Pearson Chapter 14 Flashcards
What cellular structure protects bacteria from drying out?
Glycocalyx
What type of microbe has lipid A?
Gram-negative bacteria
Which general group of microbes cannot be isolated in pure culture?
Viruses
All of the following might lead to a disease caused by an opportunistic pathogen EXCEPT __________.
immune suppression
an encounter with an infected animal
hormonal changes
changes in diet
an encounter with an infected animal
Human normal microbiota begin to develop __________.
during birth
E. coli living in the colon of a human is an example of a _________ relationship.
mutualism
Rabies is an example of a zoonosis that is hard to control because __________.
Its reservoir contains both domestic and sylvatic animals
If an individual is a carrier of an infectious disease, he is __________.
both asymptomatic and infective
A Deadly Carrier
In 1937, a man employed to lay water pipes was found to be the source of a severe epidemic of typhoid fever. The man, an asymptomatic carrier of Salmonella enterica serotype Typhi, the bacterium that causes typhoid, habitually urinated at his job site. In the process, he contaminated the town’s water supply with bacteria from his bladder. Over 300 cases of typhoid fever developed, and 43 people died before the man was identified as the carrier.
Part A
How was this carrier identified?
sputum sample
nasal swab
throat swab
urine culture
urine culture
A Deadly Carrier
In 1937, a man employed to lay water pipes was found to be the source of a severe epidemic of typhoid fever. The man, an asymptomatic carrier of Salmonella enterica serotype Typhi, the bacterium that causes typhoid, habitually urinated at his job site. In the process, he contaminated the town’s water supply with bacteria from his bladder. Over 300 cases of typhoid fever developed, and 43 people died before the man was identified as the carrier.
Based on the data supplied, what was the approximate mortality rate for this outbreak?
0.14 %
1 %
14 %
43 %
(43 / 300) × 100 = 14 %
A Deadly Carrier
In 1937, a man employed to lay water pipes was found to be the source of a severe epidemic of typhoid fever. The man, an asymptomatic carrier of Salmonella enterica serotype Typhi, the bacterium that causes typhoid, habitually urinated at his job site. In the process, he contaminated the town’s water supply with bacteria from his bladder. Over 300 cases of typhoid fever developed, and 43 peo
What is the reservoir for this disease organism, Salmonella enterica serotype Typhi?
dogs
humans
cats
horses
humans
How could this epidemic be stopped without firing the worker?
Educate the worker about personal hygiene and use of an outhouse or designated bathroom. Instruct him to thoroughly wash his hands with clean soap and water after using the facilities.
What are the clinical signs and symptoms of typhoid fever?
fever and rose-spotted rash
What is a relationship called between two types of organisms in which one benefits while the other remains unaffected?
Commensalism
What is a zoonosis?
A zoonosis is a disease with an animal reservoir from which the disease can spread to humans.
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 prevent infection by this pathogen.
Which of the following is an example of the parenteral route?
A pathogen crosses the placenta and infects a fetus.
A person steps on a nail.
A person rubs his or her eyes with contaminated fingers.
A pathogen enters the body through a hair follicle.
A person steps on a nail.
Infection and disease are NOT the same thing because __________.
disease does not necessarily result from an infection
On which microbes do glycoproteins serve as adhesion factors?
Bacteria and viruses
While investigating a newly discovered Gram-negative bacterium, you find that when the bacteria die, the host experiences severe fever and inflammation. You suspect that the bacterium has __________ in its outer wall membrane
lipid A
In an asymptomatic individual, which of the following might still be detectable?
leukocytosis
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 make it difficult for phagocytes to surround and grip the bacterial cell.
They are usually made of chemicals normally found in the body.
They contain chemicals that are lethal to phagocytes.
They contain chemicals that are lethal to phagocytes.
A patient’s immune system is typically fully responsive during which of the following stages of disease?
decline
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?
indirect contact transmission
What is the difference between the terms infection and disease?
Infection refers to the invasion of a pathogen into the body, while disease means that the body’s normal function is disrupted.
What is an example of a sign (as opposed to a symptom) of disease?
A rash
How do the enzymes hyaluronidase and collagenase increase bacterial virulence?
By allowing bacteria to invade deeper into tissues, making the infection more likely to cause disease
What effect do enterotoxins have?
They affect the gastrointestinal system.
How is Streptococcus pneumoniae able to avoid destruction by a phagocyte?
Their capsules make them “slippery” to phagocytes
Which microorganism requires the low pH inside a phagolysosome in order to reproduce?
Coxiella burnetii
Which of the following microorganisms use M protein to avoid destruction of a phagocyte?
Streptococcus pyogenes
Endotoxins are also known as
Lipid A.
When would endotoxins be released from a bacterial cell?
When the cell dies
Which of the following would be the first sign of an infection that resulted in the release of endotoxin?
Nausea
Pain
Fever
Weakness
Fever
