1601. Genome of Pox Viruses comprised of:
A. ssDNA
B. dsDNA ✅
C. ssRNA
D. dsRNA
A. ssDNA
B. dsDNA ✅
C. ssRNA
D. dsRNA
1602. Negri bodies are observed in cells infected by:
A. CMV
B. EBV
C. HSV
D. Rabies virus ✅
A. CMV
B. EBV
C. HSV
D. Rabies virus ✅
1603. Dengue virus belongs to genus:
A. Togavirus
B. Flavivirus ✅
C. Filovirus
D. Retrovirus
A. Togavirus
B. Flavivirus ✅
C. Filovirus
D. Retrovirus
1604. T cytotoxic cells are also known as ______.
A. CD4+ cells
B. CD8+ cells ✅
C. Macrophages
D. Megakaryocytes
A. CD4+ cells
B. CD8+ cells ✅
C. Macrophages
D. Megakaryocytes
1605. Public health surveillance includes various activities. Which one is not part of public health surveillance?
A. Data collection
B. Data dissemination
C. Disease control ✅
D. Data analysis
A. Data collection
B. Data dissemination
C. Disease control ✅
D. Data analysis
1606. The complement fixation test (CFT) has largely been replaced by improved assays for evidence of infection. Select the organism for which CFT remains a useful laboratory diagnostic test of infection.
A. Coxiella burnetii ✅
B. Cytomegalovirus
C. Herpes simplex virus
D. Neisseria gonorrhoeae
A. Coxiella burnetii ✅
B. Cytomegalovirus
C. Herpes simplex virus
D. Neisseria gonorrhoeae
1607. A 5-year-old boy is seen in the paediatric respiratory clinic for regular review of his cystic fibrosis. He has a productive cough and a specimen is forwarded to the laboratory. Select the culture medium which would be most appropriate to isolate Haemophilus influenzae from this patient.
A. Blood agar
B. Chocolate bacitracin agar ✅
C. MacConkey agar
D. Methicillin mannitol salt agar
A. Blood agar
B. Chocolate bacitracin agar ✅
C. MacConkey agar
D. Methicillin mannitol salt agar
1608. Ochratoxins are produced by:
A. Candida species
B. Cryptosporidium species
C. Aspergillus species ✅
D. Clostridium species
A. Candida species
B. Cryptosporidium species
C. Aspergillus species ✅
D. Clostridium species
1609. Which DOES NOT provide long term immunity?
A. Artificially acquired active immunity
B. Artificially acquired passive immunity ✅
C. Naturally acquired active immunity
D. None of the above
A. Artificially acquired active immunity
B. Artificially acquired passive immunity ✅
C. Naturally acquired active immunity
D. None of the above
1610. An epitope is _________.
A. a B-cell.
B. a hapten.
C. an antibody.
D. the antigen determinant site. ✅
A. a B-cell.
B. a hapten.
C. an antibody.
D. the antigen determinant site. ✅
1611. An immunoglobulin is a ________.
A. Carbohydrate.
B. Fatty acid.
C. Glycoprotein. ✅
D. Protein.
A. Carbohydrate.
B. Fatty acid.
C. Glycoprotein. ✅
D. Protein.
1612. Which of the following is the major immunoglobulin in human serum, accounting for 80% of the immunoglobulin pool?
A. IgA
B. IgD
C. IgG ✅
D. IgM
A. IgA
B. IgD
C. IgG ✅
D. IgM
1613. Which immunoglobulin is the least prevalent?
A. IgA
B. IgD
C. IgE ✅
D. IgM
A. IgA
B. IgD
C. IgE ✅
D. IgM
1614. Which of the following is useful to STIMULATE antibody production?
A. An adjuvant ✅
B. A hapten
C. Antiserum
D. Purified antigen
A. An adjuvant ✅
B. A hapten
C. Antiserum
D. Purified antigen
1615. Compared to the secondary antibody response, the primary response.
A. Attains a higher IgG titer.
B. Has a longer lag phase. ✅
C. Persists for a longer plateau period.
D. Produces Igs with a higher affinity for antigen.
A. Attains a higher IgG titer.
B. Has a longer lag phase. ✅
C. Persists for a longer plateau period.
D. Produces Igs with a higher affinity for antigen.
1616. Many antiviral drugs act by inhibition of a viral DNA polymerase enzyme. Select the virus for which this class of drugs would be effective.
