Bacteria, single-celled microorganisms invisible to the naked eye, exist in an astonishing number of environment types. Bacteria can flourish in water, in organic matter like rotting leaf litter and fallen trees and dead animals, in hot springs, in caves, and even inside the bodies of living animals, including humans. Because they’re so tiny we can’t see them without a microscope, we rarely think of bacteria existing except as the vague concept of disease-causing germs. But the world of bacteria is vast and hugely populated, and they’re everywhere, outnumbering all the other multicellular organisms on earth. In that sense, bacteria are quite common.
Some bacteria are incredibly useful in bio-research and the development of medications and vaccines. Other bacteria have more humble-seeming uses, like helping to manage septic systems and cleaning up oil spills, or making yogurt and cheese and wine. Bacteria within the human body can benefit the body, depending on the types of bacteria they are. Some bacteria help train the immune system and help prevent allergies. Others protect the body from harmful disease-causing bacteria. Bacteria are responsible for helping us digest our food, and some produce enzymes, hormones, and vitamins that are very useful for the human body.
But many bacteria live up to their reputation as disease-causing germs. It is many of these bacteria that are well-known to us, as we have grown familiar with the names of these harmful bacteria. Some common bacteria include Heliobacter pylori, the bacteria known to contribute to stomach ulcers, gastritis, and sometimes even stomach cancer. Staph and strep are two more common bacteria known to cause a host of diseases including meningitis, pneumonia, skin maladies, and sore throats and fever. Typhus is caused by a bacterium, as is Rocky Mountain Spotted Fever. Tetanus, tuberculosis, and leprosy can all be attributed to bacteria, too.
One of the most famous, if not a particularly common bacterium, is Yersinia pestis. Y. pestis is the rod-shaped bacteria infamous for causing bubonic plagues, including the Black Death of 1300s in Europe. Y. pestis has not been eradicated, and there are still outbreaks of bubonic plague, but nothing on the par of the plague that killed half the European population.
Because there is such a vast number of bacteria, and because we can’t see them and know relatively little about them, the world of bacteria is mysterious to us, and often unconsidered by the general population. But their vast numbers make them more common on earth than we are. We will always live our lives in parallel to the equally impressive world of bacteria.