Immunology Questions and Answers – Bacterial Infections

This set of Immunology Multiple Choice Questions & Answers (MCQs) focuses on “Bacterial Infections”.

1. Bacterial populations are of two types: Good bacteria and Harmful bacteria.
a) True
b) False
View Answer

Answer: a
Explanation: Bacterial populations usually reside on skin, intestine or in genital area. Bacterial populations are divided into two major types: 1) Good bacteria (also referred to as healthy bacteria) which do not cause diseases or infections and they are actually helpful. They enhance the mechanism of good health. 2) Harmful bacteria (also referred to as pathogenic bacteria) are the type of bacteria that cause harmful diseases and infections.  

2. Which of the following bacteria causes meningitis?
a) E. coli
b) Salmonella
c) Neisseria meningitidis
d) Staphylococcus aureus
View Answer

Answer: c
Explanation: Neisseria meningitidis causes meningitis mostly in children. It promotes mortality and morbidity in young adults and children. The word meningitis refers to the meninges of human brain. Meninges are the membranes that cover the brain and spinal cord. Its main purpose is providing protection. Meningitis causes inflammation in these meninges when the fluid surrounding the meninges becomes infected. Neisseria meningitidis forms colonies of their population around the meninges in order to infect them.

3. Which of the following is one of the most classic symptoms of bacterial infections?
a) Fever
b) Diarrhoea
c) Headache
d) Sour throat
View Answer

Answer: a
Explanation:  Symptoms of bacterial diseases vary depending on the type of bacterial infection, the area of the body that is infected, and other factors, such as the patient’s age and health history. The symptoms of bacterial infections may also be due to viral infections. However, the most common and classic symptom is fever. Around 80% of people feel feverish at first when a bacterial infection is detected. 
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4. Which one of the following is NOT a risk factor of being infected by bacteria?
a) Consumption of undercooked food
b) Not washing hands frequently
c) Having immunodeficiency disorders
d) Lack of sleep
View Answer

Answer: d
Explanation: Bacterial infections can occur in any age group but a number of factors increase the risk pf developing bacterial infection out of which the most important risk factor is consumption of undercooked food or expired food. Bacterial spoilage of food can definitely cause bacterial infections whereas other factors like not washing hands before eating or having any kind of chronic or immunodeficiency disorder can also be risky. On the other hand, lack of sleep or developing stress can cause a minute viral infection such as fever, flu or even headache which is quite normal. 

5. Who discovered Penicillin to be used as an antibiotic against bacterial infections?
a) Edward Jenner
b) Alexander Fleming
c) Pasteur
d) Ellis Reinherz
View Answer

Answer: b
Explanation: Alexander Fleming, in 1928, found a mold which certainly tried to inhibit growth of bacteria. This mold belonged to genus Penicillium. As a result, he called this unknown mold as Penicillin. He performed various experiments in order to show the confirmatory tests of the inhibitory mechanism of Penicillin. 10 years later, scientists of the Oxford University tested this Penicillin on mice by injecting bacterial infection. They found out that it completely inhibited the bacterial infection caused in the mice.

6. Bacteria, structurally is NOT found in which of the following shapes?
a) Rectangular
b) Spherical
c) Rod-shaped
d) Spiral
View Answer

Answer: a
Explanation: Bacteria are single-celled microorganisms (also known as prokaryotes). They can live in almost any type of environment and they mainly show three shapes: 1) Spherical bacteria (these are also called as cocci), 2) Rod shaped bacteria (mainly called as bacilli) and 3) Spiral (these are usually coiled bacteria called as spirilla). 

7. Plague is caused by which bacteria?
a) E. coli
b) Yersinia pestis
c) Acidobacteria
d) Cyanobacteria
View Answer

Answer: b
Explanation: Plague is caused by a bacterium named Yersinia pestis (Y. pestis). This bacterium is usually found in rodents and flea. Plague occurs in human if the rodents or flea bites humans. The incubation period of this bacteria is nearly of seven days. After its incubation period, the infected person starts to show symptoms like inflammation in lymph nodes, breathing problems, etc. The plague outbreak was first observed in China.
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8. Otitis media is the bacterial disease of which part of human body?
a) Lungs
b) Heart
c) Eyes
d) Ears
View Answer

Answer: d
Explanation:  Otitis media is the infection of ear. Specifically, it occurs in the are behind the eardrum called as the middle ear. It generally occurs in young children and infants. Crying, irritability and neck pain are some of the common signs to know whether children have otitis media. The eustachian tube is the tube that runs from the middle of the ear to the back of the throat. This tube becomes swollen or blocked and traps fluid in the middle ear. The trapped fluid can become infected. 

