Chapter 15 Study Questions

D) gram-negative bacterial infections.

Antibiotics can lead to septic shock if used to treat A) gram-positive bacterial infections. B) helminth infestations. C) protozoan infections. D) gram-negative bacterial infections. E) viral infections.

A) boiling food prior to consumption.

Botulism is caused by ingestion of a proteinaceous exotoxin; therefore, it can easily be prevented by A) boiling food prior to consumption. B) not eating canned food. C) administering antibiotics to patients. D) preventing fecal contamination of food. E) filtering food.

E) erythrogenic toxin.

Twenty-five people developed symptoms of nausea, vomiting, and diarrhea three to six hours after attending a church picnic where they ate a ham and green bean casserole with cream sauce. The most likely cause of this case of food intoxication is A) botulinum toxin. B) cholera toxin. C) staphylococcal enterotoxin. D) aflatoxin. E) erythrogenic toxin.

C) Legionella pneumophila

Which most easily causes an infection? A) E. coli O157:H7 (ID50=20) B) Treponema pallidum (ID50=57) C) Legionella pneumophila (ID50=1) D) Shigella (ID50=10) E) It cannot be determined from the information provided.

E) numbers of microorganisms that gain access to a host, evasion of host defenses, and toxin production

Which of the following contributes to the virulence of a pathogen? A) toxin production B) evasion of host defenses C) numbers of microorganisms that gain access to a host D) numbers of microorganisms that gain access to a host and evasion of host defenses E) numbers of microorganisms that gain access to a host, evasion of host defenses, and toxin production

B) release of enzymes from lysosomes

Which of the following cytopathic effects is cytocidal? A) giant cells B) release of enzymes from lysosomes C) antigenic changes D) inclusion bodies E) transformation

A) cell walls

Which of the following does NOT contribute to the symptoms of a fungal disease? A) cell walls B) toxins C) allergic response of the host D) capsules E) metabolic products

B) toxin production

Which of the following is NOT a cytopathic effect of viruses? A) inclusion bodies forming in the cytoplasm or nucleus B) toxin production C) increased cell growth D) host cells fusing to form multinucleated syncytia E) cell death

D) A-B toxin

Which of the following is NOT a membrane-disrupting toxin? A) streptolysin O B) streptolysin S C) hemolysin D) A-B toxin E) leukocidin

B) the invasion and lysis of intestinal cells by E. coli

Which of the following is an example of direct damage due to bacterial infection? A) the uncontrolled muscle contractions in Clostridium tetani infection B) the invasion and lysis of intestinal cells by E. coli C) the fever, nausea, and low blood pressure in a Salmonella infection D) the hemolysis of red blood cells in a staphylococcal infection E) the excessive secretion of fluids in a Vibrio cholera infection

E) inducing TNF

Which of the following mechanisms is used by gram-negative bacteria to cross the blood-brain barrier? A) inducing endocytosis B) producing fimbriae C) antigenic variation D) producing toxins E) inducing TNF

B) It is readily digested by phagocytes.

Which of the following statements about M protein is FALSE? A) It is heat- and acid-resistant. B) It is readily digested by phagocytes. C) It is a protein. D) It is found on fimbriae. E) It is found on Streptococcus pyogenes.

C) They are resistant to heat.

Which of the following statements about exotoxins is generally FALSE? A) They are more potent than endotoxins. B) They are composed of proteins. C) They are resistant to heat. D) They are produced by gram-positive bacteria. E) They have specific methods of action.

E) It is produced by Staphylococcus aureus growing in the host's intestines.

Which of the following statements about staphylococcal enterotoxin is FALSE? A) It causes diarrhea. B) It is an exotoxin. C) It causes vomiting. D) It is a superantigen. E) It is produced by Staphylococcus aureus growing in the host's intestines.

D) Coagulase destroys blood clots.

Which of the following statements is FALSE? A) Hemolysins lyse red blood cells. B) Kinase destroys fibrin clots. C) Leukocidins destroy neutrophils. D) Coagulase destroys blood clots. E) Hyaluronidase breaks down substances between cells.

