Archive for September 2018

A pelvic examination of a 23-year-old woman showed vesicles and ulcerated lesions on her labia. Cultures were negative for Neisseria and Chlamydia; the VDRL test was negative. Which of the following is probable?

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A pelvic examination of a 23-year-old woman showed vesicles and ulcerated lesions on her labia. Cultures were negative for Neisseria and Chlamydia; the VDRL test was negative. Which of the following is probable?



A) candidiasis
B) genital herpes
C) gonorrhea
D) NGU
E) syphilis


Answer: genital herpes

A pelvic examination of a 23-year-old woman showed vesicles and ulcerated lesions on her labia. Cultures were negative for Neisseria and Chlamydia; the VDRL test was negative. Which treatment is appropriate?

09:42 Add Comment

A pelvic examination of a 23-year-old woman showed vesicles and ulcerated lesions on her labia. Cultures were negative for Neisseria and Chlamydia; the VDRL test was negative. Which treatment is appropriate?



A) acyclovir
B) metronidazole
C) miconazole
D) penicillin
E) surgery


Answer: acyclovir

A 25-year-old male presented with fever, malaise, and a rash on his chest, arms, and feet. Diagnosis was based on serological testing. The patient then reported that he had an ulcer on his penis two months earlier. This disease can be treated with

09:42 Add Comment

A 25-year-old male presented with fever, malaise, and a rash on his chest, arms, and feet. Diagnosis was based on serological testing. The patient then reported that he had an ulcer on his penis two months earlier. This disease can be treated with



A) acyclovir.
B) metronidazole.
C) miconazole.
D) penicillin.
E) surgery


Answer: penicillin

A 25-year-old man presented with fever, malaise, and a rash on his chest, arms, and feet. Diagnosis was based on serological testing. The patient then reported that he had an ulcer on his penis two months earlier. What stage of disease is the patient in?

09:42 Add Comment

A 25-year-old man presented with fever, malaise, and a rash on his chest, arms, and feet. Diagnosis was based on serological testing. The patient then reported that he had an ulcer on his penis two months earlier. What stage of disease is the patient in?



A) NGU
B) primary
C) secondary
D) tertiary


Answer: secondary

A 25-year-old man presented with fever, malaise, and a rash on his chest, arms, and feet. Which of the following will be most useful for a rapid diagnosis?

09:41 Add Comment

A 25-year-old man presented with fever, malaise, and a rash on his chest, arms, and feet. Which of the following will be most useful for a rapid diagnosis?



A) bacterial culture
B) microscopic examination of blood
C) serological test for antibodies
D) serological test for antigen
E) viral culture


Answer: serological test for antibodies

A patient is experiencing profuse greenish-yellow, foul-smelling discharge from her vagina. She is complaining of itching and irritation. What is the most likely treatment?

09:36 1 Comment

A patient is experiencing profuse greenish-yellow, foul-smelling discharge from her vagina. She is complaining of itching and irritation. What is the most likely treatment?




A) metronidazole
B) cephalosporins
C) acyclovir
D) miconazole
E) No treatment is available


Answer: metronidazole

Which of the following is greater?

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Which of the following is greater?



A) the number of reported cases of gonorrhea last year
B) the number of reported cases of AIDS last year
C) The number of reported cases of gonorrhea and AIDS are likely equal


Answer: the number of reported cases of gonorrhea last year

Infants born to asymptomatic mothers with recurrent genital herpes are less likely to acquire herpesvirus at birth than infants born to newly infected mothers because

09:35 Add Comment

Infants born to asymptomatic mothers with recurrent genital herpes are less likely to acquire herpesvirus at birth than infants born to newly infected mothers because



A) maternal antibodies offer protection.
B) the disease cannot be transmitted to newborns.
C) the disease is not communicable.
D) prophylactic antibiotics are administered to the newborn.
E) the virus is not growing


Answer: maternal antibodies offer protection

Which of the following is NOT a complication of gonorrhea?

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Which of the following is NOT a complication of gonorrhea?



A) arthritis
B) pelvic inflammatory disease
C) endocarditis
D) meningitis
E) None of the answers are correct; all of these are potential complications of gonorrhea


Answer: none of these answers are correct; all of these are potential complications of gonorrhea

Which of the following is NOT a predisposing factors to cystitis in females?

09:30 Add Comment

Which of the following is NOT a predisposing factors to cystitis in females?



A) the proximity of the anus to the urethra
B) the length of the urethra
C) sexual intercourse
D) poor personal hygiene
E) None of the answers is correct; all of these are predisposing factors


Answer: none of the answers is correct; all of these are predisposing factors

Which of the following is NOT an antimicrobial feature of the urinary system?

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Which of the following is NOT an antimicrobial feature of the urinary system?



A) physiological valves found in the ureter
B) pH of the urine
C) flushing action of urine
D) the use of the urethra for seminal fluid in women
E) None of the answers is correct; all of these are antimicrobial features of the urinary system


Answer: the use of the urethra for seminal fluid in women

Which of the following pairs is mismatched?

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Which of the following pairs is mismatched?



A) trichomoniasis — fungus
B) gonorrhea — gram-negative cocci
C) chancroid — gram-negative rod
D) Gardnerella — clue cells
E) syphilis — gram-negative spirochete


Answer: trichomoniasis - fungus

Pyelonephritis usually is caused by

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Pyelonephritis usually is caused by



A) Pseudomonas aeruginosa.
B) Proteus spp.
C) Escherichia coli.
D) Enterobacter aerogenes.
E) Streptococcus pyogenes


Answer: Escherichia coli

All of the following result from N. gonorrhoeae infection. Which one leads to the others?

