A Population Genomics View of Pneumococcal Antimicrobial Resistance
Stephen Bentley PhD
Wellcome Trust Sanger Institute
Abstract：
Streptococcus pneumoniae (the pneumococcus) is able to acquire resistance to a range of antimicrobials with up to 40% is invasive disease strains carrying resistance to at least one drug. However, reductions in rates of resistance have been observed in association with interventions such as vaccine introduction and control of antimicrobial prescription; the polysaccharide conjugate vaccines have specifically targeted serotypes associated with high rates of resistance and strict antimicrobial stewardship in one country drove the disarming of a highly resistant pandemic clone.
Evolution in the pneumococcus is charaterised by a high rate of homologous recombination which plays a major role in acquisition of some resistance determinants, particularly those due to mutations in housekeeping functions. Resistance determinants that are due to gene acquisition tend to be carried on mobile elements, particularly Integrative Conjugative Elements (ICE).
Through population genomic analysis we are able to observe the changes that have lead to the creation of multiply resistant pandemic clones alongside strains with similar characteristics that have not progressed. We can also discover the details of genetic decay as a prevalent clone loses resistance and declines in frequency. Furthermore signals of changes in antimicrobial usage may be seen reflected in the phylogenies of individual genes.
The co-existence of resistant and susceptible isolates within a population is puzzling and by observing the details of the dynamic gain and loss of resistance determinants we hope to further understand the forces balancing the population.
Time: Nov. 24th, 2015, 16:00
Venue: New Biology Building, Room 143
Host: Prof. Jingren Zhang
举办单位：生命科学联合中心