A. Cytomegalovirus ✅
B. Influenza
C. Measles
D. Mumps
A. Cytomegalovirus ✅
B. Influenza
C. Measles
D. Mumps
1617. Each of the following statements concerning the fluorescent treponemal antibody-absorbed (FTA-ABS) test for syphilis is correct EXCEPT:
A. Once positive, the test remains so despite appropriate therapy.
B. The test is specific for Treponema pallidum.
C. The patient’s serum is absorbed with saprophytic treponemes.
D. The test is rarely positive in primary syphilis. ✅
A. Once positive, the test remains so despite appropriate therapy.
B. The test is specific for Treponema pallidum.
C. The patient’s serum is absorbed with saprophytic treponemes.
D. The test is rarely positive in primary syphilis. ✅
1618. The transmission electron microscope has the greatest resolving power because it uses an electron beam to view the sample instead of a light beam. The electron beam is used because electrons:
A. Do not penetrate the sample
B. Are less invasive
C. Have longer wavelengths than light waves
D. Have shorter wavelengths than light waves ✅
A. Do not penetrate the sample
B. Are less invasive
C. Have longer wavelengths than light waves
D. Have shorter wavelengths than light waves ✅
1619. Which of the following statements about Transmission Electron Microscopy is NOT true?
A. Specimen must be stained with acidic stain. ✅
B. Specimens must be sliced very thin.
C. Beam is focused by electromagnetic lenses.
D. Specimens are placed in vacuum for viewing.
A. Specimen must be stained with acidic stain. ✅
B. Specimens must be sliced very thin.
C. Beam is focused by electromagnetic lenses.
D. Specimens are placed in vacuum for viewing.
1620. Place the structures of the compound light microscope in the order that light passes through them on the way to the observer’s eyes:
(1) condenser, (2) ocular lens, (3) illuminator, (4) specimen, (5) objective lens.
A. 2-1-4-5-3
B. 3-5-4-1-2
C. 3-1-4-5-2 ✅
D. 3-4-1-5-2
(1) condenser, (2) ocular lens, (3) illuminator, (4) specimen, (5) objective lens.
A. 2-1-4-5-3
B. 3-5-4-1-2
C. 3-1-4-5-2 ✅
D. 3-4-1-5-2
1621. Most light microscope contains a/an ___________ that converges the light beam so that it passes through the specimen.
A. Condenser ✅
B. Objective lens
C. Ocular lens
D. Iris diaphragm
A. Condenser ✅
B. Objective lens
C. Ocular lens
D. Iris diaphragm
1622. Light of ________ wavelength typically will result in _______ resolving power.
A. shorter, better ✅
B. longer, better
C. any, poor
D. shorter, worse
A. shorter, better ✅
B. longer, better
C. any, poor
D. shorter, worse
1623. Which of the following is defined as the ability to distinguish or separate two adjacent objects or points from one another in a microscopic specimen?
A. Refraction
B. Resolving power ✅
C. Magnification
D. Illuminate
A. Refraction
B. Resolving power ✅
C. Magnification
D. Illuminate
1624. Negative staining is useful for observing:
A. Endospores
B. Flagella
C. Capsule ✅
D. Mycolic acid
A. Endospores
B. Flagella
C. Capsule ✅
D. Mycolic acid
1625. In ________, surface of a specimen is bombarded with electrons during sample preparation.
A. Dark field Microscope
B. Scanning Electron Microscope ✅
C. Bright-light Microscope
D. Transmission Electron Microscope
A. Dark field Microscope
B. Scanning Electron Microscope ✅
C. Bright-light Microscope
D. Transmission Electron Microscope
1626. When a microscopic image is brightly illuminated, but is surrounded by a black field, what type of microscope is being used?
A. Fluorescence
B. Phase-contrast
C. Dark-field ✅
D. Bright-field
A. Fluorescence
B. Phase-contrast
C. Dark-field ✅
D. Bright-field
1627. Monochromatic light is sometimes used to increase the resolution of light microscopes. Light of which color below would give you the best resolution?
