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15 Cards in this Set

  • Front
  • Back
What are the microorganisms that live on our bodies and within its cavities?
Normal Flora
Our borders include?
Yeast,bacteria,protozoa,and some viruses.
How does Yeast,bacteria, and protozoa compare in size?
Yeast is the largest, bacteria is the smallest, and potozoa is intermediate.
What microbes are the most common in our bodies?
Commonsals don't cause our body any harm or direct benits, but they do have what benefits.
They compete with pathogens for space to prevent them from colonizing our bodies, and they make the area undesirable to pathogens keeping them from causing disease.
what benefits are there from the Escherichia coli and other species that live in our colon?
They break down left overs in digestive tack producing vitamin K, A, and some B that our bodies can absorb and use.
What are diphtheroids?
Pleomorphic Gram varible microorganisms.
List two areas of the body where diphtheroids are found.
Skin and throat.
List one beneficial effect of the diphtheroids.
They break down sebum releasing fatty acids that lower the ph of skin and inhibit the growth of some pathogens.
What property of mannitol salt agar makes it selective for staphylococci?
It contains 7.5% salt which inhibits the growth of many bacterial species but not the staphylococci.
How can colonies of Staph. aureus and staph. epidermidis be distinguished on mannitol salt agar?
S.aureus ferments mannitol producing acid that turns the agar yellow,S.epidermidis does not ferment mannitol and produces gray colonies without changing the color of the agar
How is tellurite agar differential for diphtheroids?
They reduce tellurite ions in the medium forming a black precipitate and resulting in the formation of black colonies.
How do you differentiate Streptococcus?
By using blood agar.
Explain the following reactions and tell how each is recognized when colonies are grown on blood agar. (1.alpha hemolysis)
Bacteria produce an enzyme that reduces hemoglobin producing green color around the colonies.
(2.beta hemolysis)
bacteria produce enzyme that lyses red blood cells producing clear area around the the colonies.