Microorganisms Identification and classification



1. Which of the following microorganism has the cocci cell shapes and sizes arranged usually in tetrad structures?
a) Streptococcus pneumoniae
b) Staphylococcus aureus
c) Chlamydia trachomatis
d) Neisseria meningitidis

2. What are the different growth morphology and cell structures used for the classification of fungi? Select all the correct answers
a) Yeast
b) Mold
c) Mycelia
d) Protozoa

3. Which of the following RNA virus is a highly contagious respiratory pathogen that can easily spread from person to person?
a) Coronavirus 
b) Dengue virus
c) Epstein Barr virus
d) Hepatitis B virus

4. Which of the following metabolic characteristic is a distinguishing characteristic and identification of colonies of E. coli?
a) Hydrogen sulfide formation
b) Indole Formation
c) Lactose fermentation    
d) Urea Degradation

5. Which of the following bacteria is an endospore-forming bacteria that is also a common foodborne pathogen?
a) Bordetella pertusis
b) Clostridium botulinum
c) Klebsiella pneumoniae
d) Streptococcus pneumoniae    

6. A 19-year-old male living in a tropical region of India visited the hospital. He came with a lesion on the lower part of the left leg that according to him first appeared about a week before visiting the hospital. A skin biopsy test was performed and the infection was diagnosed to be a parasitic infection.
Which of the following is a vector-borne disease that can be transmitted to humans by the bite of infected sandflies?
a) Leishmaniasis   
b) Lassa fever
c) Malaria
d) Yellow fever

7. Which of the following is the example of encapsulated gram positive bacteria?
a) Klebsiella pneumoniae
b) Clostridium perfringens     
c) Streptococcus pneumoniae
d) Haemophilus influenzae

8. Which of the following morphological characteristics is an important identification characteristic of Neisseria gonorrhoeae?
a) Gram-Negative Diplococci
b) Gram-Positive Bacilli
c) Gram-Negative Bacilli
d) Gram-Positive Diplococci

9. A 7 year old girl developed a sore throat and fever for 2 days. On the second day, the symptoms got worse and she was taken to the hospital. Microscopic examination and culture of the sputum sample revealed gram-positive cocci that appear in chains.
Which of the following bacteria could be the possible pathogen?
a) Acinetobacter baumannii
b) Chlamydia trachomatis
c) Staphylococcus aureus
d) Streptococcus pyogenes

10. Which of the following are the growth morphology of the protozoa?
a) Multicellular and non motile
b) Unicellular and non motile
c) Multicellular 
d) Unicellular and motile

11. A 24 year old sexually active woman had an infection in the vaginal area with genital discharge while urinating. Urinary tract infection was suspected, urine sample and swab specimen were taken and cultured on suitable agar media, a microscopic examination was performed.
Which of the following gram negative bacteria is a sexually transmitted pathogen and cannot be isolated by using regular agar media used in the microbiology laboratory?
a) Mycobacterium tuberculosis
b) Chlamydia trachomatis
c) Neisseria meningitidis
d) Klebsiella oxytoca

12. Which of the following gram positive bacteria is a strict anaerobe and can only grow in the absence of oxygen?
a. Streptococcus pneumoniae
b. Bordetella pertussis
c. Clostridium tetani
d. Staphylococcus epidermidis

13. A 70 year old male visited a clinic with chronic cough, chest pain, fever, chills, and weakness. When examined he said the cough first started about a month ago, he said no other symptoms appeared in the first week, he complained about the loss of appetite due to which he lost some of his body weight. Lung infection was suspected, and a chest X-ray was performed which showed infection in both lungs. A sputum sample was taken for the lab diagnosis for the isolation and identification of the microorganism.
Which of the following could be the possible infection?
a) Candidiasis
b) Tuberculosis
c) Measles
d) Cystic fibrosis 

14. Which of the following pulmonary pathogens cannot be easily detected by the gram staining technique when performing a microscopy test?
a) Pseudomonas aeruginosa
b) Streptococcus pneumoniae
c) Bordetella pertussis
d) Mycobacterium tuberculosis

15. The cell structure of gram positive and gram negative bacteria appear as the picture given below after the gram staining procedure
                           Gram positive bacteria                              Gram negative bacteria

Which of the following bacterial cell structure possesses the thick layer of peptidoglycan?
a) Gram positive bacteria
b) Gram negative bacteria





Answers:
1.  b) Staphylococcus aureus

2. d) Streptococcus pyogenes, is a gram-positive coccus that appears in the chains. Acinetobacter baumannii is a gram-negative rod. Chlamydia trachomitis is gram-negative bacteria. Staphylococcus aureus is a gram-positive coccus present in clusters. 

