Differences between Anthrax bacilli and Anthracoid bacilli

S.N Anthrax Bacilli S.N Anthracoid Bacilli
1. All are non-motile. 1. Generally, are motile.
2. Presence of capsule. 2. Absence of capsule.
3. Growth occurs in long chain form. 3. Growth occurs in short chain form.
4. Medusa head colony in nutrient agar. 4. Medusa head colony absent.
5. Growth in penicillin agar is not found. 5. Usually growth in penicillin agar found.
6. Very weak or absence of hemolysis. 6. Well marked hemolysis usually.
7. Inverted fir tree growth and gelatin liquefaction is slow. 7. Gelatin liquefaction occurs rapidly.
8. In broth, turbidity is not noticed. 8. In broth, turbidity is noticed usually.
9. Gives negative salicin fermentation test. 9. Gives positive salicin fermentation test.
10. Growth at 450 C not found. 10. Growth usually found at 450 C.
11. Chloral hydrate inhibits the growth. 11. Chloral hydrate does not inhibit the growth.
12. Susceptible towards gamma phase. 12. No susceptibility found towards gamma phase.
13. Laboratory animals are affected i.e., pathogenic in nature. 13. Laboratory animals are not affected i.e., non-pathogenic.
14. Gives positive ascoli’s precipitin test. 14. Gives negative ascoli’s precipitin test.
15. Gives positive fluorescent antibody test with anthrax antiserum. 15. Gives negative fluorescent antibody test with anthrax antiserum.
16. Very weak lecithinase activity in egg yolk agar. 16. Marked lecithinase activity in egg yolk agar.
17. Spores are central and do not bulge out. 17. Spores are central, sub-terminal or terminal, may bulge out.

Differences between Anthrax bacilli and Anthracoid bacilli

Image source: microbiologynote

References: 

i) https://microbiologyinfo.com/difference-between-anthrax-bacilli-and-anthracoid-bacilli/

ii) http://ecoursesonline.iasri.res.in/mod/page/view.php?id=66763

Differences between Anthrax bacilli and Anthracoid bacilli