Micro Quiz 6 Strep, Enterococci, Strep like Org

Streptococcus agalactiae typically exhibits this type of hemolysis.

Beta

Abiotrophia, formerly known as nutrionally variant streptococci, will not grow on routine Blood or chocolate agars because they are deficient in:

pyridoxal

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

Bile esculin and salt tolerance

Which of the following organisms on a gram stain will typically appear in clusters and tetrads?

Pediococcus

A common member of the normal flora of the upper respiratory tract is:

Viridans streptococcus

Which organism out of the following is: catalase: Positive, PYR- Positive, LAP-Negative, 6.5% NaCl - Positive, Bile Esculin: Positive and Vancomycin: Susceptible

Aerococcus spp.

Characteristically, enterococci are;

relatively resistant to penicillin

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

Erythromycin

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

enterotoxins.

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

Pharyngitis

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?

The physician should perform a throat culture.

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

Bacitracin

Common schemes to classify streptococci include all the following, except

flagellar antigens.

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 β-hemolysis around and under the colonies. What organism could this be?

Streptococcus pyogenes

Streptococcus pneumoniae is sensitive to this antibiotic which helps differentiate it from other α-hemolytic species.

Optochin

A vaccine is available to the elderly for the prevention of infections caused by the organism:

S. pneumoniae

What two tests are used to presumptively identify Enterococcus?

Bile esculin and 6.5% NaCl broth

The bile solubility test takes advantage of the Streptococcus pneumoniae autocatalytic enzyme

amidase.

Solubility in the presence of sodium desoxycholate is characteristic of:

Streptococcus pneumoniae

The atmospheric conditions best suited to grow streptococci and enterococci are

oxygen-free atmosphere.

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

Optochin

The Streptococcal group that cannot be identified with Lancefield sera:

Viridans Group Streptococci

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

Hippurate hydrolysis

β Hemolysis is:

Complete clearing of erythrocytes in a blood agar plate around and under the colony

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?

Necrotizing fascilitis

What is VRE?

Vancomycin-resistant Enterococcus

Microorganisms associated with bacterial endocarditis include all of the following EXCEPT:

Escherichia coli

Rust colored sputum in cases of lobar pneumonia is characteristic of which of the following possible etiologic agents?

Streptococcus pneumoniae

It is recommended that all pregnant women be screened for group B streptococcus (GBS) at _____ weeks’ gestation.

35 to 37

Characteristically, enterococci are;

relatively resistant to penicillin

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

 

Gemella.

 

Lactococcus.

 

Aerococcus.

 

Moraxella.

Moraxella

Other Streptococcal groups that are beta-hemolytic and rarely human pathogens:

Group C & G

Which organism in the Streptococcaceae family may produce a pseudocatalase?

Enterococcus sp

Two serious complications of an infection with Group A streptococci are

acute glomerulonephritis and rheumatic fever.

An isolate of an unknown beta-hemolytic Streptococcus is streaked perpendicular to a streak of beta-lysin producing Staphylococcus aureus.  After incubation a zone of arrowhead hemolysis is noted at the interface of the 2 streaks.  What is the name of the test and the presumptive identification of the unknown Streptococcus?

CAMP test & S. agalactiae

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

Streptolysin O

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

Streptococcus. pneumoniae.

The bile solubility test takes advantage of the Streptococcus pneumoniae autocatalytic enzyme

amidase

A negative PYR (L-pyrolidonyl-alpha-naphthylamide) test is demonstrated by:

Viridans streptococci

It is important to differentiate between Enterococcus and group D streptococci because:

enterococci often show more antibiotic resistance than group D streptococci

A beta-hemolytic streptococci that is bacitracin-sensitive and CAMP-negative is:

Group A

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

Penicillin

Which Streptococcus virulence factor is responsible for hemolysis on sheep blood agar (SBA)incubated aerobically?

Streptolysin S

Streptococcus agalactiae typically exhibits this type of hemolysis.

Beta

Rheumatic fever typically follows

Streptococcus pyogenes pharyngitis.

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?

Streptococcus pneumoniae

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 β-hemolysis around and under the colonies. What organism could this be?

Streptococcus agalactiae

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

M proteins

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

Bacitracin

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

PYR

Which of the following may be used as a positive quality control organism for the bile esculin test?

Enterococcus faecalis

What test differentiates staphylococci from streptococci?

Catalase

Aerococci resemble this genus microscopically.

Staphylococci

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

Streptococcus agalactiae

What causes the red spreading rash in scarlet fever?

Streptococcal pyrogenic exotoxins

The _______ group and the enterococci possess the group D antigen.

Streptococcus bovis

The organism most commonly associated with neonatal purulent meningitis is:

group B streptococci

Three sets of blood cultures were obtained from an adult patient with fever and suspected endocarditis.  The aerobic bottle of one set had growth of Staphylococcus epidermidis at 5 days of incubation.  This indicates that: