Chapter 10:Host-Microbe Interactions and Pathogenesis HW

Septic shock is typically associated with -exotoxins or endotoxin. -superantigens.exotoxins -.Gram-negative infections. -either Gram-negative or Gram-positive infections.

-.Gram-negative infections.

Which domain of the A-B toxin binds to cell surface receptors on the host cell? -B domain -Both the A and B domains have the ability to bind to cell surface receptors. -A domain -A-B toxins do not bind to cell surfaces.

-B domain

Which biosafety level is incorrectly matched with its description? -BSL-1: non-pathogens or those that rarely cause disease in healthy people -BSL- 2: known pathogens but the disease is treatable or preventable -BSL-2+: known animal pathogens which do not infect humans -BSL-4: dangerous, lethal pathogens with no cures or treatments -BSL-3: serious, lethal pathogens though some diseases may be treatable

-BSL-2+: known animal pathogens which do not infect humans

How are symptoms of an infection associated with the mode of transmission of the pathogen? -Bodily fluids are rarely a source of disease transmission during an infection. -Bodily fluids produced during an illness are often rich in infectious organisms. -There is no relationship between symptoms and mode of transmission. -The worse the patient feels, the more likely the disease is transmissible to others. -Lack of symptoms indicates that the infection is not transmissible to others.

-Bodily fluids produced during an illness are often rich in infectious organisms.

How can capsules enable bacteria to evade the immune system? -Capsules block the complement biding sites on the surface of the pathogen. -A capsule is a superantigen that distracts the immune system. -Capsules can bind up IgA, rendering it inactive.

-Capsules block the complement biding sites on the surface of the pathogen.

Which microorganism requires the low pH inside a phagolysosome in order to reproduce? -Coxiella burnetii -Streptococcus pyogenes -Haemophilus influenzae -Streptococcus pneumoniae

-Coxiella burnetii

Which of the following would be the first sign of an infection that resulted in the release of endotoxin? -Pain -Weakness -Nausea -Fever

-Fever

Which of the following features of Salmonella prevent it from being phagocytosed? -Invasins -Flagella -Fimbriae

-FlagellaWhere do Salmonella pathogens grow and replicate in the infected host? Where do Salmonella pathogens grow and replicate in the infected host?Inside Shigella cellsInside phagocytesInside intestinal epithelial cellsInside M cells

Which of the following is an example of dysbiosis? -Staphylococcus epidermidis, a normal flora found on the skin, secretes bacteriocidins to kill rival pathogenic bacteria. -Your patient regularly ingests probiotics such as Lactobacillus acidophilus to improve symptoms associated with irritable bowel syndrome. -Following extended use of amoxicillin, your patient develops oral thrush as a result of the overgrowth of Candida albicans. -Patient serum antibodies are used to neutralize the influenza virus.

-Following extended use of amoxicillin, your patient develops oral thrush as a result of the overgrowth of Candida albicans.

Which of the following can be a potential disease reservoir for a pathogen which infects humans? -only humans or non-human animals -environmental niches such as soil or water -Humans, non-human animals, inanimate objects, or environmental niches can all serve as reservoirs for a pathogen which infects humans. -only humans -only humans or inanimate objects that an infected human directly handles

-Humans, non-human animals, inanimate objects, or environmental niches can all serve as reservoirs for a pathogen which infects humans.

Which of the following enzymes breaks down the "glue" that holds cells together? -Collagenase -Streptokinase -Hyaluronidase -Fibrinolysin

-Hyaluronidase

Where do Salmonella pathogens grow and replicate in the infected host? -Inside Shigella cells -Inside phagocytes -Inside intestinal epithelial cells -Inside M cells

-Inside phagocytes

Which of the following is/are examples of virulence factors? To be marked correct, you'll need to select all true statements, as there may be more than one correct answer. -Iron-binding proteins -Complement -Capsule -Flagella

-Iron-binding proteins -Capsule -Flagella

How does the protozoan Trypanosoma evade detection by the immune system? -It prevents phagosome-lysosome fusion. -It can change the surface antigens frequently, preventing the immune system from tracking it. -It can resist oxidation inside macrophages. -It produces a capsule which is composed of polysaccharides similar to those found in the host.

