What distinguishes the Fite-Faraco acid-fast stain from other acid-fast stains?

The Fite-Faraco acid-fast stain is characterized by its use of hematoxylin as a counterstain instead of the more common counterstains employed in other acid-fast staining techniques, such as methylene blue or safranin. This specific choice of counterstain contributes to the distinctive appearance of acid-fast bacilli under microscopy, as hematoxylin provides a contrasting background that enhances the visualization of the stained organisms.

The use of carbol fuchsin in the primary staining process is consistent with acid-fast staining principles, as it binds to the lipid-rich cell walls of acid-fast organisms. However, the key distinguishing feature of the Fite-Faraco technique lies in the counterstaining step, where hematoxylin plays a crucial role. This method is particularly useful in isolating mycobacteria, especially in tissue samples where clarity is essential for diagnostic purposes.

In other options, alternative counterstains like methylene blue, safranin, and malachite green are not utilized in this specific method, making them less relevant when discussing the uniqueness of the Fite-Faraco stain. The option regarding India ink also does not apply, as this would not conform to the established techniques used for acid-fast