Question

In patients infected with nonresistant strains of the tuberculosis bacterium, antibiotics can relieve symptoms in a few weeks. However, it takes much longer to halt the infection, and patients may discontinue treatment while bacteria are still present. How might this result in the evolution of drug-resistant pathogens?

Answer 1

When patients infected with nonresistant strains of tuberculosis discontinue treatment before completing the full course, it can lead to the evolution of drug-resistant bacteria. This is because some bacteria may survive and develop resistance to the antibiotics.

Step-by-step explanation:

Patients infected with nonresistant strains of the tuberculosis bacterium may discontinue treatment once their symptoms are relieved, but before the planned course of treatment is complete. This can result in the evolution of drug-resistant pathogens. The reason for this is that when patients stop taking antibiotics prematurely, there is a higher chance that some bacteria may survive and develop resistance to the drugs. These drug-resistant bacteria can then continue to spread and cause infections that are more difficult to treat.

Answer 2

Infectious dose refers to the minimum number or amount of pathogens required in order to produce a disease or its symptoms. In the given case, the bacterium is non-resistant and is treated with antibiotics.

The antibiotics help in neutralizing the infectious agents; however, full course should be done to eliminate the infectious agent completely out of the body.

If the course is left in between then, there are very high chances that some bacteria may survive. They might not produce disease or symptoms as they would be less than infectious dose.

However, with time, the survived bacteria gain more and more mutations during replication which can develop antibiotic resistance capability in them.

In addition, it is also possible that the survived bacteria can get R-plasmid (which has antibiotic resistant gene) from body's normal flora or from any other infectious agent present in the body by the process of transformation or conjugation.

The R-plasmid enables them to survive even in the presence of antibiotics due to which the treatment of the disease might become difficult.