Which short rod-shaped bacteria are the most common bacteria which produces diseases such as tetanus (lock jaw), typhoid fever, tuberculosis, and diphtheria?

Which short rod-shaped bacteria are the most common bacteria which produces diseases such as tetanus (lock jaw), typhoid fever, tuberculosis, and diphtheria?

• A. Bacilli
• B. Spirilla
• C. Cocci
• D. Staphylococci

Answer: (A)

Bacilli are short rod-shaped bacteria, and many disease-causing microbes fall into this form. Tetanus is caused by Clostridium tetani, a rod-shaped bacterium; typhoid fever by Salmonella typhi, which is also rod-shaped; tuberculosis by Mycobacterium tuberculosis, another rod-shaped organism; and diphtheria by Corynebacterium diphtheriae, likewise rod-shaped. The other shapes described—spirilla (spiral-shaped), cocci (spherical), and staphylococci (spherical in clusters)—do not match these particular pathogens. So the rod-shaped form best groups these diseases, making bacilli the correct description.

Bacilli are short rod-shaped bacteria, and many disease-causing microbes fall into this form. Tetanus is caused by Clostridium tetani, a rod-shaped bacterium; typhoid fever by Salmonella typhi, which is also rod-shaped; tuberculosis by Mycobacterium tuberculosis, another rod-shaped organism; and diphtheria by Corynebacterium diphtheriae, likewise rod-shaped. The other shapes described—spirilla (spiral-shaped), cocci (spherical), and staphylococci (spherical in clusters)—do not match these particular pathogens. So the rod-shaped form best groups these diseases, making bacilli the correct description.