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What do hyaluronidase and kinase have in common?
They are both enzymes involved in evading host defense.
According to your Concept Map, which of the following organisms exhibits antigenic variation?
Which of the following virulence factors could directly prevent phagocytosis and/or phagocytic degradation?
all of the above
How are immune cells able to detect foreign pathogens?
They are able to detect structures on the surfaces of foreign cells that are not found in the host.
How does a capsule help certain bacteria evade detection by the immune system?
The capsule is composed of polysaccharides that are similar to those found in the host; thus, the immune system does not recognize it as foreign.
How does the protozoan Trypanosoma evade detection by the immune system?
It can change the surface antigens frequently, preventing the immune system from tracking it.
How do superantigens enable pathogens to hide from the immune system if they actually stimulate the immune system?
They cause the immune system to produce an exaggerated response, distracting it from the actual pathogen.
How can capsules enable bacteria to evade the immune system?
Capsules block the complement biding sites on the surface of the pathogen.
Which of the following would be the first sign of an infection that resulted in the release of endotoxin?
Why is a release of endotoxin into the bloodstream potentially deadly?
It can lower blood pressure and cause the patient to go into shock.
How are superantigens different from other types of exotoxins?
Superantigens cause an overstimulation of the host immune system.
A person who attended a picnic early in the day develops a very high fever and is unresponsive by the evening. This person most likely has been exposed to a(n)
A patient who has been hospitalized with uncontrolled muscle spasms has probably been infected with bacteria that secrete a(n)
In mice, the LD50 for staphylococcal enterotoxin is 1350 ng/kg, and the LD50 for Shiga toxin is 250 ng/kg. Which of the following statements is true?
Shiga toxin is more lethal than staphylococcal enterotoxin.
Which of the following would be an example of an infection initiated via the parenteral route?
An individual contracts hepatitis B from an accidental stick with a contaminated needle.
Which statement regarding endotoxins is true?
One consequence of endotoxins is the activation of blood-clotting proteins.
Which type of bacterial enzyme helps spread Streptococcus pyogenes by digesting blood clots?
In which of the following cases would the Limulus amebocyte lysate (LAL) assay be used?
to ensure that a sterilized medical device is free of endotoxin
Which of the following statements about adherence is true?
Most bacterial adhesins are glycoproteins or lipoproteins.
Which of the following toxins and does NOT match the description?
Vibrio enterotoxin: a superantigen that destroys epithelial cells
Which disease would be potentially propagated in an environment without functional plumbing and in which drinking water is contaminated with sewage?
Which of the following statements about lysogenic conversion is true?
Exotoxin production by bacteria is frequently the result of a lysogenic infection.
How do Shigella cells move between host cells?
They can polymerize actin molecules from the epithelial cells into tail-like structures that propel them from one cell to another.
Certain traits that allow pathogens to create infection and cause disease are termed
How do fibrinolysins enhance a pathogen's virulence?
They break down fibrin proteins that are involved in clot formation, allowing the cells to penetrate deep into damaged skin.
Which of the following is NOT a cytopathic effect (CPE) of viruses?
All of the above are possible CPE.
The most frequently used portal of entry for pathogens is the
mucous membranes of the respiratory tract.
The ability of some microbes, such as Trypanosoma or Giardia to alter their surface molecules and evade destruction by the hosts antibodies is called
The fimbriae of Neisseria gonorrhea and enteropathogenic E. coli are examples of
adhesins and ligands.
Botulism is caused by ingestion of a proteinaceous exotoxin; therefore, it can easily be prevented by
boiling food prior to consumption.
Symptoms of protozoan and helminthic diseases are due to
tissue damage due to growth of the parasite on the tissues, waste products excreted by the parasite, and products released from damaged tissues.
Which of the following statements about staphylococcal enterotoxin is FALSE?
It is produced by Staphylococcus aureus growing in the host's intestines.
Which of the following contributes to the virulence of a pathogen?
numbers of microorganisms that gain access to a host, evasion of host defenses, and toxin production
Lysogenic bacteriophages contribute to bacterial virulence because bacteriophages
give new gene sequences to the host bacteria.
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
Symptoms of intense inflammation and shock occur in some gram-positive bacterial infections due to
Which of the following is an example of direct damage due to bacterial infection?
the invasion and lysis of intestinal cells by E. coli
Polio is transmitted by ingestion of water contaminated with feces containing polio virus. What portal of entry does polio virus use?
mucous membranes only
Cholera toxin polypeptide A binds to surface gangliosides on target cells. If the gangliosides were removed,
polypeptide B would not be able to enter the cells.
Bacteria such as E. coli and Salmonella produce invasins that bind host cells, thus causing the cells to
engulf the bacteria.
Which of the following mechanisms is used by gram-negative bacteria to cross the blood-brain barrier?
Gram-negative septic shock results from the following events. What is the second step?
LPS is released from gram-negative bacteria.
Bacteria that cause periodontal disease have adhesins for receptors on streptococci that colonize on teeth. This indicates that
streptococcal colonization is necessary for periodontal disease.
In response to the presence of endotoxin, phagocytes secrete tumor necrosis factor. This causes
a decrease in blood pressure.
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