MDS PREP
Which of the following statements about the fermentation of sugars by Anthracoid bacilli is true?
1) Anthracoid bacilli ferment glucose, maltose, lactose, and sucrose, producing acid and gas.
2) Anthracoid bacilli do not ferment glucose but ferment maltose, lactose, and sucrose.
3) Anthracoid bacilli only ferment glucose.
4) Anthracoid bacilli ferment glucose, maltose, and lactose, but not sucrose.
Anthracoid bacilli ferment glucose, maltose, lactose, and sucrose, producing acid and gas.
The term cold sterilization has been employed to refer to
1. physical methods of sterilization
2. prolonged exposure to 20° C
3. exposure to low temperature steam
4. chemical disinfection
Microbiology
Answer: 4
chemical disinfection is cold strelization
Which of the following is a characteristic microscopic feature of amoebic dysentery that distinguishes it from bacillary dysentery?
1) Presence of RBCs in the stool
2) Presence of pus cells in the stool
3) Presence of Charcot-Leyden crystals
4) Presence of ghost cells
General Microbiology Answer: 3
Amoebic dysentery, caused by the protozoan parasite Entamoeba histolytica, is characterized by the presence of ghost cells in the stool. Ghost cells are the remnants of red blood cells that have been phagocytosed by the amoeba. These cells are ingested and their cytoplasm is removed, leaving only the cell membrane, which gives them a "ghost-like" appearance under the microscope. This feature helps distinguish amoebic dysentery from bacillary dysentery, which is caused by bacteria such as Shigella species. Bacillary dysentery typically shows the presence of white blood cells (pus cells) and red blood cells in the stool, but not ghost cells.
What is the typical microscopic finding in amoebic dysentery?
1) Numerous pus cells
2) Abundant Charcot-Leyden crystals
3) Many motile bacteria
4) Abundant pyknotic bodies
The typical microscopic finding in amoebic dysentery includes numerous pus cells and abundant Charcot-Leyden crystals.
Which of the following is NOT a type of C1. Perfringens that can cause food poisoning?
1) C1. Perfringens type A
2) C1. Perfringens type B
3) C1. Perfringens type C
4) C1. Perfringens type D
General Microbiology Answer: 4
C1. Perfringens types A, B, and C are capable of producing toxins that cause food poisoning. Type D, however, is not associated with foodborne illness. It is primarily involved in diseases such as gas gangrene and other infections due to the production of different types of toxins.
There are some enzymes that cause protein to coagulate rather than to produce simpler compund These are known as
1. lab enzymes
2. coagulase
3. proteolytic enzymes
4. wenmycin
Microbiology
Answer: 1
There are some enzymes that cause protein to coagulate rather than to produce simpler compund These are known as lab enzymes
1. Coagulase:
Definition: Coagulase is an enzyme produced by certain
bacteria, most notably Staphylococcus aureus. It catalyzes the
conversion of fibrinogen (a soluble plasma protein) into fibrin (an
insoluble protein), leading to the clotting of blood.
Function: The production of coagulase is a virulence
factor for Staphylococcus aureus, as it helps the bacteria evade
the host's immune system by forming a protective clot around the bacterial
cells. This clot can shield the bacteria from phagocytosis and other immune
responses.
Clinical Relevance: Coagulase is used in laboratory
tests to differentiate between pathogenic Staphylococcus aureus (coagulase-positive)
and non-pathogenic staphylococci (coagulase-negative).
2. Proteolytic Enzymes:
Definition: Proteolytic enzymes, also known as
proteases or peptidases, are enzymes that catalyze the breakdown of proteins
into smaller peptides or amino acids by cleaving the peptide bonds between
amino acids.
Function: These enzymes play crucial roles in various
biological processes, including digestion, protein turnover, cell signaling,
and immune responses. They are found in many organisms, including humans,
where they are involved in the digestion of dietary proteins in the stomach
and small intestine.
Types: Proteolytic enzymes can be classified based on
their mechanism of action (e.g., serine proteases, cysteine proteases,
aspartic proteases, and metalloproteases) and their substrate specificity.
Wenmycin is an antibiotic that is derived from the
bacterium Streptomyces wenyangensis. It belongs to the class of
compounds known as macrolide antibiotics, which are
characterized by their large lactone ring structure. Wenmycin has been studied
for its antimicrobial properties, particularly against certain types of
bacteria.
What is the unique feature of S. gallinarum-pullorum compared to other Salmonella species?
1) It is always motile.
2) It is always nonmotile.
3) It ferments mannitol.
4) It is always a pathogen in humans.
General Microbiology Answer: 2the unique feature of S. gallinarum-pullorum compared to other Salmonella species is that it is always nonmotile. This is in contrast to the typical motility of Salmonella species, which is conferred by the presence of flagella.
What is the typical incubation period for typhoid fever?
1) 1-3 days
2) 4-7 days
3) 10-14 days
4) 21-28 days
General Microbiology Answer: 3The typical incubation period for typhoid fever is 10-14 days: After the ingestion of Salmonella typhi, it typically takes 10-14 days for symptoms to appear. This period can sometimes be shorter or longer, but this is the most common range.