Bacteriology:

The bacteriology is further classified into basic and clinical bacteriology.

Prokaryotes:

Ø  Prokaryotes are organisms  containing prokaryotic cells

Ø  No well defined nucleus

Ø  Genetic material DNA and RNA are present

Ø  Membrane bounded structures such as mitochondria, endoplasmic reticulum, chloroplast and Golgi bodies are absent

Ø  Contain small sized ribosome of 70S

Ø  Cell division occur by fission mitosis is absent

Ø  Examples are bacteria, blue green algae

Bacteria:

§  Bacteria are the prokaryote found in every part of the world where life can exist.

§  Largest size is 7µm and average size is 0.2µm - 5µm

§  The inner half of bacterial cell wall is made up of peptidoglycan while the outer half vary (made up of polysaccharides)

§  Bacteria show growth by exponential division during suitable conditions

Bacteria are found in three different forms (shapes)

                    i.            Cocci:

They are spherical or rounded in shape.

                  ii.            Bacilli:

They are rod in shape.

                iii.            Spirilla:

They are spiral or twisted in shape.

Classification:

 According to arrangement are:

a.      Pair:

Diplococci

b.      Chain:

Streptococci

c.       Cluster:

Staphylococci

A.     Gram positive bacteria:

These bacteria on treatment with crystal violet dye take the color of the dye and retain it if treated with ethanol. The outer covering is thick as compared to gram negative.

B.     Gram negative bacteria:

These bacteria on treatment with crystal violet dye do not take the color of the dye.

Both the gram positive and negative may or may not have capsule. The capsule act as endotoxin which causes low BP, increased Temperature, peripheral dilatation and decreased cardiac output.

The type of antigen present on the capsule performs the following functions:

v  Identify the type of bacteria

v  Adherence to the tissue of host

v  Determine virulence of bacteria

Classification:

According to availability or absent are the following.

a)      Obligate aerobes:

The bacteria which grow in oxygen suitable condition

Bacteria are obligate aerobes on our skeletal muscles when we are at rest.

b)      Obligate anaerobes:

The bacteria which grow in oxygen deficient condition

c)       Facultative aerobes:

Those bacteria prefer aerobic conditions but can also avail anaerobic conditions. Bacteria are facultative aerobes on our skeletal muscles when we are at exertion.

Posted in: Pathology; Bacteriology