In this thread we will be dealing with the subject of how antibiotic resistance appears in bacteria in a specific experimental setup. What I would like to do is have the community come up with hypotheses at each step, and possible ways of testing those hypotheses with experiments. IOW, how can we apply the scientific method as it relates to the emergence of antibiotic resistance. Many of you are already familiar with this subject, so don't give away the punch line too early.
We start with a simple observation in a laboratory setting. I have a standard strain of E. coli that I streak on a plate to get an isolated colony. This is a standard technique that spreads out bacteria so that a single bacterium gives rise to several hundred thousand bacteria. This allows us to start our experiment with a single, founding bacterium that is the single ancestor of the rest of the bacteria used in the experiment. This is an important part of the experiment, so don't forget it.
We use this isolated colony to seed a liquid culture which produces trillions of bacteria from the hundreds of thousands found in the original colony that was itself founded by a single bacterium. We then spread some of that liquid culture onto two agar plates, one containing an antibiotic and the other one without antibiotic. We incubate it overnight and come back the next day to find a handful of colonies growing on the antibiotic plate, each of which was founded by a single bacterium. We compare this antibiotic plate to another that does not contain antibiotic and we find that the no antibiotic plate is overrun with bacteria without any isolated colonies. Obviously, only a handful of the billions of bacteria put on the antibiotic plate were antibiotic resistant.
So how did this antibiotic resistance come about? What are your hypotheses?
Suggested Forums: "Is It Science?" or "Biological Evolution"
Edited by Taq, : No reason given.
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