MICROBIO LEC 4

Question 1

Which of the following does NOT pertain to infant botulism?

A. Symptoms include flaccid paralysis and respiratory complications
B. Symptoms include “floppy baby” appearance
C. Neurotoxin is not involved in the disease process
D. Ingested spores can germinate in the immature intestine of the neonate

Answer 1

C. Neurotoxin is not involved in the disease process

Question 2

Which of the following is NOT characteristic of Bacillus anthracis?

A. Capsule and exotoxins are virulence factors
B. Reservoir includes infected grazing animals and contaminated soil
C. Anaerobic
D. Spore-former

Answer 2

C. Anaerobic

Question 3

Disease/s caused by Streptococcus pneumoniae include

A. otitis media
B. meningitis
C. pneumonia
D. All of these choices are correct

Answer 3

D. All of these choices are correct

Question 4

Which organism can infect deeper wound sites and produce exotoxins, enzymes, and gas that cause tissue and muscle necrosis?

A. Clostridium perfringens
B. Clostridium tetani
C. Clostridium botulinum
D. Clostridium difficile

Answer 4

A. Clostridium perfringens

Question 5

A specimen was collected from a deep wound. A smear was prepared and Gram stained and samples were inoculated onto two blood agar plates. Both blood agar plates were incubated for 48 hours at 35⁰C, but one blood agar plate was incubated aerobically and the other was incubated in an anaerobe jar. The Gram stain of the original specimen showed large gram-positive bacilli. After incubation, there was no growth on the blood agar plate that was incubated aerobically, but the plate incubated in the anaerobe jar grew beta hemolytic colonies. A Gram stain of these colonies showed large gram positive bacilli, some with unstained inclusions, suggestive of endospores. What is the most likely genus of bacteria observed?

A. Mycobacterium
B. Bacillus
C. Clostridium
D. Corynebacterium

Answer 5

C. Clostridium

Question 6

Which of the following is not true about diphtheria?

A. A pseudomembrane may form in the back of the throat
B. It is an upper respiratory infection
C. Humans can be healthy carriers
D. It is a zoonosis

Answer 6

D. It is a zoonosis

Question 7

The food-borne disease that involves neurotoxin is

A. botulism
B. Bacillus cereus intoxication
C. gastrointestinal anthrax
D. Clostridium perfringens gastroenteritis

Answer 7

A. botulism

Question 8

Production of a neurotoxin that binds to target sites on spinal cord neurons responsible for inhibiting skeletal muscle contraction is a characteristic of

A. Clostridium perfringens
B. Clostridium difficile
C. Clostridium botulinum
D. Clostridium tetani

Answer 8

D. Clostridium tetani

Question 9

Which of the following pertains to diphtheria?

A. It results in meningitis
B. Symptoms include vomiting and diarrhea
C. It is prevented by the DTaP immunization DTaP stands for Diphtheria, Tetanus, and Pertussis given at 2 months of age
D. All of the choices are correct

Answer 9

C. It is prevented by the DTaP immunization DTaP stands for Diphtheria, Tetanus, and Pertussis given at 2 months of age

Question 10

Which is not correct about Bacillus cereus?

A. Associated with cooked rice, potato, and meat dishes that are stored at room temperature
B. Causes a zoonosis
C. Produces enterotoxins
D. Causes food-borne intoxication

Answer 10

B. Causes a zoonosis

Question 11

Production of a neurotoxin that prevents acetylcholine release from motor neurons at neuromuscular junctions is a characteristic of

A. Clostridium tetani
B. Clostridium botulinum
C. Clostridium perfringens
D. Clostridium difficile

Answer 11

B. Clostridium botulinum

Question 12

Which of the following does NOT pertain to Clostridium difficile infection?

