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

Question 1

The enzyme that coagulates pla is

A) catalase.
B) coagulase.
C) hyaluronidase.
D) staphylokinase.
E) Dnase.

Answer 1

B

Question 2

Staphylococci can be differentiated from streptococci by the

A) Gram stain.
B) coagulase test.
C) catalase test.
D) fermentation of mannitol.

Answer 2

C

Question 3

The most common site where carriers of Staphylococcus aureus carry this pathogen is

A) all over the skin.
B) under the fingernails.
C) anterior nares nostrils).
D) mouth.
E) intestines.

Answer 3

C

Question 4

Which pathogen is the most common cause of neonatal pneumonia, sepsis, and meningitis in the United States?

A) Staphylococcus aureus
B) Staphylococcus epidermidis
C) Staphylococcus saprophyticus
D) Streptococcus pyogenes
E) Streptococcus agalactiae

Question 5

A common food intoxication is caused by enterotoxin-producing strains of

A) Staphylococcus aureus.
B) Staphylococcus epidermidis.
C) Staphylococcus saprophyticus.
D) Streptococcus pyogenes.
E) Streptococcus agalactiae.

Question 6

Symptoms of Toxic Shock Syndrome include all the following, except

A) fever and muscle pain.
B) appearance of flesh being "eaten" down to the muscle.
C) nausea, vomiting and diarrhea.
D) sunburn-like rash.
E) kidney and liver failure.

Question 7

Necrotizing fasciitis is

A) also called impetigo.
B) possibly caused by antibodies to Group A streptococci that cross-react with body tissues.
C) associated with strains of Streptococcus pyogenes producing destructive enzymes and toxins.
D) typically a sequelae of streptococcal pharyngitis.
E) not treatable with antimicrobic drugs.

Question 8

Streptococcal pharyngitis involves all the following, except

A) a purulent exudate over the tonsils.
B) can lead to scarlet fever if it is an erythrogenic toxin-producing strain.
C) can lead to serious sequelae.
D) is usually caused by the viridans streptococci.
E) causes redness, difficulty in swallowing, and fever.

Question 9

Infections caused by Staphylococcus aureus include all of the following, except

A) folliculitis.
B) furuncles and carbuncles.
C) sore throat.
D) osteomyelitis.
E) pneumonia.

Question 10

Which pathogen has drug-resistant strains called MRSA?

A) Staphylococcus aureus
B) Staphylococcus epidermidis
C) Staphylococcus saprophyticus
D) Streptococcus pyogenes
E) Streptococcus agalactiae

Question 11

All species of Staphylococcus

A) produce catalase.
B) are motile.
C) have endospores.
D) produce coagulase.
E) All of these choices are correct.

Question 12

The bright red rash and fever of scarlet fever is due to

A) enterotoxins.
B) hemolysins.
C) toxic shock syndrome toxin.
D) exfoliative toxin.
E) erythrogenic toxin.

Question 13

Which organism is associated with commonly causing urinary tract infections in sexually active young adult and adolescent females?

A) Staphylococcus aureus
B) Staphylococcus epidermidis
C) Staphylococcus saprophyticus
D) Streptococcus pyogenes
E) Streptococcus agalactiae

Question 14

Streptococcus pyogenes causes all the following, except

A) necrotizing fasciitis.
B) erysipelas.
C) impetigo.
D) scarlet fever.
E) scalded skin syndrome.

Question 15

All the following pertain to Staphylococcus epidermidis infections, except

A) they often develop from an endogenous source.
B) they typically occur after insertion of shunts and prosthetic devices.
C) catheterization can introduce the organism and lead to urinary tract infection.
D) the organism is coagulase negative.
E) the organism produces a large number of tissue damaging enzymes and toxins.

Question 16

Which is incorrect about Staphylococcus aureus food intoxication?

A) Food becomes contaminated by a human carrier.
B) Common associated foods include custards, ham, cream pastries, processed meats.
C) After contamination, food must be left unrefrigerated for a few hours.
D) Ingestion of the pathogen allows it to multiply and damage the GI tract lining.
E) Symptoms come on quickly, and include nausea, vomiting, diarrhea.

Question 17

Scarlet fever is caused by strains of

A) Staphylococcus aureus.
B) Staphylococcus epidermidis.
C) Staphylococcus saprophyticus.
D) Streptococcus pyogenes.
E) Streptococcus agalactiae.

Question 18

The toxin of Staphylococcus aureus strains that causes blisters and desquamation of skin in scalded skin syndrome is

A) enterotoxin.
B) hemolysin.
C) toxic shock syndrome toxin.
D) exfoliative toxin.
E) erythrogenic toxin.

Question 19

Rebecca Lancefield differentiated streptococci on the basis of differences in their

A) cell wall carbohydrates in a serological test.
B) patterns of hemolysis on blood agar.
C) ability to produce catalase.
D) Gram stain appearance.
E) All of these choices are correct.