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All of the following result from N. gonorrhoeae infection. Which one leads to the others?



A) Antibody production is stopped.
B) CD4+ T lymphocytes do not activate.
C) There is an increased risk of other STIs.
D) Opa protein attaches to CD4+ T lymphocytes.
E) CD4+ T lymphocytes do not proliferate


Answer: Opa protein attaches to CD4+ T lymphocytes

Pyelonephritis may result from

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Pyelonephritis may result from



A) urethritis.
B) cystitis.
C) ureteritis.
D) systemic infections.
E) All of the answers are correct


Answer: All of the answers are correct

Cystitis is most often caused by

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Cystitis is most often caused by



A) Escherichia coli.
B) Leptospira interrogans.
C) Candida albicans.
D) Neisseria gonorrhoeae.
E) Pseudomonas aeruginosa


Answer: Escherichia coli

The relative risks shown in Table 25.1 were calculated for foods suspected of transmitting Salmonella. Which food is the most likely source of infection?

09:22 Add Comment

The relative risks shown in Table 25.1 were calculated for foods suspected of transmitting Salmonella. Which food is the most likely source of infection?



A) black beans
B) corn soup
C) jalapeño peppers
D) roma tomatoes
E) The answer cannot be determined based on the information provided


Answer: jalapeño peppers

Following a county fair, 160 persons complained of gastrointestinal symptoms. Symptoms included diarrhea (84 percent), abdominal cramps (96 percent), nausea (84 percent), vomiting (82 percent), body aches (50 percent), fever (60 percent; median body temperature = 38.3°C); median duration of illness 6 days (range 10 hr to 13 days).

09:22 Add Comment
Following a county fair, 160 persons complained of gastrointestinal symptoms. Symptoms included diarrhea (84 percent), abdominal cramps (96 percent), nausea (84 percent), vomiting (82 percent), body aches (50 percent), fever (60 percent; median body temperature = 38.3°C); median duration of illness 6 days (range 10 hr to 13 days).

In Situation 25.1, fecal samples should be cultured for all of the following EXCEPT


A) Salmonella enterica.
B) Shigella spp.
C) Campylobacter jejuni.
D) enteropathogenic Escherichia coli.
E) Giardia lamblia


Answer: Giardia lamblia


In Situation 25.1, fecal samples were found to be negative when cultured. The next step in diagnosing the cause of illness would be


A) to begin antibiotic therapy.
B) blood cultures.
C) microscopic examination of feces for oocysts.
D) microscopic examination of feces for viruses.
E) muscle biopsy.


Answer: microscopic examination of feces for oocysts

Which of the following is mismatched?

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Which of the following is mismatched?



A) beef — E. coli O157:H7
B) custard and cream pies — Staphylococcus aureus
C) eggs — Trichinella spiralis
D) chicken — Campylobacter jejuni
E) oysters — Vibrio parahaemolyticus


Answer: eggs - trichinella spiralis

What is a Dane particle?

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What is a Dane particle?



A) the chlorine-resistant virus that causes HAV
B) the infectious virion that causes HBV
C) the spherical particles found in serum of patients with HBV
D) the filamentous particles that cause HAV
E) another name for an HBV surface antigen


Answer: the infectious virion that causes HBV

All of the following pertain to pinworm infections EXCEPT

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All of the following pertain to pinworm infections EXCEPT



A) transmission is typically by contact with fomites or inhalation of eggs.
B) diagnosis is by detecting eggs on transparent tape pressed to the perianal area.
C) all family members living with the patient must also be treated.
D) it is most commonly transmitted by cysts in water.
E) it is a helminth disease


Answer: it is most commonly transmitted by cysts in water

Which of the following pertains to typhoid fever?

09:19 Add Comment

Which of the following pertains to typhoid fever?



A) It is acquired via ingestion of contaminated meat.
B) Enterotoxin spreads via the blood.
C) It is caused by several different species of Salmonella.
D) Causative microorganism multiplies in patient phagocytes.
E) It is also called bacillary dysentery


Answer: Causative microorganism multiples in patient phagocytes

A 38-year-old man had onset of fever, chills, nausea, and myalgia while vacationing on the Gulf of Mexico. On April 29, he had eaten raw oysters and gone wading in the warm coastal waters. On May 2, he was admitted to a hospital because of a fever of 39°C and two circular necrotic lesions on the left leg. He had a history of alcoholic liver disease. He was transferred to the ICU; therapy with antibiotics was initiated. On May 4, he died. Which of the following is the most likely cause?

09:19 1 Comment

A 38-year-old man had onset of fever, chills, nausea, and myalgia while vacationing on the Gulf of Mexico. On April 29, he had eaten raw oysters and gone wading in the warm coastal waters. On May 2, he was admitted to a hospital because of a fever of 39°C and two circular necrotic lesions on the left leg. He had a history of alcoholic liver disease. He was transferred to the ICU; therapy with antibiotics was initiated. On May 4, he died. Which of the following is the most likely cause?




A) Bacillus cereus
B) Cyclospora cayetanensis
C) Salmonella typhi
D) Vibrio vulnificus
E) hepatitis C virus


Answer: Vibrio vulnificus

Which of the following correctly lists the stages of tooth decay?

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Which of the following correctly lists the stages of tooth decay?