3. a) Coronavirus. Coronavirus is an RNA virus that is a highly contagious respiratory pathogen. Dengue virus is an RNA virus transmitted to humans via mosquito bites. Epstein Barr virus is a DNA virus that causes infectious mononucleosis. Hepatitis B virus is a DNA virus that causes liver infection. 

4. c) Lactose fermentation. E. coli is a lactose fermentor while Salmonella is non-lactose fermentor. The lactose fermentation results in an acid environment thereby yielding a pink colony of E. coli. Hydrogen sulfide, indole formation, and urea degradation (Urease test) are different biochemical tests that are not related to MacConkey agar

5. b) Clostridium botulinum.  Clostridium botulinum is a gram positive foodborne pathogen. Bordetella pertussis is a gram negative bacteria and Klebsiella pneumoniae is a gram negative bacteria that are common respiratory pathogens and do not form endospores. Streptococcus pneumoniae is a gram positive bacteria that is a common respiratory pathogen that does not produce endospores

6. a) Leishmaniasis, the infection commonly occurs in the tropical part of the world and is transmitted to humans from the bite of the infected sandflies. Lassa fever is transmitted to humans by rodents, Malaria, and Yellow fever are transferred to humans by the bite of mosquitoes.

7. c) Streptococcus pneumoniae is a gram positive encapsulated bacteria. Clostridium perfringens is a gram positive bacteria with no capsules present in the outer cell structure. Klebsiella pneumoniae and Haemophilus influenzae are gram negative encapsulated bacteria.

8. a) Gram-Negative Diplococci, N. gonorrheae is one of the major pathogens that causes sexually transmitted disease. It is properly isolated and identified by using Chocolate agar. 

9. d) Streptococcus pyogenes, is a gram positive coccus. Acinetobacter baumannii and Chlamydia trachomatis are gram negative bacteria. 

10. d) Unicellular and motile. Protozoa is a single cell eukaryotic, motile microorganism, an example is the most widely known Plasmodium falciparum that can cause malaria.

11. b) Chlamydia trachomatis, is a gram negative bacteria that causes sexually transmitted disease that is mainly seen in women. It is one of the major pathogens of eye infection and blindness, the bacteria can be isolated by using egg yolk sac or tissue culture method. Mycobacterium tuberculosis is a gram negative, acid fast bacteria that is a major pathogen of respiratory infections. Neisseria meningitidis is a gram negative diplococcus that is a major cause of meningitis. Klebsiella oxytoca is a gram negative bacillus that can cause colitis and sepsis in humans.

12. c) Clostridium tetani, is a gram positive, spore forming, and strictly anaerobic bacteria, isolation of the bacteria is difficult in the presence of even a tiny amount of oxygen. Streptococcus pneumonia is an anaerobic bacteria and can grow in the presence of a small amount of oxygen. Bordetella pertussis is a gram negative anaerobic bacteria. Mycoplasma pneumoniae is a gram positive bacteria that can grow anaerobically as well as aerobically. 

13. a) Tuberculosis, is a lung infection disease, it is one of the major bacterial diseases causing a number of deaths each year around the world. It can be spread through respiratory secretions, the common symptoms are fever and cough which can usually last up to months and the infection can become chronic. Without proper treatment, a person can die. 
Candidiasis is a fungal infection, skin infection, and mouth or vaginal infection that can occur due to the overgrowth of the fungus, Candida albicans. 
Measles is a disease caused by a virus, it is spread via respiratory droplets. The common symptoms are pink or red spots on the skin surface, dry cough, and runny nose. Children are more susceptible to this disease.
Cystic fibrosis is an inherited disease, infection in the lungs and digestive system. Symptoms include cough and lung infection.
 
14.d) Mycobacterium tuberculosis, is acid-fast bacilli that consist of mycolic acid in the cell wall. Thus it cannot be properly identified by using the common gram staining method. Ziehl-Neelsen stain is the stain used for acid-fast bacteria. 

15. a) Gram positive bacteria, peptidoglycan is present in both types of bacteria, however, in gram positive bacteria the layer is much thicker than in gram negative bacteria. 































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