Question 1

Plate reading is:

Accepted Answer

A) examining the colonial morphology of bacteria. 
B) a comparative examination of bacteria growing on a variety of culture media. 
C) setting up biochemical tests to identify bacteria. 
D) determining if the inoculum is mixed. 
A) examining the colonial morphology of bacteria. 
B) a comparative examination of bacteria growing on a variety of culture media. 
C) setting up biochemical tests to identify bacteria. 
D) determining if the inoculum is mixed. B

Question 2

When differentiating colony size on the culture plates, what organisms generally have the larger colonies by comparison?

Accepted Answer

A) Gram-negative rods 
B) Gram-positive cocci 
C) Gram-negative diplococci 
D) Gram-positive rods 
A) Gram-negative rods 
B) Gram-positive cocci 
C) Gram-negative diplococci 
D) Gram-positive rods A

Question 3

A microbiologist is reading stool culture plates.She sees an organism that has a large, mucoid pink colony on MacConkey (MAC).What is a good presumptive identification of this organism?

Accepted Answer

A) Enteric pathogen 
B) Escherichia/Citrobacter-like organism 
C) Klebsiella/Enterobacter-like organism 
D) Haemophilus influenzae 
A) Enteric pathogen 
B) Escherichia/Citrobacter-like organism 
C) Klebsiella/Enterobacter-like organism 
D) Haemophilus influenzae C

Question 4

What bacteria is said to have a fruity or grapelike smell?

Accepted Answer

A) Staphylococcus aureus 
B) Proteus mirabilis 
C) Pseudomonas aeruginosa 
D) Nocardia sp. 
A) Staphylococcus aureus 
B) Proteus mirabilis 
C) Pseudomonas aeruginosa 
D) Nocardia sp.

Question 5

Colony morphology is defined as colony:

Accepted Answer

A) characteristics and form. 
B) size and color. 
C) smell and shape. 
D) constitution and environmental conditions. 
A) characteristics and form. 
B) size and color. 
C) smell and shape. 
D) constitution and environmental conditions.

Question 6

When looking at a tube of thioglycollate broth, streamers or vines and puffballs are visible.What organism grows like this in thioglycollate?

Accepted Answer

A) Gram-negative rods (Enterobacteriaceae) 
B) Streptococcus spp. 
C) Yeast 
D) Pseudomonas spp. 
A) Gram-negative rods (Enterobacteriaceae) 
B) Streptococcus spp. 
C) Yeast 
D) Pseudomonas spp.

Question 7

The colonies of this organism form large, rough, greenish, hemolytic colonies on blood agar.What organism is it?

Accepted Answer

A) Staphylococcus aureus 
B) Escherichia coli 
C) Streptococcus pyogenes 
D) Bacillus cereus 
A) Staphylococcus aureus 
B) Escherichia coli 
C) Streptococcus pyogenes 
D) Bacillus cereus

Question 8

Swarming is:

Accepted Answer

A) many bacterial colonies crowded together at one place on the agar plate. 
B) when colonies on a blood agar plate have a "halo" around the bacterial colony. 
C) when a bacterial colony on a blood agar plate grows over the top of the erythrocytes it hemolyzed. 
D) a hazy blanket of growth on the surface of the agar that extends way beyond the streak lines. 
A) many bacterial colonies crowded together at one place on the agar plate. 
B) when colonies on a blood agar plate have a "halo" around the bacterial colony. 
C) when a bacterial colony on a blood agar plate grows over the top of the erythrocytes it hemolyzed. 
D) a hazy blanket of growth on the surface of the agar that extends way beyond the streak lines.

Question 9

A microbiologist is reading stool culture plates.She sees an organism that has a dry, pink colony with a surrounding "halo" of pink on MacConkey (MAC).What is a good presumptive identification of this organism?

Accepted Answer

A) Enteric pathogen 
B) Escherichia/Citrobacter-like organism 
C) Klebsiella/Enterobacter-like organism 
D) Haemophilus influenzae 
A) Enteric pathogen 
B) Escherichia/Citrobacter-like organism 
C) Klebsiella/Enterobacter-like organism 
D) Haemophilus influenzae

Question 10

A microbiologist is reading a vaginal culture on the bench.There is growth on the sheep blood agar (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 b-hemolysis around and under the colonies.What organism could this be?

Accepted Answer

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

Question 11

Streptococcus pneumoniae typically produces colonies that are said to resemble coins.The technical term for this colony shape is:

Accepted Answer

A) umbonate. 
B) flat. 
C) umbilicate. 
D) raised. 
A) umbonate. 
B) flat. 
C) umbilicate. 
D) raised.

Question 12

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?

Accepted Answer

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

Question 13

A microbiologist is reading the plates from a sputum culture.The culture is from a patient with cystic fibrosis.One organism dominates the blood agar, chocolate, and MacConkey plates.The MacConkey plate shows an organism with a green pigment and a metallic sheen.The probable identification for this organism is:

Accepted Answer

A) Pseudomonas aeruginosa. 
B) Serratia marcescens. 
C) Chromobacterium violaceum. 
D) Prevotella melaninogenica. 
A) Pseudomonas aeruginosa. 
B) Serratia marcescens. 
C) Chromobacterium violaceum. 
D) Prevotella melaninogenica.

Question 14

a-Hemolysis is:

Accepted Answer

A) complete clearing of erythrocytes in a blood agar plate around and under the colony. 
B) partial lysing of erythrocytes in a blood agar plate around and under the colony. 
C) when organisms have no lytic effect on the erythrocytes in the blood agar plate. 
D) a pink "halo" around a colony. 
A) complete clearing of erythrocytes in a blood agar plate around and under the colony. 
B) partial lysing of erythrocytes in a blood agar plate around and under the colony. 
C) when organisms have no lytic effect on the erythrocytes in the blood agar plate. 
D) a pink "halo" around a colony.

