Guest Blogger: Michelle Osten, VMS Undergrad
The most excruciating stomach cramps woke me last night. They grew progressively worse throughout the day, and now it’s seven at night on Easter Sunday. I lie in the Emergency Room with an IV drip of morphine; I had a panic attack when the nurse inserted the needle into my vein, but I’m starting to get over that. Mom sits in the corner, giving me her concerned-mom looks. I am feeling closer and closer to death, and I have a sneaking suspicion I know what is making me sick.
Whether it’s through a lab mishap or eating undercooked beef, becoming infected with pathogenic (disease-causing) E. coli is brutal. When E. coli infects a person, it attaches to the intestinal wall and the infection begins. There is a particular set of proteins that E. coli makes that allow the bacterium to be incredibly successful at infection. These structures, called the Type III secretion system, look and act like tiny syringes. They essentially “inject” their own DNA and proteins into the host’s cells. Not only do E. coli use Type III secretion to wreak havoc on the host, but they also can release a chemical called Shiga toxin. This toxin can enter cells, disrupt host protein synthesis, and even burst the intestinal cells. A build up of this toxin is extremely detrimental to the host. Although E. coli infections are relatively uncommon, they are serious business and can’t be taken lightly.
Now, I don’t want you to think all E. coli are bad guys. Most E. coli are an integral part of our lives and without them, we wouldn’t function. We, as healthy humans, harbor thousands of (non-pathogenic) E. coli bacteria and benefit from their metabolic processes. These bacteria live in our guts and contribute to the digestion of our foods. Not only that, but E. coli serves as our primary source of vitamin K, which plays a crucial role in the coagulation of blood. When you get cut, vitamin K helps to form an external clot to stop the blood flow thereby protecting you from severe blood loss. The E. coli in our guts produce this essential vitamin as a byproduct of their metabolism. These little guys are doing us a favor and they don’t even know it!
E. coli is also irreplaceable in a laboratory setting. We use these bacteria to study gene expression, mechanisms of bacterial infection, and as tiny lab rats to make antibiotics. The useful applications for E. coli are limitless and essential for our wellbeing and our advances in science.
I may not have been thinking about the amazing things E. coli can do for us while I lay in that hospital bed, but now I can appreciate the value it has biologically and scientifically. E. coli is not something to be afraid of, but it is a microbe we should get to know and understand.
This entry is part of the MICR 354 (Scientific Writing) student-blog series.