The bacteria we are interested are the ones that kill people and/or make people very sick. E. coli, Salmonella, Listeria, etc. You may have heard of a few of these. Suffice to say I know a lot about bacteria. How they live. How they make you sick. How they grow. What they like to eat. What they look like on a petri dish, and under a microscope. When you work with dangerous microorganisms safety is a high priority. Proper aseptic technique, appropriate personal protective equipment (PPE), and thorough disinfection/sterilization protocols are critical to keeping yourself and your labmates safe. One of the most important pieces of equipment in any microbiology lab is called an autoclave.
Basically it is a giant pressure cooker. It’s designed to reach high temperatures and pressures, enough to kill any microorganism that might be present on the materials that are placed into the machine for sterilization. When bacteria grow on petri dishes each of those round splotches (colonies they are called) actually consists of roughly one million to ten million (106 to 107 CFU) individual bacteria. CFU stands for colony forming unit. Each individual bacteria in the colony is genetically identical to every other (they are referred to as clonal because of this genetic similarity). One petri dish (plate) can have anywhere from one to more than a thousand colonies depending on how they were prepared.
The technique for isolating colonies on plates is learned by every first year microbiology student and forms the basis for many important classical culture based approaches for detecting, isolating, and characterizing bacteria. Multiply one thousand times ten million and you can begin to get a feel for the unbelievably massive numbers of bacteria that can be growing on a single petri dish. To put things in perspective the population of the planet earth is approximately 7.1 billion people. That is 7.1 x 109 people. A single petri dish might contain 1010 bacteria.
The entire population of the earth is an order of magnitude less than the bacterial population on a single plate. A typical microbiology lab might generate a few hundred to many thousand petri dishes per day. In a food pathogen lab like mine that represents a huge potential safety hazard especially since the infectious dose of many of the most common pathogens is as low as 1 CFU. This is where the autoclave comes in. All of those contaminated plates are loaded into specially designed bags and sterilized by treating in the autoclave. I have worked in microbiology labs for over 20 years now and have loaded countless bags of plates. I never gave it much thought until recently. Bacteria are living organisms. They are not intelligent in the conventional sense.
Certainly they don’t have a “soul” and cant experience emotions or feel pain. God I hope they cant feel pain. I have been responsible for the death of untold numbers of bacteria over the course of my career. I never once felt any regret, sorrow, or remorse. Last night all of my thinking changed. I was loading the autoclave as I had done innumerable times before.
As I transferred the bag from the cart into the loading bay I heard something coming from inside the bag. At first I thought I was hallucinating. It was late and it had been a long day. However as I began to slowly close the autoclave door I distinctly heard a scream come from the bag. I slammed the door shut hard and initiated the sterilization cycle. The scream was muffled by the workings of the machine but I could hear the pitch change as the heat and pressure began to build. The high pitched wailing went on for minutes as entire worlds worth of bacteria were destroyed. At some point the screaming stopped. I know I can never go back to my profession. Those screams sounded so human. May god forgive me for what I have done. May god forgive all of us.