Deck 15: Streptococcus, enterococcus, and Other Catalase-Negative Gram-Positive Cocci

Question 1

Which of the following is the drug of choice for treating most streptococcal infections?

A) Erythromycin
B) Cephalothin
C) Penicillin
D) Gentamicin

Answer 1

C
Despite widespread use,penicillin is the drug of choice in treating most streptococcal infections.However,penicillin-resistant Streptococcus pneumonia and viridans group isolates have been reported worldwide,and the incidence of penicillin-resistant S.pneumoniae seems to be increasing.

Question 2

Skin or pyodermal infections with group A streptococci result in all the following syndromes EXCEPT:

A) Impetigo
B) Bullous impetigo
C) Cellulites
D) Erysipelas

Answer 2

B
Skin or pyodermal infections with group A streptococci result in the syndrome of impetigo,cellulitis,erysipelas,wound infection,or gangrene.

Question 3

The atmospheric conditions best suited to grow streptococci and enterococci are:

A) Room air
B) Oxygen-free atmosphere
C) High carbon dioxide concentration
D) Low carbon dioxide concentration

Answer 3

B
Most members of the genera Streptococcus and Enterococcus behave as facultative anaerobes.Because they grow in the presence of oxygen but are unable to use oxygen for respiration,they may be considered aerotolerant anaerobes.

Question 4

Physiologic classification of streptococci divide the species into all the following groups EXCEPT:

A) Pyogenic streptococci
B) Lactococci
C) b-Hemolytic streptococci
D) Enterococci

Question 5

What test presumptively differentiates b-hemolytic group A streptococci and nonhemolytic group D enterococci from other streptococcal species?

A) Bacitracin
B) Hippurate hydrolysis
C) PYR
D) Optochin

Question 6

What test differentiates staphylococci from streptococci?

A) Catalase
B) Coagulase
C) b-Hemolysis
D) All of the above

Question 7

What is the name of the test used to presumptively identify group B streptococci?

A) CAMP
B) Lancefield
C) Bacitracin
D) Optochin

Question 8

Streptokinase is an enzyme produced by group A streptococci that:

A) Breaks down staphylococci
B) Breaks down connective tissue
C) Produces a maculopapular rash in rheumatic fever
D) Lysis fibrin clots

Question 9

What is the cell wall of streptococci and enterococci made out of?

A) Lipopolysaccharide and carbohydrates
B) Protein A and phospholipids
C) Cholesterol and teichoic acid
D) Teichoic acid and peptidoglycan

Question 10

Common schemes to classify streptococci include all the following EXCEPT:

A) Biochemical characteristics
B) Serologic grouping or typing of C carbohydrate
C) Physiologic characteristics
D) Flagellar antigens

Question 11

All of the following are additional virulence factors associated with group A streptococcus EXCEPT:

A) Enterotoxins
B) Hemolysins
C) Toxins
D) Enzymes

Question 12

What two tests have been mainstays in identification schemes for the non-b-hemolytic,catalase-negative,gram-positive cocci?

A) Bacitracin and PYR
B) Hippurate hydrolysis and Optochin
C) Nitrate and PYR
D) Bile esculin and salt tolerance

Question 13

What is the inexpensive test used to presumptively identify Streptococcus pyogenes?

A) Optochin
B) Bacitracin
C) Nitrate
D) Citrate

Question 14

What is the cellular structure that Streptococcus pyogenes relies on for its virulence?

A) Peptidoglycan
B) Lipopolysaccharide
C) S antigens
D) M proteins

Question 15

What is the hemolysin responsible for hemolysis on SBA incubated anaerobically?

A) Hyaluronidase
B) Streptolysin O
C) Streptolysin D
D) Hemolysin O

Question 16

What test can be used to differentiate S.agalactiae from other b-hemolytic streptococci?

A) Bacitracin
B) Hippurate hydrolysis
C) PYR
D) Optochin

Question 17

What is one of the most common diseases caused by streptococci?

A) Strep throat
B) Rheumatic fever
C) Acute glomerulonephritis
D) Scarlet fever

Question 18

What causes the red spreading rash in scarlet fever?

A) Hyaluronidase
B) Streptolysin O
C) Streptococcal pyrogenic exotoxins
D) Streptolysin S

Question 19

What test is used as a presumptive identification of Streptococcus pneumoniae?

