Microbiology I Final
Which of the following would be an example of disease transmission via indirect contact?
A student sneezes on her test booklet. The instructor grades it and catches her cold.
Which of the following is NOT a membrane-disrupting toxin?
A-B toxin
Which of the following would be an example of an infection initiated via the parenteral route?
An individual contracts hepatitis B from an accidental stick with a contaminated needle.
Which of the following statements concerning phagocytosis is true?
Bacteria are digested when the phagosome fuses with a lysosome.
The complement protein cascade is the same for the classical pathway, alternative pathway, and lectin pathway after the point in the cascade where the activation of ________ takes place.
C3
Which of the following statements concerning cellular immunity is FALSE?
Cellular immunity involves cells that recognize antigens and make specific antibodies against them.
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.
Which of the following is an example of the symbiotic relationship known as mutualism?
E. coli within the large intestine
All of the following protect the skin and mucous membranes from infection EXCEPT
HCl.
The antibodies found in mucus, saliva, and tears are
IgA.
The antibodies that can bind to large parasites are
IgE
The most abundant class of antibodies in serum is
IgG
The presence of which of the following indicates a current infection rather than a previous infection or vaccination?
IgM
In addition to IgG, the antibodies that can fix complement are
IgM.
Large antibodies that agglutinate antigens are
IgM.
__________ is/are always present in an individual's blood. However, in the absence of infection, it is in an inactive form.
Kinins
Which statement regarding the lymphatic system is true?
Lymphatic capillaries possess one-way valves. These valves permit the uptake of fluid from the body but do not allow the fluid to flow back out of the capillaries into the intracellular spaces.
In mice, the LD50 for staphylococcal enterotoxin is 1350 ng/kg, and the LD50 for Shiga toxin is 250 ng/kg. Which of the following statements is true?
Shiga toxin is more lethal than staphylococcal enterotoxin.
Emergence of infectious diseases can be attributed to all of the following EXCEPT
The emergence of infectious diseases can be attributed to all of these.
Koch's postulates established criteria for proving that a specific organism causes a specific disease. Which of the following is NOT one of the criteria given by Koch's postulates?
The pathogen must be isolated from inoculated animals and must be different from the original organism.
Which of the following statements about the development of infectious diseases is correct?
The period of convalescence is the time during which the person regains health and fully recovers (back to the pre-disease state).
Which of the following statements about fixed macrophages is FALSE?
They develop from neutrophils.
Which of the following toxins and descriptions do NOT match?
Vibrio enterotoxin: a superantigen that destroys epithelial cells
Which of the following is the best definition of antigen?
a chemical that elicits an antibody response and can combine with these antibodies
In response to the presence of endotoxin, phagocytes secrete tumor necrosis factor. This causes
a decrease in blood pressure.
Which of the following is a fomite?
a hypodermic needle
Which of the following is NOT a reservoir of infection?
a sick person a healthy person a hospital a sick animal None of the answers is correct; all of these can be reservoirs of infection.
A nosocomial infection is
acquired during the course of hospitalization.
The fimbriae of Neisseria gonorrhea and enteropathogenic E. coli are examples of
adhesins and ligands.
Which of the following can contribute to postoperative infections?
antibiotic resistance errors in aseptic technique normal microbiota on the operating room staff using syringes more than once All of the answers are correct.
The classical pathway for complement activation is initiated by
antigen-antibody reactions.
The ability of some microbes, such as Trypanosoma or Giardia to alter their surface molecules and evade destruction by the host's antibodies is called
antigenic variation.
Which of the following are best described as short chains of amino acids that are very stable and can have a variety of different antimicrobial activities, such as forming pores in bacterial plasma membranes and inhibiting cell wall synthesis?
antimicrobial peptides
Symptoms of disease differ from signs of disease in that symptoms
are changes felt by the patient.
Transient microbiota differ from normal microbiota in that transient microbiota
are present for a relatively short time.
A chill is a sign that
body temperature is rising.
Botulism is caused by ingestion of a proteinaceous exotoxin; therefore, it can easily be prevented by
boiling food prior to consumption.
In which of the following patterns of disease does the patient experience no signs or symptoms?
both incubation and convalescence
Which of the following diseases is NOT spread by droplet infection?
botulism
Which of the following does NOT contribute to the symptoms of a fungal disease?
cell walls
Which of the following is mismatched?
chemotaxis chemical degradation inside a phagolysosome
Which disease would be potentially propagated in an environment without functional plumbing and in which drinking water is contaminated with sewage?
cholera
Which of the following is found normally in serum?
complement
After ingesting a pathogen, lysosomal enzymes produce all of the following EXCEPT
complement.
Superantigens produce intense immune responses by stimulating lymphocytes to produce
cytokines.
the table shows the ID50 for Staphylococcus aureus in wounds with and without the administration of ampicillin before surgery. Based on the data, the administration of ampicillin before surgery
decreases the risk of staphylococcal infection.
