MCQs on Listeria, Corynebacterium, Arthrobacter (gram positive): Medical microbiology (with clinical case)

              MCQs on Listeria, Corynebacterium, Arthrobacter (with clinical case)

1. Which of the following groups is most susceptible to severe Listeria infections?
A) Children
B) Elderly    
C) Teenagers
D) Young adults

2. What is the most common food source associated with Listeria outbreaks?
A) Fresh fruits and vegetables
B) Salty crackers
C) Raw eggs
D) Soft cheeses  

3. Which of the following symptoms is NOT typically associated with Listeria infection?
A) Diarrhea    
B) Fever
C) Nausea
D) Muscle aches

4. What is the recommended temperature for storing refrigerated foods to prevent Listeria growth?
A) 32°F (0°C)
B) 40°F (4°C)   
C) 50°F (10°C)
D) 60°F (15°C)

5. The primary virulence factor in Corynebacterium diphtheriae is:

A) Capsule

B) Endotoxin

C) Exotoxin    

D) Lipopolysaccharide

6. A 7 year old boy is presented to the emergency department because he had been experiencing a sore throat for the past few days. Initially, it started as a mild discomfort, but it had progressively worsened. Over the last 24 hours, he developed difficulty swallowing, and his breathing became increasingly labored. His parents also noticed a grayish-white membrane forming in the back of his throat.

The boy had a history of incomplete immunizations, and he had not received his diphtheria-tetanus-pertussis (DTaP) vaccinations as recommended for her age.

Upon examination, the healthcare provider noted that the boy's throat appeared severely inflamed, with the presence of a thick, grayish-white membrane covering the tonsils and pharynx.

The boy was in respiratory distress, with increased respiratory rate and the use of accessory muscles to breathe. He had a low-grade fever, lymph nodes appeared enlarged.

Based on the clinical presentation and the characteristic grayish-white membrane in the throat, the healthcare team suspected diphtheria. 

Which of the following antibiotic is commonly given for the treatment of diphtheria? 

a) Azithromycin

b) Ceftriaxone

c) Ketoconazole

d) Penicillin 

7. How can Listeria contamination in food be reduced or prevented?
A) Washing hands thoroughly before eating
B) Cooking meat and poultry thoroughly
C) Avoiding raw seafood
D) All of the above     

8. Which of the following diseases is NOT caused by Corynebacterium species?

A) Acne

B) Diphtheria

C) Skin infections

D) Tetanus 

9. What is the treatment of choice for severe Listeria infections?
A) Antibiotics     
B) Antiviral drugs
C) Antifungal medications
D) No specific treatment is available

10. What is the Gram stain reaction of Listeria monocytogenes and Corynebacterium diphtheriae?

A) Acid fast bacilli

B) Gram-positive bacilli      

C) Gram-negative bacilli

D) Gram-variable

11. Listeria monocytogenes is often misidentified in clinical specimens as:

A) Diphtheroids    

B) Diplococci    

C) Staphylococci

D) Spirochetes

12. Cutaneous diphtheria is often associated with:

A) Eye infections

B) Genital ulcers

C) Open wounds or sores     

D) Respiratory symptoms

13. What is the primary mode of transmission for Listeria monocytogenes in healthy individuals?

A) Airborne transmission

B) Foodborne transmission      

C) Person-to-person contact

D) Waterborne transmission

14. What is the main clinical manifestation of Listeria monocytogenes infection in healthy individuals?

A) Gastrointestinal symptoms    

B) Respiratory infection

C) Skin rash

D) Urinary tract infection

15. Which of the following clinical conditions is often associated with Corynebacterium urealyticum infections?

A) Conjuctivitis

B) Pneumonia

C) Skin abscesses 

D) Urinary tract infections    

16. Which of the following is NOT a characteristic of Listeria monocytogenes?

A) Facultative anaerobic

B) Gram-positive

C) Oxidase-positive    

D) Non-branching rod

17. Which of the following is a common symptom of Listeria monocytogenes foodborne infection?

a) Abdominal cramps and watery diarrhea    

b) Bloody diarrhea with low fever

c) Fever, abdominal cramps, and diarrhea

d) Vomiting and non-blood diarrhea

18. Corynebacterium urealyticum is commonly is considered a potential cause of:

A) Jaundice

B) Kidney stones   

C) Peptic ulcers

D) Tuberculosis

19. What is a common symptom of listeriosis?

a) High fever

b) Rash

c) Stiff neck    

d) Vision problems

20. Which vaccine is typically administered to prevent diphtheria in children as part of routine immunization schedules?

a) MMR vaccine

b) Hepatitis B vaccine

c) DTaP vaccine

d) Influenza vaccine

Answers:

1. B) Elderly

2. D) Soft cheeses  

3. A) Diarrhea

4. B) 40°F (4°C)   

5. C) Exotoxin

6. d) Penicillin    

7. D) All of the above     

8. D) Tetanus  

9. A) Antibiotics

10. B) Gram-positive bacilli  

11. A) Diphtheroids 

12. C) Open wounds or sores  

13. B) Foodborne transmission  

14. A) Gastrointestinal symptoms  

15. D) Urinary tract infections    

16. C) Oxidase-positive   

17. A) Abdominal cramps and watery diarrhea  

18. B) Kidney stones

19. C) Stiff neck   

20. c) DTaP vaccine. Diphtheria-tetanus-pertussis (DTaP) vaccinations is recommended for children to prevent diphtheria.

                                 Source: Centers for Disease Control and Prevention (CDC)