Microbes and Us

Very often we hear parents, including my good friend, telling their children to throw away food that has been accidentally dropped on the floor/soil because it has been contaminated with microbes. Yes true, the microbes are present everywhere: in the air, water, the soil, surfaces and in all plants and animals including man. That on ingestion they can cause disease is well known. But millions of these minute creatures, invisible to the naked eye, live in symbiotic relations, mutualism or parasitism in the plants and animals including the human body. They do us little or no harm. Some do us good.

The microbes harbour in practically every part of our body. Collectively the microbes constitute the microbiome. They are found in a person’s gut, in his mouth, on his skin and in all the crevices and orifices present on the body’s surface. The type, role and number vary from location to location. The mouth, for example, harbours more microorganisms than there are people on the earth. The gut has trillions of microbes, and of different types at specific points in the alimentary canal.

The microbes in the gut manufacture vitamins and anti-inflammatory proteins, others help us digest our food, and a lot of carbohydrates would be indigestible if the digestive system were to rely on its own enzymes only. Resident bacteria on our skin produce secretions that serve as moisturiser, preventing cracks and invasion of pathogens. In the nostrils there is one very common micro organism called Staphyloccus, which is not harmful in general (benign) but can turn virulent particularly when it leaves its environment and causes pimples on the face and infection/sepsis in broken skins. There is another microbe, Helicobacter pylori, that causes stomach ulcers. The list is really very long…

We get a big load of the microbes at birth from our mother. The baby is contaminated by a bacterium, Lactobacillus johnsonii, during its passage out. This bacterium is helpful for the digestion of milk. We get the rest of our microbiota as we grow up. The association of the microbes and man is more an alignment of interests, the exchange/sharing of food and other materials, provision of shelter, protection, etc., built into a wonderful ecosystem. Neither party wishes the other harm but sometimes there is breakdown of the alignment in the system with varying consequences. When we take antibiotics much of the helpful microbes get caught in the line of fire and we end up with a disturbed gut microbiota and a loose motion. We destroy the microflora of the skin, nostrils, mouth by the use of powerful sanitizers/soaps and very often allow the opportunistic harmful bacteria to take over and cause infection.

We should appreciate the relevance and richness of the man’s microbial ecosystem. The microbiome seems to play a crucial role in the control of conditions like diabetes, cardiovascular ailments, asthma, obesity and other disease of nutrition. So let’s not consider all micro organisms as killers to be hunted down and eradicated before they spread. The relationship between our microbes and ourselves is fragile. It is viewed as a dynamic ecosystem that should be maintained in a healthy state.

Let’s not be paranoiac about the microbes. They also are God’s creatures and have a place on earth… be it our body.

• Published in print edition on 21 August 2015