Which staining technique is commonly used to differentiate bacterial types?

Gram staining is a critical laboratory technique used to differentiate bacterial types based on the properties of their cell walls. The method involves applying a series of stains to bacterial samples, leading to a color change that indicates the presence of either a thick peptidoglycan layer or an outer membrane. Bacteria are classified as either Gram-positive, which will appear purple due to the retention of the crystal violet stain, or Gram-negative, which will take on a pink color from the counterstain, safranin. This differentiation is crucial for both identifying bacteria and determining appropriate treatments, as Gram-positive and Gram-negative bacteria often respond differently to antibiotics.

Other staining techniques serve different purposes; for example, the Schaeffer-Fulton stain is primarily used to identify bacterial spores, while acid-fast staining is specific for mycobacteria and relies on the lipid-rich cell wall structure of these bacteria. Simple staining provides a basic visualization of cell shape and arrangement without the differentiation of bacterial types. Thus, Gram staining stands out as the preferred method for distinguishing between different groups of bacteria based on their cell wall characteristics.