A) plaque accumulation, destruction of enamel, advancement of decay through enamel, decay in dentin, decay in tooth pulp
B) decay in dentin, plaque accumulation, destruction of enamel, advancement of decay through enamel, decay in tooth pulp
C) plaque accumulation, destruction of enamel, decay in tooth pulp, advancement of decay through enamel, decay in dentin
D) destruction of enamel, advancement of decay through enamel, plaque accumulation, decay in dentin, decay in tooth pulp
E) destruction of enamel, plaque accumulation, advancement of decay through enamel, decay in dentin, decay in tooth pulp


Answer: plaque accumulation, destruction of enamel, advancement of decay through enamel, decay in dentin, decay in tooth pulp

The most common mode of HAV transmission is

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The most common mode of HAV transmission is



A) contamination of food during preparation.
B) contamination of food before it reaches a food service establishment.
C) blood transfusion.
D) contaminated hypodermic needles.
E) airborne.


Answer: contamination of food during preparation

Which of the following is mismatched?

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Which of the following is mismatched?



A) ergot — gangrene
B) Salmonella endotoxin — lyses red blood cells
C) Vibrio enterotoxin — secretion of Cl-, K+, and H2O
D) aflatoxin — liver cancer
E) shiga toxin — tissue destruction


Answer: Salmonella endotoxin - lyses red blood cells

Typhoid fever differs from salmonellosis in that in typhoid fever

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Typhoid fever differs from salmonellosis in that in typhoid fever




A) the microorganisms multiply within macrophages.
B) the incubation period is much longer.
C) the symptoms are due to infection of the gallbladder.
D) infection is spread only in the feces of domesticated animals.
E) infection occurs due to ingestion of endospores


Answer: the incubation period is much longer

Which of the following is mismatched?

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Which of the following is mismatched?



A) hydatid disease — humans are the definitive host
B) Taenia infestation — humans are the definitive host
C) trichinellosis — humans eat larva of parasite
D) pinworm infestation — humans ingest parasite's eggs
E) hookworm infestation — parasite bores through skin


Answer: hydatid disease - humans are the definitive host

Which of the following statements about staphylococcal food poisoning is FALSE?

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Which of the following statements about staphylococcal food poisoning is FALSE?



A) It is caused by ingesting an enterotoxin.
B) It can be prevented by adequate refrigeration of food.
C) It can be prevented by heating foods to 50°C for 15 minutes.
D) It is treated by replacing water and electrolytes.
E) It is characterized by rapid onset and short duration of symptoms.


Answer: it can be prevented by heading foods to 50 degrees C for 15 minutes

In humans, beef tapeworm infestations are acquired by ingesting

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In humans, beef tapeworm infestations are acquired by ingesting



A) the eggs of Taenia saginata.
B) segments of Taenia solium tapeworms.
C) water contaminated with Diphyllobothrium latum eggs.
D) cysticerci of Taenia saginata in undercooked meat.
E) cysticerci of Taenia solium in undercooked meat


Answer: cysticerci of Taenia saginata in undercooked meat

The digestive tract is essentially one long tube. The order of the structures, beginning with the mouth, is

09:10 Add Comment

The digestive tract is essentially one long tube. The order of the structures, beginning with the mouth, is



A) pharynx, esophagus, stomach, small intestine, large intestine.
B) esophagus, pharynx, stomach, small intestine, large intestine.
C) pharynx, esophagus, stomach, large intestine, small intestine.
D) esophagus, stomach, pharynx, small intestine, large intestine.
E) pharynx, stomach, esophagus, small intestine, large intestine


Answer: pharynx, esophagus, stomach, small intestine, large intestine

Which of the following statements about salmonellosis is FALSE?

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Which of the following statements about salmonellosis is FALSE?



A) It is a bacterial infection.
B) Severity of disease depends on number of organisms ingested.
C) A healthy carrier state exists.
D) The mortality rate is high.
E) It is often associated with poultry products


Answer: the mortality rate is high

How does the membrane attack complex (MAC) kill Gram-negative bacteria?

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How does the membrane attack complex (MAC) kill Gram-negative bacteria?



a. through opsonization
b. it dissolves the lipid membrane
c. it creates a pore on membrane through which cellular content leaks out, killing the cell
d. it creates a pore on membrane through which lysozyme in body fluid enters, to cleave peptidoglycan
e. it creates a pore on membrane through which sodium and water enter the cell to cause osmotic lysis


Answer: d. it creates a pore on membrane through which lysozyme in body fluid enters, to cleave peptidoglycan

Toll-like receptors are eukaryotic membrane proteins that bind with bacterial surface molecules and:

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Toll-like receptors are eukaryotic membrane proteins that bind with bacterial surface molecules and:



a. form channels through which bacterial proteins can enter the eukaryotic cell
b. cause the cell to phagocytize the bacteria
c. release antibiotics to kill the bacteria
d. release chemicals that trigger host defenses against the bacteria
e. activate the complement cascade


Answer: d. release chemicals that trigger host defenses against the bacteria

Which of the following is an example of a semi specific, innate immune mechanisms associated with mucosal surfaces?

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Which of the following is an example of a semi specific, innate immune mechanisms associated with mucosal surfaces?



a. secretory IgA prevents adhesion to mucosal surface
b. extravasation of neutrophils is triggered by specific signals
c. interferons produced by host will act on specific viruses in the mucosa
d. Toll-like receptors on host bind specific pathogen-associated molecular pattern (PAMP)
e. type of inflammation mounted varies with pathogen


Answer: d. Toll-like receptors on host bind specific pathogen-associated molecular pattern (PAMP)

Natural killer cells target:

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Natural killer cells target:



a. infected cells that have lost MHC class I
b. bacterial cells that have lost MHC class I
c. bacterial cells that are coated with complement
d. infected cells that have lost C-reactive protein
e. infected cells that secrete cytokines


Answer: a. infected cells that have lost MHC class I

How does IFN-gamma protect the host?

