Microbiology Chapters 14/15- Mastering Questions

A patient who has been hospitalized with uncontrolled muscle spasms has probably been infected with bacteria that secrete a(n)

neurotoxin

which of the following is not a communicable disease? TB typhoid fever tetanus AIDS malaria

tetanus

which of the following statements is true regarding hand-washing

Frequent and proper hand washing should be routinely done by patients and by healthcare workers, both prior to and after interaction.

For a particular disease at a specific time period, morbidity rates should always be equal or greater than mortality rates.

True

During his research on West Nile virus, Bill learned that this virus is placed within a functional grouping known as arboviruses. What is meant by the term arbovirus?

an arbovirus is an arthropod-borne virus and an arbovirus is maintained in nature through biological transmission

the yeast Candida albicans does not normally cause disease because of

antagonistic bacteria

what features of West Nile virus make it an emerging disease of special concern?

-West Nile virus is an arthropod-borne virus transmitted by mosquitoes. -West Nile virus has a high mortality rate in immunosuppressed humans and infects many species of birds in southern Europe, the Mediterranean basin, and North America. -West Nile virus is maintained in nature through biological transmission between susceptible hosts by blood-feeding arthropods.

Which of the following characteristics do commensalism, mutualism, and pathogenicity have in common?

-life cycle coordination between the host and symbiont -common physical requirements between the organisms

matching

1. Capsules : This viscous outer covering found in certain microorganisms helps pathogens evade the host's defenses by impairing phagocytosis. 2. Cell wall components : These structures contain substances that contribute to a pathogen's virulence; for example, M protein mediates microbial attachment to epithelial cells. 3. Enzymes : These proteins contribute to a pathogen's virulence by, for example, forming and breaking down fibrin clots, breaking down connective proteins, and countering certain types of antibodies. 4. Antigenic variation : This process allows pathogens to alter their surface antigens to avoid attack by antibodies produced by the immune system. 5. Invasins : These microbial surface proteins rearrange the host cell's actin filaments, allowing pathogens to enter and move in and between cells.

matching

1. Siderophores : These proteins bind up iron obtained from the host cell's iron-transport proteins and transport this iron to bacteria through interactions with cell surface receptors. 2. Direct damage : This occurs as a result of nutrient depletion, accumulation of waste products, pathogen entry and exit, and ruptured host cells. 3. Toxins : These poisonous substances cause most of the damage to host cells; they can be transported by the blood or lymph and may produce far-reaching effects. 4. Lysogenic conversion : This results in a change in microbe characteristics due to the presence of prophage genes that confer new properties. 5. Cytopathic effects : These describe the visible effects of viral infections that results in host cell damage.

number of invading microbes vs. adherence to host tissue

2 options fit under the number of invading microbes category, 4 options fit under the adherence category pretty self explanatory- if there are numbers in it, it goes with number of invading microbes

according to the animation, surgical infections account for what percentage of nosocomial infections?

20%

likely to cause infection

A pathogen that causes gastrointestinal infections is accidentally ingested in contaminated food. A pathogen in quantities more than double its infectious dose is introduced at the appropriate portal of entry. A healthy individual inhales droplets from a person infected with a respiratory virus. A population of microbes less than the infectious dose is introduced in a compromised human host.

not likely to cause infection

A pathogen with multiple virulence factors is introduced in a healthy host, but in quantities far below its infectious dose. A population of microbes greater than the infectious dose is introduced in a healthy individual, but these microbes are unable to adhere to host tissues. A pathogen that causes urinary tract infections is accidentally ingested in contaminated water.

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

A-B toxins

How might a patient who is not being treated with an antibiotic still be exposed to an antibiotic?

Antibiotics can be used in aerosols, thereby entering the environment

The CDC is located in

Atlanta GA

which domain of the AB toxin binds to cell surface receptors on the host cell

B domain

what type of nosocomial infection is likely to arise from intravenous catheterizations?

Bacteremia

which of the following statements is False?

Coagulase destroys blood cells

The brain tissue of the birds indicated the possibility of encephalitis. What is encephalitis, and why should this type of infection cause concern among health care professionals?

Encephalitis is an inflammation of the brain tissue. It is a concern to health care professionals because an infection in the brain means the virus has breached protective measures.

Which of the following statements about M protein is False?

It is readily digested by phagocytes

endotoxins are also known as

Lipid A

which of the following virulence factors would be found in Staphylococcus aureus

Staphylokinase

During a six-month period, 239 cases of pneumonia occurred in a town of 300 people. A clinical case was defined as fever 39°C lasting >2 days with three or more symptoms (i.e., chills, sweats, severe headache, cough, aching muscles/joints, fatigue, or feeling ill). A laboratory-confirmed case was defined as a positive result for antibodies against Coxiella burnetii. Before the outbreak, 2000 sheep were kept northwest of the town. Of the 20 sheep tested from the flock, 15 were positive for C. burnetii antibodies. Wind blew from the northwest, and rainfall was 0.5 cm compared with 7 to 10 cm during each of the previous three years.

