Pathophysiology chp 13 Mechanisms of Infection and Host Protection
As part of the adaptive immune system, antibodies are released to defend against extracellular pathogens in the blood and lymph. Which type of response is occurring? Cell-mediated immune response Innate immunity response Humoral immune response Passive immunity response
Humoral immune response Humoral immune response results in plasma cells releasing an antibody in response to an antigen. Cell-mediated immune response releases T cells to attack and destroy an invading pathogen. Passive immunity is the type of immunity acquired at birth from the mother. Innate immunity is the first line of defense against any pathogen and is present at birth.
The mother of an 11-year-old child asks the nurse, "Why is it important that I have my child vaccinated for the human papillomavirus (HPV)?" Which response by the nurse is accurate? "HPV can remain dormant in the body for many years until an environmental trigger activates it." "HPV kills the target cells that it infects, causing tissue damage." "HPV vaccine can prevent your child from acquiring a sexually transmitted disease." "Certain viruses, such as HPV, can cause cancer."
"Certain viruses, such as HPV, can cause cancer." HPV, which causes genital warts, is an oncogenic virus. Oncogenic viruses increase the risk of cancer through the inactivation of the proteins that inhibit growth and reproduction of cells. Specifically, HPV is a sexually transmitted disease but can greatly increase the risk of cervical cancer due to the inactivation of proteins that regulate cellular reproduction. Some viruses fuse to cells and transmit from cell to cell without detection by the immune system. HIV is an example of this type. Lytic viruses kill the target cells they infect. Latent infections consist of dormant cells that remain in the body for months to years without causing an infection. Additional facts about HPV include: Of the more than 100 types of HPV, over 40 types can be passed from one person to another through sexual contact. In the United States, approximately 79 million Americans currently have HPV, and an estimated 14 million new genital HPV infections occur each year. Cervical cancer strikes nearly half a million women each year worldwide, claiming more than a quarter of a million lives, and is the second most common cancer in women.
The nurse asks the new graduate to explain why bacteria are able to reproduce so quickly in the log phase. Which statement best explains this phase? "During the log phase, the duplication of the mitochondria in the cell occurs." "This phase includes the duplication of the nuclear membrane." "During the log phase, replication of the cell's DNA takes place." "During this phase, each bacterial cell produces two equivalent daughter cells."
"During this phase, each bacterial cell produces two equivalent daughter cells." Bacteria produce by simple binary fission, producing two equivalent daughter cells from the original cell. The log phase is when bacteria are increasing in number exponentially. There is no nuclear membrane or mitochondria in a bacterial cell. Replication of DNA is the primary mode of reproduction of mammalian cells but is not how bacterial cells reproduce.
A patient presents in the emergency department and is diagnosed with salmonellosis. The patient asks the nurse, "Why am I not receiving an antibiotic?" Which response by the nurse is accurate? "Salmonella does not cause systemic infection and will resolve in 2-5 days." "Salmonella replicates quickly and reproduces at a faster rate than it is destroyed by antibiotics." "Salmonella has many different species and it is difficult to isolate which type of salmonella causes the infection." "Salmonella has a thick cell wall that is resistant to any antibiotics."
"Salmonella does not cause systemic infection and will resolve in 2-5 days." Salmonellosis is transmitted through contaminated food and does not have a human reservoir. It invades the epithelial tissues and is usually self-limiting, lasting 2-5 days. Since there is no systemic infection, antibiotics are not effective in treating salmonella infection. The cell wall of Salmonella is not especially resistant to phagocytosis, and the replication rate is not faster than treatment with antibiotics. In addition, there is only one single species of Salmonella, although there may be numerous antigenic types, only a few of which infect humans.
The patient diagnosed with a virus asks the nurse, "I just had this virus last year. I thought once you had a virus you'd be immune to it. Why wasn't I immune?" Which response by the nurse is accurate? "It is often difficult for your immune system to recognize the virus if too much time passes between occurrences." "The structure of the cell wall protects it against your immune system, so immunity cannot happen with previous exposure." "Because viruses grow very slowly, they develop a resistance to your immune system." "Some viruses replicate at a rapid rate creating a new strain which your immune system does not recognize."
