microlab quiz 9

How do you check the Tryptone Broth media from the previous lab?

Add 10-15 drops of Kovac's reagent, and DO NOT SHAKE.

How do you check the Methyl Red test?

Add Methyl Red to the tubes and shake sideways.

How do you evaluate the Citrate test?

Look at the color.

How do you perform the V-P Test?

Add 5-10 drops of αα-Napthol

What are the four general shared characteristics of Staphylococcus and Streptococcus species?

They are Gram positive, non-spore forming, cocci shaped, and cause opportunistic infections.

Where are Staphylococcus species naturally present on the human body?

On the nasal membrane, the root of the hair, and on the skin.

What types of minor and major infections do Staphylococcus species cause?

Minor infections include abscesses, pimples, and boils. A major infection is septicemia (blood poisoning).

What is the typical antibiotic resistance of Staphylococcus?

Most are penicillin-resistant.

How many identified species of Staphylococcus are there, and what are 3 common examples?

There are 19 identified species. Common examples include Staphylococcus aureus, S. epidermidis, and S. saprophyticus.

What are the specific characteristics and chemical capabilities of Staphylococcus aureus?

It is 0.8 to 1 μμm in size, can tolerate up to 10% salt, ferments mannitol, and produces coagulase. It also produces αα-toxin which hemolyzes red blood cells, leading to ββ-hemolysis (total destruction

How are Streptococcus species typically arranged structurally?

They are arranged in chains.

What three diseases/conditions are associated with Streptococcus infections and potential autoimmune responses?

Endocarditis (Heart), Pharyngitis (Strep throat - Pharynx), and Glomerulonephritis (Kidney).

How do Streptococcus infections lead to autoimmune diseases?

The infection causes the body to produce antibodies that attack the host like foreign cells.

Where are Streptococcus species commonly found in/on the body?

Teeth surface, saliva, skin, colon, rectum, and vagina.

What are three examples of Streptococcus species and their specific pathogenicity/hemolysis types?

1. Streptococcus pneumoniae (αα).

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2. S. pyogens -> super pathogenic (ββ).

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3. S. lactis -> non-pathogenic (γγ).

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How are Streptococcus species identified on blood agar?

By their degree of hemolysis (RBC death), which is categorized into 3 kinds: αα, ββ, and γγ.

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Define αα-hemolysis (Alpha).

Incomplete destruction of RBCs (Hemoglobin converts to Methemoglobin). It appears green on a blood agar plate.

Define ββ-hemolysis (Beta).

Complete destruction of RBCs. It appears clear on a blood agar plate.

Define γγ-hemolysis (Gamma).

No destruction of RBCs. There is bacterial growth, but no destruction.

What does MRSA stand for according to the notes?

Methicillin Resistant.

Define Epidemic.

A sudden raise in reported cases of disease.

Define Pandemic and give four examples.

Spread across more than 2 continents. Examples include Bird Flu, Ebola, SARS, and MERS

Define Epidemiology and name the organization associated with it in the notes.

The study of how, where, when, what, and who are involved in the spread and distribution of disease in a society. It is associated with the Center for Disease Control (CDC).

What is the lab exercise method for the MSA plate?

Use a wet cotton swab to take a nose sample, then streak it in the middle of the plate

What is the composition of a Blood Agar Plate and what is the sample collection method used in the lab?

It is composed of Sheep Blood (5%) + TSA. The sample is collected with a cotton swab from the back of the throat.