Angela Brueggemann: Pneumococcal diseases
Although there are two available pneumococcal conjugate vaccines, they cannot protect against all types of pneumococci. Additionally, pneumococci will evolve to escape vaccination through altering their protein coat. By understanding how pneumococci evolve in response to vaccination new, more effective vaccines and antibiotics can be designed.
Q: Angela, can you tell us a bit about streptococcus pneumoniae?
AB: Streptococcus pneumoniae is one of the major bacterial pathogens worldwide. We often refer to it as the pneumococcus and it infects people of all age groups but particularly young children under the age of 5 and older adults. It causes a range of different types of diseases, from relatively mild infections like ear infections in young children, to much more serious, potentially life-threatening diseases like pneumonia and meningitis. Pneumonia is probably the most important serious pneumococcal disease and the World Health Organisation estimates that about half a million children die every year as a result of pneumococcal disease. The vast majority of those children die from pneumococcal pneumonia.
Q: Why are the pneumococcal diseases so difficult to treat?
AB: It is possible to treat pneumococcal diseases with antibiotics and the most commonly used antibiotics are penicillin and erythromycin. However as you might expect, antibiotic resistance is a problem worldwide. Here in the UK most pneumococci are susceptible to antibiotics but, for example in some parts of Asia, as much as 60% of some types of pneumococci are resistant to antibiotics and are often resistant to many different types of antibiotics. This makes it very difficult in some cases to treat pneumococcal infections.
Q: How is you research helping with vaccine development?
AB: There are currently two available vaccines that were developed for young children and these are called pneumococcal conjugate vaccines. Both of these vaccines are very safe and very effective and represent a very big public health success story. When these vaccines are introduced in to countries the burden of pneumococcal diseases decreases significantly and the number of children dying from pneumococcal diseases decreases significantly. However these vaccines do not protect against all types of pneumococci.
Pneumococci have a coat that surrounds the bacterial cell and that coat helps them avoid being destroyed by the human immune system. We know that there are over 90 different coats that the pneumococcus might wear and these vaccines only protect against a very small number of these coats, so this is a problem. Furthermore, we know that when the vaccine is introduced in a country that it changes the pneumococcal population and sometimes that can also relate to changes in the DNA, the genetic components of the pneumococci, such that the pneumococcus evolves to escape the vaccine. A major part of our research is to understand how the organism is evolving in response to vaccination.
Q: What are the most important lines of research that have developed over the last 5 or 10 years?
AB: Probably the most important, most significant impact recently is the ability to cheaply and easily sequence the pneumococcal genome. We literally now have 1000s of pneumococcal genomes which we can use to understand more about how the organism evolves with response to vaccination or antibiotics. We can understand more about the pneumococcal biology in general and we can use that information to try and understand how to prevent disease and how to develop new vaccines and antibiotics.
Q: Why does your line of research matter and why should we put money in to it?
AB: It's quite clear that vaccines save lives and it is much better to be able to prevent disease from occurring in the first place rather than have to try and treat disease. In addition, some children who survive serious pneumococcal diseases like meningitis will often have long-term disabilities e.g. brain damage, hearing disability or developmental problems, meaning that it is much better to prevent the disease rather than treat the disease.
Q: How does your research fit in to translational medicine within the department?
AB: Our overriding aim is to use genomics to understand pneumococcal biology and pneumococcal evolution. We have a lot more information available and if we use this information appropriately then hopefully we can develop ways to improve the current vaccines and antibiotics or possibly to develop new vaccines and antibiotics, which would be a big success.