"Some viruses replicate at a rapid rate creating a new strain which your immune system does not recognize." The rapid rate of replication in viruses leads to increased incidence of errors, or mutations. As a result, viruses readily change their structure, producing new strains of virus that are able to evade host immune defense mechanisms. Viral mutations can alter viral structure in such a way that the viral type is no longer recognized by a previously immunized host's immune system. Viruses do not have a cell wall. Viruses do not grow slowly, but replicate quickly. The influenza virus goes through rapid replication and mutation, making influenza treatment difficult.
A patient states, "I spoke with my doctor and he told me my infection is very virulent. What does this mean?" Which response by the nurse is accurate? "Virulence refers to the number of microorganisms needed to cause disease." "Virulence refers to the degree to which a microorganism is capable of causing infectious disease." "Virulence refers to the ability of a microorganism to reproduce in a given environment." "Virulence refers to how resistant a microorganism is to antibiotics."
"Virulence refers to the degree to which a microorganism is capable of causing infectious disease." factors that enhance the pathogenicity of a microorganism are called virulence factors. Virulence describes the degree to which a microorganism is capable of causing infectious disease. Some microorganisms occur normally, or in small numbers in the body, and do not result in disease. Others reproduce quickly and result in infection. The ability of a microorganism to reproduce may contribute to its overall virulence but does not describe virulence. Resistance to antibiotics has become problematic with certain microorganisms, but this does not describe the virulence. The number of microorganisms that cause disease is part of the infection process, but is not the virulence. An example of microorganisms with different virulence is the Shigella vs. Vibrio cholerae. Both pathogens cause gastrointestinal illness, but it takes fewer than 200 Shigella bacilli to cause disease, whereas it takes over 100 million Vibrio cholerae. The virulence of Shigella is much higher than Vibrio (which produces cholera), although both can cause disease.
The nurse is caring for several patients. Which should the nurse consider as being the most susceptible to a Pseudomonas aeruginosa infection? A patient with a Staphylococcus aureas wound infection A middle-aged patient who has a laceration from a fall An older adult female patient who is incontinent A transplant recipient receiving immunosuppressant therapy
A transplant recipient receiving immunosuppressant therapy Pseudomonas aeruginosa is an opportunistic pathogen, which are microorganisms that use the opportunity to infect a host that has weakened defense mechanisms, such as individuals with AIDS, transplant recipients, and individuals with an autoimmune disease on immunosuppressive therapy. A middle-aged patient with a laceration is at greater risk for S. aureas because the skin is broken. A patient with an existing wound infection would most likely be at a greater risk for developing methacillin-resistant staphylococcus aureas (MRSA). An incontinent older adult female patient is at increased risk for a urinary tract infection from E. coli.
What advantage does a cell wall provide for bacteria? Ability to survive over a century in a dormant state Ability to resist infection control measures Ability to reproduce quickly without a nucleus Ability to survive in a hostile environment
Ability to survive in a hostile environment A cell wall provides a layer of protection, like an exoskeleton, to bacteria. This allows them to survive and reproduce in hostile environments. A cell wall does not facilitate reproduction without a nucleus. A cell wall can provide a layer of protection for the cell but is not responsible for resistance to infection control measures. Spores have the ability to survive for over a century in a dormant state.
The nurse is administering the flu vaccine to patients at a clinic. Which type of immunity will this vaccine provide? Passive immunity Herd immunity Active immunity Natural immunity
Active immunity Vaccines provide an artificial, but effective, active immunity. Dead or attenuated (weakened) viruses are given in order to stimulate the immune system into producing antibodies. Passive immunity is passed from mother to child at birth. Natural immunity occurs when an individual experiences an infectious disease and memory cells are formed. Vaccination provides herd immunity when a significant portion of a population is immunized, thus reducing the number of susceptible hosts enough to slow or halt the spread of an infectious agent.
The patient asks, "Why is it called the avian flu since this refers to birds." Which process should the nurse explain to the patient? Prodrome Pandemic Antigenic drift Antigenic shift
Antigenic shift An antigenic shift is a mutation that occurs, allowing a virus to jump from one species to another. For example, HIV began as a disease in rhesus monkeys but mutated enough to infect humans. A prodrome is the phase of viral infection in which the immune response causes symptoms such as fever, malaise, and body aches. An antigenic drift occurs when a mutation occurs that results in increased incidence and resistance of a virus, resulting in an epidemic. A pandemic is an outbreak of a particular virus that affects a certain population of an entire region.
