Normal bacterial flora

Normal Bacterial flora

Prof. Dr Shahina Yasmin

, LOs
• Define the following terms: normal bacterial flora,
Symbiosis, Neutralism, Mutualism, Commensalism,
Parasitism
• Enlist the organisms forming normal flora at various
body sites e.g. skin, respiratory system, GIT, GU system
• Explain the factors effecting type of flora at various
body sites
• Compare and contrast the role of normal flora in the
body with respect to advantages, disadvantages and
clinical implications
• Knowledge

, Normal flora
• Definition: Micro organisms associated with a particular
tissue, structure or environment.
• Microorganisms present in the Healthy animal /human
body without causing any harm to the part of the body
where it resides.
• In human, population of organisms inhabit certain body
sites e.g. skin, mucous membranes, colon, vagina etc.
• Also called as Commensals
• Flora of each individual of one site is different from other
individual depending on age, diet and geographic habitat
• Derive benefit and do not damage host.
• Physiological factors responsible for flourishing at a site
include: Temperature, Moisture, Nutrient, Inhibitory

substances