Microbial Interaction

We may think of ourselves as a highly evolved species of conscious individuals, but we are all far less human than most of us appreciate. Scientists have long recognized that the bacterial cells inhabiting our skin and gut outnumber human cells by ten-to-one. Indeed, Princeton University scientists compared the approximately 30,000 human genes found in the average human to the more than 3 million bacterial genes inhabiting us, concluding that we are at most one percent human. We are only beginning to understand the sort of impact our bacterial companions have on our daily lives.

Moreover, these bacteria have been implicated in the development of neurological and behavioral disorders. For example, gut bacteria may have an influence on the body=s use of vitamin B6, which in turn has profound effects on the health of nerve and muscle cells. They modulate immune tolerance and, because of this, they may have an influence on autoimmune diseases, such as multiple sclerosis.

They have been shown to influence anxiety-elated behavior, although there is controversy regarding whether gut bacteria exacerbate or ameliorate stress related anxiety responses. In autism and other pervasive developmental disorders, there are reports that the specific bacterial species present in the gut are altered and that gastrointestinal problems exacerbate behavioral symptoms. A newly developed biochemical test for autism is based, in part, upon the end products of bacterial metabolism.

Regardless of how these intestinal guests exert their influence, these studies suggest that brain-directed behaviors, which influence the manner of interaction with the external world, may be deeply influenced by the relationship with the microbial organisms living in the gut. And the discovery that gut bacteria exert their influence on the brain may have important implications for developmental brain disorders.  Read more…



Normal Flora of the Skin

The mixture of organisms regularly found at any human anatomical site is referred to as the normal flora. Populations of microbes – such as bacteria and yeasts – inhabit the skin and mucus surfaces and are the body=s first lines of defense against illness and injury.

Their health depends upon the delicate balance between our own cells and the millions of bacteria and other one-celled microbes. Their role forms part of normal, healthy human physiology, however if microbe numbers grow beyond their typical ranges (often due to a compromised immune system) or if microbes populate atypical areas of the body (such as through poor hygiene or injury), disease can result.

It has been calculated that the surface of a human adult is covered with approximately 2 square meters of skin. The density and composition of the normal flora of the skin varies with anatomical locale. The high moisture content of the axilla, groin, and areas between the toes supports the activity and growth of relatively high densities of bacterial cells, but the density of bacterial populations at most other sites is fairly low, generally in the hundreds or thousands per square cm.

The greatest influence on bacterial populations appears to be body location. For example, the bacteria under our arms are likely more similar to those under another person=s arm than they are to the bacteria on any other part of the body. Most bacteria on the skin are sequestered in sweat glands and while sweat is essentially odorless some bacteria may consume it and create by products which result in body odor. In fact the vast colonies of microbes that live on us – bacterial, viral and fungal – are mostly harmless and necessary for our own good health.   Read more…



A Day Without Microbes

A world without bacteria may seem ideal at first. But the more we think about it, the more we realize that we cannot live without microbes.

There would be no food poisoning, no diarrhea, no coughs and colds, no sore throats, no tuberculosis, no cholera, no small pox, no polio, no sexually transmitted diseases. There would be no decay. Foods would not get spoiled and we would not need preservatives, refrigeration and wasteful packaging.

But if nothing decays, what happens to all the plants, animals and people at the end of their life-cycle? They would be preserved forever.

Microbes are essential to humans and the environment, as they participate in the Earth’s carbon and nitrogen cycles, as well as fulfilling a vital role in our digestive and immune systems.

Although each individual microbe is an almost weightless, one-celled organism, microbes account for most of the planet’s biomass – the total weight of all living things. With their collective strength, microbes control every ecological process, from the decay of dead plants and animals to the production of oxygen.

No part of Earth escapes the influence of microbes, the oldest living organism. Self-sufficient, invisible, mysterious, deadly – and absolutely essential for all life, they are the Earth’s bacteria. No form of life is more important and no form of life is more fascinating. No other living thing combines their elegant simplicity with their incredibly complex role – bacteria keep us alive, supply our food and regulate our biosphere. We cannot live a day without them, they are our partners, even though some of them, under the right conditions, will kill us.  Read more…


The importance of beneficial bacteria for a healthy baby

Doctors have long known that infants who are breast-fed contract fewer infections than those who are given formula. Humans are born extremely immature, with the major organs and immune system not fully developed. For its survival the infant depends on an extraordinary well-adapted evolutionary strategy shared by all mammals, breast-feeding. But what does milk contain that makes it so essential for the newborn and how does it provide immunity, nutrition and a source for optimal growth?

Human milk is a very complex living fluid which includes proteins, carbohydrates, lipids, cells and other biologically important components. These milk components interact with each other and their environment (the infants gut) with the final result being that breast-milk feeds and protects the newborn.

Most physicians presumed that breast-fed children fared better simply because milk supplied directly from the breast is free of bacteria. Yet even infants who receive sterilized formula suffer from more meningitis and infection in the gut, ear, respiratory tract and urinary tract. All newborns receive some coverage in advance of birth. During pregnancy the mother passes antibodies to her fetus through the placenta. These proteins and the added protection of breast-milk circulate in the infant’s blood for weeks to months after birth and because the mother makes antibodies to pathogens in her environment, the baby receives the protection it most needs against infectious agents it is most likely to encounter in the first few weeks of life.

It protects the infants against infection until they can protect themselves. Once foods other than breast-milk are introduced, the established microbes are ready to adapt and utilize the nutrients from a new source and should be able to maintain a healthy balance.

Given the importance of beneficial bacteria for a healthy baby it is essential that the mother’s health is ensured, preferably before pregnancy. A healthy mother is more likely to deliver a healthy baby.    Read more…