A. Red
B. Green
C. Blue ✅
D. Orange
A. Red
B. Green
C. Blue ✅
D. Orange
1628. All of the following are examples of special stains EXCEPT:
A. Endospore stain
B. Flagellar stain
C. Ziehl-Neelsen acid-fast stain
D. Negative stains ✅
A. Endospore stain
B. Flagellar stain
C. Ziehl-Neelsen acid-fast stain
D. Negative stains ✅
1629. Drumstick appearance in the microscopy is the distinguishing characteristics of:
A. Clostridium difficile
B. Clostridium perfringens
C. Clostridium tetani ✅
D. Clostridium botulinum
A. Clostridium difficile
B. Clostridium perfringens
C. Clostridium tetani ✅
D. Clostridium botulinum
1630. How many magnifying lenses does a compound light microscope contain?
A. One
B. Two ✅
C. Three
D. Four
A. One
B. Two ✅
C. Three
D. Four
1631. The presence of a capsule around bacterial cells usually indicates their increased disease-causing potential and resistance to disinfection. Capsules are generally viewed by:
A. Negative staining ✅
B. Ziehl-Neelsen staining
C. Scanning electron microscopy
D. Gram staining
A. Negative staining ✅
B. Ziehl-Neelsen staining
C. Scanning electron microscopy
D. Gram staining
1632. Regarding the Gram stain, which one of the following is the MOST accurate?
A. If you forget to heat-fix, both Gram-positive & Gram-negative bacteria will appear blue.
B. If you forget to stain with safranin, both Gram-positive & Gram-negative bacteria will appear blue
C. After adding crystal violet and Gram’s iodine, both Gram-positive bacteria and Gram-negative bacteria will appear blue. ✅
D. One reason why bacteria have a different color in this stain is because the Gram-positive bacteria have lipid in their membrane, whereas Gram-negative bacteria do not.
A. If you forget to heat-fix, both Gram-positive & Gram-negative bacteria will appear blue.
B. If you forget to stain with safranin, both Gram-positive & Gram-negative bacteria will appear blue
C. After adding crystal violet and Gram’s iodine, both Gram-positive bacteria and Gram-negative bacteria will appear blue. ✅
D. One reason why bacteria have a different color in this stain is because the Gram-positive bacteria have lipid in their membrane, whereas Gram-negative bacteria do not.
1633. Each of the following statements concerning Mycobacterium tuberculosis is correct EXCEPT:
A. M. tuberculosis has a large amount of mycolic acid in its cell wall.
B. M. tuberculosis appears as a red rod in acid-fast stained specimens.
C. After being stained with carbol fuchsin, M. tuberculosis resists decolorization with acid alcohol.
D. M. tuberculosis appears as a red rod in Gram-stained specimens. ✅
A. M. tuberculosis has a large amount of mycolic acid in its cell wall.
B. M. tuberculosis appears as a red rod in acid-fast stained specimens.
C. After being stained with carbol fuchsin, M. tuberculosis resists decolorization with acid alcohol.
D. M. tuberculosis appears as a red rod in Gram-stained specimens. ✅
1634. While viewing the stained slides in 100x, a drop of oil is placed between the tip of the oil immersion lens and the specimen on a glass slide. What is the purpose of using the oil?
