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

Question 1

What test is used for the presumptive identification of Streptococcus pneumoniae?

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

Answer 1

A

Question 2

Which of the following tests can be used to identify Group B streptococci?

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

Answer 2

A

Question 3

Physiologic classification of streptococci divide the species into all the following groups, except

A) pyogenic streptococci.
B) lactococci.
C) $\beta$ -hemolytic streptococci.
D) Enterococci.

Answer 3

$\beta$ -hemolytic streptococci.

Question 4

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

A) Pharyngitis
B) Rheumatic fever
C) Acute glomerulonephritis
D) Scarlet fever

Question 5

Skin infections or pyoderma caused by Group A streptococci result in all the following syndromes, except

A) impetigo.
B) bullous impetigo.
C) cellulitis.
D) erysipelas.

Question 6

Which of the following tests can be used to presumptively identify Streptococcus pyogenes?

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

Question 7

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

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

Question 8

Most physicians' offices use a rapid throat swab method to identify Streptococcus pyogenes infections in children. 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 9

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 10

What test can be used to differentiate Streptococcus agalactiae from other $\beta$ -hemolytic streptococci?

A) Bacitracin
B) Hippurate hydrolysis
C) Pyrrolidonyl-a-naphthylamide (PYR)
D) Optochin

Question 11

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) lyses fibrin clots.

Question 12

What test presumptively differentiates $\beta$ -hemolytic Group A streptococci and nonhemolytic Group D enterococci from other streptococcal species?

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

Question 13

What test differentiates staphylococci from streptococci?

A) Catalase
B) Coagulase
C) $\beta$ -Hemolysis
D) All of the above

Question 14

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.

Question 15

Which of following is found in the cell wall made of streptococci and enterococci?

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

Question 16

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

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

Question 17

What is the hemolysin responsible for hemolysis on SBA by Group A streptococci incubated anaerobically?

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

Question 18

Which two tests are often used in the identification of the non- $\beta$ -hemolytic, catalase-negative, gram-positive cocci?

A) Bacitracin and CAMP
B) Hippurate hydrolysis and optochin
C) Nitrate and CAMP
D) Bile esculin and salt tolerance

Question 19

All of the following are virulence factors associated with Group A Streptococcus, except

A) enterotoxins.
B) hemolysins.
C) toxins.
D) enzymes.

Question 20

What causes the red spreading rash in scarlet fever?

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

Question 21

Why do Streptococcus pneumoniae colonies on SBA sometimes 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 22

Two serious complications of an infection with Group A streptococci 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

A microbiologist is reading a sputum culture on the bench. There is growth on the BAP and CHOC plates, but no growth on the MAC plate. The colonies growing on the BAP have discolored the media to a green color around and under the colonies. What organism could this be?

A) Escherichia coli
B) Staphylococcus aureus
C) Haemophilus influenzae
D) Streptococcus pneumoniae

Question 24

What is VRE?

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

Question 25

A patient comes to the emergency department with a productive cough, shortness of breath, and a fever of 102° F. The patient is diagnosed with pneumonia. What organism commonly encountered in the microbiology laboratory can cause this disease?

A) Streptococcus pneumoniae
B) Staphylococcus aureus
C) Escherichia coli
D) Haemophilus influenzae

Question 26

Streptococcus pneumoniae causes all the following infections, except

A) pharyngitis.
B) pneumonia.
C) bacteremia.
D) meningitis.

Question 27

What organism on SBA has grayish white colonies surrounded by a small zone of $\beta$ -hemolysis?

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

Question 28

What organism forms small, transparent colonies surrounded by a wide zone of $\beta$ -hemolysis on SBA?

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

Question 29

A young girl goes to her physician'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 order?

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

Question 30

The major virulence factor for Streptococcus pneumoniae is

A) hemolysin.
B) protease.
C) hyaluronidase.
D) capsular polysaccharide.

Question 31

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 32

A 57-year-old male presents to the emergency department with a fever, productive cough, and complaining of chest pain. A STAT Gram stain reveals gram-positive oval-shaped cocci in pairs. You should suspect

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

Question 33

Where are the viridans streptococci constituents of the normal microbiota?

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

Question 34

What are two tests presumptively used to identify Group B streptococci?

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

Question 35

Streptococcus agalactiae is a significant cause of

A) pharyngitis.
B) cystitis.
C) invasive disease of the newborn.
D) vaginitis.

Question 36

Streptococcus-like organisms that resemble enterococci and viridans streptococci include all the following, except

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

Question 37

What two tests are presumptively used to identify Enterococcus?

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

Question 38

A microbiologist is reading a vaginal culture on the bench. There is growth on the SBA and chocolate (CHOC) plates, but no growth on the MacConkey (MAC) plate. The colonies growing on the SBA have produced a narrow, diffuse zone of $\beta$ -hemolysis around and under the colonies. What organism could this be?

A) Escherichia coli
B) Streptococcus agalactiae
C) Streptococcus pyogenes
D) Streptococcus pneumoniae

Question 39

A microbiologist is reading a sputum culture on the bench. There is growth on the SBA and chocolate (CHOC) plates, but no growth on the MacConkey (MAC) plate. The colonies growing on the SBA have produced a wide, deep, clear zone of $\beta$ -hemolysis around and under the colonies. What organism could this be?

A) Escherichia coli
B) Staphylococcus aureus
C) Streptococcus pyogenes
D) Streptococcus pneumoniae

Question 40

What disease is produced by Group A streptococci that are 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