Normal Flora Flashcards
The majority of vacteria are present in :
In the large bowel
Normal flora are present in:
In those parts of the body that are exposed to, or communicate with, external env..
Include : skin, mouth, nose, intestine and urogenital tracts.
Are there normal flora in the internal organs?
Internal organs and tissues are normally sterile.
Fetus …
It lives in a sterile environment protected from microbes.
How does a newborn get micorbes?
It is confronted with the mother’s vaginal microbes and environmental organisms.
Pathogenesis of microbial infection …
the recovery of the organism in Normally sterile site is the Hallmark of pathogenesis of microbial infection.
Escherechia coli resides in :
Gastrointestinal tract
Are viruses and parasites are considered as members of the normal flora?
No, they are not.
Because they are not found as commensals in the host.
Certain organisms that are never present as a part of normal flora and cause diseases:
Bacillus anthracis, Brucella spp., Francisella tularensis, and Histoplasma capsulatum, etc)
Function of Resident flora:
1.Maintains a protected env that prevent colonization with potentially pathogenic organisms.
2.production of proteolytic enzymes for digestion
Sythesize vit and other biological products
Colicins production
Clostridium difficile produces GIT disease when:
When the normal flora have been reduced or removed by antibiotics.
Nares are inhabited by small number of organsims, which include:
Staphylococcus, Corynebacterium, peptostreptococcus and Fusobacterium species.
The microbial population in the masopharynx is more complex with predominance of :
Streptococci and Neisseria species.
Streptococcus salivarius, streptococcus parasanguis and streptococcus pneumoniae can be readily recovered from the nasopharynx.
Oropharynx and tonsils:
Gram+ and Gram- cocci predominate in the oropharynx
The most common anaerobic bacteria present in the oropharynx are :
peptostreptococcus, veillonella, Actinomyces and Fusobacterium