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How does IFN-gamma protect the host?



a. It induces dsRNA endonucleases.
b. It interferes directly with viral replication.
c. It has an immunomodulatory role.
d. It induces fever at the hypothalamus.
e. It blocks adhesion of pathogens.


Answer: c. It has an immunomodulatory role.

Interferons:

13:21 Add Comment

Interferons:



a. are antibacterial agents produced by skin, GIT, and lung cells
b. are secreted by eukaryotic cells in response to intracellular infection
c. only produced by activated phagocytes
d. are host-specific and virus-specific
e. can block virus replication


Answer: b. are secreted by eukaryotic cells in response to intracellular infection

Which of the following can interfere with adherence of phagocytic cells to the pathogen?

13:20 Add Comment

Which of the following can interfere with adherence of phagocytic cells to the pathogen?



a. M protein on cell walls of Streptococcus pyogenes
b. lipid produced by Mycobacterium tuberculosis
c. leukocidin released by staphylococci
d. lipopolysaccharide of Gram-negative bacteria
e. ability of Rickettsia rickettsii to prevent release of lysosomal enzymes


Answer: a. M protein on cell walls of Streptococcus pyogenes

What is the correct order of the events in phagocytosis? (1) discharge of waste material, (2) fusion of the phagosome with a lysosome, (3) adherence of the microbe to phagocytes, (4) digestion of ingested microbe, (5) formation of a phagosome, (6) ingestion of microbe by phagocyte

13:19 Add Comment

What is the correct order of the events in phagocytosis? (1) discharge of waste material, (2) fusion of the phagosome with a lysosome, (3) adherence of the microbe to phagocytes, (4) digestion of ingested microbe, (5) formation of a phagosome, (6) ingestion of microbe by phagocyte



a. 3, 6, 5, 2, 4, 1
b. 3, 4, 6, 5, 2, 1
c. 6, 5, 2, 4, 3, 1
d. 5, 2, 3. 6, 4, 1
e. none of the above


Answer: a. 3, 6, 5, 2, 4, 1

Which of the following pairs is mismatched?

13:19 Add Comment

Which of the following pairs is mismatched?



a. extravasation—movement of leukocytes through endothelial cells into tissues
b. pus—tissue debris and dead phagocytes in a white or yellow fluid
c. chemotaxis—chemical degradation inside a phagolysosome
d. autophagy—destruction of intra phagocytic pathogen
e. scab—dried blood clot over injured tissue


Answer: c. chemotaxis—chemical degradation inside a phagolysosome

All of the following statements are correct regarding defensins EXCEPT:

13:15 Add Comment

All of the following statements are correct regarding defensins EXCEPT:



a. They are produced by skin, GIT, and lung cells for defense when stimulated.
b. They form channels in bacterial cytoplasmic membranes, ultimately killing the cell.
c. The transmembrane electrical potential allows defensins to penetrate and kill cells.
d. Like antibodies, they are highly specific in pathogen neutralization.
e. Variation in defensins produced by different animals partially explains varying susceptibility of hosts to pathogens.


Answer: d. Like antibodies, they are highly specific in pathogen neutralization.

Defensins are short cationic peptides that:

13:15 Add Comment

Defensins are short cationic peptides that:



a. are produced by skin, GIT, and lung cells for defense when stimulated
b. bind to specific receptors to gain entry into cells
c. are only produced by phagocytes upon activation
d. inhibit microbial DNA synthesis
e. are equally effective at killing eukaryotic and prokaryotic


Answer: a. are produced by skin, GIT, and lung cells for defense when stimulated

In cystic fibrosis, a mutation has rendered the receptor for binding and inactivating Pseudomonas defective. The affected gene is the CFTR. Where is the CFTR gene product located?

13:14 Add Comment

In cystic fibrosis, a mutation has rendered the receptor for binding and inactivating Pseudomonas defective. The affected gene is the CFTR. Where is the CFTR gene product located?



a. cytosol
b. nucleus
c. plasma membrane surface
d. mitochondria
e. phagosome


Answer: c. plasma membrane surface

A woman falls and suffers a 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?

13:13 Add Comment

A woman falls and suffers a 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?



a. mucociliary escalator
b. normal skin flora
c. acidic skin secretions
d. lysozyme
e. phagocytosis and the inflammatory response


Answer: e. phagocytosis and the inflammatory response

Which of the following is correct regarding inflammation?

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Which of the following is correct regarding inflammation?



a. The cardinal signs include rash.
b. Some of the phagocytes are stimulated to secrete antibodies specific for the invading pathogen.
c. The response is the same for viruses, bacteria, and injury to the body.
d. Differentiation of B cells into plasma cells occurs at the site of infection.
e. AIDS patients have little or no inflammatory response when they infected.


Answer: c. The response is the same for viruses, bacteria, and injury to the body.

Which of the following organisms are commonly used as probiotics?

