MDS PREP
Which of the following is a distinguishing feature of orthomyxoviruses?
1) Single linear RNA
2) 80-120 nm in size
3) Hemolysin present
4) Cytoplasmic replication
General Microbiology Answer: 2Orthomyxoviruses, which include the influenza viruses, are characterized by their single-stranded RNA genome. This feature distinguishes them from other virus families that may have different types of genetic material. Orthomyxoviruses are distinguished by their single linear RNA genome, which is essential for their replication and pathogenicity.
Which of the following is a characteristic of endotoxins that makes them distinct from exotoxins?
1) They are heat labile
2) They are actively secreted by bacterial cells
3) They are proteins
4) They are part of the bacterial cell wall
General Microbiology Answer: 4
Endotoxins are components of the outer membrane of Gram-negative bacteria and are released when the bacteria die or divide. This structural characteristic differentiates them from exotoxins, which are secreted by living bacteria.
What is a key characteristic of the colonies formed by Streptococcus pneumoniae?
1) Dome-shaped
2) Initially dome-shaped, later draughtsman colonies
3) Granular turbidity with a powdery deposit
4) Not typically seen in culture
Streptococcus pneumoniae colonies are initially dome-shaped and later develop draughtsman colonies.
Which of the following tests uses killed Treponema pallidum?
1) TPI test
2) TPA test
3) RPCF test
4) FTA test
General Microbiology Answer: 2The Treponema pallidum agglutination test (TPA) utilizes killed Treponema pallidum organisms to detect antibodies in the serum of patients suspected of having syphilis. This test is more sensitive than other tests and is used for confirming syphilis infections.
Which of the following compounds have the narrowest effective antimicrobial range?
1. Cresols
2. Glutaraldehydes
3. Soaps
4. 70% isopropanol
Microbiology
Answer: 3
Soaps typically have the narrowest effective antimicrobial range among the listed compounds. They are primarily effective against certain bacteria and viruses but may not be as potent against a broader spectrum of pathogens compared to glutaraldehyde or alcohols like 70% isopropanol.
Which of the following statements is true about the colony morphology and cultural characteristics of Anthrax bacilli?
1) Anthrax bacilli are motile and produce a turbidity in broth.
2) The Medusa head appearance is seen in non-virulent strains of anthrax bacilli.
3) Virulent capsulated strains form smooth colonies.
4) The inverted fir tree appearance is characteristic of Anthracoid bacilli.
General Microbiology Answer: 2
The Medusa head appearance is characteristic of virulent strains of anthrax bacilli.
What is the typical color of Salmonella colonies on MacConkey agar, except for Sh. Sonnei?
1) Colorless
2) Pink
3) Red
4) Yellow
General Microbiology Answer: 1Salmonella species, excluding Shigella sonnei, which is lactose non-fermenting, will ferment lactose in MacConkey agar, turning the colonies pink due to the formation of acidic end-products
The first person becoming sick in an epidemic is called -
1. Primary case
2. Source of infection
3. Reservoir of infection
4. Index case
Microbiology
Answer: 4
The first recognized case in an epidemic outbreak is termed as the index case. Although both the index case and primary case appear to be the same yet they differ slightly. The term primary case refers to the person who first brings a disease into a group of people.