A. The oil increases the total power of magnification.
B. The oil prevents light from bending as it passes through the specimen.
C. The oil increases the degree of refraction. ✅
D. The oil helps to illuminate the specimen.
A. The oil increases the total power of magnification.
B. The oil prevents light from bending as it passes through the specimen.
C. The oil increases the degree of refraction. ✅
D. The oil helps to illuminate the specimen.
1635. Transmission electron microscopy is best for high magnification viewing of:
A. Surface membranes of live, motile cells.
B. Internal structure of fixed cells. ✅
C. Surface structure of fixed cells
D. Internal structure of live, motile cells.
A. Surface membranes of live, motile cells.
B. Internal structure of fixed cells. ✅
C. Surface structure of fixed cells
D. Internal structure of live, motile cells.
1636. Which of the following microscopic techniques provide three-dimensional images of a bacterial cell?
A. Scanning electron microscopy ✅
B. Transmission electron microscopy
C. Fluorescent microscopy
D. Dark-field microscopy
A. Scanning electron microscopy ✅
B. Transmission electron microscopy
C. Fluorescent microscopy
D. Dark-field microscopy
1637. Which of the following stains is used to classify microorganisms based on their cell wall content?
A. Capsular stain
B. Gram stain ✅
C. Methylene blue
D. Negative stain
A. Capsular stain
B. Gram stain ✅
C. Methylene blue
D. Negative stain
1638. What type of microscopy allows for the visualization of internal components within live, unstained specimens?
A. Dark-field
B. Electron
C. Fluorescence
D. Phase-contrast ✅
A. Dark-field
B. Electron
C. Fluorescence
D. Phase-contrast ✅
1639. The compound light microscope can be used to observe:
A. Viruses, bacteria, cell organelles, and RBCs
B. Ribosomes, bacteria, cell organelles, and DNA
C. Atoms, proteins, viruses, and bacteria
D. Bacteria, cell organelles, and red blood cells ✅
A. Viruses, bacteria, cell organelles, and RBCs
B. Ribosomes, bacteria, cell organelles, and DNA
C. Atoms, proteins, viruses, and bacteria
D. Bacteria, cell organelles, and red blood cells ✅
1640. The order of reagents used in the Gram stain are:
A. Iodine, crystal violet, safranin, alcohol
B. Crystal violet, iodine, safranin, alcohol
C. Crystal violet, iodine, alcohol, safranin ✅
D. Crystal violet, safranin, alcohol, iodine
A. Iodine, crystal violet, safranin, alcohol
B. Crystal violet, iodine, safranin, alcohol
C. Crystal violet, iodine, alcohol, safranin ✅
D. Crystal violet, safranin, alcohol, iodine
1641. Which of the following statements is MOST CORRECT about the differential Gram stain?
A. Gram’s iodine differentially stains Gram positive cells.
B. Safranin differentially stains Gram negative cells. ✅
C. Crystal violet differentially stains Gram positive cells.
D. Alcohol differentially destains Gram negative cells.
A. Gram’s iodine differentially stains Gram positive cells.
B. Safranin differentially stains Gram negative cells. ✅
C. Crystal violet differentially stains Gram positive cells.
D. Alcohol differentially destains Gram negative cells.
1642. Your patient is a 30-year-old woman with nonbloody diarrhea for the past 14 hours. Which one of the following organisms is LEAST likely to cause this illness?
A. Streptococcus pyogenes ✅
B. Clostridium difficile
C. Salmonella enteritidis
D. Shigella dysenteriae
A. Streptococcus pyogenes ✅
B. Clostridium difficile
C. Salmonella enteritidis
D. Shigella dysenteriae
1643. Each of the following agents is a recognized cause of diarrhea EXCEPT:
A. Clostridium perfringens
B. Vibrio cholerae
C. Mycobacterium tuberculosis ✅
D. Escherichia coli
A. Clostridium perfringens
B. Vibrio cholerae
C. Mycobacterium tuberculosis ✅
D. Escherichia coli
1644. _______ process involves a sex pilus.
A. Integration of a temperate bacteriophage
B. Transduction of a chromosomal gene
C. Conjugation resulting in transfer of an R (resistance) factor ✅
D. Transposition of a mobile genetic element
A. Integration of a temperate bacteriophage
B. Transduction of a chromosomal gene
C. Conjugation resulting in transfer of an R (resistance) factor ✅
D. Transposition of a mobile genetic element
1645. The first vaccine for human use produced using recombinant DNA technology was the:
A. Polio vaccine
B. Hepatitis A vaccine
C. AIDS vaccine
D. Hepatitis B vaccine ✅
A. Polio vaccine
B. Hepatitis A vaccine
C. AIDS vaccine
D. Hepatitis B vaccine ✅
1646. The form of genetic exchange in which donor DNA is introduced to the recipient by a bacterial virus is:
A. Transformation
B. Transduction ✅
C. Conjugation
D. Transfection
A. Transformation
B. Transduction ✅
C. Conjugation
D. Transfection
1647. Which one of the following organisms that infects the gastrointestinal tract is the MOST frequent cause of bacteremia?
A. Salmonella typhi ✅
B. Campylobacter jejuni
C. Vibrio cholerae
D. Shigella flexneri
A. Salmonella typhi ✅
B. Campylobacter jejuni
C. Vibrio cholerae
D. Shigella flexneri
1648. A family has a diarrhea after eating raw shellfish due to an oxidase positive, gram-negative curved bacillus that requires a special media for growth. Which of the following is the most likely cause?
A. Clostridium botulinum
B. Staphylococcus aureus
C. Vibrio parahaemolyticus ✅
D. Bacillus anthracis
A. Clostridium botulinum
B. Staphylococcus aureus
C. Vibrio parahaemolyticus ✅
D. Bacillus anthracis
1649. The total magnification of a microscope is calculated by:
A. Multiplication of the objective lens and condenser lens magnification powers.
B. Addition of the objective lens and ocular lens magnification powers.
C. The objective lens power squared.
D. Multiplication of the objective lens and ocular lens magnification powers. ✅
A. Multiplication of the objective lens and condenser lens magnification powers.
B. Addition of the objective lens and ocular lens magnification powers.
C. The objective lens power squared.
D. Multiplication of the objective lens and ocular lens magnification powers. ✅
1650. A 26-year-old male with AIDS presents with painful bloody diarrhea. Stool culture on MacConkey agar medium and subsequent analyses reveals predominantly a gram -negative facultative anaerobic rod, which is oxidase negative, lactose negative, H2S negative and non-motile. Which of the following is the most likely cause of this infection?
A. Staphylococcus aureus
B. Vibrio cholerae
C. Shigella flexneri ✅
D. Clostridium botulinum
A. Staphylococcus aureus
B. Vibrio cholerae
C. Shigella flexneri ✅
D. Clostridium botulinum
1651. Which of the following pathogenic bacteria is MOST COMMONLY associated with traveler’s diarrhea?
A. Salmonella Typhimurium
B. Escherichia coli ETEC (enterotoxingenic) ✅
C. Clostridium botulinum
D. Treponema pallidium
A. Salmonella Typhimurium
B. Escherichia coli ETEC (enterotoxingenic) ✅
C. Clostridium botulinum
D. Treponema pallidium
1652. The formation of a mating pair during the process of conjugation in Escherichia coli requires:
A. Intergration of Transposon
B. Transfer of both strands of DNA
C. Restriction endonuclease
D. Sex pilus ✅
A. Intergration of Transposon
B. Transfer of both strands of DNA
C. Restriction endonuclease
D. Sex pilus ✅
1653. The ability of a cell to bind DNA to its surface and import it is required for which genetic process?
A. Transformation ✅
B. Specialized transduction
C. Conjugation
D. Generalized transduction
A. Transformation ✅
B. Specialized transduction
C. Conjugation
D. Generalized transduction
1654. A 25-year-old female medical student reports that she had lunch at an Indian restaurant in afternoon. She is presented in the emergency department of hospital with the complaints of abdominal cramps, nausea and vomiting. Culture and gram stain reveal gram- positive aerobic rods. Which of the following is the most likely cause of this infection?
A. Bacillus cereus food poisoning ✅
B. Clostridium botulinum food poisoning
C. Staphylococcal food poisoning
D. Clostridium perfringens food poisoning
A. Bacillus cereus food poisoning ✅
B. Clostridium botulinum food poisoning
C. Staphylococcal food poisoning
D. Clostridium perfringens food poisoning
1655. A specimen suspected of containing members of Enterobacteriaceae was subjected to a few laboratory tests and generated the following results: Gram negative rod; colorless colonies on MacConkey agar. All of following microorganisms may be included in the diagnosis, EXCEPT
A. Salmonella species
B. Escherichia coli
C. Both Salmonella and Shigella
D. Shigella species ✅
A. Salmonella species
B. Escherichia coli
C. Both Salmonella and Shigella
D. Shigella species ✅
1656. Five hours after eating reheated rice at a restaurant, a 24-year-old woman and her husband both developed nausea, vomiting, and diarrhea. Which one of the following organisms is the MOST likely to be involved?
A. Bacillus cereus
B. Clostridium perfringens ✅
C. Enterotoxigenic Escherichia coli
D. Salmonella typhi
A. Bacillus cereus
B. Clostridium perfringens ✅
C. Enterotoxigenic Escherichia coli
D. Salmonella typhi
1657. For which one of the following enteric illnesses is a chronic carrier state MOST likely to develop?
A. Shigella enterocolitis
B. Campylobacter enterocolitis
C. Typhoid fever ✅
D. Cholera
A. Shigella enterocolitis
B. Campylobacter enterocolitis
C. Typhoid fever ✅
D. Cholera
1658. Which of the following mechanisms is most likely to be involved in multiple drug resistance transfer from one cell to another?
A. Conjugation with a cell with chromosomal drug resistance appears in the genome of a bacteriophage that has infected it.
B. Transformation of chromosomal genes
C. Specialized transduction of a chromosomal gene for drug resistance
D. Conjugation with a cell with a free plasmid carrying drug resistance. ✅
A. Conjugation with a cell with chromosomal drug resistance appears in the genome of a bacteriophage that has infected it.