E) It cannot be determined from the information provided.

Which organism causes the most severe disease? A) E. coli O157:H7 (ID50=20) B) Treponema pallidum (ID50=57) C) Legionella pneumophila (ID50=1) D) Shigella (ID50=10) E) It cannot be determined from the information provided.

C) LPS is released from gram-negative bacteria.

Gram-negative septic shock results from the following events. What is the second step? A) IL-1 is released. B) Body temperature is reset in the hypothalamus. C) LPS is released from gram-negative bacteria. D) Phagocytes ingest gram-negative bacteria. E) Fever occurs.

E) a decrease in blood pressure.

In response to the presence of endotoxin, phagocytes secrete tumor necrosis factor. This causes A) a fever. B) the disease to subside. C) a aram-negative infection. D) an increase in red blood cells. E) a decrease in blood pressure.

C) the Limulus amoebocyte lysate test.

Injectable drugs are tested for endotoxins by A) culturing bacteria. B) filtering out the cells. C) the Limulus amoebocyte lysate test. D) looking for turbidity. E) counting the viable bacteria.

A) give new gene sequences to the host bacteria.

Lysogenic bacteriophages contribute to bacterial virulence because bacteriophages A) give new gene sequences to the host bacteria. B) carry plasmids. C) kill human cells. D) kill the bacteria, causing release of endotoxins. E) produce toxins.

E) iron-transport proteins.

Siderophores are bacterial proteins that compete with the host's A) receptors. B) white blood cells. C) antibodies. D) red blood cells. E) iron-transport proteins.

D) toxins.

All of the following contribute to a pathogen's invasiveness EXCEPT A) cell wall components. B) hyaluronidase. C) coagulases. D) toxins. E) capsules.

B) Salmonella typhi.

All of the following organisms produce exotoxins EXCEPT A) Clostridium botulinum. B) Salmonella typhi. C) Corynebacterium diphtheriae. D) Clostridium tetani. E) Staphylococcus aureus.

A) Clostridium botulinum.

All of the following bacteria release endotoxin EXCEPT A) Clostridium botulinum. B) Salmonella typhi. C) Neisseria meningitidis. D) Haemophilus influenzae. E) Proteus vulgaris.

B) hair follicle.

All of the following are examples of entry via the parenteral route EXCEPT A) surgery. B) hair follicle. C) injection. D) skin cut. E) bite.

C) membrane-disrupting toxins.

All of the following are methods of avoiding host antibodies EXCEPT A) antigenic changes. B) inducing endocytosis. C) membrane-disrupting toxins. D) IgA proteases. E) invasins.

B) A-B toxins.

All of the following are used by bacteria to attach to host cells EXCEPT A) ligands. B) A-B toxins. C) M protein. D) capsules. E) fimbriae.

E) engulf the bacteria.

Bacteria such as E. coli and Salmonella produce invasins that bind host cells, thus causing the cells to A) destroy the bacteria. B) release TNF. C) release cytokines. D) produce iron-binding proteins. E) engulf the bacteria.

E) streptococcal colonization is necessary for periodontal disease.

Bacteria that cause periodontal disease have adhesins for receptors on streptococci that colonize on teeth. This indicates that A) streptococci cause periodontal disease. B) streptococci get bacterial infections. C) bacteria that cause periodontal disease adhere to gums and teeth. D) bacteria that cause periodontal disease adhere to teeth. E) streptococcal colonization is necessary for periodontal disease.

C) polypeptide B would not be able to enter the cells.

Cholera toxin polypeptide A binds to surface gangliosides on target cells. If the gangliosides were removed, A) Vibrio would bind to target cells. B) polypeptide A would enter the cells. C) polypeptide B would not be able to enter the cells. D) polypeptide A would bind to target cells. E) Vibrio would not produce cholera toxin.

B) viral infections.

