Deck 14: Streptococcus Enterococcus and Similar Organisms

Question 1

The colonial morphologic features of this organism resemble a donut as it ages, and it has a polysaccharide capsule that is responsible for its virulence.What two characteristics describe this organism?

A) Beta-hemolytic and susceptible to optochin
B) Alpha-hemolytic and bile solubility-negative
C) Gamma-hemolytic and resistant to optochin
D) Alpha-hemolytic and bile solubility-positive

Answer 1

D
Based on the morphologic features listed, the organism is Strep pneumoniae.The organism is alpha hemolytic and positive for bile solubility so the only answer that describes this organism is D.

Question 2

Which species of bacteria is responsible for causing diseases such as rheumatic fever, glomerulonephritis, and exudative pharyngitis?

A) Streptococcus agalactiae
B) S. pyogenes
C) S. pneumoniae
D) Enterococcus

Answer 2

B
S.pyogenes causes all of these diseases.

Question 3

Optochin, PYR, bile solubility, esculin, and 6.5% NaCl are tests most likely performed on a(n)_______ Streptococcus.

A) alpha-hemolytic
B) beta-hemolytic
C) nonhemolytic
D) gamma-hemolytic

Answer 3

A
The tests listed are those used to differentiate various alpha-hemolytic streptococci.

Question 4

The bacterial species that can be described as able to hydrolyze hippurate, is beta-hemolytic, is a major cause of neonatal meningitis and sepsis, and is a producer of the Christie, Atkins, Munch-Petersen (CAMP)factor is:

A) Enterococcus faecalis.
B) Streptococcus pneumoniae.
C) S. pyogenes.
D) S. agalactiae.

Question 5

Bacitracin, pyrrolidonyl arylamidase (PYR), CAMP factor, and hippurate are tests most likely performed on a(n)_______ Streptococcus.

A) alpha-hemolytic
B) beta-hemolytic
C) nonhemolytic
D) gamma-hemolytic

Question 6

Which of the following organisms best describes a catalase-negative, gram-positive coccus that is beta-hemolytic on sheep blood agar?

A) Streptococcus pyogenes
B) S. pneumoniae
C) Staphylococcus epidermidis
D) Micrococcaceae spp.

Question 7

Differentiation of the pleomorphic strains of streptococci and the similar corynebacteria or lactobacilli can be best accomplished by:

A) examination of Gram stain of the colony.
B) vancomycin-susceptibility testing.
C) serologic testing.
D) examination of the morphologic features after growth in thioglycollate broth.

Question 8

What name is given to the type of hemolysis that produces complete hemolysis and a clearing of the medium?

A) Beta hemolysis
B) Gamma hemolysis
C) Alpha hemolysis
D) Kappa hemolysis

Question 9

The bacterial species that can be described as able to grow in 6.5% sodium chloride (NaCl)and 40% bile, is part of the normal fecal flora of animals and humans, is usually nonhemolytic, and is a major cause of nosocomial infections is:

A) Enterococcus faecalis.
B) Streptococcus pneumoniae.
C) S. pyogenes.
D) S. agalactiae.

Question 10

Streptococcus pneumoniae can be described as:

A) resistant to bile and optochin.
B) beta-hemolytic.
C) catalase-positive.
D) often carrying an antiphagocytic capsule.

Question 11

The development of acute rheumatic fever and subsequent valvular heart disease are problems that may be encountered by patients infected with:

A) Enterococcus faecalis.
B) Streptococcus pneumoniae.
C) S. pyogenes.
D) S. agalactiae.

Question 12

The drugs of choice for most enterococcal infections are:

A) vancomycin and a penicillin.
B) clindamycin and vancomycin.
C) penicillin and an aminoglycoside.
D) septra.

Question 13

What morphologic feature is a major consideration in determining an identification scheme for streptococci?

A) Colony shape and color
B) Hemolytic pattern
C) Smell
D) Consistency

Question 14

Enterococci can be described as:

A) able to hydrolyze bile esculin.
B) usually beta-hemolytic.
C) a major cause of pharyngitis.
D) often carrying an antiphagocytic capsule.

Question 15

Generally speaking, nutritionally variant streptococci require what ingredient not found in most conventional media?

A) Vitamin B6
B) Nalidixic acid and its components
C) Nicotinamide adenine dinucleotide (NAD) enrichment
D) Blood or blood products

Question 16

The development of glomerulonephritis is a problem that may be encountered by patients infected with:

A) Enterococcus faecalis.
B) Streptococcus pneumoniae.
C) S. pyogenes.
D) S. agalactiae.

Question 17

What name is given to the type of hemolysis that produces incomplete hemolysis and a greening discoloration of the medium?

A) Beta hemolysis
B) Gamma hemolysis
C) Alpha hemolysis
D) Kappa hemolysis

Question 18

The CAMP factor is produced by:

A) Enterococcus faecalis.
B) Streptococcus pneumoniae.
C) S. pyogenes.
D) S. agalactiae.

Question 19

Erythrogenic toxin, hyaluronidase enzyme, and hemolysins S and O are extracellular products of:

A) Enterococcus faecalis.
B) Streptococcus pneumoniae.
C) S. pyogenes.
D) S. agalactiae.

Question 20

The major etiologic agent of bacterial endocarditis in the United States is:

A) Enterococcus faecalis.
B) Streptococcus pneumoniae.
C) S. pyogenes.
D) viridans streptococci.