Bacteria and Humans

Bacteria exist all around us, and have affected mankind since the beginning of time. Some have helped fuel revolutions in science, medicine, or food production. Others have caused the downfall of entire populations of people and the collapse of civilizations. Others still have become so prevalent in the lives of people that they have become inseparable from us.

Bacteria as Tools

Through observation and trial and error, people through the generations have identified several types of bacteria that, through various means, can be exploited to help enrich humanity. Their varied interactions, products, and fast doubling time have been used by people for thousands of years to great benefit. One of the oldest examples of humans exploiting bacteria is the use of microbes like Streptococcus thermophilus and Lactobacillus helveticus, which are used to turn milk into things like yogurt and cheese, along with microbes like Lactobacillus fermentus to make alcohol. Of course, the people of the time had no idea the microscopic help they were getting in this production, but they would be the unwitting start of humans utilizing microorganisms. More recent uses of bacteria would be things like the use of E. coli for protein production, Ideonella sakaiensis for plastic disposal, alongside various species like Streptomyces griseus for antibiotics.

I. sakaiensis eating plastic

Bacteria as Enemies

The most famous relationship between humans and bacteria is that of disease. Disease-causing bacteria are and have always been a major hazard to human health. One of the leading causes of death before the advent of antibiotics was infections caused by bacteria. Microbes like Mycobacteria tuberculosis and Streptococcus pyrogenes were constant and common threats to people for millennia. Yersinia pestis caused what is probably the most famous pandemic of all time, the Black Death, which killed more than 200 million people. Bacteria can make us sick, our animals sick, they can spoil food, and destroy crops. Careful management and oversight of these harmful pathogens has laid the foundation for the modern world, but it is a constant struggle.

Plague victims infected with Y. pestis

Bacteria as Friends

People, especially in the modern day, have an aversion to the idea of bacteria due to their disease-causing tendencies. However, no matter what one does, bacteria are unavoidable. In fact, they are in you right now and have been your entire life. Humans, and all other animals, have evolved to live in symbiosis with various species of microorganisms, including many species of bacteria. Helpful species like Bacteroides thetaiotaomicron and Lactobacillus acidophilus live in humans and help with things like development and digestion. The collection of these bacteria, along with other organisms, forms the human microbiome. It is often by killing or overcrowding these helpful bacteria that harmful bacteria cause disease. These species help especially to demonstrate mankind's strange, storied, and eclectic relationship to bacteria as a whole.