Leeuwenhoek had stolen and peeped into the fantastic sub-visible world of little things, creatures that had lived, had bred, had battled, had died, completely hidden from and unknown to all men from the beginning of time. Beasts these were of a kind that ravaged and annihilated whole races of men ten million times larger than they were themselves. Beings these were, more terrible than fire-spitting dragons or hydra-headed monsters. They were silent assassins that murdered babies in warm cradles and kings in sheltered places. It was this invisible, insignificant, but implacable-and sometimes friendly- world Leeuwenhoek had looked into for the first time of all men of all countries. ~Microbe Hunters

Monday, 15 April 2013

MacConkey Agar

M is for MacConkey Agar. It is also for Monday Mornings, Mildly exhausted from last night`s studying, and Might die today in finals.  I also dont know what I wrote here, so I apologize for any Mistakes.
Agar is a solid jell-o like substance that comes solidified conveniently in little dishes called petri dishes. In order to grow bacteria in the lab, we add ingredients to the base agar to make certain bacteria inhibited, or enrich the agar to make it easier for certain (fastidious) bacteria to grow, and add things like carbohydrates and indicators to be able to differentiate between what is growing on the plate. MacConkey agar is used to selectively isolate gram negative bacteria (i.e. E. coli or salmonella infections) from samples known to yield mixed specimens (i.e. stool samples in which the majority is bacteria).

If we find just one salmonella or E. coli infection in the lab, we have to report it to the Public Health Agency of Canada (PHAC). WHY? It’s not like we are having an outbreak… Well, if you think about it, you ate a McDonalds hamburger coming home from Gramma’s house. Then, you get sick and go to the closest hospital back home. Someone else eats a hamburger from the same McDonalds and they head home after their hockey tournament and go to the hospital closest to them. Someone else sticks it out at home. Someone else flew out to Alberta for the Calgary Stampede. Someone else goes to the hospital beside the McDonalds which gave them the food poisoning. All of a sudden, there is an outbreak of E. coli spread across Canada. The purpose of the PHAC is to track down where all these people ate and what they ate to prevent further spreading.

Some strains of E.coli (O:157 H:7) are what’s known as hemorrhagic  E.coli. This is what caused the Walkerton, Ontario outbreak where lots of people got very sick, and some died. (Summary of what happened in Walkerton: raw sewage contaminated drinking water because a valve was broken in a treatment plant). The sad thing about E.coli infections are that you cannot kill the infection with antibiotics and get rid of the damage. The toxins produced by this bacteria cause ulceration in the intestines. Once you have the ulceration, or bleeding sores, in the large intestine, they don’t go away and people have to live with the infection all their lives. If you try and treat it with antibiotics, the E.coli will just release more toxins causing even more damage. A new innovation, that sounds disgusting, is having a fecal transplant. Yep, they take someone else’s poop (usually familial cross generations with the same gender i.e. mother-daughter, father-son) and shove it up there. Remember that poop mainly consists of bacteria which is healthy and actually helps to aid in digestion and normal body regulatory systems. By adding some healthy bacteria back to your system, they hope to restore a more normal atmosphere in your intestines for health and digestion. They also do this regularly for the nosocomial (hospital acquired) infection of C. difficile.  

E.coli is the cause of the infection known as Traveller’s Diarrhea. The tropical places we travel to do not have proper treatment plants and often have fecal (E.coli) contamination in their drinking water. To get sick, you would have to ingest a lot of the bacteria. This can be prevented with a simple vaccination or relying on bottled water. Eating a few of the fruits and vegetables washed in contaminated water should not get you sick because the high number of organisms required to make you sick. Especially if you spray them with Lysol before eating them. Kidding, don’t do that. I also don’t know the effects that pina colada has on the action of bacteria, but I like to say that alcohol disinfects :p 

Darn good and sure of it,



  1. This was fascinating. I had no idea that treating E. coli with antibiotics causes it to release more toxins. Neither had I heard of the healthy poo treatment. Kind of gross, but hey, whatever works, right?

    Hope you kick butt in finals.

    1. Thanks so much! And I'm glad you learned something :)

  2. Just catching up on reading posts. Your posts are informative, on the topic of Medical Laboratory. E-Coli is the reason I cannot eat red meat today. Many years ago my job sent me to food handling classes because someone on my shift needed the food handling card and I drew the short straw. E-Coli took up three days of classes. After those classes and learning how food can kill us, if I didn't grow it myself, I didn't eat it.

    1. Thanks!!
      Food-borne illnesses are scary!! As long as you handle preparation and cooking properly, it really limits the number of ill people. It's amazing how many cross-contamination and insufficiently cooked foods have made people sick, especially with the Maple Leaf incidents!