Definition

1. Adjective:
   • Resistant to decolorization by acids: Describes a property of certain bacteria and other microorganisms that, once stained, retain the dye even when washed with an acid-alcohol solution. This characteristic is crucial for identification in laboratory diagnostics.
   • Pertaining to specific microorganisms: Primarily associated with bacteria of the genus Mycobacterium, such as Mycobacterium tuberculosis (the causative agent of tuberculosis) and Mycobacterium leprae (the causative agent of leprosy).

Usage Examples

• Adjective:
  • The laboratory report confirmed the presence of acid-fast bacilli in the sputum sample, suggesting tuberculosis.
  • A Ziehl-Neelsen stain is a common technique used to identify acid-fast organisms under the microscope.

Advanced Usage

• "Acid-fast stain": A specific laboratory staining procedure used to differentiate acid-fast bacteria from non-acid-fast bacteria.
  • The microbiologist performed an acid-fast stain to rule out a mycobacterial infection.
• "Acid-fastness" (noun): The quality or property of being acid-fast.
  • The acid-fastness of the bacterium is due to the high lipid content of its cell wall.

Variants and Related Words

• Non-acid-fast (adj): Easily decolorized by acid-alcohol solutions; describes most bacteria that do not belong to the genus.
  • In contrast to tubercle bacilli, common staphylococci are non-acid-fast.

Synonyms

• Acid-resistant: Having the ability to withstand the effects of acid (often used in a broader chemical context, but can relate to staining in microbiology).

Related Phrases

• Acid-fast bacilli (AFB): A standard medical term for the rod-shaped bacteria detected by acid-fast staining, typically referring to mycobacteria.
  • The patient was started on treatment after the smear was positive for acid-fast bacilli.

Adjective

1. not easily decolorized by acid solutions; pertains to micro-organisms (especially the tubercle bacillus that causes tuberculosis)