Bacterial Flora Flashcards
NORMAL FLORA:
These are mixture of micro-organisms that are ______________________
regularly found at any anatomical site on or within the body of a healthy person.
Estimation of the Normal flora
It has been calculated that the normal flora human body about 10^__ bacteria on the skin, 10^___ in the mouth, and 10^___ in the gastrointestinal tract.
12
10
14
Importance of The Normal Flora
They constitute a ___________ mechanism
by ________
protective host defense
occupying ecological niches.
Normal Microbial Flora:
Resident Flora:
– Microbes that are _______________
always present on or within body
Normal microbial Flora:
Transient Flora:
– Microbes that __________ for _______ then __________
live in or on the body
a period of time (hours, days, weeks, months)
move on or die off
EXAMPLES OF TISSUE TROPISM OF SOME BACTERIA ASSOCIATED WITH HUMANS
Throat
Urogenital epithelium
Tooth surfaces
Corynebacterium diphtheriae
N.gonorrhoeae
S.mutans
EXAMPLES OF TISSUE TROPISM OF SOME BACTERIA ASSOCIATED WITH HUMANS
Tongue surfaces
Small intestine epithelium
Nasal membranes
Skin
S.salivarius
E.coli
S. aureus
S.epidermidis
Normal flora of Skin:
Important bacteria:
Mention 4
1.Staphylococcus epidermidis
2. Micrococcus sp.
3. Corynebacterium sp.
4. Mycobacterium smegmatis
Normal Flora of the Conjunctiva:
List 7
- Staphylococcus epidermidis 2. Corynebacterium spp.
- Propoinibacterium acnes 4. Staphylococcus aureus
- Viridans streptococci
- Neisseria spp.
- Haemophilus influenzae
Normal Flora of the Respiratory Tract: A). The nares (nostrils) :
List 6
- Staphylococcus epidermidis 2. Corynebacteria spp.
- Staphylococcus aureus
- Neisseria spp.
- Haemophilus spp.
- Streptococcus pneumoniae
Normal Flora of the Respiratory Tract: B) The upper respiratory tract (nasopharynx):
List 7
- Non-hemolytic streptococci 2. Alpha-hemolytic streptococci 3. Neisseria spp.
- Streptococcus pneumoniae
- Streptococcus pyogenes
- Haemophilus influenzae
- Neisseria meningitidis
The lower respiratory tract:(trachea, bronchi, and pulmonary tissues): Usually _______.
sterile
Normal Flora of the Respiratory Tract: C) The lower respiratory tract:(trachea, bronchi, and
pulmonary tissues): Usually sterile.
The individual may become susceptible to infection by pathogens descending from the nasopharynx:
e.g. ______,_______
H. influenzae, S. pneumoniae
Normal Flora of the Human Oral Cavity:
Oral bacteria include:
List 8
- Viridans streptococci
- Lactobacilli
- Staphylococci (S. aureus and S. epidermidis) 4. Corynebacterium sp.
- Bacteroides sp.
- Streptococcus sanguis (dental plaque)
- Streptococcus mutans (dental plaque)
- Actinomyces sp
The Normal Flora of The Ears (i.e. external ear)
The external ears contains a variety of micro- organisms. These include:
????
- Staphylococcus epidermidis 2. Staphylococcus aureus
- Corynebacterium sp
Normal flora of the Urogenital Tract:
b) The vagina:
Most important one is??
Lactobacillus acidophilus*
Bacteria/gram contents (increases or decreases?) as we go from duodenum to rectum
Increases
In breast-fed infants :
___________ account for more than 90% of the total intestinal bacteria.
Bifido bacteria
In bottle-fed infants, Bifidobacteria are predominant.
T/F
F
Bifidobacteria are not predominant.
In the upper GIT of adult humans mainly acid- tolerant lactobacilli present:
e.g. _____——
Helicobacter pylori
THE ROLE/ BENEFITS OF THE NORMAL
FLORA:
1. The normal flora synthesize and excrete ______ in excess of their own needs, which can be _____________
For example, enteric bacteria secrete ______ and ______, while lactic acid bacteria produce certain _____
vitamins
absorbed as nutrients by the host.
Vitamin K and Vitamin B12
B-vitamins.
THE ROLE/ BENEFITS OF THE NORMAL
FLORA:
The normal flora prevent ______ by pathogens by ____________ or ________
colonization
competing for attachment sites or for essential nutrients.
THE ROLE/ BENEFITS OF THE NORMAL FLORA:
- The normal flora may ______ other bacteria through the ___________________________________
antagonize
production of substances which inhibit or kill non-indigenous species.
Intestinal bacteria produce a variety of substances like ________,_________, and ________, which inhibit or kill other bacteria.
non-specific fatty acids, peroxides and highly specific bacteriocins
The normal flora stimulates the development of certain tissues
T/F
If T, give example
If F, why ?
T
the caecum (in animals) and certain lymphatic tissues (Peyer’s patches) in the GI tract.
The normal flora does not stimulate the production of “cross-reactive antibodies’’.
T/F
F
It does
Sterile tissues:
In a healthy human, the internal tissues such as:
List 4
blood
brain
muscle
Cerebrospinal fluid (CSF)
Sterile tissues are normally free of microorganisms.
T/F
T
We have no Commensalistic relationships with Bacteria
T/F
T
Escherichia coli - normally in our ______ where it causes no problems, but if it gets into the ________ it can become pathogenic.
digestive tract
urinary tract
Staphylococcus aureus – commonly found in the __________, but if it gets into a _____ or _______ it can become pathogenic
upper respiratory tract,
wound or a burn
Probiotic:
–____ administration of ________ to promote health
– Species specific: adherence and growth (tropism)
Oral
living organisms