-It can change the surface antigens frequently, preventing the immune system from tracking it.

Why is a release of endotoxin into the bloodstream potentially deadly? -Endotoxin can quickly enter the brain from the bloodstream, causing brain damage. -It can lower blood pressure and cause the patient to go into shock -.It causes necrosis of the liver. -It results in dehydration of the patient.

-It can lower blood pressure and cause the patient to go into shock

Which of the following criteria is/are used to assign pathogens to a specific biosafety level? To be marked correct, you'll need to select all true statements, as there may be more than one correct answer. -Level of infectivity -Mode of transmission -Size of microorganism -Availability of preventions and treatments for the diseas

-Level of infectivity -Mode of transmission -Availability of preventions and treatments for the diseas

Endotoxins are also known as -cytokines. -prostaglandins. -interleukin-1. -Lipid A.

-Lipid A.

Where is the site of Shigella attachment in the host? -M cells -Intestinal epithelial cells -Phagocytes -Leukocytes

-M cells

You receive an accidental needle stick from a needle contaminated with Hepatitis B virus. In this example, Hepatitis B enters the host through which portal of entry? -Otic -Parenteral entry -Transplacental -Skin

-Parenteral entry

What is the etiologic agent of typhoid? -Shigella -Salmonella -E. coli

-Salmonella

Siderophores such as enterobactin promote virulence through which mechanism? -Protects the pathogen from phagocytosis -Functions as an outer membrane bacterial adhesin. -Sequesters iron from the host =Facilitates the invasion of the pathogen into host tissue

-Sequesters iron from the host

Which of the following virulence factors would be found in Staphylococcus aureus? -Staphylokinase -Collagenase -Streptokinase -Hyaluronidase

-Staphylokinase

Which of the following microorganisms use M protein to avoid destruction of a phagocyte? -Haemophilus influenzae -Streptococcus pyogenes -Streptococcus pneumoniae -Coxiella burnetii

-Streptococcus pyogenes

How are superantigens different from other types of exotoxins? -Superantigens comprise two functional domains. -Superantigens only act against host neurons. -Superantigens must be endocytosed into a target cell before becoming active. -Superantigens cause an overstimulation of the host immune system.

-Superantigens cause an overstimulation of the host immune system.

Which of the following is/are standard precaution(s)? To be marked correct, you'll need to select all applicable statements, as there may be more than one correct answer. -Surfaces must be disinfected. -New gloves should be worn when encountering blood, mucous membranes, non-intact skin, or other bodily fluids, and gloves should be changed between procedures. -Airtight, pressurized, full-body hazardous material suits must be worn with immunocompromised patients. -Hand hygiene should be performed before and after each patient contact

-Surfaces must be disinfected. -New gloves should be worn when encountering blood, mucous membranes, non-intact skin, or other bodily fluids, and gloves should be changed between procedures. -Hand hygiene should be performed before and after each patient contact

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. -Capsules have the ability to destroy antibodies secreted by the immune system. -Capsules allow the bacteria to stick together, creating a larger mass that is too big for immune cells to engulf. -The capsule makes the bacterium too sticky to be phagocytosed by the immune cells.

-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.

Which of the following provides the best definition of the term reservoir? -An anatomical site that the pathogen uses for entry into the host. -The anatomical site that the pathogen uses to exit the host. -The habitat where a pathogen is typically found. -The object which disseminates the pathogen from the environment to the host.

-The habitat where a pathogen is typically found.

Listeria monocytogenes is an intracellular bacterial pathogen that replicates within macrophages. Secretion of listeriolysin O and phospholipase helps the pathogen to escape phagolysosome formation following internalization by the host cell. In this example, listeriolysin O and phospholipase A perform which essential function? -These virulence factors function as adhesins. -These virulence factors help the pathogen find a portal of entry. -These virulence factors help the pathogen evade host defenses. -These virulence factors help the pathogen sequester iron and other nutrients from the host cell

-These virulence factors help the pathogen evade host defenses.

