Chapter 14 Mastering Microbiology

Human normal microbiota begin to develop….?
during adulthood
at puberty
during birth
before birth

during birth

If an individual is a carrier of an infectious disease, he is __________.
both symptomatic and noninfective
both asymptomatic and infective
infective
asymptomatic

both asymptomatic and infective. page 411

Fecal-oral infections are usually a result of __________.
airborne transmission
bodily fluid transmission
foodborne transmission
waterborne transmission

waterborne transmission. page 422

Which of the following types of diseases has the shortest time frame?
latent disease
chronic disease
subacute disease
acute disease

acute disease. Acute diseases develop rapidly and last a relatively short time.

Which of the following is an example of the parenteral route?
A pathogen enters the body through a hair follicle.
A person rubs his or her eyes with contaminated fingers.
A person steps on a nail.
A pathogen crosses the placenta and infects a fetus.

A person steps on a nail. It involves a puncture through the skin.

A patient’s immune system is typically fully responsive during which of the following stages of disease?
prodromal period
decline
incubation period
illness

decline

Identification of the index case is an important part of which of the following types of epidemiology?
analytical epidemiology
experimental epidemiology
descriptive epidemiology
None of the listed responses is correct.

descriptive epidemiology. The time course and chains of transmission are important aspects of descriptive epidemiology, so the identification of the index case is usually very important in this field.

All of the following might lead to a disease caused by an opportunistic pathogen EXCEPT __________.
an encounter with an infected animal
immune suppression
hormonal changes
changes in diet

an encounter with an infected animal. Immune suppression, changes in one’s diet, and hormonal changes can all lead to an opportunistic infection resulting in disease.

Rabies is an example of a zoonosis that is hard to control because __________.
-it can be spread by nonliving reservoirs as well as by animal hosts
-its true animal reservoir is unknown
-its reservoir contains both domestic and sylvatic animals
-it can be spread both by humans and by animals

its reservoir contains both domestic and sylvatic animals. When a large number of different types of animals carry a particular zoonosis such as rabies, the disease will be more easily transmitted to humans and more difficult to control.

Which of the following is the most effective way to reduce the number of nosocomial infections?
-handwashing
-limiting patient stays
-antibiotic therapy
-specimen collection

handwashing

A new drug blocks the adhesins on the surface of a bacterial pathogen. What would likely be the major effect of this drug?
-It will inhibit the growth and reproduction of this pathogen.
-It will prevent formation of the glycocalyx in this pathogen.
-It will kill the pathogen.
-It will prevent infection by this pathogen.

It will prevent infection by this pathogen.

In an asymptomatic individual, which of the following might still be detectable?
-lethargy
-leukopenia
-itching
-nausea

leukopenia. Nausea, lethargy, and itching are all symptoms and, by definition, would not be present in an asymptomatic individual; however, signs such as leukopenia could still be present and detectable by the appropriate tests.

Which of the following is NOT a reason why bacterial capsules are effective in the inhibition of phagocytosis?
-They are ineffective at stimulating the host’s immune response.
-They are usually made of chemicals normally found in the body.
-They make it difficult for phagocytes to surround and grip the bacterial cell.
-They contain chemicals that are lethal to phagocytes.

They contain chemicals that are lethal to phagocytes. Bacterial capsules are generally made out of chemicals already found in the body, such as hyaluronic acid, so they are often ignored by the immune system. They are also rather slippery, which automatically makes phagocytosis more difficult.

A patient contracted a disease just by being in the same room with an infected individual for an extended period of time. Which of the following modes of disease transmission is most applicable in this situation?
-vehicle transmission
-vector transmission
-vehicle and vector transmission
-direct contact transmission

vehicle transmission. Any of these modes of transmission are theoretically possible. However, evidence suggests that the infectious agent was probably spread through the air, a type of vehicle transmission.

The typical relationship between the resident microbiota and the transient microbiota is which of the following?
-commensalism
-mutualism
-parasitism
-antagonism

antagonism. Transient microbiota do not persist in the body due to many factors; one such factors is the competition or antagonism they face from the resident microbiota growing in the same locations.

Infection and disease are NOT the same thing because __________.
-infections last longer than diseases
-disease refers only to microbes growing inside the body
-they are caused by different kinds of pathogens
-disease does not necessarily result from an infection

disease does not necessarily result from an infection. Infection refers to the mere invasion of the body by a pathogen, whereas disease results only when the pathogen replicates sufficiently to disrupt the normal functions of the body.

An epidemiologist collects drinking glasses, tissues, and bed sheets from the apartment of an individual infected with a particular disease. Which of the following modes of transmission is being investigated for this disease?
-vehicle transmission
-vector transmission
-direct contact transmission
-indirect contact transmission

indirect contact transmission. Inanimate objects, also known as fomites, are instrumental in the spread of pathogens by indirect contact transmission.

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

Lipid A

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

-When the cell dies

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

Fever

Why is a release of endotoxin into the bloodstream potentially deadly?
-It causes necrosis of the liver.
-It results in dehydration of the patient.
-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 can lower blood pressure and cause the patient to go into shock.

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

-Flagella

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

Inside phagocytes

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

M cells

How do Shigella cells move between host cells?
-They lyse the M cell, releasing thousands of new cells to infect other host cells.
-They are secreted directly into the epithelial cells from the M cells.
-They are secreted by phagocytes.
-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.

What is the etiologic agent of typhoid?
-salmonella
-shigella
-e coli

salmonella

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

cytotoxin.

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

B domain

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

-Superantigens cause an overstimulation of the host immune system.