M. tuberculosis then known as the `` tubercle bacillus , '' was first described on March 24 , 1882 by Robert Koch , the bacterium is also known as Koch 's bacillus . M. tuberculosis , then known as the tubercle bacillus , was first described on 24 March 1882 by Robert Koch , who subsequently received the Nobel Prize in physiology or medicine for this discovery in 1905 ; the bacterium is also known as Koch 's bacillus .