Monday, May 06, 2013

Bacteria strains change after vaccine introduction.

Genome sequencing provides unprecedented insight into causes of pneumococcal disease 


May 5, 2013 in Genetics A new study led by researchers from Harvard School of Public Health (HSPH) and the Wellcome Trust Sanger Institute in the UK has, for the first time, used genome sequencing technology to track the changes in a bacterial population following the introduction of a vaccine. The study follows how the population of pneumococcal bacteria changed following the introduction of the 'Prevnar' conjugate polysaccharide vaccine

Read more at: http://medicalxpress.com/news/2013-05-genome-sequencing-unprecedented-insight-pneumococcal.html#jCp

Rates of pneumococcal disease—an infection that can lead to pneumonia, meningitis, and other illnesses—dropped in young children following the introduction of a vaccine in 2000. However, strains of the bacteria that are not targeted by the vaccine rapidly increased and drug resistance appears to be on the rise
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This study confirmed that the parts of the bacterial population targeted by the vaccine have almost disappeared, and, surprisingly, revealed that they have been replaced by pre-existing rare types of bacteria. The genetic composition of the new population is very similar to the original one, except for a few genes that were directly affected by the vaccine. This small genetic alteration appears to be responsible for the large reduction in the rates of pneumococcal disease.

More information: "Population Genomics of Post-Vaccine Changes in Pneumococcal Epidemiology," Nicholas J. Croucher, Jonathan A. Finkelstein, Stephen I. Pelton, Patrick K. Mitchell, Grace M. Lee, Julian Parkhill, Stephen D. Bentley, William P. Hanage, Marc Lipsitch Nature Genetics, online May 5, 2013. dx.doi.org/10.1038/ng.2625

Read more at: http://medicalxpress.com/news/2013-05-genome-sequencing-unprecedented-insight-pneumococcal.html#jCp

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