Bedding with Germs

Scientists are beginning to discover that “germs”, perceived generically as enemies of man, may indeed be our partners who keep us healthy. What has come as an astonishing finding is why healthy humans carry a load of 6 Kg of microbes in our body, and why they often fall ill when we try to reduce this load.

The human microbiome, as it is called, consists of the sum total of all small germs (bacteria, fungi, viruses) that are present in our body, with the largest numbers residing in our intestines and on the skin. There are around 100 trillion (1014) of these organisms in a single human body, a number several times larger than the stars in our universe. This figure amounts to10 times the number of all the cells of our body. With around 500 species already identified till date, microbes constitute atleast 90% of all the genes present in an individual. Despite these large numbers, the contribution of microbes to our body’s weight is around 10% due to their smaller size as compared to human cells.

Scientists are now beginning to study what these small creatures that nature has loaded our bodies with, might be doing to our health and lives. Much like the eight different common blood types, researchers announced last year the existence of at least three distinct human "enterotypes", or intestinal bacterial communities. Each genera is characterized by the predominance of one of the 3 types of germs Bacteroides,   Prevotellaor  or  Ruminococcus. And just as our driving licence and medical records carry our blood group, time may not be far when our medical records will mention our enterotypes and microbial flora.

Early warnings that our indiscriminate “killer appraoch” to germs was flawed has come in the discovery of a difficult germ called Clostridiun difficile that colonizes vacant spots created in the intestine due to killing of friendly flora by broad spectrum antibiotics. This germ produces a toxin that causes diarrhoea and produces ulcers in the intestine.It is becoming increasingly clear that a more prudent way to treat this condition may be to recolonize the gut with friendly bugs than try to use yet another antibiotic to kill the Clostridium germ.

These early observations have made doctors change their strategy to fortifying the healthy flora than resorting to indiscriminate killing of germs in which the friendly ones also get killed in cross fire. Studies show that babies who receive several courses of antibiotics often grow up to suffer from asthma and allergies, indicating that tampering with their flora early in life may result in serious consequences later on.

Our microbial flora has come under the spotlight to such an extent that scientists have launched called the Human Microbiome Project this year. The exercise is aimed at unravelling the nature and role of the friendly germs that we harbour. Curd or yogurt is loaded with healthful lactobacilli and a glass of lassi that grandma had suggested could be a perfect way to start the day.

As published in HT City ( Hindustan Times) dated 17th February, 2013.