The statement that all bacteria are pathogenic and harmful is not true. Nature contains several bacterial species that are essential for sustained growth of an ecosystem. The human body contains approximately ten times more number of bacterial cells than human cells.

Uses of bacteria in human health:
i. Helicobacter pylori have been shown to be colonized the human gut approximately 0.1 million years ago and coevolved along with the human digestive system. Even though it has been implicated in gastritis and stomach cancer, several scientific reports show that it plays a protective role against asthma, GERD, and esophageal disease. Satiety signals are triggered by H. pylori helping to avoid overeating. Approximately 50% of the world population are colonized by H. pylori, but most of them do not show disease symptoms. The deleterious effects are shown only when there is a microbial imbalance in the gut which leads to the overgrowth of H. pylori.
ii. Lactobacillus acidophilus resides in the intestine. It produces lactic acid which helps in the digestion process. It also produces hydrogen peroxide which inhibits the growth of other harmful bacteria.
iii. Escherichia coli is responsible for the biosynthesis of vitamin K. Vitamin K is essential for blood clotting and sexual competence.

Uses of bacteria in the ecosystem:
i. Nitrogen fixing bacteria are the only source of fixing atmospheric nitrogen into biologically available form to other organisms.
ii. Sulfur metabolizing bacteria can reduce the harmful effects of sulfur on the ecosystem by metabolizing it.
iii. Several decomposing bacteria (Ex: Methanogenic bacteria) grow on organic waste and decompose them and recycle the nutrients into the ecosystem. They are essential in the recycling of nutrients.

Considering the immense importance of bacteria in human health and ecosystem maintenance, the war on bacteria would be a bad idea. Instead, the war on bad bacteria should be implemented

1. If you were to run this experiment using plates with a lawn of S...