You note that the body temperature of one of your patients is starting to increase. As a result, you can infer that all of the following may be occurring in this patient EXCEPT __________.
dilation of blood vessels
Malaria is an infectious disease caused by infection with a protozoan. In certain tropical regions, malaria is constantly present. We would say that malaria is a(n) __________ disease in these regions.
endemic
Patients developed inflammation a few hours following eye surgery. Instruments and solutions were sterile, and the Limulus assay was positive. The patients' inflammation was due to
endotoxin
If one is examining a blood smear from a patient with a parasitic worm infection, which of the following leukocytes would be found in increased numbers?
eosinophils
Which of the following is involved in resistance to parasitic helminths?
eosinophils
The graph in the figure shows the incidence of polio in the United States. The period between 1945 and 1955 indicates a(n)
epidemic level.
The science that deals with when diseases occur and how they are transmitted is called
epidemiology.
All of the following are effects of histamine EXCEPT
fever.
Which type of bacterial enzyme helps spread Streptococcus pyogenes by digesting blood clots?
fibrinolysin
The swelling associated with inflammation decreases when the fluid
goes into lymph capillaries.
Which one of the following does NOT contribute to the incidence of nosocomial infections?
gram-negative cell walls
Which of the following is an effect of opsonization?
increased adherence of phagocytes to microorganisms
One effect of washing regularly with antibacterial agents is the removal of normal microbiota. This can result in
increased susceptibility to disease.
A needlestick is an example of
indirect contact transmission by fomite.
Which of the following mechanisms is used by gram-negative bacteria to cross the blood-brain barrier?
inducing TNF
The antimicrobial effects of AMPs include all of the following EXCEPT
inhibition of phagocytosis.
Siderophores are bacterial proteins that compete with the host's
iron-transport proteins.
Innate immunity
is nonspecific and present at birth.
A disease in which the causative agent remains inactive for a time before producing symptoms is referred to as
latent.
The alternative pathway for complement activation is initiated by
lipid-carbohydrate complexes and C3.
Focal infections initially start out as
local infections.
The lectin pathway for complement action is initiated by
mannose on the surface of microbes.
A commensal bacterium
may also be an opportunistic pathogen.
All of the following are methods of avoiding host antibodies EXCEPT
membrane-disrupting toxins.
The major significance of Robert Koch's work is that
microorganisms cause disease.
Which non-specific defense mechanism is mismatched with its associated body structure or body fluid?
mucociliary escalator intestines
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
Pseudomonas bacteria colonized the bile duct of a patient following his liver transplant surgery. This is an example of a
nosocomial infection.
Which of the following contributes to the virulence of a pathogen?
numbers of microorganisms that gain access to a host, evasion of host defenses, and toxin production
A child falls and suffers a deep cut on her leg. The cut went through her skin and she is bleeding. Which of the following defense mechanisms will participate in eliminating contaminating microbes?
phagocytosis in the inflammatory response
Cholera toxin polypeptide A binds to surface gangliosides on target cells. If the gangliosides were removed,
polypeptide B would not be able to enter the cells.
Neutrophils with defective lysosomes are unable to
produce toxic oxygen products.
Which of the following cytopathic effects is cytocidal?
release of enzymes from lysosomes
Endotoxins in sterile injectable drugs could cause
septic shock symptoms.
All of the following are iron-binding proteins found in humans EXCEPT
siderophorin.
Bacteria that cause periodontal disease have adhesins for receptors on streptococci that colonize on teeth. This indicates that
streptococcal colonization is necessary for periodontal disease.
Symptoms of intense inflammation and shock occur in some gram-positive bacterial infections due to
superantigens.
Which one of the following is NOT a zoonosis?
tapeworm rabies cat-scratch disease Hantavirus pulmonary syndrome All of these are zoonoses.
Which of the following is NOT a communicable disease?
tetanus
The ID50 is
the dose that will cause an infection in 50 percent of the test population.
A differential cell count is used to determine each of the following EXCEPT
the number of red blood cells.
The specificity of an antibody is due to
the variable portions of the H and L chains.
All of the following are part of the mechanism of action of alpha and beta interferons EXCEPT
they are effective for long periods.
All of the following are true regarding NK cells EXCEPT
they destroy infected body cells by phagocytosis.
Normal microbiota provide protection from infection in each of the following ways EXCEPT
they produce lysozyme.
Symptoms of protozoan and helminthic diseases are due to
tissue damage due to growth of the parasite on the tissues, waste products excreted by the parasite, and products released from damaged tissues.
In which of the following cases would the Limulus amebocyte lysate (LAL) assay be used?
to ensure that a sterilized medical device is free of endotoxin
Nonpathogenic Vibrio cholerae can acquire the cholera toxin gene by
transduction.
Which cytokines are believed to contribute to autoimmune disease, such as rheumatoid arthritis?
tumor necrosis factor (TNF)
In which of the following diseases can gender be considered a viable predisposing factor?
urinary tract infections
The rise in herd immunity amongst a population can be directly attributed to
vaccinations.
Cytopathic effects are changes in host cells due to
viral infections.
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