Bacteria are supposed to be the first life forms to appear on the face of the earth, and will surely survive any severe form of natural calamities or even a nuclear holocaust. Bacteria are our earliest ancestors, and it has been found that around one-third of our 20,000 genes are bacterial in origin. Bacteria has also played a significant part in the evolutionary process, apart from contributing to our genome. It is now widely accepted that the evolution of mammals were actually a process of interaction between the particular species, its environment and bacterial partners. This kind of co-evolution is supposed to form the basis of many essential bodily functions of humans, including digestion and maintenance of body temperature.
Bacteria and other microorganisms are also useful in our daily lives, and many of our domestic and industrial processes are dependent on it. Bacteria play a vital role in the fermentation process of foods like curd and yoghurt. Nitrogen fixation is a unique ability of certain leguminous plants and they convert atmospheric nitrogen to ammonia, which can be utilized by other plants to make nitrogenous substances like proteins. Bacteria living on the roots of these plants play the most important role in biological nitrogen fixation, which finally increases the nutritive value of the soil. Bacterial action is also important in production of several industrial enzymes and pigments, apart from the production of biofuels. Bacteria are also important in degradation of plant and animal waste (including dead animals); and ensures that our surroundings are kept relatively clean. It is now observed that certain bacteria has the potential to degrade environmental pollutants like petroleum products and plastics. The role of bacteria in modern sewage treatment plants also needs to be highlighted here, as the presence of these microbes are quintessential in completion of the process. Bacteria is now used extensively in the production of several medicines (eg. Insulin for treatment of Diabetes) through recombinant DNA technology. In this, human genes are inserted into the bacterial genome and the microorganism is forced to produce the protein encoded by the human gene.
All of these examples shows that most bacteria are either harmless or essential for human existence. We are related or dependent on these small creatures, in more ways that we can think of. Only a very small proportion of bacteria are disease-causing, and result in harm for the human body. Even among the disease-causing bacteria, most of them do not cause harm if the immunity status of human body is not compromised. Therefore, it is time we recognised that bacteria is not always our enemy, and adopt a rational approach in understanding these tiny creatures.