acid-fast

American  

[as-id-fast, -fahst] / ˈæs ɪdˌfæst, -ˌfɑst /

adjective

1. resistant to decolorizing by acidified alcohol after staining.

---

acid-fast British  

adjective

1. (of bacteria and tissues) resistant to decolorization by mineral acids after staining

---

Other Word Forms

• acid-fastness noun

Etymology

Origin of acid-fast

First recorded in 1900–05

Example Sentences

The tubercle bacillus does not stain easily, but when it does, it clings tenaciously to the dye, in spite of immersion in alcohol and strong acids, and for this reason is called " acid-fast."

From Time Magazine Archive

But the acid-fast germs are encased in or contain fatty cells called " lipoids," which resist digestion when injected into the body and thus generate no antibodies.

From Time Magazine Archive

This method is supposed to differentiate between B. tuberculosis and other acid-fast micro-organisms.

From The Elements of Bacteriological Technique A Laboratory Guide for Medical, Dental, and Technical Students. Second Edition Rewritten and Enlarged. by Eyre, J. W. H. (John William Henry)

Chronic bacterial dysentery is a chronic infectious disease of bovines caused by an acid-fast bacillus simulating the tubercle bacillus and characterized by marked diarrhea, anemia, and emaciation, terminating in death.

From Special Report on Diseases of Cattle by United States. Bureau of Animal Industry

It belongs to that small group known as acid-fast bacteria.

From Common Diseases of Farm Animals by Craig, R. A., D. V. M.