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Which of the following organisms are commonly used as probiotics?



a. Streptococcus mutans and Lactobacillus acidophilus
b. Bacteroides and Lactobacillus acidophilus
c. Enterococcus and Enterobacter species
d. Bifidobacterium and Lactobacillus acidophilus
e. Diphtheroids and Fusobacterium species


Answer: d. Bifidobacterium and Lactobacillus acidophilus

The mucociliary escalator functions to:

13:10 Add Comment

The mucociliary escalator functions to:



a. trap and sweep pathogens into the urine
b. kill via lysozyme activity
c. harbor normal flora that discourage pathogens from colonizing
d. produce fatty acids with a low pH that kills microbes
e. trap and sweep microbes from the bronchi back up to the throat to be swallowed


Answer: e. trap and sweep microbes from the bronchi back up to the throat to be swallowed

Neisseria species:

13:10 Add Comment

Neisseria species:



a. are never found as normal microbial flora of humans
b. cause serious diarrhea
c. are used as probionts
d. are obligate intracellular parasites
e. are Gram-positive cocci


Answer: a. are never found as normal microbial flora of humans

All of the following statements are correct about microbial colonization of the human body EXCEPT:

13:09 Add Comment

All of the following statements are correct about microbial colonization of the human body EXCEPT:



a. The skin is a highly selective niche for certain microbes.
b. Oral microbiota can cause endocarditis after dental surgery.
c. Cardiovascular normal flora are commensal species.
d. There are 1,000 times more anaerobes in the colon than aerobes.
e. Intestinal bacteria help modulate human mucosal immunity.


Answer: c. Cardiovascular normal flora are commensal species.

HPV strains that cause cervical cancer produce protein E7, which:

13:03 Add Comment

HPV strains that cause cervical cancer produce protein E7, which: 



a. causes the degradation of pRb
b. frees up the transcription factor E2F to express the oncogen
c. ADP ribosylates protein synthesis factor EF2
d. activates G proteins
e. down-regulates MHC proteins on the cell surface


Answer: frees up the transcription factor E2F to express the oncogen

HPV strains that cause cervical cancer produce protein E7, which:

13:03 Add Comment

HPV strains that cause cervical cancer produce protein E7, which: 



a. causes the degradation of pRb
b. frees up the transcription factor E2F to express the oncogene
c. ADP ribosylates protein synthesis factor EF2
d. activates G proteins
e. down-regulates MHC proteins on the cell surface


Answer: frees up the transcription factor E2F to express the oncogene

During the latent stage of herpes virus infection:

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During the latent stage of herpes virus infection: 



a. host cells rapidly undergo apoptosis causing cold sores
b. the viral genome exists as a plasmid in the cell
c. apoptosis is inhibited by small RNA encoded by virus
d. cold sores are common
e. the host is highly infectious


Answer: apoptosis is inhibited by small RNA encoded by virus

What is a possible role for quorum sensing in pathogenicity?

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What is a possible role for quorum sensing in pathogenicity? 



a. It detects and responds to the pH as an indicator of the environment.
b. It delays production of toxins that may alert the host to the presence of the bacteria.
c. It monitors and responds to concentrations of ions such as magnesium.
d. It senses and responds to the population of phagocytes at the infection site.
e. It helps the pathogen escape the adaptive immune response


Answer: It delays production of toxins that may alert the host to the presence of the bacteria.

Which of the following is correct about Salmonella and Shigella?

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Which of the following is correct about Salmonella and Shigella? 



a. They both produce shiga tox.
b. They are Gram-positive rods.
c. They are resistant to the gastric acid kill.
d. They cause typhoid fever.
e. They are facultative intracellular pathogen


Answer: They are facultative intracellular pathogen

Tropheryma whipplei is the causative agent for Whipple's disease. It could not be cultured until recently when the genomic data showed:

13:00 Add Comment

Tropheryma whipplei is the causative agent for Whipple's disease. It could not be cultured until recently when the genomic data showed: 



a. it was auxotrophic for some amino acids
b. that it was an obligate intracellular pathogen
c. it needed a helper virus to grow
d. that it needed high levels of iron
e. that it is a virus that needed cell culture


Answer: it was auxotrophic for some amino acids

Which of the following types of information CANNOT be derived from the full genome of an uncultured bacterial pathogen?

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Which of the following types of information CANNOT be derived from the full genome of an uncultured bacterial pathogen? 



a. its nutritional requirements
b. the virulence factors employed in pathogenesis
c. infectious and lethal doses
d. mechanisms of disease
e. tissue tropism and disease progression


Answer: infectious and lethal doses

Antigenic shifts and phase variants are important virulence assets for which bacteria?

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Antigenic shifts and phase variants are important virulence assets for which bacteria? 



a. E. coli and Vibrio cholera.
b. Clostridium tetani and Bacillus anthracis
c. Neisseria gonorrhoeae and Salmonella spp.
d. Streptococcus pneumonia and Staphylococcus aureus
e. Helicobacter pylori and Enterobacter cloacae


Answer: Neisseria gonorrhoeae and Salmonella spp.

Which of the following techniques will you use to identify unknown virulence genes that are only expressed in the host?

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Which of the following techniques will you use to identify unknown virulence genes that are only expressed in the host? 



a. in situ hybridization of cultured bacteria
b. creating genomic library of open reading frames of pathogen
c. mutational studies in vitro
d. culture techniques
e. in vivo expression technology


Answer: in vivo expression technology

E. coli O157:H7 has a very low infectious dose because:

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E. coli O157:H7 has a very low infectious dose because: 



a. it is encapsulated
b. disease results from a synergistic action with Shigella
c. it is resistant to the gastric acid kill
d. the intestine has many receptors for the toxin
e. it secretes a superantigen


Answer: it is resistant to the gastric acid kill

Superantigens:

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Superantigens: 



a. bore holes on eukaryotic cell membranes
b. inhibit phagocytosis
c. prevent degranulation of macrophages
d. are antipyrogenic
e. activate immune cells without being processed


Answer: activate immune cells without being processed

Which of the following statements is NOT correct about a patient who died from endotoxin pathologies?