B. Transformation of chromosomal genes
C. Specialized transduction of a chromosomal gene for drug resistance
D. Conjugation with a cell with a free plasmid carrying drug resistance. ✅
1659. The process by which bacterial DNA may be mistakenly incorporated (during assembly) into one phage being produced by the lytic life cycle and then that DNA-transferred to another bacterial cell which may acquire some new genetic traits is called:
A. Homologous recombination
B. Conjugation
C. Transformation
D. Transduction ✅
A. Homologous recombination
B. Conjugation
C. Transformation
D. Transduction ✅
1660. Phages that destroy host cell DNA, direct synthesis of phage particles, and cause lysis of the host cell are called:
A. Virulent phages ✅
B. Prophages
C. Transductions
D. Lysogenic phages
A. Virulent phages ✅
B. Prophages
C. Transductions
D. Lysogenic phages
1661. What bacterial gene transfer process is most sensitive to extracellular nucleases?
A. Homologous recombination
B. Conjugation
C. Transduction
D. Transformation ✅
A. Homologous recombination
B. Conjugation
C. Transduction
D. Transformation ✅
1662. In the laboratory, cells can be rendered ______ by the use of cold calcium chloride or electroporation.
A. Transducible
B. Competent ✅
C. Conjugated
D. Transposable
A. Transducible
B. Competent ✅
C. Conjugated
D. Transposable
1663. Diarrhea associated with prolonged antibiotic treatment, including pseudomembranous colitis, is MOST FREQUENTLY caused by:
A. Shigella dysenteriae
B. Salmonella Typhimurium
C. Clostridium difficile ✅
D. Rota Virus
A. Shigella dysenteriae
B. Salmonella Typhimurium
C. Clostridium difficile ✅
D. Rota Virus
1664. Hybridomas are formed by fusing antibody-producing white blood cells with:
A. Viruses
B. Red blood cells
C. Myeloma cells ✅
D. Bone marrow cells
A. Viruses
B. Red blood cells
C. Myeloma cells ✅
D. Bone marrow cells
1665. Which of the following events is most likely due to bacterial transformation?
A. A strain of Neisseria gonorrhoeae starts producing a plasmid-encoded beta-lactamase similar to that another Gram-negative strain.
B. A formerly non-toxigenic strain of Corynebacterium diphtheriae becomes toxigenic. ✅
C. A non-encapsulated strain of Streptococcus pneumoniae acquires a gene for capsule formation from the extract of an encapsulated strain.
D. A gene for gentamicin resistance from an Escherichia coli chromosome
A. A strain of Neisseria gonorrhoeae starts producing a plasmid-encoded beta-lactamase similar to that another Gram-negative strain.
B. A formerly non-toxigenic strain of Corynebacterium diphtheriae becomes toxigenic. ✅
C. A non-encapsulated strain of Streptococcus pneumoniae acquires a gene for capsule formation from the extract of an encapsulated strain.
D. A gene for gentamicin resistance from an Escherichia coli chromosome
1666. Which type of genetic exchange in bacteria is susceptible to the activity of deoxyribonuclease?
A. Transfection
B. Generalized transduction
C. Specialized transduction
D. Transformation ✅
A. Transfection
B. Generalized transduction
C. Specialized transduction
D. Transformation ✅
1667. Which of following statements is INCORRECT:
A. People with TB infection may or may not develop TB disease
B. risk of developing TB disease is highest in first 2 years after infection
C. Every individual exposed to TB develops disease ✅
D. People who are exposed to TB may or may not develop TB infection
A. People with TB infection may or may not develop TB disease
B. risk of developing TB disease is highest in first 2 years after infection
C. Every individual exposed to TB develops disease ✅
D. People who are exposed to TB may or may not develop TB infection
1668. The scientist who discovered M. tuberculosis was:
A. Jean-Antoine Villemin
B. Robert Koch ✅
C. Calmette and Guerin
D. Edward Jenner
A. Jean-Antoine Villemin
B. Robert Koch ✅
C. Calmette and Guerin
D. Edward Jenner
1669. Which of the following statements concerning antigenic drift in influenza viruses is correct?
A. It results in new sub types over time
B. It is exhibited by only influenza A viruses
C. It is due to frame shift mutations in viral genes
D. It results in major antigenic changes ✅
A. It results in new sub types over time
B. It is exhibited by only influenza A viruses
C. It is due to frame shift mutations in viral genes
D. It results in major antigenic changes ✅
1670. XDR TB is defined as:
A. MDR TB that is resistant to either one of the injectable second line drugs or second-line therapeutic fluoroquinolones.
B. Strain resistant to more than one drug (excluding co resistance to INH and rif).
C. resistant to two most effective first-line therapeutic drugs, isoniazid and rifampin irrespective of resistance to any other drug.
