MDS PREP
The virus which is most resistant to chemical and physical agents is the one which causes
1. infectious hepatitis
2. mumps
3. influenza
4. serum hepatitis
Microbiology
Answer: 4
Infectious hepatitis (Hepatitis A virus): While HAV is
resistant to some environmental conditions, it is generally less resistant
than HBV.
Mumps virus: This is an enveloped virus and is not
particularly resistant to environmental factors.
Influenza virus: This is also an enveloped virus and is
susceptible to heat and many disinfectants.
Serum hepatitis (Hepatitis B virus): HBV is known for
its resilience. It can survive outside the body for long periods and is
resistant to many disinfectants and physical agents, making it one of the
more resistant viruses.
In summary, the correct answer is indeed 4. serum hepatitis
(Hepatitis B virus), as it is more resistant to chemical and physical
agents
The most efficient method of sterilization in dental practice is
1. ultraviolet radiation
2. moist heat at 121°C for 20 min
3. boiling for 20 mm
4. dry heat at 40° C for 2 hours
Microbiology
Answer: 2
The most efficient method of sterilization in dental practice is moist heat at 121°C for 20 min
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
What is the first X-linked immunodeficiency disease to have been recognized?
1) X-linked agammaglobulinemia
2) Severe combined immunodeficiency (SCID)
3) X-linked chronic granulomatous disease (CGD)
4) Wiskott-Aldrich syndrome
General Microbiology Answer: 1the first X-linked immunodeficiency disease to be recognized is X-linked agammaglobulinemia. It is a primary immunodeficiency disorder caused by a mutation in the X-chromosome-linked gene responsible for the production of antibodies (specifically, immunoglobulins), leading to a deficiency of B cells and impaired humoral immunity.
What is the definition of the flocculating unit (Lf) of diphtheria toxin?
1) The amount that causes rapid flocculation with one unit of antitoxin
2) The amount that causes the bacteria to clump together
3) The amount that causes the bacteria to produce toxin
4) The amount that confers resistance to bacteriophages
The flocculating unit (Lf) of diphtheria toxin is defined as the amount that causes rapid flocculation with one unit of antitoxin.
The period from disease initiation to disease detection in non-infectious disease is called -
1. Incubation period
2. Serial interval
3. Latent period
4. Lag time
Microbiology
Answer: 3
Incubation period: This term is typically used for
infectious diseases and refers to the time between exposure to the
infectious agent and the onset of symptoms.
Serial interval: This refers to the time between
successive cases in a chain of transmission, specifically in infectious
diseases.
Latent period: This is the time from the initiation of
the disease process (or exposure to a risk factor) until the disease is
detectable or until symptoms appear. In non-infectious diseases, this period
can be significant, as the disease may be developing without any noticeable
symptoms.
Lag time: This term can refer to various delays in
processes but is not specifically defined in the context of disease
initiation and detection.
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
The presence of Charcot-Leyden crystals is a characteristic microscopic feature of amoebic dysentery that distinguishes it from bacillary dysentery.
Which of the following is NOT a direct method for diagnosing tuberculosis?
1) Smear examination
2) ELISA
3) Culture methods
4) Nucleic acid technology
General Microbiology Answer: 2ELISA: While ELISA (Enzyme-Linked Immunosorbent Assay) can be used to detect antibodies to the tuberculosis bacterium, it is not a direct method for diagnosing active TB infection. Direct methods include smear examination, culture, and nucleic acid technology, which detect the actual presence of the bacteria in the patient sample.