MDS PREP
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.
Selective medium for streptococcus mutans?
1 mac conkey medium
2 mitis salivarius bacitracin agar
3 neutrient agar
4 tellurite medium
Microbiology
Answer: 2
Colonies of E. coli serotype O157:H7 appear on Mac Conkey Sorbitol Agar as colourless colonies non-sorbitol fermenter. Others E. coli, sorbitol fermenters, give red colonies and gram-negative non-sorbitol fermenters appear translucent.
Which of the following is NOT a characteristic of anthracoid bacilli?
1) Generally motile
2) Non-capsulated
3) Grow in long chains
4) Pathogenic to laboratory animals
Anthracoid bacilli are generally non-motile and non-capsulated, and they do not grow in long chains.
The most pronounced effect on the oral microflora of a reduction in rate of salivary flow is a
1. significant increase in number of oral bacteria
2. shift towards a more acidogenic microflora
3 significant decrease in number of oral bacteria
4 shift towards a more aerobic micro flora
Microbiology
Answer: 2
The most pronounced effect on the oral microflora of a reduction in rate of salivary flow is a shift towards a more acidogenic microflora
Which of the following statements is true regarding Bacillus anthracis?
1) It is motile.
2) It is capsulated.
3) It grows in short chains.
4) It is susceptible to chloral hydrate.
Bacillus anthracis is capsulated, which is a key feature of its virulence.
What is the primary reservoir for S. typhi?
1) Domestic animals
2) Insects
3) Water and food
4) Human carriers
General Microbiology Answer: 4The primary reservoir for S. typhi is Human carriers: Typhoid fever is primarily a human disease with human carriers serving as the main reservoir for the bacterium. While the bacteria can also be found in water and food, it is typically humans who carry and transmit the infection.
What is the typical biochemical profile of E. coli on the IMViC test series?
1) Indole positive, Methyl red positive, Voges-Proskauer positive, Citrate positive
2) Indole positive, Methyl red positive, Voges-Proskauer negative, Citrate positive
3) Indole positive, Methyl red negative, Voges-Proskauer positive, Citrate negative
4) Indole positive, Methyl red negative, Voges-Proskauer negative, Citrate positive
General Microbiology Answer: 3
The IMViC test series is used to differentiate members of the Enterobacteriaceae family, including E. coli. E. coli typically has an indole positive (indole is produced when tryptophan is metabolized), methyl red positive (indicating the ability to ferment glucose and produce acid), Voges-Proskauer positive (produces acetoin from glucose), and citrate negative (does not utilize citrate as a sole carbon source) biochemical profile. This profile helps distinguish it from other related bacteria like Proteus and Klebsiella species.
What is the primary target of antibodies in neutralizing the action of exotoxins?
1) Cell wall components
2) Lipopolysaccharides
3) Protein components of the toxin
4) Enzymes involved in toxin production
General Microbiology Answer: 3
Antibodies neutralize exotoxins by binding to their protein components, preventing them from interacting with host cells and causing damage. This immune response is critical for protecting the host from the harmful effects of these toxins.