Which statement is true about standard precautions? -They are in force only for bloodborne pathogens. -They are used in student labs that only handle BSL-1 pathogens -They apply to all healthcare providers working with all patients. -They are used only when the patient is known to be infected with a BSL-2 or higher pathogen. -They require full face shields, gloves, and barrier gowns for all patient contact situations.

-They apply to all healthcare providers working with all patients.

How are immune cells able to detect foreign pathogens? -They can compare the DNA sequences from the foreign cells to host DNA. -They detect foreign, unfamiliar chemical substances released by the invading cells. -They are able to detect structures on the surfaces of foreign cells that are not found in the host.

-They are able to detect structures on the surfaces of foreign cells that are not found in the host.

How do fibrinolysins enhance a pathogen's virulence? -They destroy the molecules that hold cells together. -They break down fibrin proteins that are involved in clot formation, allowing the cells to penetrate deep into damaged skin. -They destroy the fibers that are found at the base of superficial tissues, allowing for deeper penetration by the pathogen.

-They break down fibrin proteins that are involved in clot formation, allowing the cells to penetrate deep into damaged skin.

How do Shigella cells move between host cells? -They are secreted by phagocytes. -They are secreted directly into the epithelial cells from the M cells. -They lyse the M cell, releasing thousands of new cells to infect other host cells. -They can polymerize actin molecules from the epithelial cells into tail-like structures that propel them from one cell to another.

-They can polymerize actin molecules from the epithelial cells into tail-like structures that propel them from one cell to another.

How do superantigens enable pathogens to hide from the immune system if they actually stimulate the immune system? -They cause the immune system to destroy IgA antibodies. -They cause the immune system to produce an exaggerated response, distracting it from the actual pathogen. -They cause fever, which destroys the complement proteins. -They cause the immune system to turn on itself.

-They cause the immune system to produce an exaggerated response, distracting it from the actual pathogen.

A virulence study was performed using Staphylococcus aureus in mice. It was determined that the LD50 for the S. aureus alpha-toxin was 0.045 µg/kg of body weight toxin (a relatively low LD50). In the same mouse population, the ID50 was determined to be 200,000 cells (a relatively high ID50). What do these results taken together mean? -This S. aureus strain is highly infectious, and its alpha-toxin is highly-toxic. -This S. aureus strain is less infectious, and its alpha-toxin is minimally-toxic. -This S. aureus strain is highly infectious, but its alpha-toxin is minimally-toxic. -This S. aureus strain is less infectious, but its alpha-toxin is highly-toxic.

-This S. aureus strain is less infectious, but its alpha-toxin is highly-toxic.

Which of the following microorganisms actually grows inside the macrophage? -Leishmania -Legionella -Shigella -Tuberculosis bacterium -Streptococcus pneumoniae

-Tuberculosis bacterium

When would endotoxins be released from a bacterial cell? -When the cell dies -During bacterial conjugation -When the cell attaches to a host cell in the human body -When the cell moves toward a energy source

-When the cell dies

An exotoxin that has the ability to kill or damage host cells is referred to as a(n) -A-B toxin. -enterotoxin. -cytotoxin. -neurotoxin. -superantigen.

-cytotoxin.

Which factors may result in a normal microbiota species causing disease? -dysbiosis due to antibiotic therapy or immune system attack on the host's own tissue -dysbiosis due to antibiotic therapy -immune system attack on the host's own tissues -invasion of other tissues by the microbiota species -dysbiosis due to antibiotic therapy or invasion of other tissues by the microbiota species

-dysbiosis due to antibiotic therapy or invasion of other tissues by the microbiota species

Adhesins -allow pathogens to stick to host tissues only in a nonspecific manner. -are limited to only a few known types.make poor targets for vaccine development. -include molecules that are typically found deep inside the pathogenic cell. -include molecules that bind to host factors such as fibronectin, sialic acid, and heparin / heparin sulfate.