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Which of the following statements is NOT correct about a patient who died from endotoxin pathologies? 



a. Disseminated intravascular coagulation may have contributed to death.
b. The MRSA superbug is a likely suspect.
c. The patient may have died from hypotension.
d. The patient may not have run a fever if AIDS was present.
e. The lipid A in the endotoxin is responsible for the virulence


Answer: The MRSA superbug is a likely suspect.

Exotoxins:

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Exotoxins:



a. are secreted by Gram-positive bacteria only
b. contain glycolipids primarily
c. are protein toxins made by Gram-positive and Gram-negative bacteria
d. serve as adhesins for mucosal pathogens
e. contain lipid


Answer: are protein toxins made by Gram-positive and Gram-negative bacteria

Biofilms play a major role in enhancing bacterial virulence because:

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Biofilms play a major role in enhancing bacterial virulence because: 



a. biofilm strains are mutants
b. the exopolymer matrix is highly toxic and mutagenic
c. biofilm bacteria are intracellular pathogens
d. bacteria in biofilms are more resistant to antimicrobials and phagocytosis
e. low bacteria density does not alert the human immune system


Answer: bacteria in biofilms are more resistant to antimicrobials and phagocytosis

Synthesis of flagella and pili filaments in Gram negatives share which of the following in common?

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Synthesis of flagella and pili filaments in Gram negatives share which of the following in common? 



a. Protein export systems are used to deliver subunits to the outside.
b. Chaperons are not needed for protein transport.
c. There is no periplasmic stopover.
d. Flagellar and pili proteins are added to the base of the structure.
e. Flagellar and pili proteins are added to the tip of the structure


Answer: Protein export systems are used to deliver subunits to the outside.

Which of the following bacteria would you expect to cause the most severe blood disease in a susceptible host?

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Which of the following bacteria would you expect to cause the most severe blood disease in a susceptible host?



a. a rapidly growing encapsulated bacteria
b. a flagellated acidophile
c. a biofilm-producing strain
d. a piliated slow -growing Gram negative
e. a halophilic psychrophile


Answer: a rapidly growing encapsulated bacteria

Which of the following statements is NOT correct about disease reservoirs?

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Which of the following statements is NOT correct about disease reservoirs? 



a. Reservoirs are mammals or birds but not insects.
b. A vector can be the reservoir of a disease.
c. A reservoir is an integral part of the disease cycle.
d. Disease-control measures must consider the biological reservoir.
e. A reservoir is ultimately the source of infection in a population


Answer: Reservoirs are mammals or birds but not insects.

What do yellow fever and West Nile virus have in common?

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What do yellow fever and West Nile virus have in common? 



a. both cause cancer
b. birds are the reservoir for both viruses
c. both are close relatives of herpes virus
d. both are diarrheagenic viruses
e. both are both flaviviruses


Answer: both are both flaviviruses

Consider two isolates A and B: microbe 'A' had a LD50 of 5 × 104 while microbe 'B' recorded a LD50of 5 × 107.Which isolate is more virulent?

12:49 Add Comment

Consider two isolates A and B: microbe 'A' had a LD50 of 5 × 104 while microbe 'B' recorded a LD50of 5 × 107.Which isolate is more virulent? 



a. cannot tell with information provided
b. microbe A
c. microbe B
d. equally virulent since they killed the animals
e. the values indicate that neither one is virulent


Answer: microbe A

A chef cut his finger accidentally while making salad. The next morning he felt pain and warmth and had a little swelling and redness on that finger (signs of inflammation). By night, he was just fine. Which of the following pertains to the chef?

12:44 Add Comment

A chef cut his finger accidentally while making salad. The next morning he felt pain and warmth and had a little swelling and redness on that finger (signs of inflammation). By night, he was just fine. Which of the following pertains to the chef? 



a. He had an overt microbial disease.
b. He had an infection.
c. The inflammation was a response to the cut not a microbe.
d. Microbial toxins, not the vegetative cells, induced inflammation.
e. The cut introduced ectoparasites that could not survive


Answer: He had an infection.

A patient with recurring nut allergies enrolls in an experimental desensitization trail at the local allergy clinic; what should this patient expect?

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A patient with recurring nut allergies enrolls in an experimental desensitization trail at the local allergy clinic; what should this patient expect? 



a. injection of large doses of suspected antigen over the next few months, in hopes to begin producing antiallergen IgA
b. injection of small doses of antiantigen antibody over the next few months, in hopes to begin producing antiantibody IgE
c. injection of small doses of suspected antigen over the next few months, in hopes to begin producing antiallergen IgG
d. injection of medium doses of suspected antigen over the next few days, in hopes to begin producing antiallergen IgM
e. injection of medium doses of antiantigen antibody over the next few years, in hopes of removing all antiantigen IgE


Answer: injection of small doses of suspected antigen over the next few months, in hopes to begin producing antiallergen IgG

A 30-year old woman presented in the emergency room with hives all over her body. After a full examination it was determined that the zoo she had visited that morning caused the reaction. What was the most likely cause of this response?

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A 30-year old woman presented in the emergency room with hives all over her body. After a full examination it was determined that the zoo she had visited that morning caused the reaction. What was the most likely cause of this response? 



a. type I hypersensitivity reaction
b. type II hypersensitivity reaction
c. type III hypersensitivity reaction
d. type IV hypersensitivity reaction
e. type V hypersensitivity reaction


Answer: type I hypersensitivity reaction

The binding of released histamine to a H1 (histamine 1) receptor during an allergic attack induces a proinflammatory state through which pathway(s)?

