Transient normal floras are non-pathogenic or potentially pathogenic microorganisms that inhabit the skin and mucus membrane for a short period of time like hours, days and weeks.
Roles of (Resident) normal flora
Prevent colonization by pathogenic micro-organisms possible disease through “bacterial interference”.
Competition for nutrition with pathogenic bacteria
Competition for binding sites with pathogenic bacteria.
Mutual inhibition by their toxic metabolites.
Mutual inhibition by bacteriocins.
Synthesis of vitamin K in the gastrointestinal tract
Aid in the absorption of nutrients in the small intestine.
NB: Normal flora can cause disease when the defense mechanisms of the body is breached or when the micro-organism is placed in the abnormal body site. Normal flora of the skin The skin is rich in resident bacterial flora, estimated at 104 microbes per square inch. . Staphylococcus epidermidis . Propionibacterium acne . Peptostreptococci and peptococci . Diphtheroids . Alpha-hemolytic streptococci and non-hemolytic streptococci