Question 1

Staphylococcus, Streptococcus, and Neisseria tend to stimulate pus production and are collectively referred to as _____ cocci.

Accepted Answer

The answer of Staphylococcus, Streptococcus, and Neisseria tend to stimulate...

Question 2

The production of the enzyme _____ by Staphylococcus aureus is a key characteristic used to identify it from other species of Staphylococcus.

Accepted Answer

The answer of The production of the enzyme _____ by...

Question 3

All of the following are correct about Streptococcus pyogenes, except:

Accepted Answer

Most strains of Streptococcus pyogenes do have a capsule. Capsules help bacteria avoid phagocytosis by host immune cells.

Question 4

Streptokinase causes the symptoms of scarlet fever.

Accepted Answer

Streptokinase is an enzyme produced by certain bacteria, including Streptococcus pyogenes, which can cause infections such as strep throat and impetigo. Scarlet fever is also caused by this bacterium, but the symptoms are due to a toxin called erythrogenic toxin, not streptokinase.

Question 5

Impetigo involves itching papules that break and form a very contagious yellow crust.

Accepted Answer

This is a characteristic symptom of impetigo.

Question 6

Pneumovax is a vaccine for prevention of disease caused by strains of Neisseria meningitidis.

Accepted Answer

Pneumovax is actually a vaccine for prevention of pneumococcal disease, which is caused by the bacteria Streptococcus pneumoniae.

Question 7

The two important hemolysins of Group A streptococci are _____ and _____.

Accepted Answer

The answer of The two important hemolysins of Group A...

Question 8

It is theorized that rheumatic fever and acute glomerulonephritis could be the result of antibodies to Group A streptococci that cross-react with patient tissues.

Accepted Answer

Rheumatic fever and acute glomerulonephritis are both believed to be caused by an autoimmune response triggered by Group A streptococci infections. The antibodies produced by the immune system to fight the infection mistakenly attack the patient's own tissues, leading to inflammation and damage to various organs. This is known as molecular mimicry, where the invading bacteria and the host tissues are similar enough to create a cross-reaction.

Question 9

Which of the following antibiotics specifically disrupt protein synthesis of streptococci?

Accepted Answer

Macrolides specifically disrupt protein synthesis in streptococci by binding to the 50S subunit of the bacterial ribosome, preventing the movement of the ribosome along the messenger RNA (mRNA), thus ultimately inhibiting protein synthesis. Beta-lactams and cephalosporins target the cell wall synthesis, while ansamycin targets bacterial transcription, and aminoglycosides target bacterial protein synthesis by binding to the 30S subunit of the bacterial ribosome.

Question 10

The viridans group of streptococci and the pneumococcus produce _____ hemolysis on blood agar.

Accepted Answer

The answer of The viridans group of streptococci and the...

Question 11

Local Staphylococcus aureus infections often involve formation of an abscess.

Accepted Answer

Local Staphylococcus aureus infections can often lead to the formation of an abscess, which is a localized collection of pus that can be painful and inflamed.

Question 12

Sue brought her daughter Amy to the pediatrician complaining of a sore throat.The physician examines Amy and observes that her throat is bright red and there are white pus-filled nodules on her tonsils.Which of the following conclusions should be made?

Accepted Answer

The white pus-filled nodules on Amy's tonsils suggest that she may have strep throat, which is caused by the bacteria Streptococcus pyogenes. However, a rapid strep test should be performed to confirm the diagnosis before starting antibiotics. This is important because unnecessary antibiotic use can contribute to the development of antibiotic-resistant bacteria. Resting at home may be recommended, but a diagnosis should be made first. Waiting two days for a strep test to show up is not necessary as rapid strep tests provide results within minutes. Staphylococcal sore throats are not as common as strep throat and would require a different course of antibiotics.

Question 13

Neisseria meningitidis and Neisseria gonorrhoeae are fastidious, gram-negative cocci that produce oxidase.

Accepted Answer

Neisseria meningitidis and Neisseria gonorrhoeae are both fastidious, gram-negative cocci that produce oxidase.

Question 14

List three enzymes and four toxins produced by Staphylococcus aureus.For each enzyme and toxin, discuss its effect on patient tissues and how it contributes to virulence of this pathogen.

Accepted Answer

The answer of List three enzymes and four toxins produced...

Question 15

All of the following are correct about Staphylococcus aureus, except:

Accepted Answer

The body's most powerful defense against Staphylococcus aureus lies in the production of antibodies and the activity of phagocytic cells, not the T-cell response.

Question 16

Most strains of Streptococcus pyogenes produce penicillinase.

Accepted Answer

Most strains of Streptococcus pyogenes are sensitive to penicillin and do not produce penicillinase. However, some strains have developed resistance to penicillin and can produce penicillinase.

Question 17

Streptococcus agalactiae is known as Group _____ streptococci. B

Accepted Answer

The answer of Streptococcus agalactiae is known as Group _____...

Question 18

An individual with asymptomatic N.gonorrhoeae may not spread the disease.

Accepted Answer

Even if a person with asymptomatic N.gonorrhoeae does not have any symptoms, they can still spread the disease to others through sexual contact. It is important to get tested and treated for N.gonorrhoeae to prevent the spread of the infection.

Question 19

If left untreated, an infection with ___ can lead to pelvic inflammatory disease and infertility.

Accepted Answer

Neisseria gonorrhoeae is the only option listed that can cause pelvic inflammatory disease and infertility if left untreated. Streptococcus pneumoniae causes pneumonia, Neisseria meningitidis causes meningitis, Streptococcus pyogenes causes strep throat and other infections, while Staphylococcus aureus can cause a variety of infections but is not typically associated with pelvic inflammatory disease or infertility.

Question 20

All staphylococci can be differentiated from all streptococci because only staphylococci produce the enzyme _____ that is easily detected in the lab.

Accepted Answer

The answer of All staphylococci can be differentiated from all...

Quiz 18: The Gram-Positive and Gram-Negative Cocci of Medical Importance