Bacteria are often able to grow in hostile environments, such as the intestine. Which structure provides them with this ability? Cell wall Cell membrane Nucleus Mitochondria
Cell wall The cell wall provides bacteria with an advantage to survive in hostile environments. The interlocking molecular chains of gram-positive microorganisms provide a mesh-like exoskeleton protective layer. The cell wall of gram-negative microorganisms contains an outer layer of endotoxin, which can contribute to sepsis. Bacterial cells do not contain mitochondria or a cell nucleus. The cell membrane does not provide any additional layer of protection for a bacterial cell.
An 85-year-old female patient, who has a urinary catheter inserted, presents with symptoms of a urinary tract infection. Which microorganism does the nurse most likely suspect as the cause of this infection? Shigella Pseudomonas Escherichia coli Staphalococcus aureus
Escherichia coli are enteric gram-negative thatinhabit the intestinal tract. E. coli causes urinary tract infections in woman more than men because the womens urethra is shorter in woman than men,. Pseudomonas aeruginosa (catheters), staphyloccocus saprophyticus (cystitis) also cause UTIS
During a routine office visit, a patient states she has been exposed to the common cold virus. The nurse determines that a patient is in the prodrome phase of influenza. Which clinical manifestations would the patient most likely be presenting? No symtoms at this stage Sore throat, sinus congestion, rhinitis Acute symptoms diminishing Fatigue and headache
Fatigue and headache The clinical manifestations of prodrome occur as a result of the immune system reaction to the virus. The prodrome period is manifested by nonspecific symptoms such as lethargy, headache, and fever. The first stage of infection is the incubation period, which is the interval of time from when the pathogen enters the body and the appearance of the first symptoms. A patient with the common cold would exhibit sore throat, sinus congestion, and rhinitis during this phase of illness. Recovery from illness occurs when symptoms have diminished.
Defense mechanisms such as skin, saliva, natural killer cells, and macrophages are components of which type of immune system? Acquired immunity Adaptive immune system Innate immune system Pattern-recognition receptors
Innate immune system Innate immunity are the defense mechanisms that quickly respond to exposure to an infectious virus. This is the immunity present at birth and the first line of defense against infection and includes both physical and biochemical barriers. Adaptive immune system is comprised of antigen-specific defense mechanisms and is designed to recognize a few highly conserved structures that are present in many different microorganisms. These mechanisms are known as pattern-recognition receptors. Acquired immunity is similar to adaptive immunity and includes measures such as vaccines. The innate immune system refers to the defense mechanisms present at birth and acts as the first line of defense against infection. Structures such as skin and mucous membranes, and cellular defense mechanisms such as killer cells and macrophages, work to defend the body against invading organisms.
A patient diagnosed with pulmonary tuberculosis (TB) asks why the doctor stated that the disease is difficult to treat. The nurse should inform the patient that Mycobacterium tuberculosis is difficult to treat for which reason? Tuberculosis reproduces quickly, and infection is usually very advanced before it is diagnosed. TB is slow to develop and therefore slow to respond to treatment. Tuberculosis forms spores, which can live an extended period of time. Mycobacterium have cell walls that are resistant to common antibiotics.
Mycobacterium have cell walls that are resistant to common antibiotics. Mycobacterium grow very slowly and have a thick cell wall made up of complex lipids, making them very resistant to phagocytosis and treatment with antibiotics. Currently, a prolonged multidrug regimen is used to treat TB. Persistent problems of drug-resistant strains of the tubercle bacilli make TB a continuing healthcare challenge. Tuberculosis does not form spores, although the bacteria can live outside of the host Mycobacterium and are slow growing, but this is not why they are difficult to treat. Mycobacterium do not reproduce quickly, but the slow rate of growth can result in a delay in the onset of symptoms.
The patient has been diagnosed with a viral infection of the gastrointestinal tract. The nurse identifies this virus as having which property? Nonenveloped Attenuated Mutated Enveloped
Nonenveloped Nonenveloped viruses are hardier and can survive harsh conditions of the egastrointestinal GI tract and are resistant to common disinfectants, can survive inadequate sewage treatment. Enteric viruses cause GI gasterointestinal infections are Nonenveloped.
