Microbiology

ESSAY 3

1. Why is each of the following bacteria often resistant to disinfectants?

a. Mycobacterium

Answer below:

Mycobacterium is often resistant to disinfectants because the cell wall of this genus contains a “waxy, lipid-rich component.” Although mycobacterium are non-endospore forming bacteria, they are highly resistant to most antibiotics and chemical biocides. Mycobacterium tuberculosis and Mycobacterium leprae are highly contagious and life threatening diseases. Acid-fast tests are required to detect these microbes because their cell walls are susceptible to alcohols and phenolics (Tortora, p. 206).

b. Pseudomonas

Answer below:

Gram-negative bacteria are generally more resistant to chemical biocides including Pseudomonas. One of the principle factors is the external lipopolysaccharide layer. Another factor that characterizes resistance to disinfectants includes porins. Porins are structural openings in the wall of gram-negative bacteria that are highly selective of molecules. This prevents or restricts many antimicrobial agents from being effective against Pseudomonas (Tortora, p. 206).

c. Bacillus

Answer below:

Bacterial endospores are like seeds that form a protective layer. This makes them resistant to most biocides. Also, with Bacillus, the formation of cysts and oocysts make them resistant to biocides. A cyst is like a protective bubble filled with fluid that acts as a barrier to chemical disinfection (Tortora, p. 206).

If I were a PA, I would be required to know that some microorganisms are more resistant than others. Some physicians make the mistake of providing the one-cure-fix all. This means that they provide the easiest solution without having to determine actual cause of the problem. This can lead to over-prescription of general antibiotics.

Case in point, a friend of mine recently had a near death experience. His family had become sick with Strep infections. Although he did not have a Strep infection or...