-include molecules that bind to host factors such as fibronectin, sialic acid, and heparin / heparin sulfate.

Which method of hiding from the host immune system is incorrectly matched with its description? -antigen mimicry: the pathogen's antigens are similar in structure to host molecules -antigen masking: the pathogen covers itself in host factors to avoid detection of its own antigens -living intracellularly: a pathogen resides on the surface of a host cell where it is hidden by host cell surface molecules -latency: a pathogen exists quietly inside the host cell -antigen variation: the pathogen frequently switches its antigens

-living intracellularly: a pathogen resides on the surface of a host cell where it is hidden by host cell surface molecules

Escherichia coli living in the human large intestine is known to produce vitamin K and B-complex vitamins in exchange for a nutrient-rich habitat. This host-microbe interaction is an example of __________. -mutualism -parasitism -dysbiosis -commensalism

-mutualism

A patient who has been hospitalized with uncontrolled muscle spasms has probably been infected with bacteria that secrete a(n) -neurotoxin -.enterotoxin. -superantigen. -membrane disrupting toxin.

-neurotoxin

Which portal of entry is mismatched to its description? -otic: pathogen enters via the ear -parenteral: pathogen is passed from mother to child through the placenta -urogenital: often associated with sexually-transmitted pathogens -ocular: via the conjunctiva -gastrointestinal: often involves fecal-to-oral transmission

-parenteral: pathogen is passed from mother to child through the placenta

Exotoxins are -secreted. -secreted and the targets of some childhood vaccines. -the targets of some childhood vaccines. -only made by Gram-positive bacteria. -secreted and only made by Gram-positive bacteria.

-secreted and the targets of some childhood vaccines.

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) -enterotoxin. -cytotoxin. -superantigen. -membrane disrupting toxin.

-superantigen.

Measles viruses are capable of inactivating host defenses by -producing superantigens. -producing leukocidins. -destroying complement proteins. -suppressing the immune system.

-suppressing the immune system.

ID50 describes -the percentage of individuals which will develop an infection after exposure to 50 cells or virions. -the number of cells or virions needed to establish an infection in 50 percent of exposed hosts. -the number of cells or virions which will kill 50% of exposed hosts.the amount of toxin lethal to a 50-pound human or other animal. -the number of cells or virions which will kill 50 individuals.

-the number of cells or virions needed to establish an infection in 50 percent of exposed hosts

Which type of bacterial toxin is matched incorrectly with its description? -endotoxin: enters the bloodstream during infection with Gram-negative bacteria -toxemia: a toxin produced during a viral infection -type 2 exotoxin: disrupt and damage the host cell membrane leading to cell lysis -type 3 exotoxin: bind to a membrane receptor then enter the cell -type 1 exotoxin: bind to the targeted host cell at a membrane receptor but do not enter the cell

-toxemia: a toxin produced during a viral infection

Certain traits that allow pathogens to create infection and cause disease are termed -collagenases. -streptokinases -.hyaluronidases. -virulence factors.

-virulence factors.

Toxemia is a condition -where a toxin acts as a superantigen. -where a vaccine is used to protect against a toxin. -that may describe both localized and systemic effects. -where a toxin is acting on tissues locally. -where a toxin has entered the bloodstream resulting in systemic effects.

-where a toxin has entered the bloodstream resulting in systemic effects.

What are leukocidins? -Molecules that are capable of destroying phagocytes -Molecules that can degrade IgA -Molecules that destroy the complement proteins

Molecules that are capable of destroying phagocytes

Meningitis and gonorrhea are caused by -Neisseria species. -Pseudomonas species. -measles virus.

Neisseria species.

How is Streptococcus pneumoniae able to avoid destruction by a phagocyte? -Their capsules make them "slippery" to phagocytes. -They cause the lysosomes to empty their contents into the phagocyte, killing it. -They prevent the fusion of the lysosome and phagosome.

Their capsules make them "slippery" to phagocytes.

The degree or extent of disease that a pathogen causes is -attenuation. -pathogenicity. -toxicity. -virulence. -a host factor.

virulence.