A) Optochin
B) Bacitracin
C) PYR
D) Hippurate hydrolysis

Question 20

Most doctors' offices use the rapid throat swab methods to identify Streptococcus pyogenes.If the test is positive,the physician treats the patient.What should happen if the test is negative?

A) The physician should treat the patient to be safe.
B) The physician should perform a throat culture.
C) The physician should repeat the rapid strep tests.
D) None of the above.

Question 21

Streptococcus pneumoniae causes all the following infections EXCEPT:

A) Pharyngitis
B) Pneumonia
C) Bacteremia
D) Meningitis

Question 22

Two serious complications of an infection with group A streptococcal disease are:

A) Toxic shock syndrome and scarlet fever
B) Gangrene and rheumatic fever
C) Acute glomerulonephritis and necrotizing fasciitis
D) Acute glomerulonephritis and rheumatic fever

Question 23

One major virulence factor for Streptococcus pneumonia is:

A) Hemolysin
B) Protease
C) Hyaluronidase
D) Capsular polysaccharide

Question 24

What is VRE?

A) Vancomycin-ready erythromycin
B) Very-reliable erythromycin
C) Vancomycin-resistant enterococcus
D) Veocin-resistant enterococcus

Question 25

Where are the viridans streptococci constituents of the normal florae?

A) Upper respiratory tract
B) Female genital tract
C) Gastrointestinal tract
D) All of the above

Question 26

What is the drug of choice to treat Streptococcus pneumoniae?

A) Erythromycin
B) Penicillin
C) Zithromax
D) Chloramphenicol

Question 27

An 80-year-old woman is admitted from a nursing home where she has been sick with a cough and fever for two days.She is coughing up thick,rust-colored sputum.The physician prescribed penicillin,but she is not getting any better.What is her most probable diagnosis?

A) Viral pneumonia
B) Pneumococcal pneumonia with penicillin-resistant organism
C) Enterococcal pneumonia with vancomycin-resistant enterococci (VRE)
D) S. agalactiae infection

Question 28

What two tests are used to presumptively identify Enterococcus?

A) PYR and hippurate hydrolysis
B) Bile esculin and 6.5% NaCl broth
C) Bacitracin and PYR
D) Catalase and coagulase

Question 29

What is the drug of choice to treat group A streptococci when the patient cannot tolerate penicillin?

A) Penicillin
B) Erythromycin
C) Gentamicin
D) Cefoxitin

Question 30

What are two tests used to presumptively identify group B strep?

A) Hippurate hydrolysis and CAMP
B) Optochin and PYR
C) Bacitracin and PYR
D) PYR and hippurate hydrolysis

Question 31

Streptococcus-like organisms that resemble enterococci and viridans streptococci include all the following EXCEPT:

A) Moraxella
B) Aerococcus
C) Gemella
D) Lactococcus

Question 32

Why do Streptococcus pneumoniae colonies on sheep blood agar (SBA)appear like a coin-raised edges and a depressed center?

A) The older growth at the center is smaller due to lack of nutrients.
B) The newer growths on the outside of the colony undergo the Quellung reaction.
C) The older growth at the center is killed due to autolysis.
D) The newer growth has a thicker capsule, therefore it appears raised.

Question 33

What disease is produced by group A streptococci that is characterized by a rapidly progressing inflammation and necrosis of the skin,subcutaneous fat,and fascia?

A) Erysipelas
B) Scarlet fever
C) Necrotizing fasciitis
D) Streptococcal toxic shock syndrome

Question 34

What organism on sheep blood agar (SBA)has colonies that are small and transparent,surrounded by a wide zone of b-hemolysis?

A) Streptococcus agalactiae
B) Streptococcus pyogenes
C) Enterococcus
D) Viridans strep

Question 35

Streptococcus agalactiae is a significant cause of?

A) Pharyngitis
B) Cystitis
C) Invasive disease of the newborn
D) Vaginitis

Question 36

A young girl goes to her doctor's office with a fever,headache,and a sore throat.The mother states the girl has a fever of 38.8° C (102° F).What test should the physician perform?

A) Throat culture
B) Antistreptolysin O
C) Optochin
D) Gram stain

Question 37

What organism on sheep blood agar (SBA)has grayish white colonies surrounded by a small zone of b-hemolysis?

A) Viridans strep
B) Enterococcus
C) Streptococcus pyogenes
D) Streptococcus agalactiae