). BIGSdb: Scalable analysis of bacterial genome variation at the population level. BMC Bioinformatics 11:595
• Present in 30% (TI) and 16% (TII) of invasive pneumococci
• Bind to host extra-cellular matrix
• Interference between piliated strains and Staphylococcus aureus
Regev-Yochay et al (2009) The pneumococcal pilus predicts the absence of Staphylococcus aureus co-colonization in pneumococcal carriers. Clin. Inf. Dis. 15: 760.
Zahner et al (2010) Increase in Pilus Islet 2–encoded Pili among Streptococcus pneumoniae Isolates, Atlanta, Georgia, USA. Emerging Infectious Diseases. 16: 155.
Increase in Type II pili among 19A strains (1.5% -> 40%)