Review Questions for Quiz # 4 from Lesson Content 5 (10 MCQ)

What is the catalase test?

A test used to identify organisms that produce the enzyme catalase, indicating the ability to break down hydrogen peroxide.

What is the coagulase test?

A test used to determine if an organism produces coagulase, which can cause blood plasma to clot.

What is the name of the test used to differentiate between streptococcus from staphylococcus?

The Gram stain test is commonly utilized for this differentiation.

What is the name of the test used to differentiate Staphylococcus aureus from other Staphylococcus species?

The coagulase test.

What is the name of the reagent used in the catalase test to see the bubbles of oxygen?

Hydrogen peroxide.

What other biochemical tests are performed?

Tests such as the oxidase test, urease test, and sugar fermentation tests among others.

When is antimicrobial susceptibility performed?

When an infection is identified, to determine the most effective antibiotic treatment.

What is the difference between susceptible and resistant?

Susceptible means the organism can be inhibited or killed by the antibiotic, while resistant means the antibiotic has no effect.

What is the antimicrobial susceptibility test for, and what are the two different methods?

It is for determining the effectiveness of antibiotics on bacteria; methods include disk diffusion and broth dilution.

What is minimum inhibitory concentration? Also explain.

The lowest concentration of an antibiotic that inhibits the growth of a microorganism.

What is the broth dilution method?

A method where serial dilutions of antibiotics are made in broth to determine the MIC.

Kirby-Bauer method uses what type of media plate?

Mueller-Hinton agar plates.

Explain the Kirby-Bauer method.

A disk diffusion method where antibiotic-impregnated disks are placed on an agar plate inoculated with bacteria, measuring zones of inhibition.

What does zone of inhibition mean?

An area around the antibiotic disk where bacteria cannot grow, indicating sensitivity.

What is the Etest?

A method for determining the MIC using a strip containing a gradient of antibiotic concentrations.

If you want to collect a specimen for culture and sensitivity, should you be on antibiotics or off antibiotics a few days before collection?

You should be off antibiotics a few days before collection.

Should we collect the C&S specimen before or after administration of antibiotics?

Before administration of antibiotics.

Name the three automated identification systems used.

Systems such as Vitek, MicroScan, and Phoenix.

What does the Vitek system contain and include?

It contains various cards for biochemical testing and antibiotic susceptibility.

Automated microbiology systems are designed to replace what?

Manual procedures for pathogen identification and susceptibility testing.