Watch: How do bacteria develop drug resistance?

Ever wondered how a drug resistant bacteria is formed. Harvard Medical School recently put up a video showing how the microorganisms multiply

Like all living organisms, bacteria evolve over a period of time. However, given that they are less complex than mammals, they evolve and multiply faster. These microorganisms usually have a lag period in which they adapt to the environment they are in. Following this, they multiply exponentially before they go into a lag phase again. 

In the experiment conducted by Harvard Medical School, a gigantic petri dish measuring 4 feet x 2 feet was taken. The team then divided this dish into nine bands. Nutrient agar was added to the base of these bands, along with different concentrations of an antibiotic. The outermost zones had no antibiotic, the second and the eighth zones had barely any antibiotic for the survival of E coli, the bacterium used in the experiment to survive. The third and seventh zones had 10 times the concentration for E coli to survive, the fourth and the sixth zones had 100 times the concentration of antibiotic. The middle zone had the highest concentration of antibiotic i.e. 1,000 times the concentration of what E coli could survive in.

When the bacteria began to multiply, it took some time before it grew in the zone with 10 times the concentration. In 11 days since the experiment was conducted, the bacteria had even managed to multiply in the centre of the petri dish. 

The experiment shows that despite medical advancements, there will always be drug-resistant bacteria, and this is the biggest challenge faced by the pharmaceutical industry while developing medicines for diseases like tuberculosis, given the number of drug-resistant TB cases today