FREE LABORATORY SCIENCE AND STUDY GAMES ABOUT

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FREE LABORATORY SCIENCE AND STUDY GAMES ABOUT

MICROBIOLOGY EXAM QUESTIONS

Actual Qs and Ans Expert-Verified Explanation

This Exam contains:

-Guarantee passing score -37 Questions and Answers -format set of multiple-choice -Expert-Verified Explanation Question 1: Group B, beta-hemolytic streptococci may be distinguished from other hemolytic streptococci by which procedure?

Answer:

latex antigen typing Question 2: Which is the MOST frequent cause of prosthetic heart valve infections occurring

within 2-3 months after surgery is:

Answer:

Staphylococcus epidermidis Question 3: Gram-positive cocci in chains are seen on a Gram stain from a blood culture. The organism grows as a beta-hemolytic colony. Further tests that could be performed include:

Answer:

bile esculin, PYR, bacitracin, and hippurate Question 4: The enterotoxin produced by certain strains of hemolytic, coagulase positive

Staphylococcus aureus:

Answer:

causes one type of bacterial food poisoning

Question 5: Which 2 diseases are usually preceded by infection with beta-hemolytic streptococci?

Answer:

glomerulonephritis and rheumatic fever Question 6: A urine Gram stain shows gram-positive cocci in clusters. The organisms tested catalase positive. To SPECIATE this organism form culture, the tech should perform a

coagulase test and a/an:

Answer:

novobiocin susceptibility Question 7: In the optochin susceptibility test, if there is a zone of inhibition of 19-30mm surrounding the disk following overnight incubation at 37C, the colony MOST likely consist of:

Answer:

pneumococci Question 8: An important cause of acute exudative pharyngitis is:

Answer:

Streptococcus pyogenes Question 9: Which would best differentiate Streptococcus agalactiae from Streptococcus pyogenes?

Answer:

hydrolysis of sodium hippurate Question 10: Which organism may be used as a positive quality control organism for the bile esculin test?

Answer:

Enterococcus faecalis Question 11: It is important to differentiate between Enterococcus and group D strep because:

Answer:

enterococci often show more antibiotic resistance than group D streptococci

Question 12: A beta-hemolytic Streptococcus that is bacitracin-resistant and CAMP-positive is"

Answer:

group B Question 13: A gamma-hemolytic Streptococcus that blackens bile esculin agar but does not

grow in 6.5% NaCl broth is MOST likely:

Answer:

group D Streptococcus Question 14: Characteristically, enterococci are:

Answer:

relatively resistant to penicillin Question 15: The organism MOST commonly associated with neonatal purulent meningitis is:

Answer:

group B streptococci Question 16: A gram-pos coccus isolated from a blood culture has the following characteristics: optochin suscept-neg, bacitracin suscept-neg, bile esculin hydrolysis-neg, hippurate

hydrolysis-pos, catalase-neg. The organism is MOST likely:

Answer:

Streptococcus agalactiae Question 17: Gram stain examination from a blog culture bottle shows dark blue, spherical organisms in clusters. Growth on sheep blood agar shows small, round, pale yellow colonies.

Further tests should include:

Answer:

catalase production and coagulase test Question 18: The MOST critical distinction between Staphylococcus aureus and other

Staphylococcus is:

Answer:

coagulase production

Question 19: A beta-hemolytic streptococcus that has been isolated from an ear culture grows up to the edge of a 0.04 unit bacitracin disk. Which tests would help to determine if the organism is Entercoccus?

Answer:

growth in 6.5% NaCl broth Question 20: The Gram stain from a blood culture shows gram-pos cocci in chains. No growth occurs on blood agar plates incubated aerobically and anaerobically. Additional testing should

be done to detect the presence of:

Answer:

Abiotrophia defectiva Question 21: A light yellow colony from a skin lesion grew aerobically and was catalase positive and coag neg. Gram stained as positive cocci in clusters, modified oxidase positive, bacitracin susceptible and resistant to lysostaphin. The identification is?

Answer:

Micrococcus luteus

Question 22: A yellow colony from a wound culture tested catalase-positive and

coagulase-negative. The organism stained as gram-positive cocci in clusters. Which tests would differentiate between coat-neg staph and Micrococcus?

Answer:

furazolidone susceptibility Question 23: A reliable test for distinguishing Staphylococcus aureus from other

staphylococcus is:

Answer:

coagulase Question 24: Which organisms is, to date, considered universally susceptible to penicillin:

Answer:

Streptococcus pyogenes Question 25: An outbreak of Staphylococcus aureus has occurred in a hospital nursery. In order to establish the epidemiological source of the outbreak, the MOST commonly used typing

method is:

Answer:

pulsed-field ges electrophoresis