12:40 Add Comment

The binding of released histamine to a H1 (histamine 1) receptor during an allergic attack induces a proinflammatory state through which pathway(s)? 



a. classical complement pathway
b. liopoxygenase pathway and cycloxygenase pathway
c. signal transduction pathway causing IL-2 production
d. lectin complement pathway
e. epinephrine producing pathway


Answer: liopoxygenase pathway and cycloxygenase pathway

Inhalation of allergenic pollen in a susceptible person causes the induction of what primary event triggering an allergy reaction?

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Inhalation of allergenic pollen in a susceptible person causes the induction of what primary event triggering an allergy reaction? 



a. crosslinking of IgE sensitized mast cells
b. immediate anaphylaxis
c. binding to sensitized T cytotoxic cells
d. increased cAMP levels
e. immediate leukotriene release


Answer: crosslinking of IgE sensitized mast cells

Regulation of complement destruction of normal body cells is controlled by:

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Regulation of complement destruction of normal body cells is controlled by: 



a. CD8, serum factor C3b, and serum albumin
b. CD58, serum factor H, and decay-accelerating factor
c. CD4, serum factor Bb, and decay-accelerating factor
d. MHC I, serum factor C5a, and serum lipoprotein
e. MHC II, serum albumin, and T regulatory cells


Answer: CD58, serum factor H, and decay-accelerating factor

Mycobacteria sp. have evolved a mechanism to evade adaptive immunity by:

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Mycobacteria sp. have evolved a mechanism to evade adaptive immunity by:



a. creating autoantibodies against activated T-cell populations
b. triggering T- and B-cell apoptosis
c. hiding within red blood cells of the body (similar to malarial infection)
d. inducing the production of anti-inflammatory cytokines (IL-6 and IL-10)
e. producing phagocytic chemorepellants and paralyzing neutrophils


Answer: inducing the production of anti-inflammatory cytokines (IL-6 and IL-10)

An activated TC cell trying to kill off influenza infection in the lungs would:

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An activated TC cell trying to kill off influenza infection in the lungs would: 



a. release proinflammatory cytokines throughout the entire lung
b. produce monoclonal anti-influenza antibodies
c. activate B cells to make influenza-specific plasma cells
d. bind to the infected host cells then release perforin and granzymes
e. travel to the thymus and undergo positive selection


Answer: bind to the infected host cells then release perforin and granzymes

Staphylococcal exfoliative toxin (exoliatin A) reacts in the human body as a superantigen, intoxication with this means:

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Staphylococcal exfoliative toxin (exoliatin A) reacts in the human body as a superantigen, intoxication with this means: 



a. polyclonal T-cell stimulation by overriding the normal route of antigen presentation
b. monoclonal B-cell stimulation without T-cell signaling
c. direct overactivation of TH1 cells causing TC cell response only
d. dramatic downregulation in genes controlling all cells producing pro-inflammatory cytokines
e. decreased antigen presentation by APC followed by autoantibody formation


Answer: polyclonal T-cell stimulation by overriding the normal route of antigen presentation

The secondary signal needed from a T cell for a B cell to differentiate into a plasma cell, is the crosslink between:

12:38 Add Comment

The secondary signal needed from a T cell for a B cell to differentiate into a plasma cell, is the crosslink between:



a. CD8 (on TC cell) with MHC I (on B cell)
b. CD4 (on TH cell) with CD40 (on B cell)
c. MHC II (on TC cell) with CD4 (on B cell)
d. CD8 (on TC cell) with CD40 (on B cell)
e. CD154 (on TH cell) with CD40 (on B cell)


Answer: CD154 (on TH cell) with CD40 (on B cell)

The secondary signal needed for TH0 helper cells to differentiate into either TH1 cells or TH2 cells is the crosslink between:

12:38 Add Comment

The secondary signal needed for TH0 helper cells to differentiate into either TH1 cells or TH2 cells is the crosslink between:



a. CD154 (on TH0 helper cells) and CD40 (on APC cell)
b. MHC I (on TH0 helper cells) and B7 (on APC cell)
c. CD4 (on TH0 helper cells) and MHC II (on APC cell)
d. CD8 (on TH0 helper cells) and MHC I (on APC cell)
e. CD28 (on TH0 helper cells) and B7 (on APC cell)


Answer: CD28 (on TH0 helper cells) and B7 (on APC cell)

Bacteremia is a condition where live bacteria enter the bloodstream, but not the cells of the body; which form of processing would occur to stimulate a cell-mediated immune response?

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Bacteremia is a condition where live bacteria enter the bloodstream, but not the cells of the body; which form of processing would occur to stimulate a cell-mediated immune response? 



a. bacterial peptide transported from cytoplasm to rER for presentation on MHC I
b. endocytosis by APC followed by presentation on MHC II
c. neutrophil phagocytosis with presentation on Fc receptor
d. cytotoxic T-cell endocytosis for presentation on CD8 receptor
e. B-cell capping for presentation on the B-cell receptor


Answer: endocytosis by APC followed by presentation on MHC II

Myasthenia gravis is an autoimmune neuromuscular disease characterized by weakness of the skeletal muscles due to antiacetylcholine receptor antibodies; thymectomy is a successful treatment for this condition in some patients because it:

12:37 1 Comment

Myasthenia gravis is an autoimmune neuromuscular disease characterized by weakness of the skeletal muscles due to antiacetylcholine receptor antibodies; thymectomy is a successful treatment for this condition in some patients because it: 



a. removes all auto-reactive B cells from the body
b. primes APC to reverse their response to self tissue
c. neutralizes the autoantibodies from the body
d. produces proteins to bind the autoantibodies before reaching their target
e. prevents further miseducation of T-cell population


