Carbol-Fuchsin after ZIEHL-NEELSEN (cold Staining)

Ziehl-Neelsen carbolic fuchsin is a cold staining solution mainly used in microbiology. The solution consists of an aqueous base and contains fuchsin, phenol, ethanol, Cremophor A25 and is filtered through a rapid filter.

The application of this solution is in the identification of acid fast bacteria, especially mycobacteria such as Mycobacterium tuberculosis. The staining allows these bacteria to be distinguished from other non-acid-fast microorganisms in a sample.

The chemical mode of operation is based on the affinity of basic fuchsin for bacterial cell wall material, particularly the mycolic acids in acid-fast bacteria. Phenol and ethanol act as solvents that facilitate penetration of the dye into the cell wall. Cremophor A25 improves the wettability of the sample surface and enables uniform staining.

The special suitability of Ziehl-Neelsen carbolfuchsin lies in its ability to selectively stain acid-fast bacteria, facilitating the identification of mycobacteria and other acid-fast organisms in microbiological samples. The cold staining method offers the advantage of being less time-consuming than traditional hot staining while providing comparable sensitivity and specificity.