Microbiology Quiz 10

Animal diseases transmissible to humans are known as

zoonoses

The most severe and fatal form of anthrax is

inhalation anthrax

Soldiers or refuges in crowded unsanitary conditions are MOST susceptible to which rickettsial disease?

typhus

The MOST important potential common source of infectious disease is

water

A student travels to Brazil by boat on the Amazon River, without visiting the doctor prior to traveling for recommended vaccinations for travel to South America. The student becomes ill during the trip and is quarantined. Which of the diseases listed below does the student most likely have?

yellow fever

At what temperature are most household freezers kept?

-20°C

In the United States, individuals become infected with Vibrio cholerae most commonly by

?consuming contaminated shellfish.

Clostridium tetani is an obligate anaerobe that can cause tetanus. When it enters the human body, it can produce tetanus toxin. Considering that C. tetani is an obligate anaerobe, which of the following explains how it can survive and cause disease in the human body? C. tetani can't access atmospheric oxygen, so it can grow as long as it stays on the surface of the skin rather than in well-oxygenated deeper tissues. C. tetani can only survive when other bacteria are available to consume oxygen and to keep oxygen levels low. It doesn't survive; it simply releases toxin as it dies. Especially in deep wounds, C. tetani can sometimes survive in areas with damaged tissue and poor to no blood flow.

Especially in deep wounds, C. tetani can sometimes survive in areas with damaged tissue and poor to no blood flow.

(T/F) Erythema migrans is associated with typhus.

False

Which of the following pathogens is spread by infected lice? Rickettsia prowazekii Plasmodium falciparum Yersinia pestis Borrelia burgdorferi

Rickettsia prowazekii

Disease research and epidemiology bring together many different facets to help us better understand disease pathology and spread. Which of the following statements are true? Select all that apply. The ID50 value refers to the number of microbes needed to cause half of an infected population to die. The interactions that occur between a microbe and host influence the evolution of both. Bacterial exotoxins can be altered to create toxoids, which can be used to produce protective immunity in a host. Some pathogens are able to cause disease within a host without penetrating the body. Intoxications result from a bacterial infection in which a large amount of bacterial toxin is produced. The terms pathogenicity and virulence can be used interchangeably to describe the severity of an infection.

The interactions that occur between a microbe and host influence the evolution of both, bacterial exotoxins can be altered to create toxoids, which can be used to produce protective immunity in a host, some pathogens are able to cause disease within a host without penetrating the body.

Lyme disease and syphilis are similar in that they __________.

are both caused by spirochetes and are chronic infections that involve the nervous systems

A person is MOST likely to contract diseases such as Rocky Mountain spotted fever and ehrlichiosis if he or she visits/participates in

camping and hiking in the backcountry.

The degree of susceptibility a food has to microbial activity is determined by its

chemical characteristics, physical characteristics, and water content.

Animal-transmitted diseases are generally spread to accidental hosts by

direct contact, aerosols, and bites.

The ability of Vibrio cholerae to cause disease depends on a number of factors. Which of the following are requirements for causing disease within a host? Select all that apply. direct damage of host tissues depleting the host of nutrients at the site of infection evasion of host defenses production of exotoxins gaining access to the host via a portal of entry adherence to host tissues

evasion of host defenses, gaining access to the host via a portal of entry, adherence to host tissues

The presence of specific ________ signals that a given water source might be contaminated with pathogens.

indicator microorganisms

Vibrio cholerae primarily infects the

small intestine

The Staphylococcus aureus toxins are

superantigen toxins

The rate of contaminant microbial growth during the exponential phase in food depends on

temperature, nutrient value, and water content.

Many West Nile virus infections are not properly identified because

the symptoms are often subacute.

Controlling most rickettsial diseases involves managing

the vector

Hantaviruses are most commonly transmitted by ________ of virus-contaminated rodent ________.

inhalation / excreta

Hantavirus pulmonary syndrome is a viral respiratory disease caused by contact with

rodents

Severe cases of Staphylococcus aureus food poisoning may require treatment

?with powerful antibiotics.

Although cholera can be treated with antibiotics, data suggest that antibiotic treatment alone is NOT the most effective therapy. Which of the following statements describes the most likely reason for supplementing antibiotic therapy? Antibiotic therapy addresses only the growth of V. cholerae; it doesn't address the extreme dehydration suffered by a person infected with V. cholerae. Because V. cholerae is a gram-negative organism, it is not very effectively treated with antibiotics. The production of cholera toxin helps V. cholerae resist antibiotic treatment. As with V. cholerae, the acidic environment of the stomach can have a negative impact on antibiotic activity.

Antibiotic therapy addresses only the growth of V. cholerae; it doesn't address the extreme dehydration suffered by a person infected with V. cholerae.

