3. Describe the types of bacteria by staining characteristics.

The medically important types of bacteria are grouped into gram negative, gram positive and capsulated bacteria.

Explanation:

Classification of bacteria can be carried out according to the type of stain in accepts in microbiology laboratory. The stains used to identify bacteria includes the gram stain and Ziehl–Neelsen stain.

Gram staining technique follows the principle that the presence of thick layers in gram positive bacteria known as peptidoglycan will cause the cell wall to stain purple while the absence of peptidoglycan in gram negative bacteria will cause it to stain pink. This technique has led to the classification of bacteria into the following groups:

--> Gram-positive cocci,

--> Gram-positive bacilli,

--> Gram-negative cocci, and

--> Gram-negative bacilli

While other bacteria that are encapsulated can best be identified with the use of Ziehl–Neelsen stain ( which is a stain that shoes acid fastness) are classified as:

--> mycobacteria