The Intricate Field of Immunity: Normal Microbial Flora (Coursework Sample)

The term “normal microbial flora” denotes the population of microorganisms that inhabit the healthy normal persons. Normal flora basically consist of bacteria and Fungi that are permanent residents of body sites specially skin, oropharynx, colon and vagina. Viruses and protozoa which are major groups of microorganisms are not considered members of normal flora. In a healthy human, the internal tissues, e.g. blood, brain, muscle, etc., are normally free of microorganisms. The skin and mucous membranes always harbor a variety of microorganisms.
It has both advantages as well as disadvantages.
Advantages
(i) They prevent or suppress the entry of the pathogens.
(ii) These synthesize the vitamins especially Vit.-K and several B Group vitamins.
(iii) Antigenic stimulation provided by intestinal flora is considered important in ensuring the normal development of the immune system.(iv). Antibodies produced in response to normal flora cross react with pathogens thus raising immune status of the host.
Disadvantages
(i) They become pathogenic when the immunity is lowered.
(ii) They may act as pathogens in different tissue (other than their normal habitat) e.g. normal flora of intestine may cause urinary tract infection (UTI).