Question 1

Changes in what host structures can result in lower virulence of a microorganism?

Accepted Answer

A) Pili 
B) Adhesin receptors 
C) Surface polysaccharides 
D) Phagocytes 
A) Pili 
B) Adhesin receptors 
C) Surface polysaccharides 
D) Phagocytes B

Question 2

Organisms that participate in a biologic relationship where both benefit from one another are called:

Accepted Answer

A) parasites. 
B) symbionts. 
C) hosts. 
D) flora. 
A) parasites. 
B) symbionts. 
C) hosts. 
D) flora. B

Question 3

What is the name of a leukocidin that is lethal to leukocytes and produced by staphylococci?

Accepted Answer

A) Panton-Valentine 
B) Lancefield 
C) Hemolysin 
D) Adhesins 
A) Panton-Valentine 
B) Lancefield 
C) Hemolysin 
D) Adhesins A

Question 4

Diabetics may sometimes be infected with their own resident flora.This type of infection is called:

Accepted Answer

A) an opportunistic infection. 
B) a carrier state. 
C) symbiosis. 
D) a parasitic infection. 
A) an opportunistic infection. 
B) a carrier state. 
C) symbiosis. 
D) a parasitic infection.

Question 5

After perforation of the colon, surgeons must guard against infection in the _____ because of leakage of the contents of the colon.

Accepted Answer

A) peritoneal cavity 
B) urinary bladder 
C) vaginal flora 
D) renal vein 
A) peritoneal cavity 
B) urinary bladder 
C) vaginal flora 
D) renal vein

Question 6

What mechanism allows strict anaerobes to grow in the cervices and areas between the teeth when plaque is present?

Accepted Answer

A) A low oxidation-reduction potential occurs at the tooth surface under the plaque. 
B) The bacteria secrete sugar to nourish the strict anaerobes. 
C) The normal flora secrete antibiotics to kill all the other bacteria and allow the strict anaerobes to thrive. 
D) The plaque-causing bacteria secrete an alkaline fluid and change the pH around the tooth. 
A) A low oxidation-reduction potential occurs at the tooth surface under the plaque. 
B) The bacteria secrete sugar to nourish the strict anaerobes. 
C) The normal flora secrete antibiotics to kill all the other bacteria and allow the strict anaerobes to thrive. 
D) The plaque-causing bacteria secrete an alkaline fluid and change the pH around the tooth.

Question 7

Dissemination of a pathogen is when:

Accepted Answer

A) a pathogen penetrates and grows in tissues. 
B) a pathogen multiplies intracellularly. 
C) a pathogen circumvents host antibodies by shifting key cell-surface antigens. 
D) infection with a pathogen spreads from the initial infection site to distant sites such as organs and tissues. 
A) a pathogen penetrates and grows in tissues. 
B) a pathogen multiplies intracellularly. 
C) a pathogen circumvents host antibodies by shifting key cell-surface antigens. 
D) infection with a pathogen spreads from the initial infection site to distant sites such as organs and tissues.

Question 8

A physician notices that several patients are infected with Clostridium difficile, but only a few of the patients are symptomatic for disease.The reason for this discrepancy is:

Accepted Answer

A) only those strains of the organism carrying the extrachromosomal DNA coding for the toxin gene will produce toxin and cause the individuals to be symptomatic. 
B) only those strains of the organism carrying DNA coding for the toxin within its main DNA molecule will produce toxin and cause the individuals to be symptomatic. 
C) the exotoxin produced contains only the nontoxic portion. 
D) the exotoxin must be produced in conjunction with extracellular enzymes to cause problems. 
A) only those strains of the organism carrying the extrachromosomal DNA coding for the toxin gene will produce toxin and cause the individuals to be symptomatic. 
B) only those strains of the organism carrying DNA coding for the toxin within its main DNA molecule will produce toxin and cause the individuals to be symptomatic. 
C) the exotoxin produced contains only the nontoxic portion. 
D) the exotoxin must be produced in conjunction with extracellular enzymes to cause problems.

Question 9

One of the most effective defenses bacteria have against phagocytosis is:

Accepted Answer

A) enzymes. 
B) the capsule. 
C) plasmids. 
D) lipopolysaccharide layer. 
A) enzymes. 
B) the capsule. 
C) plasmids. 
D) lipopolysaccharide layer.

Question 10

Because infections can be encountered via the air, _____ can cause transmission of some pathogens.

Accepted Answer

A) cuts 
B) eyes 
C) coughing 
D) eating 
A) cuts 
B) eyes 
C) coughing 
D) eating

Question 11

The stomach can be considered a first line of defense against microbial infections because:

Accepted Answer

A) most microorganisms are susceptible to the antibiotics and alkaline pH present in the stomach. 
B) most microorganisms are killed by the liver enzymes that are emptied into the stomach during a meal. 
C) the stomach produces proteases, which attacks the lipopolysaccharide cell wall of the organisms. 
D) most microorganisms are susceptible to the acid pH of the stomach. 
A) most microorganisms are susceptible to the antibiotics and alkaline pH present in the stomach. 
B) most microorganisms are killed by the liver enzymes that are emptied into the stomach during a meal. 
C) the stomach produces proteases, which attacks the lipopolysaccharide cell wall of the organisms. 
D) most microorganisms are susceptible to the acid pH of the stomach.

Question 12

The classic example of a bite-wound infection is:

Accepted Answer

A) rabies. 
B) S.aureus. 
C) plague. 
D) Ebola. 
A) rabies. 
B) S.aureus. 
C) plague. 
D) Ebola.