Question 15

MacConkey agar is used to:

Accepted Answer

A) differentiate between hemolytic and nonhemolytic gram-negative rods. 
B) show the clear, pinpoint colonies of Haemophilus influenzae. 
C) demonstrate the large, pink colonies of Neisseria meningitidis. 
D) differentiate between lactose fermenters and lactose nonfermenters. 
A) differentiate between hemolytic and nonhemolytic gram-negative rods. 
B) show the clear, pinpoint colonies of Haemophilus influenzae. 
C) demonstrate the large, pink colonies of Neisseria meningitidis. 
D) differentiate between lactose fermenters and lactose nonfermenters.

Question 16

Which of the following descriptions will directly facilitate identification of bacteria?

Accepted Answer

A) Environmental growth temperature 
B) Physical characteristics of colony morphology 
C) Environmental growth atmosphere 
D) Colony color 
A) Environmental growth temperature 
B) Physical characteristics of colony morphology 
C) Environmental growth atmosphere 
D) Colony color

Question 17

The elevation of bacterial colonies is described by all the following except:

Accepted Answer

A) raised. 
B) pointed. 
C) convex. 
D) umbilicate. 
A) raised. 
B) pointed. 
C) convex. 
D) umbilicate.

Question 18

A microbiologist is reading a sputum culture on the bench.There is growth on the sheep blood agar (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 b-hemolysis around and under the colonies.What organism could this be?

Accepted Answer

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

Question 19

b-Hemolysis is:

Accepted Answer

A) complete clearing of erythrocytes in a blood agar plate around and under the colony. 
B) partial lysing of erythrocytes in a blood agar plate around and under the colony. 
C) when organisms have no lytic effect on the erythrocytes in the blood agar plate. 
D) a pink "halo" around a colony. 
A) complete clearing of erythrocytes in a blood agar plate around and under the colony. 
B) partial lysing of erythrocytes in a blood agar plate around and under the colony. 
C) when organisms have no lytic effect on the erythrocytes in the blood agar plate. 
D) a pink "halo" around a colony.

Question 20

What organism forms a small, fuzzy-edged colony with an umbonate center on blood or chocolate agar?

Accepted Answer

A) Eikenella corrodens 
B) Staphylococcus aureus 
C) Escherichia coli 
D) Streptococcus pyogenes 
A) Eikenella corrodens 
B) Staphylococcus aureus 
C) Escherichia coli 
D) Streptococcus pyogenes

Exam 8: Use of Colony Morphology for the Presumptive Identification of Microorganisms

Plate reading is:

When differentiating colony size on the culture plates, what organisms generally have the larger colonies by comparison?

A microbiologist is reading stool culture plates.She sees an organism that has a large, mucoid pink colony on MacConkey (MAC).What is a good presumptive identification of this organism?

What bacteria is said to have a fruity or grapelike smell?

Colony morphology is defined as colony:

When looking at a tube of thioglycollate broth, streamers or vines and puffballs are visible.What organism grows like this in thioglycollate?

The colonies of this organism form large, rough, greenish, hemolytic colonies on blood agar.What organism is it?

Swarming is:

A microbiologist is reading stool culture plates.She sees an organism that has a dry, pink colony with a surrounding "halo" of pink on MacConkey (MAC).What is a good presumptive identification of this organism?

Streptococcus pneumoniae typically produces colonies that are said to resemble coins.The technical term for this colony shape is:

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-Hemolysis is:

MacConkey agar is used to:

Which of the following descriptions will directly facilitate identification of bacteria?

The elevation of bacterial colonies is described by all the following except:

b-Hemolysis is:

What organism forms a small, fuzzy-edged colony with an umbonate center on blood or chocolate agar?

Bacterial Cell Structure, Physiology, Metabolism, and Genetics

Host-Parasite Interaction

The Laboratory Role in Infection Control

Control of Microorganisms

Performance Improvement in the Microbiology Laboratory

Specimen Collection and Processing

Microscopic Examination of Materials From Infected Sites

Biochemical Identification of Gram-Negative Bacteria

Immunodiagnosis of Infectious Diseases

Applications of Molecular Diagnostics

Antimicrobial Agent Mechanisms of Action and Resistance

Antimicrobial Susceptibility Testing

Staphylococci

Streptococcus, Enterococcus, and Other Catalase-Negative, Gram-Positive Cocci

Aerobic Gram-Positive Bacilli

Neisseria Species and Moraxella Catarrhalis

Haemophilus and Other Fastidious Gram-Negative Bacilli

Enterobacteriaceae

Vibrio, Aeromonas, Plesiomonas, and Campylobacter Species

Nonfermenting and Miscellaneous Gram-Negative Bacilli

Anaerobes of Clinical Importance

The Spirochetes

Chlamydia, Rickettsia and Similar Organisms

Mycoplasma and Ureaplasma

Mycobacterium Tuberculosis and Nontuberculous Mycobacteria

Medically Significant Fungi

Diagnostic Parasitology

Clinical Virology

Agents of Bioterror and Forensic Microbiology

Biofilms: Architects of Disease

Upper and Lower Respiratory Tract Infections

Skin and Soft Tissue Infections

Gastrointestinal Infections and Food Poisoning

Infections of the Central Nervous System

Bacteremia and Sepsis

Urinary Tract Infections

Genital Infections and Sexually Transmitted Diseases

Infections in Special Populations

Zoonotic Diseases

Ocular Infections

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