CHAPTER ONE
1.0 INTRODUCTION
A diverse microbial flora is associated with the skin and mucous
membrane of every human being from shortly after birth until death. The
human body which contains about 1013 cells routinely harbors about
1014 bacteria. This bacterial population constitutes the normal
microbial flora. The normal microbial flora is relatively stable with
specific genera populating various body regions during particular
periods in an individual’s life. Tannock (1995).
Microorganisms of the normal flora may aid the host [By competing
for micro-environment more effectively than such pathogens Salmonella Spp or
by producing nutrients that the host can use. It may harm the host by
causing dental caries, abscesses or other infectious diseases or it may
exist as commercials by inhabiting the host for long periods without
causing detectable harm or benefits. Even though most elements of the
normal microbial flora inhabiting the human skin, nails, eyes,
genitalia and gastrointestinal tract are harmless in healthy
individuals, these organisms frequently cause disease in compromised
hosts.
The normal flora in human usually develops in an orderly sequence,
after birth leading to the stable populations of bacteria that made up
the normal adult flora. The main factor determining the composition of
the normal flora in a body region is the nature of the local
environment which is determined by pH, temperature, redox potential,
oxygen, water and nutrient levels. Other factors such as peristalsis,
saliva hysozyme secretion and secretion of immunoglobulin also play
roles in flora control. The local environment is like a concern to in
which one principal instrument usually dominates. For example, an
infact begins to contact organisms as it moves through the birth canal.
A gram positive population [Bifido bacteria]
predominates in the gastrointestinal tract early in life. If the infant
is breast-fed. This bacterial population is reduced and displaced some
what by a gram negative flora [Entero bacteriaceae]
when the baby is bottle feel. The type of liquid diet provided to the
infant is the principal instrument of this flora controls,
immunoglobulins and perhaps other element is breast milk may also be
important.