Question 13

What type of bacteria is able to live in the colon with little to no oxygen and is the predominant organism?

Accepted Answer

A) Anaerobes 
B) Facultative anaerobes 
C) Facultative gram-negative rods 
D) Gram-positive cocci 
A) Anaerobes 
B) Facultative anaerobes 
C) Facultative gram-negative rods 
D) Gram-positive cocci

Question 14

During the childbearing years, the normal flora of the vagina maintain a low pH, thus encouraging colonization with all the following types of organisms except:

Accepted Answer

A) lactobacilli. 
B) gram-negative rods. 
C) anaerobic gram-negative bacilli. 
D) gram-positive cocci. 
A) lactobacilli. 
B) gram-negative rods. 
C) anaerobic gram-negative bacilli. 
D) gram-positive cocci.

Question 15

What virus causes immune suppression in the host by targeting and destroying the host's CD4+ T cells?

Accepted Answer

A) HIV 
B) Hepatitis B 
C) Epstein-Barr 
D) Cytomegalovirus 
A) HIV 
B) Hepatitis B 
C) Epstein-Barr 
D) Cytomegalovirus

Question 16

Factors that determine the pathogenicity and increase the virulence of organisms include all the following except an organism's ability to:

Accepted Answer

A) avoid phagocytosis. 
B) produce exotoxins and extracellular enzymes. 
C) produce infection when host conditions change. 
D) survive intracellularly when phagocytized. 
A) avoid phagocytosis. 
B) produce exotoxins and extracellular enzymes. 
C) produce infection when host conditions change. 
D) survive intracellularly when phagocytized.

Question 17

Healthy skin secretes what substances to help prevent colonization by transient and possibly pathogenic organisms?

Accepted Answer

A) Long-chain fatty acids 
B) Sebaceous glands 
C) Carbohydrates 
D) Antibodies 
A) Long-chain fatty acids 
B) Sebaceous glands 
C) Carbohydrates 
D) Antibodies

Question 18

The human body is constantly challenged by pathogens in the environment.It is not infected by every pathogen it encounters because the microbial flora:

Accepted Answer

A) engulf the pathogenic bacteria. 
B) produce conditions at the microenvironmental level that block colonization. 
C) prime our immune system. 
D) activate and support the action of antigen-presenting cells, cytokines, and cell-mediated immunity. 
A) engulf the pathogenic bacteria. 
B) produce conditions at the microenvironmental level that block colonization. 
C) prime our immune system. 
D) activate and support the action of antigen-presenting cells, cytokines, and cell-mediated immunity.

Question 19

Mechanisms used by the skin to prevent infection and protect the underlying tissue from invasion by potential pathogens include all the following except:

Accepted Answer

A) desquamation of the epithelium. 
B) excretion of lysozyme by sweat glands. 
C) antibiotics that inhibit many microorganisms. 
D) mechanical separation of microorganisms from the tissues. 
A) desquamation of the epithelium. 
B) excretion of lysozyme by sweat glands. 
C) antibiotics that inhibit many microorganisms. 
D) mechanical separation of microorganisms from the tissues.

Question 20

All the following are potentially pathogenic organisms found in the nasopharynx of healthy individuals except:

Accepted Answer

A) Haemophilus influenzae. 
B) Streptococcus pneumoniae. 
C) Streptococcus mutans. 
D) Neisseria meningitidis. 
A) Haemophilus influenzae. 
B) Streptococcus pneumoniae. 
C) Streptococcus mutans. 
D) Neisseria meningitidis.

Exam 2: Host-Parasite Interaction

Changes in what host structures can result in lower virulence of a microorganism?

Organisms that participate in a biologic relationship where both benefit from one another are called:

What is the name of a leukocidin that is lethal to leukocytes and produced by staphylococci?

Diabetics may sometimes be infected with their own resident flora.This type of infection is called:

After perforation of the colon, surgeons must guard against infection in the _____ because of leakage of the contents of the colon.

What mechanism allows strict anaerobes to grow in the cervices and areas between the teeth when plaque is present?

Dissemination of a pathogen is when:

A physician notices that several patients are infected with Clostridium difficile, but only a few of the patients are symptomatic for disease.The reason for this discrepancy is:

One of the most effective defenses bacteria have against phagocytosis is:

Because infections can be encountered via the air, _____ can cause transmission of some pathogens.

The stomach can be considered a first line of defense against microbial infections because:

The classic example of a bite-wound infection is:

What type of bacteria is able to live in the colon with little to no oxygen and is the predominant organism?

During the childbearing years, the normal flora of the vagina maintain a low pH, thus encouraging colonization with all the following types of organisms except:

What virus causes immune suppression in the host by targeting and destroying the host's CD4+ T cells?

Factors that determine the pathogenicity and increase the virulence of organisms include all the following except an organism's ability to:

Healthy skin secretes what substances to help prevent colonization by transient and possibly pathogenic organisms?

The human body is constantly challenged by pathogens in the environment.It is not infected by every pathogen it encounters because the microbial flora:

Mechanisms used by the skin to prevent infection and protect the underlying tissue from invasion by potential pathogens include all the following except:

All the following are potentially pathogenic organisms found in the nasopharynx of healthy individuals except:

Bacterial Cell Structure, Physiology, Metabolism, and Genetics

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

Use of Colony Morphology for the Presumptive Identification of Microorganisms

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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