When the villain starts resisting the hero
We often hear doctors remark that consumption of too many antibiotics is bad. Rather than fighting the pathogens they’re supposed to ward off, the infection causing bacteria develop immunity against the antibiotics. This might take weeks, months or years, but ‘antibiotic resistance’ is a serious issue for consumers, doctors and pharmacists alike.
Consider a scenario wherein a person gets affected by the viral infection frequently. He/she might consume antibiotics as a precautionary measure, the most common being Azithromycin. Over a period of time, the same infection recurs in the person and the patient consumes the antibiotic regularly. Gradually, the pathogens responsible for the infection become immune to the effects of the medicine. Further consumption of the antibiotic particular to this pathogen fails to ward it off, leaving the body unable to function properly for days. It is important to note that pathogens generally become immune only to those antibiotics which are consumed regularly. We explore the causes for the same in this post.
To understand the reason for the failure of antibiotics, it is important to understand what makes them effective in the first place. Antibiotics stop or interfere with a number of everyday cellular processes that bacteria rely on for growth and survival, such as crippling production of the bacterial cell wall that protects the cell from the external environment, interfering with protein synthesis by binding to the machinery that builds proteins and wreaking havoc with metabolic processes, such as the synthesis of folic acid, a type of Vitamin B that bacteria need to thrive. Synthesis of DNA and RNA is also blocked. Then how do they fail?
1. Preventing the antibiotics from reaching their targets
Over a period of time, bacteria come up with various ways to counter the effects of antibiotics. It starts with preventing the antibiotic from reaching its target. Bacteria change the permeability of their membranes and reduce the number of channels available for drugs to diffuse through. Some bacteria even use the energy from ATP, a compound used for energy transfers within the body, to power pumps that shoot antibiotics out of the cell.
2. Changing the target
Many antibiotics work by sticking to their target and preventing it from interacting with other molecules inside the cell. Some bacteria respond by changing the structure of the target (or even replacing it within another molecule altogether) so that the antibiotic can no longer recognize it or bind to it. Since antibiotics are target specific in nature, they fail to act if they cannot find the bacteria they were meant to fight.
3. Destroying the antibiotic
This tactic takes interfering with the antibiotic to an extreme. Rather than simply pushing the drug aside or setting up molecular blockades, some bacteria survive by neutralizing their enemy directly. For example, some kinds of bacteria produce enzymes called beta-lactamases that chew up penicillin. An infected person might be under the misconception that he/she is consuming the antibiotic required to fight the infection, while the antibiotic might have been destroyed in the body.
The next question that comes to the mind is how the bacteria acquire these drug-fighting capabilities. How do bacteria pick up these drug-fighting habits? In some cases, they don’t. Some bacteria are simply making use of their own inherent capabilities, their instincts. However, some bacteria acquire resistance by getting a copy of a gene encoding an altered protein or an enzyme like beta lactamase from other bacteria, even from those of a different species.
Unfortunately, if a bacterium gets a resistance gene stuck into its chromosomal DNA or picks one up in a free-floating plasmid, all of its progeny will inherit the gene and the resistance it confers. Bacteria with these genes survive and outgrow susceptible variants.
- Humans are responsible for this problem to quite an extent. We tend to stop the prescribed dose of medication once symptoms of an infection recede. This is one of the most common ways for bacteria to develop resistance towards antibiotics. It is very important to complete the course of medication irrespective of the symptoms receding or not.
- While bacteria are responsible for many infections, it is important to understand that our body also has many useful bacteria. Consuming antibiotics for every minor cold or cough affects these bacteria too, harming the body in various ways. It is extremely important to consult your doctor before consuming antibiotics.
- Also, not every antibiotic will work for every infection. Your doctor prescribes a specific drug for you based on what kind of infection you have. He or she also selects a specific dose and length for your treatment.
Antibiotic resistance is a relatively new thing because antibiotic themselves are relatively new. it is important to understand the underlying causes of this resistance and try to curb it. Humans are, to quite an extent, responsible for antibiotic resistance, and it is up to us to ensure that it doesn’t stay that way. Antibiotics are among the most useful drugs available, but abusing them will only be detrimental for us. The discovery of antibiotics has proven to be a great leap ahead in the field of medical research, and considering their ability to fight infections, one can’t help but recall a famous dialogue from Spiderman, “with great power comes great responsibility.”