Cytopathic effects are changes in host cells due to A) helminthic infections. B) viral infections. C) protozoan infections. D) fungal infections. E) bacterial infections.

B) part of the gram-negative cell wall.

Endotoxins are A) excreted from the cell. B) part of the gram-negative cell wall. C) A-B toxins. D) molecules that bind nerve cells. E) associated with gram-positive bacteria.

D) septic shock symptoms.

Endotoxins in sterile injectable drugs could cause A) giant cell formation. B) infection. C) nerve damage. D) septic shock symptoms. E) no damage, because they are sterile.

B) enter through hair follicles and sweat ducts.

Most pathogens that gain access through the skin A) just infect the skin itself. B) enter through hair follicles and sweat ducts. C) must adhere first while their invasive factors allow them to penetrate. D) must be injected. E) can penetrate intact skin.

C) transduction.

Nonpathogenic Vibrio cholerae can acquire the cholera toxin gene by A) infecting a pathogenic Vibrio cholerae. B) conjugation. C) transduction. D) transformation. E) phagocytosis.

C) endotoxin.

Patients developed inflammation a few hours following eye surgery. Instruments and solutions were sterile, and the Limulus assay was positive. The patients' inflammation was due to A) viral infection. B) exotoxin. C) endotoxin. D) bacterial infection. E) The answer cannot be determined based on the information provided.

C) mucous membranes only

Polio is transmitted by ingestion of water contaminated with feces containing polio virus. What portal of entry does polio virus use? A) skin only B) parenteral only C) mucous membranes only D) skin and parenteral E) skin, parenteral, and mucous membranes

C) cytokines.

Superantigens produce intense immune responses by stimulating lymphocytes to produce A) leukocidins. B) exotoxins. C) cytokines. D) endotoxins. E) interferons.

C) superantigens.

Symptoms of intense inflammation and shock occur in some gram-positive bacterial infections due to A) erythrogenic toxin. B) A-B toxins. C) superantigens. D) membrane-disrupting toxins. E) lipid A.

E) tissue damage due to growth of the parasite on the tissues, waste products excreted by the parasite, and products released from damaged tissues.

Symptoms of protozoan and helminthic diseases are due to A) tissue damage due to growth of the parasite on the tissues. B) waste products excreted by the parasite. C) products released from damaged tissues. D) tissue damage due to growth of the parasite on the tissues and waste products excreted by the parasite. E) tissue damage due to growth of the parasite on the tissues, waste products excreted by the parasite, and products released from damaged tissues.

D) decreases the risk of staphylococcal infection.

Table 15.1 shows the ID50 for Staphylococcus aureus in wounds with and without the administration of ampicillin before surgery. ID50 jumps from <10 to 300 with ampicillin use. Based on the data, the administration of ampicillin before surgery A) has no effect on risk of infection. B) increases the risk of staphylococcal infection. C) replaces tetracycline. D) decreases the risk of staphylococcal infection. E) The answer cannot be determined based on the information provided.

E) the dose that will cause an infection in 50 percent of the test population.

The ID50 is A) the dose that will kill 50 percent of the test population. B) a measure of pathogenicity. C) the dose that will kill some of the test population. D) the dose that will cause an infection in some of the test population. E) the dose that will cause an infection in 50 percent of the test population.

C) antigenic variation.

The ability of some microbes, such as Trypanosoma or Giardia to alter their surface molecules and evade destruction by the host's antibodies is called A) lysogenic conversion. B) virulence. C) antigenic variation. D) cytocidal effect. E) cytopathic effect.

D) adhesins and ligands.

The fimbriae of Neisseria gonorrhea and enteropathogenic E. coli are examples of A) receptors. B) ligands. C) adhesins. D) adhesins and ligands. E) adhesins, ligands, and receptors

C) mucous membranes of the respiratory tract.

The most frequently used portal of entry for pathogens is the A) parenteral route. B) skin. C) mucous membranes of the respiratory tract. D) mucous membranes of the gastrointestinal tract. E) All of these portals are used equally.