Conceptual cartoon drawing showing bacteria lining up at airport security, highlighting the movement or spread of pathogens
News • Tracking the spread and evolution of superbugs
Mapping the movement of people (and their pathogen travel companions)
A new way to map the spread and evolution of pathogens, and their responses to vaccines and antibiotics, will provide key insights to help predict and prevent future outbreaks. The approach combines a pathogen’s genomic data with human travel patterns, taken from anonymised mobile phone data.
Researchers from the Wellcome Sanger Institute, University of the Witwatersrand and National Institute for Communicable Diseases in South Africa, the University of Cambridge, and partners across the Global Pneumococcal Sequencing project1, integrated genomic data from nearly 7,000 Streptococcus pneumoniae (pneumococcus) samples collected in South Africa with detailed human mobility data2. This enabled them to see how these bacteria, which cause pneumonia and meningitis3, move between regions and evolve over time. The findings, published in Nature, suggest initial reductions in antibiotic resistance linked to the 2009 pneumococcal vaccine may be only temporary, as non-targeted strains resistant to antibiotics such as penicillin gained a 68% competitive advantage.
This is the first time researchers have been able to precisely quantify the fitness – their ability to survive and reproduce – of different pneumococcal strains. The insight could inform vaccine development to target the most harmful strains, and may be applicable to other pathogens.
Many infectious diseases such as tuberculosis, HIV, and Covid-19 exist in multiple strains or variants circulating simultaneously, making them difficult to study. Pneumococcus, a bacterium that is a leading cause of pneumonia, meningitis, and sepsis worldwide4, is a prime example with over 100 types and 900 genetic strains globally. Pneumonia alone kills around 740,000 children under the age of five each year5, making it the single largest infectious cause of death in children. Pneumococcal diversity hampers control efforts, as vaccines targeting major strains leave room for others to fill the vacant niches. How these bacteria spread, how vaccines affect their survival, and their resistance to antibiotics remains poorly understood.
In this new study, researchers analysed genome sequences from 6,910 pneumococcus samples collected in South Africa between 2000 and 2014 to track the distribution of different strains over time. They combined these data with anonymised records of human travel patterns collected by Meta2. The team d
