MDS PREP
What does one unit of antitoxin refer to in the context of diphtheria toxin?
1) The amount needed to neutralize 100 MLD of toxin
2) The amount of antitoxin that causes the toxin to flocculate
3) The amount that confers immunity to an individual
4) The amount of toxin that can cause disease in an average host
One unit of antitoxin refers to the amount needed to neutralize 100 MLD of diphtheria toxin.
What is the purpose of the puncture-proof container in bio-medical waste management?
1) To contain sharps
2) To hold non-infectious waste
3) To store chemicals used for disinfection
4) To transport pathological waste
General Microbiology Answer: 1
The purpose of the puncture-proof container in bio-medical waste management is to contain sharps, preventing injuries and contamination.
What is the typical macroscopic appearance of the stool in cases of amoebic dysentery compared to bacillary dysentery?
1) Amoebic dysentery stool is small and odorless, while bacillary dysentery stool is copious and offensive.
2) Both amoebic and bacillary dysentery stools are copious and offensive.
3) Amoebic dysentery stool is dark red and acidic, while bacillary dysentery stool is bright red and alkaline.
4) Amoebic dysentery stool is bright red and alkaline, while bacillary dysentery stool is dark red and acidic.
Amoebic dysentery stool is typically dark red and acidic, while bacillary dysentery stool is bright red and alkaline.
Dry heat sterilization of paper points without incineration is accomplished at
1. 160°C for 2hours
2. 120°C for l hour
3. 100°C for 2 hours
4. 200°C for 1 hour
Microbiology
Answer: 1
Dry heat sterilization of paper points without incineration is accomplished at 160°C for 2hours
What is the commonest subtype of Hepatitis B virus in Thailand?
1) Subtype A
2) Subtype B
3) Subtype C
4) Subtype E
General Microbiology Answer: 4
Subtype B is the most common subtype of Hepatitis B virus found in Thailand, linked to increased risks of chronic infection.
What is the primary reservoir for prions?
1) Bacteria
2) Viruses
3) Proteinaceous particles
4) Nucleic acids
General Microbiology Answer: 3Prions are infectious agents composed solely of protein. They do not have nucleic acids like DNA or RNA and are responsible for several neurodegenerative diseases. The primary reservoir for prions is thus the proteinaceous particles themselves.
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 significance of HLA class I antigens in the context of graft rejection and cell mediated cytolysis?
1) They are only involved in cell-to-cell recognition in the immune system.
2) They are the principal antigens that induce an immune response in the host against transplanted tissues.
3) They have no role in graft rejection or cell-mediated immunity.
4) They are only involved in the innate immune response.
General Microbiology Answer: 2
HLA class I antigens are the principal antigens that induce an immune response in the host against transplanted tissues.