Which mechanism is used by neutrophils to combat infectious agents? Phagocytosis Inflammatory response Secondary immune response Humoral immunity
Phagocytosis Neutrophils target invading infectious organisms to engulf and destroy them through a process called phagocytosis and cause the destruction of the organism. Humoral immunity is activated through B cells, which stimulate plasma release of antibodies. Inflammatory response creates an increase in blood flow to an affected area, which increases the number of white blood cells and circulating fluid to an affected area. A secondary immune response is a pathogen-specific response that occurs when an antigen is experienced a second time.
A nurse sustains a needlestick injury while giving an injection to a patient who is HIV-positive. Which part of the chain of infection is the needlestick injury? Susceptible host Portal of entry Portal of exit Reservoir
Portal of entry
A patient presents to the after-care clinic with lethargy, fever, and headache. It is suspected that he is in the early stages of a viral infection. Which term would the nurse use to describe this stage of the patient's infection? Incubation period Prodrome Convalescent period Latent viral state
Prodrome Prodrome is the phase of infection in which the virus replicates rapidly, and the symptoms manifested are a reaction of the immune system to the presence of the virus. These symptoms are nonspecific and usually present as headache, lethargy, and fever. The incubation period is the period of time from exposure to the virus to development of symptoms. The length of time can vary, depending on the type of virus. The latent viral state describes the period of time in which the virus is harbored in an inactive state. The convalescent period describes the time to recover from symptoms.
Which statement describes the adaptive immune system? Immunity created by vaccination Mutation of a virus that makes it incapable of causing infection Produces antibodies that target specific pathogens Defense mechanisms present at birth; not pathogen-specific
Produces antibodies that target specific pathogens The adaptive immune system works by developing pathogen-specific antibodies that defend the body against specific invaders. Innate immune system is a global immunity, present at birth, and not pathogen-specific. Immunity created by vaccine represents artificial, active immunity. Viral mutation is not a form of immunity.
Bacterial cells have distinct differences from other pathogens. Which is their classification? Prokaryotic Helminth Eukaryotic Plasmids
Prokaryotic Differences in prokaryotes (BACTERIA CELLS) and eukaryotes: ALL CELL Tissues
Which pathogen has the highest level of virulence? Shigella bacilli, about 200 organisms to cause disease Vibrio cholerae, about 100,000,000 organisms to cause disease HIV, about 1,000,000 organisms to cause disease Hepatitis A, about 10,000 organsims to cause disease
Shigella bacilli, about 200 organisms to cause disease Virulence is described as the degree to which a microorganism is capable of causing disease. In this example, the fewer organisms to cause disease, the higher the virulence An example of microorganisms with different virulence is the Shigella vs. Vibrio cholerae. Both pathogens cause gastrointestinal illness, but it takes fewer than 200 Shigella bacilli to cause disease, whereas it takes over 100 million Vibrio cholerae. The virulence of Shigella is much higher than Vibrio (which produces cholera), although both can cause disease.
A patient asks, "My healthcare provider said I need the flu shot each year because the virus has frequent mutations. Why is that?" Which mechanism will the nurse describe to explain the reason for yearly flu vaccine? Rapid rate of replication Overuse of antibiotics Thick cell wall Ability to produce spores
Rapid rate of replication
A patient states she had chicken pox as a child but was recently re-exposed as a adult. She asks, "Why didn't I get it again?" Which protective mechanism will the nurse explain to the patient? Artificial active immunity Passive immunity Primary antibody response Secondary antibody response
Secondary antibody response The second exposure to a pathogen that has previously been identified and destroyed by the immune system is the secondary response. The secondary immune response is more rapid and of greater magnitude than the primary response due to memory T lymphocytes and memory B lymphocytes, which provide subsequent immunity. The primary response is the response to the first exposure. Passive immunity is acquired by a child from a mother. Artificial active immunity is achieved through the administration of vaccines. There is currently a vaccine for chicken pox. A first exposure to an antigen will result in antibodies, but there is a greater lag time; the immune system response will be enough to fight the pathogen effectively. In a secondary immune response, or second exposure to an antigen, the response will be of greater magnitude, and lag time will be decreased because the body "remembers" the antigen.
