How does Antibiotic Resistance Develop?

As discussed in the other articles, there are various factors that can contribute towards antibiotic resistance. Methods such as antibiotic misuse and inappropriate antibiotic usage on livestock and agriculture can all speed up the process to inevitably make antibiotics worthless. As the use of antibiotic is wide spreading, the resistance is also spread at a cellular level.

Bacteria have the ability to become resistance due to genetic material that has been passed down by the previous generation, through a genetic mutation, or acquiring resistance from other bacteria.

Genetic mutations are quite rare (1 in 1 million), but one is all it needs to begin the spread. Genetic mutations usually occur in the plasmids of the bacterium. These mutations can provide protection to the bacterium such as chemicals that inactivate antibiotics, elimination of cell targets, and pumping mechanisms to expel antibiotics (P-gp transporter proteins).1

Acquiring resistance can result from transformation, transduction, and conjugation. Transformation is the act of a bacterium picking up free DNA (contains an antibiotic resistance gene) in the environment that is left from a dead bacterium. Transduction occurs when a bacteriophage invades different bacteria, indirectly transferring genetic material from one bacterium to another. Conjugation occurs when one bacterium directly transfers genetic material (including the antibiotic resistant gene) through a pili.2

Below is a simple diagram of how bacteria spread its resistance:

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 Below is a short video of the spread of antibiotic resistance:

Reference:

  1. General Background: About Antibiotic Resistance [Internet]. Emerald.tufts.edu. 2014 [cited 15 November 2016]. Available from: http://emerald.tufts.edu/med/apua/about_issue/about_antibioticres.shtml
  2. Holmes RJobling M. Medical Microbiology. 4th ed. Galveston: University of Texas Medical Branch at Galveston; 1996.
  3. Jane H. Antibiotic Resistance [Internet]. Glen Iris Medical Group. 2016 [cited 15 November 2016]. Available from: http://www.glenirismg.com.au/2016/06/antibiotic-resistance/
  4. Baym M, Lieberman T, Kelsic E, Chait R, Gross R, Kishony R. The Evolution of Bacteria on a “Mega-Plate” Petri Dish (Kishony Lab) [Internet]. 2016 [cited 15 November 2016]. Available from: https://www.youtube.com/watch?v=plVk4NVIUh8