D. MDR TB that also is resistant to fluoroquinolones and at least one of the three injectable second-line drugs used to treat TB (amikacin, kanamycin, or capreomycin). ✅
A. MDR TB that is resistant to either one of the injectable second line drugs or second-line therapeutic fluoroquinolones.
B. Strain resistant to more than one drug (excluding co resistance to INH and rif).
C. resistant to two most effective first-line therapeutic drugs, isoniazid and rifampin irrespective of resistance to any other drug.
D. MDR TB that also is resistant to fluoroquinolones and at least one of the three injectable second-line drugs used to treat TB (amikacin, kanamycin, or capreomycin). ✅
1671. Cord growth seen on mycobacterial culture is characteristic of:
A. Saprophytic strains
B. Atypical mycobacteria
C. Virulent strains ✅
D. Avirulent strains
A. Saprophytic strains
B. Atypical mycobacteria
C. Virulent strains ✅
D. Avirulent strains
1672. Which one of the following is a non-cultivable mycobacterium?
A. M. avium intracellulare
B. M. tuberculosis
C. M. leprae ✅
D. M. Bovis
A. M. avium intracellulare
B. M. tuberculosis
C. M. leprae ✅
D. M. Bovis
1673. All of the following statements regarding Mycobacterium tuberculosis are correct EXCEPT:
A. Increased CO2 tension enhances growth
B. Mycobacteria are obligate aerobes
C. Can grow in cell free media
D. Doubling time of tubercle bacilli is about 18 hours ✅
A. Increased CO2 tension enhances growth
B. Mycobacteria are obligate aerobes
C. Can grow in cell free media
D. Doubling time of tubercle bacilli is about 18 hours ✅
1674. Latency is an outcome particularly characteristic of which one of the following virus groups?
A. Herpesviruses ✅
B. Polioviruses
C. Rhinoviruses
D. Influenza viruses
A. Herpesviruses ✅
B. Polioviruses
C. Rhinoviruses
D. Influenza viruses
1675. How many pairs of flagella are present in the trophozoite of Giardia lamblia?
A. Three pairs
B. One pair
C. Four pairs
D. Two pairs ✅
A. Three pairs
B. One pair
C. Four pairs
D. Two pairs ✅
1676. Which of the following statements reflects the pathogenesis of influenza virus?
A. The virus enters the host in airborne droplets ✅
B. Viremia is common
C. Pneumonia is not associated with secondary bacterial infections
D. Viral infection does not kill cells in the respiratory tract
A. The virus enters the host in airborne droplets ✅
B. Viremia is common
C. Pneumonia is not associated with secondary bacterial infections
D. Viral infection does not kill cells in the respiratory tract
1677. What virus commonly undergoes both antigenic shifts and antigenic drifts?
A. Rabies
B. Influenza ✅
C. HIV
D. Rotavirus
A. Rabies
B. Influenza ✅
C. HIV
D. Rotavirus
1678. All of the following statements correctly describes the properties of Influenza A virus EXCEPT:
A. Mature virion are released by budding
B. Attaches to cell-surface sialic acid
C. Single stranded positive sense RNA virus
D. Viral transcription occurs in the nucleus ✅
A. Mature virion are released by budding
B. Attaches to cell-surface sialic acid
C. Single stranded positive sense RNA virus
D. Viral transcription occurs in the nucleus ✅
1679. Influenza virus contains hemagglutinin and neuraminidase. What does these represent?
A. Proteins found in the nucleus of influenza virus
B. Glycoproteins on influenza virus that contribute to virulence ✅
C. Glycoprotein receptors on influenza’s target cells
D. Proteins that surround each segment of the nucleic acid in influenza
A. Proteins found in the nucleus of influenza virus
B. Glycoproteins on influenza virus that contribute to virulence ✅
C. Glycoprotein receptors on influenza’s target cells
D. Proteins that surround each segment of the nucleic acid in influenza
1680. Which of the following is commonly used in the laboratory setting to provide a measure of protection against transmission of the human immunodeficiency virus (HIV)?