Question 20

Scarlet fever involves

A) high fever.
B) bright red rash on face, trunk, inner arms and legs, and tongue.
C) eventual desquamation of epidermis.
D) septicemia as a complication.
E) All of these choices are correct.

Question 21

A positive Quellung reaction, or capsular swelling, is confirmatory for

A) Neisseria meningitidis.
B) Staphylococcus aureus.
C) Streptococcus pyogenes.
D) Branhamella Moraxella) catarrhalis.
E) Streptococcus pneumoniae.

Question 22

A patient has a suspicious skin infection and a culture is taken. Which media would be appropriate to select for staphylococci?

A) Nutrient agar
B) Blood agar
C) Chocolate agar
D) macConkey agar
E) Mannitol salt agar

Question 23

All of the following pertain to gonorrhea, except

A) a chancre-type lesion develops at the portal of entry.
B) it is a reportable infectious disease.
C) pelvic inflammatory disease PID) and infertility are complications.
D) female infections are frequently asymptomatic.
E) symptoms include painful urination and discharge.

Question 24

Streptococcus pneumoniae is

A) called the meningococcus.
B) in the viridans group.
C) a gram-positive diplococcus with a capsule.
D) a pathogen with endotoxin.
E) All of these choices are correct.

Question 25

All of the following pertain to Enterococcus faecalis, except

A) normal flora of the human large intestine.
B) increasingly resistant to many antimicrobics.
C) cause nosocomial wound infections, urinary tract infections, and septicemias.
D) can cause endocarditis.
E) belong to Lancefield Group B streptococci.

Question 26

The viridans streptococci are

A) not entirely groupable by Lancefield serology.
B) the most numerous residents of the oral cavity.
C) opportunists that can cause subacute endocarditis.
D) introduced to deeper body tissues by dental or surgical procedures.
E) All of these choices are correct.

Question 27

All of the following are associated with subacute endocarditis, except

A) it occurs in patients that have prior heart damage.
B) it is caused by immune system autoantibodies that attack heart and valve tissue.
C) oral bacteria get introduced by dental procedures to the blood.
D) bacteria colonize previously damaged heart tissue resulting in vegetation.
E) signs and symptoms include fever, heart murmur, and possible emboli.

Question 28

Most cases of otitis media in children are due to infection with

A) Streptococcus pneumoniae.
B) Streptococcus pyogenes.
C) Branhamella Moraxella) catarrhalis.
D) Streptococcus agalactiae.
E) Staphylococcus saprophyticus.

Question 29

Meningococcemia is

A) common during gonorrhea.
B) associated with vascular hemorrhage and petechiae.
C) frequently seen in elderly.
D) caused by a gram-positive diplococcus.
E) All of these choices are correct.

Question 30

Which chemical, produced by S. aureus, digests blood clots?

A) coagulase
B) penicillinase
C) staphylokinase
D) hyaluronidase
E) toxic shock syndrome toxin

Question 31

All of the following are correct about Streptococcus pyogenes, except

A) humans are the only significant reservoir.
B) some of the streptococcal toxins act as superantigens.
C) most strains do not have a capsule.
D) it can cause impetigo and erysipelas.
E) infection is generally through direct contact.

Question 32

Long-term sequelae of Group A streptococcal infections include all the following, except

A) risk decreased with prompt treatment of skin infections and pharyngitis.
B) development of rheumatic fever.
C) appearance of sequelae within a few weeks after an initial infection.
D) transmission of sequelae via respiratory secretions from a patient with streptococcal sore throat.
E) development of acute glomerulonephritis.

Question 33

Neisseria gonorrhoeae is

A) the cause of ophthalmia neonatorum.
B) the cause of gonorrhea.
C) called the gonococcus.
D) virulent due to fimbriae and a protease that inactivates IgA.
E) All of these choices are correct.

Question 34

People at greatest risk for pneumococcal infections include all the following, except

A) elderly.
B) those with underlying lung disease and viral infections.
C) patients without a spleen.
D) adolescents and young adults.
E) young infants.

Question 35

The instillation of antibiotics in newborn's eyes will prevent ophthalmia neonatorum in newborns. This disease is caused by

A) Neisseria meningitidis.
B) Staphylococcus aureus.
C) Streptococcus pyogenes.
D) Neisseria gonorrhoeae.
E) Branhamella Moraxella) catarrhalis.

Question 36

The Group A streptococcal infection that has symptoms of fever, edema of skin near portal of entry, and an elevated red, hot vesicular lesion is

A) erysipelas.
B) impetigo.
C) necrotizing fasciitis.
D) scarlet fever.

Question 37

A pregnant woman is told she has a positive CAMP test and should be treated with a course of antibiotics. This test is indicative of

A) Group A streptococci.
B) Group B streptococci.
C) S. saprophyticus.
D) S. epidermidis.
E) S. aureus.

Question 38

Which chemical produced by S. aureus is also known as "spreading factor"?

