Role Of Viruses, Bacteria And Fungi In Our Health


Were you aware that your body houses trillions of microorganisms? And do you know that these microorganisms have a role not only in making you sick but also in keeping you healthy?

These flourishing communities of microorganisms inside our bodies - viruses, bacteria and fungi - constitute our micro-biome, which is the latest field of medical research with potential of unfolding secrets that could be of crucial importance to our health and the way we treat several complex diseases.

Recently, the Canadian Institute of Health Research, the country's premier scientific funding agency, along with several other partners, announced seven projects with a total investment of $16 million, to find out what role these microorganisms play in many important diseases and how they can be harnessed to our advantage.

We are now beginning to realize the many possibilities of linkage, that we hadn't suspected before, between our micro-biome and several diseases, especially complex ones, according to Dr. Marc Ouellette, scientific director, Institute of Infection and Immunity (CIHR).

This is a crucial emerging field in which we think we can make many new discoveries with a direct impact on our health, he said.

David Guttman of the University of Toronto is one of the researchers who have received a five year grant. His team is examining how the micro-biome of people with cystic fibrosis changes with the progress of the disease.

Cystic fibrosis is the most common, genetic diseases that affect Canadian children as well as young adults. It is a multi organ disease primarily affecting lungs and the digestive system that remains incurable to date and often leads to death.

The main problem in cystic fibrosis is the thick mucus layer that is formed in the patient's respiratory tract, said Guttman. It is not just a cause of breathing problem; it also provides a congenial environment for the growth of microbial communities.

CF patients very often, almost always, suffer from a large number of bacterial and fungal infections, said he. But what is the role played by these bacteria or fungi in the disease? Do they actually cause its exacerbation?

Guttman hopes that we will have an answer to this question once we are able to do genetic sequencing of the large number of microorganisms found in the respiratory tract as well as lungs of the CF patients, although he concedes that it will take years.

Guttman is part of another micro-biome project funded by the CIHR - a multicentre project with Anita Kozyrskyj, a University of Alberta epidemiologist, as the co-director.

The cross-Canadian project team suspects that antibiotics given to infants in the first year of their life may be a latent factor triggering asthma and allergies later in the childhood.

We all have microbiota, a "good" intestinal bacteria that help us absorb nutrients as well as protect us against harmful bacteria. However, antibiotics affect microbiota, and by the time they are one year old, more than 50% Canadian children have had an antibiotic.

A pilot study by Kozyrskyj shows that antibiotics given to infants up to three months of age affect their microbiota and cause definite changes in them.

The bacteria in the intestines of these children are less diversified, said she in a release. The question now is: Is it the use of antibiotics used early in life that reduces the types of microbiota in these children's intestines? And do these changes have anything to do with their developing asthma and allergies later in childhood? Specifically, we hope to pinpoint the "bad" bacteria that cause asthma."

Dr. Deborah Money of Women's Health Research Institute, Vancouver, is conducting a study that would examine vaginal microorganisms to find out a healthy bacterial balance for women that would protect them against sexually transmitted diseases and prevent pregnancy loss as well as premature birth.

Her team is using advanced technology to sequence, relatively rapidly, hundreds of thousands of bacterial species.

The novelty in this approach is that it is not a single bacteria, taken in isolation, that is being examined, said Money in a release. It is whole communities of bacteria we are looking at and trying to find out their patterns of interaction with each other. These patterns are crucial pointers to the process whereby a woman maintains her reproductive health, and would help in identifying the conditions in which it is adversely affected.

Dr. Ken Croitoru, a Mount Sinai Hospital gastroenterologist, in Toronto, has received a grant of $2.5 million to prepare DNA sequencing of the microorganisms inhabiting digestive system that might be playing a role in causing inflammatory bowel disease.

His research will consist of extracting different microorganisms of the intestines from biological samples collected from about 1,500 people who are at high risk of Crohn's disease, and then sequencing their genomes. Crohn's disease, which has a strong genetic basis, causes chronic inflammation of the gastrointestinal tract.

The idea behind the project is not to identify the bacteria inhabiting the intestines that cause the disease, but that possibly our body and genetic makeup allow certain types of bacteria, which may be good or bad, to interact and influence the development of such conditions as Crohn's disease, said Croitoru in an interview.

For instance, if you don't have one gene, do you get a different type of bacteria to make you more susceptible to the disease? Maybe, it's not a bad bacteria but one of a collection that usually are good. However, in the person lacking a gene, these good bacteria may be behaving badly, said he.

The goal of the project, according to him, is to identify the cause of Crohn's disease, ulcerative colitis and other inflammatory bowel diseases that may have something to do with the patient's micro-biome, in order to develop a preventive therapy or find a cure.

This is the necessary first step that would lead doctors to radically change the way they treat patients with inflammatory bowel disease as well as so many other complex diseases.