The etiologic agent of the disease in the situation is: Coxiella burnetii

If mosquitoes are the mode of transmission for West Nile virus, why did the students in Bill's virology class focus on finding the virus in the dead birds rather than collecting mosquitoes to examine?

The students tried to isolate and identify West Nile virus from birds because they are an amplifying host for the virus, making it more likely that the virus can be isolated from these animals.

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 disease would be potentially propagated in an environment without functional plumbing and in which drinking water is contaminated with sewage?

cholera

an exotoxin that has the ability to kill or damage host cells is referred to as a

cytotoxin

which of the following is NOT correct?

epidemic= a disease that is endemic across the world

the science that deals with when diseases occur and how they are transmitted is called

epidemiology

which of the following would be the first sign of an infection that resulted in the release of endotoxin

fever

which type of bacterial enzyme helps spread streptococcus pyogenes by digesting blood clots

fibrinolysin

antibiotics can lead to septic shock if used to treat gram-negative bacterial infections

gram negative bacterial infections

All of the following are examples of entry via the parenteral route EXCEPT bite. hair follicle. surgery. injection. skin cut

hair follicle

which of the following enzymes breaks down the glue that holds cells together

hyaluronidase

If a prodromal period exists for a certain disease, it should occur prior to

illness

why is a release of endotoxin into the bloodstream potentially deadly?

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

Bacillus anthracis can cause infection via three different portals of entry. The ID50 of cutaneous anthrax is 10 to 50 endospores, whereas inhalation anthrax requires 10,000 to 20,000 endospores, and gastrointestinal anthrax requires 250,000 to 1,000,000 endospores. Which statement best describes a conclusion that can be drawn based on this information?

it is significantly easier to be infected with cutaneous anthrax as compared to other forms of anthrax

A disease in which the causative agent remains inactive for a time before producing symptoms is referred to as

latent

Which of the following is the best mode of controlling the spread of West Nile infections?

limit exposure to mosquitoes to prevent the transmission of West Nile virus

a commensal bacterium

may also be an opportunistic pathogen

both portal of entry and portal of exit

mucous membrane, skin, parenteral route

classifications of mucous membranes vs. skin vs. parenteral route

mucous membrane- respiratory tract, genitourinary tract, gastrointestinal tract, conjunctiva skin- hair follicles and sweat gland ducts parenteral route- surgery deep wounds, injections

The most frequently used portal of entry for pathogens is the

mucous membranes of the respiratory tract

Polio is transmitted by ingestion of water contaminated with feces containing polio virus. What portal of entry does polio virus use?

mucous membranes only

part a: which of the following would be considered a fomite? part b: which of the following would be considered a vector? part c: when aerosols containing pathogens spread disease from a distance of less than one meter, it is considered _______ part d: which of the following is considered a mjor category of transmission of disease? part e: which is an example of vehicle disease transmission

part a) an infected toy part b) a fly carrying disease from fecal matter to food part c) contact transmission part d) contact, vehicle, and vector transmission part e) the presence of Listeria on undercooked chicken served for dinner

part a: expected prevalence of a disease is part b: sixth segment, why is disease epidemic in NA? part c: last segment, how many regions of the world experienced pandemic during april of year 4 part d: last segment, first epidemic occurs when? part e: disease occurring at fairly stable rate is called

part a) the expected occurance of a disease based on past observations part b) the disease occurs at a higher rate than what would normally be expected in this region part c) five part d) January of year three part e) endemic

endotoxins are

part of the gram negative cell wall

How can health care workers reduce the occurrence of nosocomial infections?

practice more stringent aseptic techniques

the health of the patient

should be the primary concern of the healthcare worker

which of the following characteristics of a catheter should be considered to help minimize the spread of nosocomial infections

single-use

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

staphyloccal enterotoxin

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)

superantigen

How are superantigens different from other types of exotoxins

superantigens cause an overstimulation of the host immune system

Why are invasive procedures likely to increase the risk of nosocomial infections?

these procedures allow microbes from the skin to enter the bloodstream of the patient

if a patient notices a healthcare worker not following suggested precautions

they should immediately bring it to the attention of the healthcare worker

How can surgeons help to limit nosocomial infections?

they should perform surgeries and invasive procedures only when absolutely necessary

Many pathogens use the same portal for entry and exit from the body.

true

In which of the following diseases can gender be considered a viable predisposing factor?

urinary tract infections

certain traits that allow pathogens to create infection and cause disease are termed

virulence factors

As a health care worker, you are keenly aware of how important it is to avoid harming patients. You worry about inadvertently transmitting an infectious disease to an already compromised individual. According to the CDC, what is the most important thing you can do to avoid this?

wash my hands before interacting with any patient

which of the following best describes why west nile virus is considered to be an emerging infectious disease?

west nile virus outbreaks have increased in number and affected areas since 1937

when would endotoxins be released from a bacterial cell

when the cell dies