Germs and Bacteria

Children are taught to fear germs, and as a result, many people grow up with a poor understanding of microorganisms.  Most people do not realize that most microscopic organisms are not pathogenic and that they are an important part of the food chain.  Without so-called “good bacteria”, there would be no such thing as yogurt or cheese.

What Is a Germ?

The word “germ” is not a scientific term.  It was originally used in the seventeenth century, when microscopes were invented, to refer to any organism so small that you can only see them under a microscope.  In the vernacular, people use the word “germs” to refer to pathogens; a pathogen is any kind of microorganism that causes disease.  Pathogens include bacteria, viruses, fungi, and protists.

What Are Bacteria?

Bacteria are single-celled, prokaryotic organisms.  A prokaryotic organism is one that does not have a cell nucleus.  This means that bacteria are much simpler life forms that plants, animals, and even protozoa like amoebas.  The oldest fossils of living things are of bacteria.

Some of the most common bacterial illnesses in the United States are caused by E. coli, which causes digestive illnesses, streptococci, which cause fever and sore throat in uncomplicated cases, pneumococci, which cause respiratory infections, and staphylococci, which cause skin infections.  The treatment for bacterial infections almost always takes the form of antibiotics.  Antibiotics are drugs that kill bacteria.  Because of antibiotics, almost all bacterial infections are curable, whereas they were a leadig cause of death in previous centuries.  While killing off the bacteria that cause the infection is good, bacteria in the body are actually necessary to counterbalance the yeast in the body.  People who take long courses or high doses of antibiotics often suffer from digestive upset as a side effect of the antibiotics because the antibiotics have killed a lot of the good bacteria in the intestines, in addition to killing the pathogenic bacteria.

Bacteria that are beneficial to human health are called probiotics.  At any moment, there are billions of good bacteria in your intestines, helping you digest.  These bacteria belong to the genera Lactobacillus, among others.  Eating foods like yogurt that contain large amounts of these good bacteria can help with digestive health and immunity against some diseases.  Doctors often recommend that patients who must take antibiotics to treat infections also take probiotic supplements to restore the good bacteria in their digestive systems.