A patient who had the mumps as a child asks why she will not get them again. The nurse explains it is due to the secondary antibody response. Which characteristic of this process should the nurse include in the explanation? Reduced risk of extreme reaction than the risk from the first exposure Shorter lag time before response and increased magnitude of the response Decreased antibody response, since the body has developed immunity A prolonged lag time before response and decreased magnitude of the response
Shorter lag time before response and increased magnitude of the response A secondary antibody response occurs when the pathogen has been identified and eliminated previously by the body. This response has a shorter lag time before activation and an increased magnitude of the response. There may be an increased risk of extreme reaction in a secondary antibody response. The body has developed resistance, but the increased magnitude of the secondary response is part of that immunity.
A patient presents to the after-care clinic with flu-like symptoms and a red lesion on his leg that resembles a bull's-eye. The nurse suspects that the patient's symptoms are caused by which type of bacteria? Spirochete Pyogenic cocci Fomite Spirilla
Spirochete Spirochetes are spiral or coiled organisms with flagella such as Treponema pallidum, which causes syphilis and LYME disease (flu-like and bulls-eye) The patient's clinical manifestations are indicative of Lyme disease, which is transmitted through tick bites, usually from an animal reservoir of a rodent or deer. Lyme disease usually has an early manifestation as flu-like symptoms, accompanied by a "bull's-eye" rash in about 50% of cases. It is caused by the spirochete Borrelia burgdorferi. The spirochete is a thin, flexible, spiral-shaped bacteria that has endoflagella made up of axial filaments, which allows for movement. If left untreated, the organism can spread to secondary sites, such as the brain or heart, and produce systemic diseases such as arthritis and cardiac disease. Spirilla is similar in shape to a spirochete, but are most often transmitted through consumption of contaminated chicken. Pyogenic cocci cause pus-producing infections, such as pneumonia or skin infections. Fomites are inanimate objects through which a microorganism can be transmitted, such as a work surface.
What makes spores potentially more virulent and capable of disease transmission? Spores are the active state of bacteria. Spores are resilient to infection control measures and can live for centuries. Spores contain DNA capable of binding with and mutating cells. Spores facilitate a faster rate of cell reproduction.
Spores are resilient to infection control measures and can live for centuries. Spores are bacteria that are converted into dehydrated structures than are dormant or non vegetative state, they form when the bacteria is nutrient deprived and/or harsh environmental conditions Highly resistant structures that can survive for centuries Resistant to infection control
The nurse observes an pus-producing wound on a patient's arm. Which microorganism should the nurse suspect as the cause of the infection? Staphylococcus aureus Escherichia coli Helicobacter pylori Mycobacterium tuberculosis
Staphylococcus aureus Staphylococcus aureus is a pyogenic cocci that can cause suppurative (pus-producing) infections and is often the cause of wound infections. A number of virulence factors enhance the pathogenicity of S. aureus. These include a capsule and surface proteins that resist phagocytosis. The surface proteins facilitate adherence by binding to extracellular matrix molecules (i.e., fibronectin, collagen) of the host. Once in the host, S. aureus produces a variety of tissue-degrading enzymes, such as hyaluronidase, which breaks down hyaluronic acid and facilitates its invasiveness into host tissues. Escherichia coli is a normally occurring organism in the intestinal tract. Mycobacterium tuberculosis is the organism that causes tuberculosis. Helicobacter pylori causes gastric and duodenal ulcers.
A patient with pulmonary tuberculosis (TB) states, "My doctor said this bacteria is really tough to treat. Why is that?" Which response by the nurse is accurate? The cell wall of the organism that causes TB is resistant to destruction by other body cells and antibiotics." "The cell wall of the bacteria makes the microorganism more vulnerable to antibiotics." "The cell wall of the bacteria that causes TB increases the rate of reproduction of the microorganism." "The cell wall of the bacteria facilitates a rapid growth of the microorganism causing antibiotics to not be very effective."
The cell wall of the organism that causes TB is resistant to destruction by other body cells and antibiotics." Myobacteria are acid-fast bacteria, meaning that they cannot be decolorized easily with acid solutions. They are slow growing and have a waxy cell wall that is rich in complex lipids that make the organisms resistant to phagocytosis as well as to detergents and common antibotics.
The nurse is caring for a patient diagnosed with rabies and displaying nervous system clinical manifestations due to the virus targeting nervous tissue. The nurse recognizes that the rabies virus has which property? Mutation Tropism Replication Antigenic shift
Tropism