Answer: prevents further miseducation of T-cell population

Positive selection in T-cell education refers to:

12:37 Add Comment

Positive selection in T-cell education refers to: 



a. T-cell receptors (TCR) that can bind strongly to self MHC proteins
b. CD8 receptors that can bind strongly to self MHC proteins
c. T-cell receptors (TCR) that can bind weakly to self MHC proteins
d. CD4 that can bind weakly to self MHC proteins
e. B-cell receptors that bind weakly to T-cell receptors


Answer: T-cell receptors (TCR) that can bind weakly to self MHC proteins

Chlamydia trachomatis is a bacterial STD that lives intracellularly within human host cells; what immune response would most likely prevail in this infection?

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Chlamydia trachomatis is a bacterial STD that lives intracellularly within human host cells; what immune response would most likely prevail in this infection?



a. more TH2 cells than TH1 cells
b. more TH1 cells than TH2 cells
c. equal ratio of TH1 cells to TH2 cells
d. more B cells than CD8 cells
e. mostly antibody


Answer: more TH2 cells than TH1 cells

Anti-Streptococcus antibodies found in the serum of a patient during a primary antibody response differ from the antibodies produced during a secondary response to the same antigen because of:

12:36 Add Comment

Anti-Streptococcus antibodies found in the serum of a patient during a primary antibody response differ from the antibodies produced during a secondary response to the same antigen because of: 



a. VDJ recombination
b. affinity maturation
c. class switching
d. MHC processing
e. antigen adaptatio


Answer: affinity maturation

During the course of an intestinal infection with Salmonella enteritidis, the B cells undergo class switching; what switching is most likely to occur and what causes the switch?

12:35 Add Comment

During the course of an intestinal infection with Salmonella enteritidis, the B cells undergo class switching; what switching is most likely to occur and what causes the switch? 



a. IgD to IgE; B-cell cytokines
b. IgM to IgA; T-cell cytokines
c. IgG to IgM; B-cell cytokines
d. IgA to IgG; T-cell cytokines
e. IgD to IgM; T-cell cytokines


Answer: IgM to IgA; T-cell cytokines

RAG1 and RAG2 are enzymes that control gene splicing on B-cell antibody genes, which order are segments worked on in the creation of the heavy-chain gene segment?

12:35 Add Comment

RAG1 and RAG2 are enzymes that control gene splicing on B-cell antibody genes, which order are segments worked on in the creation of the heavy-chain gene segment? 



a. VD spliced together, then J, then C
b. DJ spliced together, then V
c. VJ spliced together, then D
d. VC spliced together, then D, then J
e. VDJ segments are all spliced together simultaneously


Answer: DJ spliced together, then V

An example of an antigen that could stimulate naïve B-cell proliferation and differentiation without the help of a T cell would be:

12:34 Add Comment

An example of an antigen that could stimulate naïve B-cell proliferation and differentiation without the help of a T cell would be:



a. Proteus vulgaris, lipopolysaccharide molecule
b. Yersinia pestis, plasmid DNA molecule
c. Staphylococcus aureus, protein A molecule
d. Bacillus anthracis, anthrax toxin molecule
e. Escherichia coli, porin protein molecule


Answer: Proteus vulgaris, lipopolysaccharide molecule

Capping of B-cell receptors on the surface of an antigen-exposed B cell immediately causes what to occur?

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Capping of B-cell receptors on the surface of an antigen-exposed B cell immediately causes what to occur? 



a. VDJ gene switching, recombination, and hypermutation
b. neutrophil phagocytosis of the antigen
c. complement cascade signaling and antigen destruction
d. cell signaling cascade inducing cell proliferation and differentiation
e. T helper cell proliferation and T regulatory cell differentiation


Answer: Cell signaling cascade inducing cell proliferation and differentiation

In immunology, the term "clonal selection" best refers to:

12:34 Add Comment

In immunology, the term "clonal selection" best refers to:



a. the multiple types of cells needed to generate an antigenic specific response
b. the ability of one B cell to produce multiple isotypes of antibodies
c. the ability of specific lymphocyte subsets to proliferate upon exposure to a specific epitope
d. the ability of memory cells to induce a quick secondary antibody response
e. the process of opsonization antigen for rapid phagocytic degradation


Answer: c. the ability of specific lymphocyte subsets to proliferate upon exposure to a specific epitope

Immunization with the childhood DPT vaccine (diphtheria, pertussis, and tetanus) protects against subsequent exposure to tetanus by:

12:34 Add Comment

Immunization with the childhood DPT vaccine (diphtheria, pertussis, and tetanus) protects against subsequent exposure to tetanus by:



a. stopping isotype switching of B cells from IgM to IgA
b. preloading antigen-presenting cells
c. stimulating quick inflammation upon future exposure
d. producing life-spanning antitetanus IgE antibodies
e. generating tetanus specific memory B cells


Answer: e. generating tetanus specific memory B cells

A baby will receive antibodies from the mother before birth through the umbilical cord and then through the breast milk after birth, what classes of antibodies are received, respectively?

12:32 Add Comment

A baby will receive antibodies from the mother before birth through the umbilical cord and then through the breast milk after birth, what classes of antibodies are received, respectively?



a. IgG and IgA
b. IgM and IgD
c. IgG and IgM
d. IgM and IgA
e. IgE and IgG


Answer: a. IgG and IgA
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