What is the mechanism of action of INH against bacteria?

The effectiveness of isoniazid (INH) against bacteria, particularly Mycobacterium tuberculosis, is primarily attributed to its ability to inhibit the synthesis of mycolic acids. Mycolic acids are essential components of the cell wall in mycobacteria; they play a crucial role in the bacterial structure and protect the cells from environmental factors and immune responses. By interfering with the enzymes responsible for the biosynthesis of mycolic acids, INH disrupts the integrity of the bacterial cell wall, ultimately leading to cell death.

This targeted mechanism makes INH particularly effective against mycobacterial species, which have unique cell wall properties compared to other bacterial groups. Understanding this action is fundamental in exploring treatments for tuberculosis, as it highlights the importance of mycolic acid in the viability of the bacteria.

The other options refer to different mechanisms that drugs may utilize, such as disrupting cell membranes, blocking protein synthesis, or altering DNA, but these are not the specific actions of INH. Each of these mechanisms involves different pathways or structures that are not relevant to INH's function against mycobacteria.