Which of the following explains why treatment of symptomatic tetanus requires an antitoxin and an antibiotic? The tetanus toxin binds irreversibly, causing damage to axons. The only way to heal the axons is with an antitoxin. Because C. tetani bacteria excrete tetanus toxin, it is important to neutralize the toxin while also killing the bacteria that are producing more. It is always better to use multiple treatments to elicit a stronger response. Because the toxin is within the cell wall of the bacteria, it can only be eliminated by killing the bacteria.

Because C. tetani bacteria excrete tetanus toxin, it is important to neutralize the toxin while also killing the bacteria that are producing more.

The causative agent of Lyme disease is ________, which is carried primarily by the ________.

Borrelia burgdorferi / Ixodes sp. (deer tick)

Which of the following are properties of exotoxins? Select all that apply. Exotoxins are extremely heat stable. Exotoxins are produced primarily by gram-negative bacteria. Exotoxins target specific cellular structures or molecules. Exotoxins are protein molecules. Exotoxins are released from the cell during death or replication. Very small amounts of exotoxin can be lethal.

Exotoxins target specific cellular structures or molecules, exotoxins are protein molecules, very small amounts of exotoxins can be lethal.

Food that is heavily salted or candied does not need to be refrigerated. Why not?

Extremely concentrated solutions are very hypertonic and therefore desiccate microorganisms. As a result, there is no need for lower temperatures through refrigeration to slow growth.

Tests to monitor water safety often report the number of fecal coliform bacteria found in samples. Which of the following statements accurately reflects water safety recommendations based upon fecal coliform levels? If the level of fecal coliform bacteria is high, then the water is safe for drinking and recreational purposes. If the level of fecal coliform bacteria is high, then the water is safe for drinking and recreational purposes. If the level of fecal coliform bacteria is low, then the water was probably contaminated by sewage. If the level of fecal coliform bacteria is low, then the water may still be unsafe because of the presence of other pathogens.

If the level of fecal coliform bacteria is low, then the water may still be unsafe because of the presence of other pathogens.

Which of the following bacterial pathogens is found in aquatic environments and is commonly present in air conditioning systems? Enterobacter aerogenes Legionella pneumophila Vibrio cholerae Klebsiella pneumoniae

Legionella pneumophila

Salmonellosis is most frequently caused by

Salmonella enterica serovars Typhimurium and Enteritidis.

Which of the following is NOT characteristic of a coliform? rod shaped resistant to chlorination gram-negative facultatively aerobic

resistant to chlorination

Some studies have indicated that the ID50 for Vibrio cholerae can be as high as 108 organisms. Which of the following most likely explains the requirement for this relatively high ID50? Because V. cholerae cells are relatively small compared to host cells, thousands of bacteria must infect each cell to cause disease. V. cholerae does not produce enough virulence factors to overcome the host response and cause disease. Because the major virulence factor of V. cholerae is cholera toxin, large numbers of bacteria are required to produce enough toxin to cause disease. To establish infection, V. cholerae must survive the host immune response and the acidic environment of the stomach.

To establish infection, V. cholerae must survive the host immune response and the acidic environment of the stomach.

(T/F) Cholera can be transmitted by water or food.

True

(T/F) Not all coliforms are pathogenic.

True

(T/F) Various Ixodes spp., as well as various Borrelia spp., may be involved in the transmission and cause of Lyme disease.

True

In bubonic plague, buboes are swellings formed in the lymph nodes and filled with

Yersinia pestis.

Vibrio cholerae is a human pathogen that causes cholera. It has an unusual shape distinctive of its genus. Considering that it does not have one of the most common bacterial shapes, what is the shape of this species?

a curved rod

Legionella pneumophila is generally transmitted by

contaminated water in coolers, pools, and domestic water systems.

Coliforms in a water sample indicate ________ contamination.

fecal

Staphylococcus aureus is a common foodborne disease, because it

grows on many foods, is present in some humans that work in food processing, and produces several heat-stable enterotoxins.

Verotoxin can cause

hemorrhagic diarrhea

What type of diseases require biosafety level (BSL) 4 procedures and facilities when working with samples that may be infected?

highly infectious diseases with high mortality for which no treatment or vaccine exist

Borrelia burgdorferi is an interesting spirochete that is unusual when compared to other bacteria. Which of the following is the reason that it is so unusual? it has a linear chromosome it has ribosomes it has a cell wall it has flagella

it has a linear chromosome

Which of the following would be the best strategy to prevent the spread of yellow fever and dengue fever into the southern United States? mosquito avoidance and eradication monitoring bird populations vaccination tick avoidance

mosquito avoidance and eradication

Part complete The MOST common source of individual foodborne botulism outbreaks are due to consumption of

nonacid, home-canned vegetables.

Clostridium botulinum is a gram- ________ rod that produces an ________.

positive endospore-forming / exotoxin

The primary disease reservoir for plague is

rats

The principle behind salt or sugar preservation is to

reduce water activity (aw).

Psychrotolerant microorganisms can survive and grow at

refrigeration temperatures

Of the arthropod-borne diseases, there is a vaccine to prevent __________.

yellow fever