Question

How does AM resistance arise in TB?

Answer 1

AM resistance in TB arises when patients do not adhere to the recommended treatment, allowing TB bacteria to develop resistance to drugs. This can result in the emergence of multidrug-resistant (MDR-TB) and extensively drug-resistant (XDR-TB) strains, which are more difficult to treat.

Step-by-step explanation:

Infections with Mycobacterium tuberculosis (TB) can lead to the development of antimicrobial (AM) resistance, which refers to the ability of TB bacteria to withstand the effects of drugs commonly used for treatment. AM resistance in TB typically arises when patients do not adhere to the recommended course of treatment.

especially in cases where the treatment is long-term, such as with TB. Nonadherence leads to the survival and multiplication of TB bacteria, allowing them to develop resistance to the drugs. This can result in the emergence of multidrug-resistant (MDR-TB) and extensively drug-resistant (XDR-TB) strains, which are more difficult to treat.

Answer 2

Acquired resistance to antituberculosis drugs, including aminoglycosides like amikacin and kanamycin, arises primarily due to genetic mutations in the bacterial genome of Mycobacterium tuberculosis, the causative agent of tuberculosis (TB). The development of resistance to aminoglycosides involves several mechanisms, including:

1. Target Modification: Aminoglycosides exert their antibacterial effects by binding to the 30S ribosomal subunit of bacteria, disrupting protein synthesis and leading to cell death. Resistance can arise when mutations occur in the genes encoding the ribosomal RNA or ribosomal proteins, altering the binding sites for aminoglycosides and reducing their effectiveness.

2. Drug Inactivation: Some bacteria have the ability to produce enzymes that chemically modify aminoglycoside drugs, rendering them inactive. This inactivation is often the result of the expression of specific resistance genes, such as aminoglycoside-modifying enzymes, which can be acquired through horizontal gene transfer.

3. Decreased Drug Uptake: Resistance to aminoglycosides can also arise due to reduced drug uptake by the bacterial cell. This can result from changes in the permeability of the bacterial cell wall or membrane, limiting the entry of the drug into the cell.

4. Efflux Pumps: Bacteria can develop resistance to aminoglycosides by increasing the expression of efflux pump systems, which actively remove the drug from the bacterial cell, reducing its intracellular concentration and thus its effectiveness.

It's important to note that the development of resistance to aminoglycosides and other antituberculosis drugs is a complex and multifactorial process. The emergence of resistance can also be influenced by factors such as patient noncompliance with treatment regimens, inadequate dosing, and substandard drug quality. To combat the spread of drug resistance in TB, it is essential to employ comprehensive strategies that include accurate diagnosis, appropriate treatment regimens, patient education, and public health measures to prevent the transmission of drug-resistant strains.