9. Drinking contaminated water or eating food washed in contaminated water leads to which type of bacterial disease?
a) Typhoid
b) Bubonic plague
c) Urinary tract infections
d) Sinusitis
View Answer

Answer: a
Explanation: People who consume contaminated food or water are likely to get affected by typhoid. Typhoid can lead to vomiting, fever and diarrhoea. The gastrointestinal tract is severely affected along with liver and spleen. It can also reach lungs, gallbladder, lungs and kidney through bloodstream. Typhoid is rare and can be treated by various antibiotics. 
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10. Which bacteria causes throat infections and tonsils?
a) Streptococcus
b) E. coli
c) Acidobacteria
d) Cyanobacteria
View Answer

Answer: a
Explanation: The bacteria group A Streptococcus can cause a bacterial infection of the throat and tonsils. Another term for this condition is strep throat. The most common symptoms of strep throat include: a sore throat, pain when swallowing, tiny red dots along the roof of the mouth. Throat infections are quite painful and can be healed by betadine whereas tonsil pain gets unbearable and can be operated if suggested by doctor.

11. Cellulitus and Impetigo are which type of bacterial infections?
a) Vaginal Infection
b) Urinary tract infection
c) Skin infection
d) Brain and spinal cord infection
View Answer

Answer: c
Explanation: Cellulitis and Impetigo are a type of skin infection. Cellulitis is a common skin infection in which bacteria infect the deeper layers of the skin. It typically affects one of the limbs. Some signs and symptoms of cellulitis include swollen lymph nodes, fever and chills. On the other hand, Impetigo is another common bacterial skin infection. It typically affects the face and hands but may also affect other parts of the body. It causes swelling of lymph nodes and fatigue.

12. Which of the following antibiotics cure sepsis?
a) Amoxicillin
b) Erythromycin
c) Penicillin
d) Meropenem
View Answer

Answer: d
Explanation: Severe bacterial infection can triggers an exaggerated immune response called sepsis. This condition can lead to tissue damage, organ failure, and death. Some signs and symptoms of sepsis include fever and chills, sweaty skin or difficulty in breathing. Sepsis is caused by bacterial family staphylococcus. Antibiotics like Meropenem and Cefepime are used to inhibit the growth of bacteria. 

13. Which one of the following is the smallest bacteria?
a) E. coli
b) Oscillatoria
c) Mycoplasma genitalium
d) Thiomargarita namibiensis
View Answer

Answer: c
Explanation: The smallest bacteria is Mycoplasma genitalium. It has a diameter of around 200-300 nm. It affects the urinary bladder, genital area as well as respiratory tracts. It can grow and develop independently but still termed as a parasitic bacterium. It causes infection which results in itching and burning during urination.

14. Which bacterial infection is often referred to as food poisoning?
a) Tuberculosis
b) Salmonella
c) E. coli
d) Clostridium difficile
View Answer

Answer: b
Explanation: Salmonella is a type of infection often described as food poisoning. It causes stomach ache, diarrhoea, vomiting and burning sensations in stomach. Salmonella is a bacterial infection caused by bacterium salmonellae. It is usually localised in the intestinal tract of humans and other animals. It can also affect humans if humans consume undercooked poultry products.

15. Which type of blood test can be taken in order to detect bacterial infection?
a) Complete blood count (CBC) 
b) Liver blood test
c) Blood glucose test
d) Troponin
View Answer

Answer: a
Explanation: Most type of bacterial infections causes changes in the white blood cell count. Usually, doctors take the complete blood count (CBC) test in order to detect this change. If the WBC count is risen than the normal amount, it may result in a severe bacterial infection. This is the primary test taken to detect bacterial infection. Other tests like taking urine samples or taking a swab from nose or throat can also help in detecting the bacterial infections. 

Sanfoundry Global Education & Learning Series – Immunology.

To practice all areas of Immunology, here is complete set of 1000+ Multiple Choice Questions and Answers.

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Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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