A) coagulase
B) penicillinase
C) hemolysin
D) hyaluronidase
E) toxic shock syndrome toxin

Question 39

All of the following pertain to Neisseria meningitidis, except

A) virulence factors include a capsule, pili, endotoxin, and IgA protease.
B) it causes serious meningitis.
C) the reservoir is the nasopharynx of human carriers.
D) it is more easily transmitted in day-care facilities, dorms, and military barracks.
E) it is a common cause of bacterial pneumonia.

Question 40

Disease/s caused by Streptococcus pneumoniae include

A) otitis media.
B) meningitis.
C) lobar pneumonia.
D) bronchial pneumonia.
E) All of these choices are correct.

Question 41

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

A) β-lactams
B) macrolides
C) cephalosporins
D) ansamycin plural
E) aminoglycosides

Question 42

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

Question 43

Local Staphylococcus aureus infections often involve formation of an abscess.

Question 44

Most strains of Streptococcus pyogenes produce penicillinase.

Question 45

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

Question 46

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

Question 47

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

Question 48

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

Question 49

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

A) Streptococcus pneumoniae
B) Neisseria meningitidis
C) Neisseria gonorrhoeae
D) Streptococcus pyogenes
E) Staphylococcus aureus

Question 50

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

Question 51

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

Question 52

Streptococcus agalactiae is known as Group _____ streptococci. B

Question 53

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.

Question 54

All of the following are correct about Staphylococcus aureus, except

A) it is the coagulase-positive species.
B) the body's most powerful defense against it lies in the T-cell response.
C) carriers may be treated with antibiotics to clear them of the bacteria.
D) most strains are resistant to penicillin and ampicillin.
E) it causes furuncles, carbuncles, and abscesses.

Question 55

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

Question 56

Streptokinase causes the symptoms of scarlet fever.

Question 57

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.

Question 58

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?

A) She has a strep throat and should begin antibiotics.
B) She should have a rapid strep test performed before a diagnosis is made.
C) She should go home and rest because most sore throats are viral in origin.
D) She should go home and come back in two days for a strep test since it may take that long to show up.
E) She has a staphylococcal sore throat and should begin antibiotics immediately.

Question 59

Discuss how normal flora Staphylococcus epidermidis can cause disease in the body, and describe the diseases that it causes.

Question 60

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

Question 61

Explain what is meant by MRSA, why it is a particular concern to hospitals, and what action hospitals are taking to prevent MRSA spread.

Question 62

An 8-month old infant has been brought to the ER with a high fever. Her parents indicate that she has not been eating or drinking well and has been very irritable until the last few hours during which she has been only minimally responsive. Suspecting meningitis, a spinal tap is done and the CSF sample is sent to the lab for analysis. The white blood cell count on the sample is profoundly elevated, the protein content is elevated, and the glucose level is depressed. The Gram stained smear shows gram-positive cocci in pairs. Cultures are done and after overnight incubation, alpha hemolytic colonies are observed on the blood plate. These colonies contain gram-positive cocci, which are catalase negative. An optochin susceptibility test is done and there is a large zone of inhibition around the disk. What is the identification of this isolate?

A) Streptococcus pneumoniae
B) viridans Streptococci
C) Enterococcus faecalis
D) Neisseria meningitidis
E) Streptococcus agalactiae

Question 63

Which of the following organisms would look most similar to Neisseria meningitidis on a Gram stained smear?

A) Staphylococcus aureus
B) Branhamella catarrhalis
C) Streptococcus agalactiae
D) Streptococcus pneumoniae

Question 64

Describe the transmission of the meningococcus, and discuss the pathogenesis of meningococcal disease in the body including associated signs and symptoms.

Question 65

Having received no prenatal care, a young woman arrives at a hospital after many hours of labor and delivers a baby girl. Three days later the baby girl is listless, nursing poorly, and is running a fever. Blood cultures are done, and after 24 hours, they are Gram stained and show the presence of gram-positive cocci in pairs and short chains. Upon subculture, these form colonies that are beta hemolytic on blood agar. Further tests demonstrate that the isolate is catalase negative, resistant to bacitracin, and is CAMP test positive. What is the identification of this organism?

A) Streptococcus pyogenes
B) Streptococcus pneumoniae
C) Streptococcus agalactiae
D) Staphylococcus aureus
E) Neisseria meningitidis

Question 66

Discuss in detail why strep sore throat must be diagnosed and treated rapidly.

Question 67

A 48-year old man has had nasal surgery and absorbent material has been inserted into his nasal cavity to control bleeding. Several hours ago he began to complain of a headache and has since developed a red rash over much of his body and is experiencing muscle cramps and diarrhea. His blood pressure has dropped to 75/50 mg Hg. This patient's illness is most likely caused by

A) Staphylococcus aureus - exfoliative toxin
B) Streptococcus pyogenes - streptolysin O
C) Staphylococcus aureus - toxic shock syndrome toxin
D) Streptococcus pyogenes - erythrogenic toxin

Question 68

In which of the following situations would Staphylococcus epidermidis be the most likely etiologic agent?

A) otitis media
B) food intoxication
C) urinary bladder infection
D) infected IV catheter site
E) conjunctivitis