Concept:

• Acid-fast bacillus refers to the bacteria with the property of acid fastness. Acid fastness refers to the property to resist decolorization during staining procedures. The most common bacteria with acid fastness is Genus Mycobacterium. 
• Mycobacterium tuberculosis shows the strongest property. 
• Mycobacterium leprae has the weak property of acid fastness. M. leprae causes leprosy.
• They are hydrophobic and impermeable to stain such as gram stain. 

Explanation:

• Bacillus pertussis belongs to the genus Bordetella, which causes whooping cough. It releases Pertussis toxin. It has hemagglutinating activity.
• Corynebacterium diphtheria is a pathogenic bacteria that can cause diphtheria. It belongs to the family Corynebacteriaceae. It is gram-positive and non-acid fast.
• Salmonella typhi refers to gram-negative, rod-shaped bacteria. It shows a positive test for lipopolysaccharide antigens and polysaccharide capsular antigen Vi.

• Another acid-fast bacterias are Genus Nocardia.