Bacteria and fungi to protect against asthma

The incidence of childhood asthma is increasing throughout Europe. But there are exceptions: Some studies have shown in recent years that farm children much less likely to suffer from asthma than other children. The reason for this covered now by an international team of scientists with the participation of the Technical University Munich using epidemiological studies: the lower risk of asthma Farm children can be explained in large part by the greater variety of environmental microorganisms, which these children are exposed. What mechanisms play a role is still unclear, but researchers have already identified some germs that may be responsible for the lower risk of asthma. This result could also be the prevention of asthma in other population groups as well, as the researchers at the New England Journal of Medicine report.

Asthma is one of Europe's major chronic diseases in children, asthmatics often suffer a lifetime from their disease. Therefore, asthma is a unique social and public health relevance. It is caused by a combination of genetic and environmental factors, with several studies in recent years have shown that farmers' children have a significantly lower risk of asthma than other children. To get to the cause of this phenomenon on the ground, researchers examined the Ludwig Maximilians University of Munich (LMU) is now school children in Bavaria. As part of the two major European epidemiology studies and the PARSIFAL GABRIEL compared to physicians and Prof. Dr. Markus Ege Erika von Mutius from Dr. von Hauner Children's Hospital of the LMU children who lived on a farm, with other children from the same rural areas, although did not live on a farm.

The special feature of the new investigation: the scientists were confined to interior spaces and studied the dust from the children's rooms on fungi and bacterial DNA. The Department of Animal Hygiene at the Technical University of Munich (TUM) assumed in this context, the study on bacteria: TUM researchers analyzed using modern molecular biological method, the bacterial diversity of mattress dust samples as an indicator of exposure. The result: It was found that farm children compared to other children with a far greater variety of bacteria in contact come in and as a result, probably less from asthma. A statistical analysis based on identification of the bacteria showed that bacteria mainly from the family of Staphylococcaceae and representatives of the genera Bacillus , Listeria , Corynebacterium , Methylobacter , Xanthomonas , Enterobacter and Pantoea could help to reduce the risk of asthma.

For fungi in dust, were examined by another research team, there was a similar picture. In summary, therefore: The more diverse the Mikrozoo in house dust was, the lower was the risk of asthma. How these bacteria reduce the risk of asthma is still unclear. Scientists hold different explanations for conceivable. "Would be a possibility that the combination of certain environmental bacteria stimulate the innate immune system and asthma favorable immune situation is avoided," said Ege. Another explanation could be that the discussion of various environmental microorganisms excessive colonization of the lower airways with asthma-causing germs prevented - as in the intestine that required for a smooth function, a balanced microbial flora.

Microbial diversity alone, however, probably not enough to prevent asthma. It's probably a combination of specific species that can develop a protective effect. "In the whole investigated range, there were some seeds that could be of particular interest," said Ege, "belongs to except certain bacilli and staphylococci - such as the type Staphylococcus sciuri - including molds of the genus Eurotium . "The next challenge for scientists is Now, between the presence of microbes in house dust and the species-specific protection from asthma to examine the context - and so consideration among the candidates to find the seeds for long, for a potential vaccine in question come.

Spearheaded the study in addition to the scientists and researchers at the LMU Munich University, the Universities of Besancon (France), Marseille (France), Ulm, Basel (Switzerland), Utrecht (Netherlands) and Imperial College London (United Kingdom) were. The work was supported by the European Commission (GABRIEL and PARSIFAL study) and in the framework of the Collaborative Research Center SFB TR 22 funded by the German Research Foundation (DFG).

Publication:
"Exposure to Environmental Microorganisms and Childhood Asthma", Markus J. Ege et al New England Journal of Medicine online, 24 February 2011

Source: Technical University Munich