A. It is a colitis that is a superinfection
B. It is due to ingestion of contaminated, improperly stored, cooked meats and gravies
C. It is a major cause of diarrhea in hospitals
D. It may be on the rise due to increased use of gastric acid inhibitors

Answer 12

B. It is due to ingestion of contaminated, improperly stored, cooked meats and gravies

Question 13

What is the usual cause of pseudomembranous colitis?

A. Therapy with broad-spectrum antibiotics leading to superinfection by C. difficile
B. Improperly home-preserved foods containing botulin toxin
C. Consuming unpasteurized dairy products containing Listeria monocytogenes
D. Living in close contact with someone infected with C. perfringens

Answer 13

A. Therapy with broad-spectrum antibiotics leading to superinfection by C. difficile

Question 14

What do the bacteria that cause botulism, tetanus, and diphtheria have in common?

A. Each of these diseases is caused by an endospore forming bacterial species
B. Each of these bacteria make an exotoxin that is responsible for the disease
C. Vaccines are widely used to prevent each of these diseases
D. Each of these diseases is caused by oligately anaerobic bacteria

Answer 14

B. Each of these bacteria make an exotoxin that is responsible for the disease

Question 15

Which form of anthrax involves a black eschar on the skin?

A. Pulmonary
B. Gastrointestinal
C. Cutaneous
D. All of the choices are correct

Answer 15

C. Cutaneous

Question 16

Anthrax is
A. a zoonosis
B. transmitted by contact, inhalation, and ingestion
C. a disease that, in humans, can cause a rapidly fatal toxemia and septicemia
D. All of the choices are correct

Answer 16

D. All of the choices are correct

Question 17

Case: 29-year old Filipino male zoologist, came home from New Zealand after research with sheep 3 weeks ago:
Complaint: cough, dyspnea, and substernal pain
Diagnostics: x-ray shows mediastinal widening
Culture and Gram Stain: large gram-positive rods
What toxin is known as a major virulence factor of etiologic agent and cause of death in infected patients?

A. Protective antigen
B. Edema toxin
C. Lethal toxin
D. Exotoxin

Answer 17

C. Lethal toxin

Question 18

Case: 29-year old Filipino male zoologist, came home from New Zealand after research with sheep 3 weeks ago:
Complaint: cough, dyspnea, and substernal pain
Diagnostics: x-ray shows mediastinal widening
Culture and Gram Stain: large gram-positive rods
What is the drug of choice to target the etiologic agent?

A. Ciprofloxacin
B. Cotrimoxazole
C. Clindamycin
D. Cefuroxime

Answer 18

A. Ciprofloxacin

Question 19

Which of the following treatment modalities is of utmost priority for a patient with a necrotic wound most likely infected with C. perfringens?

A. Immediate administration of Polyvalent antitoxin
B. Extensive surgical debridement in the operating room
A. Hyperbaric oxygen
D. Immediate administration of antibiotic therapy

Answer 19

B. Extensive surgical debridement in the operating room

Question 20

Which of the following is NOT used in the treatment of B. cereus infection?

A. Cefuroxime
B. Aminoglycosides
C. Clindamycin
D. Ciprofloxacin

Answer 20

A. Cefuroxime

Question 21

Which of the following is a characteristic of Bacillus cereus?

A. Needs oxygen for growth
B. Absence of hemolysis on 5% sheep blood agar
C. It is encapsulated
D. Produces an exotoxin causing vomiting and diarrhea

Answer 21

A. Needs oxygen for growth

Question 22

What toxin is responsible for binding of Clostridium difficile to the receptors on the brush border of the gut?

A. Alpha toxin
B. Toxin A
C. Theta toxin
D. Toxin B

Answer 22

B. Toxin A

Question 23

Which of the following statements regarding Clostridium perfringens is correct?

A. It produces an endotoxin that causes tissue destruction
B. It produces non-hemolytic colonies with rough, uneven surface
C. It is the most common cause of antibiotic associated diarrhea
D. It is an anaerobic, gram positive bacilli

Answer 23

D. It is an anaerobic, gram positive bacilli

Question 24

Case: A 70-year old male admitted for ~2 weeks in Intensive Care Unit (ICU).
Complaint: Sudden development of multiple episodes of diarrhea, hypotension, fever and cramping abdominal pain
History: On prolonged antibiotic use for pneumonia
Which of the following is the most likely cause of the patient’s problem?

