Antibiotic Resistance

In today's blog, we will try to answer the question on antibiotics resistance, and with it, we will also be discussing combination therapy and its related complications.

So, what is resistance?

According to WHO drug resistance is a state of insensitivity and it refers to the unresponsiveness of microorganisms to an Antibiotic.

Now, the question is when does a microbe become resistant?

Antibiotic resistance happens when the microbes no longer react to the antibiotics. They continuously grow by developing an ability to defeat the drugs built to kill them.

Have you ever wondered why? causes of resistance

Some organisms are inherently resistant to antibiotics. However microbial species that are generally responsive to a specific drug may develop more virulent or resistant strains through spontaneous mutation or acquired resistance and selection. Some of these strains may even evolve resistant to more than one antibiotic.

The different mechanisms by which microorganisms may exhibit resistance to drugs are:

• Acquisition of resistance by a single step or multiple-step mutation.
• Changes the permeability to the drug and enhances efflux pump mechanism.
• Production of enzymes that destroy the active drug.
• Development of an alternative structure target for the drug.
• Development of an altered metabolic pathway that bypasses the reaction inhibited by the drug.
• Altered expression of the protein in drug - resistance organisms.

But why is antibiotic resistance a problem?

Infection caused by antibiotic -resistance microbes are difficult and sometimes impossible to treat and increases the risk of disease spread, severe illness, and death.

Finally, Can we prevent antibiotic resistance?

Some methods have been developed to reduce antibiotic resistance such as:-

• Using antibiotics as directed and only when necessary.

• Another strategy developed is the chemical modification of antibiotics and the use of antibiotics in combinations.

Combination therapy

It is therapeutically advisable to treat patients with a single agent that is most specific to the infecting organisms and minimize toxicity. However, some condition requires a combination of antimicrobial drugs i.e. specific combinations of antibiotics, show synergism; that is, the combination is more beneficial than either of the drugs used individually.

• The advantages of using a combination are:
• Treatment of mixed bacterial infections;
• To prevent the development of resistant microorganisms.
• If the infection is severe, a combination is used to enhance the antibacterial activity at lower doses.

The disadvantages are:

• Risk of toxicity
• Antagonism: Several antibiotics act only when organisms are multiplying. Thus, co-administration of an agent that causes bacteriostatic plus a second agent that is bactericidal may result in the first drug interfering with the actions of the second.
• Erroneous dosage
• High cost

Complications of antibiotic therapy

Even though antibiotics are selectively toxic to an invading organism, it doesn't protect the host against adverse effects. The problem that arises with the use of antibiotics are:

• Superinfection

• Toxicity

• Hypersensitivity

• Post antibiotic Effect: prolonged use of some antimicrobials which alter the intestinal flora may lead to vitamin deficiency such as vitamin B Complex and vitamin K.

This blog is in continuation with the principles of Antibiotics-I, do check it out for complete classification and brief notes on the pharmacokinetics and pharmacodynamics aspects of antibiotics. You may also look into the world of penicillin for more insight. Don't forget to subscribe to a2zpharmasci.blogspot.com for more updates.