A. Clostridium perfringens
B. Clostridium difficile
C. Bacillus cereus
D. Listeria monocytogenes

Answer 24

B. Clostridium difficile

Question 25

Case: 3-month old infant
Complaint: Poor feeding, decreased activity, poor cry
History: Given formula milked with 1 tsp honey by superstitious grandmother
Which of the following is TRUE about the etiologic agent?

A. Antigenic varieties include A, B, and G
B. Toxin produced can cross into the CNS causing symptoms
C. Agent is found in soil and animal feces
D. Spores are killed with heating honey for at least 15 minutes

Answer 25

C. Agent is found in soil and animal feces

Question 26

Which of the following antibiotics can be used to suppress the toxin-producing bacteria causing pharyngeal pseudomembranous disease?

A. Cephalosporins
B. Aminoglycosides
C. Macrolides
D. Antifungals

Answer 26

C. Macrolides

Question 27

The sudden arrest in protein synthesis resulting in necrosis and other neurotoxic manifestations in diphtheria is caused by the inactivation of what factor?

A. Heparin- binding epidermal growth factor
B. Elongation Factor-2
C. Lethal factor
D. CD-9 protein factor

Answer 27

B. Elongation Factor-2

Question 28

Case: 35-year old male sought consult for jaw stiffness.
History: punctured wound on left foot, plantar area after stepping on nail 3 weeks ago.
Complaints: gradual development of jaw stiffness, difficulty swallowing and generalized spasm.
Which of the following statements about its etiologic agent is CORRECT?

A. It is an invasive organism affecting the central nervous system
B. The presence of calcium salts and necrotic tissues inhibit its germination and spore production
C. The toxin it produces degrades synaptobrevin and blocks the release of GABA
D. It has a central spore and exists in several types because of the presence of its O antigen

Answer 28

C. The toxin it produces degrades synaptobrevin and blocks the release of GABA

Question 29

What neurotransmitter is inhibited by the botulinum toxin, causing the manifestations of the disease?

A. GABA
B. Acetylcholine
C. Serotonin
D. Glycine

Answer 29

B. Acetylcholine

Question 30

The Elek’s test is an immunodiffusion technique test performed to detect the presence of:

A. Clostridium perfringens
B. Francisella tularensis
C. Corynebacterium diphtheriae
D. Bordetella pertussis

Answer 30

C. Corynebacterium diphtheriae

Question 31

Stiffening of the jaw is also known as:

A. Risus Sardonicus
B. Trismus
C. Opisthotonous
D. Diplopia

Answer 31

B. Trismus

Question 32

Which of the following is true regarding adult botulism?

A. Botulinum toxin blocks the release of Acetylcholine and Glycine
B. Culture and isolation of bacteria in serum, gastric secretions, and stool is warranted
C. Metronidazole and Botulinum antitoxin should be given promptly after diagnosis.
D. Patients who recover do not develop antitoxins in the blood.

Answer 32

D. Patients who recover do not develop antitoxins in the blood.

Question 33

A 70 yr old male patient who was in ICU for almost 2 weeks develop multiple episodes of diarrhea, hypotension, fever, and cramping of abdominal pain. He was exposed with antibiotics because of pneumonia. What is the associated problem of the patient

A. C. Perfringes
B. B. Cerues
C. C. Difficile

Answer 33

C. C. Difficile

Question 34

How to diagnose the patient? (Causative agent: C. difficile)

A Detection using enzyme immunoassay
B Lecithinase activity in egg yolk media
C Stop the use of antibiotic and treat with clindamycin
D Giving of antitoxins

Answer 34

A Detection using enzyme immunoassay