A. Hot air
B. Germicidal soap
C. Bleach ✅
D. Iodine
A. Hot air
B. Germicidal soap
C. Bleach ✅
D. Iodine
1681. Which of the following is a limitation of the autoclave?
A. It lacks the ability to inactivate viruses
B. It will destroy heat labile materials ✅
C. It takes too long to sterilize
D. It lacks the ability to kill endospores
A. It lacks the ability to inactivate viruses
B. It will destroy heat labile materials ✅
C. It takes too long to sterilize
D. It lacks the ability to kill endospores
1682. Identify the term that can describe a disinfectant that can inhibit the growth of fungi:
A. Microbiostatic
B. Fungistatic ✅
C. Fungicidal
D. Microbicidal
A. Microbiostatic
B. Fungistatic ✅
C. Fungicidal
D. Microbicidal
1683. Which is a form of cold sterilization?
A. Gamma rays ✅
B. Hot air oven
C. Steam sterilization
D. UV rays
A. Gamma rays ✅
B. Hot air oven
C. Steam sterilization
D. UV rays
1684. Which of the following methods of infection control requires the use of an autoclave?
A. Irradiation
B. Disinfection
C. Sanitization
D. Sterilization ✅
A. Irradiation
B. Disinfection
C. Sanitization
D. Sterilization ✅
1685. All of the following disinfectant contains heavy metal EXCEPT:
A. Mercurochrome
B. Chlorine ✅
C. Copper sulfate
D. Silver nitrate
A. Mercurochrome
B. Chlorine ✅
C. Copper sulfate
D. Silver nitrate
1686. The efficiency of moist-heat sterilization is tested with:
A. Spores of Bacillus stearothermophilus ✅
B. Vegetative cells of Bacillus stearothermophilus
C. Clostridium botulinum
D. Spores of aerobic fungi
A. Spores of Bacillus stearothermophilus ✅
B. Vegetative cells of Bacillus stearothermophilus
C. Clostridium botulinum
D. Spores of aerobic fungi
1687. Which of the following process does not kill bacterial endospores?
A. Pasteurization ✅
B. Autoclave
C. Incineration
D. Hot air sterilization
A. Pasteurization ✅
B. Autoclave
C. Incineration
D. Hot air sterilization
1688. Which of the following substances can sterilize?
A. Alcohol
B. Ethylene oxide ✅
C. Silver nitrate
D. Chlorine
A. Alcohol
B. Ethylene oxide ✅
C. Silver nitrate
D. Chlorine
1689. Which of the following methods is useful for sterilization of antisera?
A. Tyndallization
B. Hot air oven
C. Filtration ✅
D. Autoclaving
A. Tyndallization
B. Hot air oven
C. Filtration ✅
D. Autoclaving
1690. The cleaning process that is required for all instruments that penetrate the skin or that come in contact with normally sterile areas of the tissue and internal organs is:
A. Ultrasonic cleaning
B. Sterilization ✅
C. Disinfection
D. Sanitization
A. Ultrasonic cleaning
B. Sterilization ✅
C. Disinfection
D. Sanitization
1691. Which of the following is most resistant to antiseptics/sterilization?
A. Prion ✅
B. Fungus
C. Bacterial Spore
D. Cyst
A. Prion ✅
B. Fungus
C. Bacterial Spore
D. Cyst
1692. The most suitable way of sterilization of oils and fats is:
A. Tyndallization
B. Autoclaving
C. Hot air oven ✅
D. Pasteurization
A. Tyndallization
B. Autoclaving
C. Hot air oven ✅
D. Pasteurization
1693. A(n) ____ is used to prevent infection by killing or inhibiting pathogen growth on animal tissues.
A. Antiseptic ✅
B. Sanitizer
C. Disinfectant
D. Sterilant
A. Antiseptic ✅
B. Sanitizer
C. Disinfectant
D. Sterilant
1694. Who is credited with developing a procedure to heat wine at temperatures well below boiling to prevent spoilage of the wine?
A. Pasteur ✅
B. Koch
C. Lister
D. Gram
A. Pasteur ✅
B. Koch
C. Lister
D. Gram
1695. Which of the following is bactericidal?
A. Freeze-drying
B. Membrane filtration
C. Ionizing radiation ✅
D. Deep freezing
A. Freeze-drying
B. Membrane filtration
C. Ionizing radiation ✅
D. Deep freezing
1696. Any process that destroys the non-spore-forming contaminants on inanimate objects is:
A. Disinfection ✅
B. Antisepsis
C. Tyndallization
D. Sterilization
A. Disinfection ✅
B. Antisepsis
C. Tyndallization
D. Sterilization
1697. Which virulence factor of the UTI causing agent is MOST important to pathogenesis?
A. Exotoxin
B. Coagulase
C. Urease ✅
D. Capsule
A. Exotoxin
B. Coagulase
C. Urease ✅
D. Capsule
1698. Each of the following organisms is an important cause of urinary tract infections EXCEPT:
A. Proteus mirabilis
B. Bacteroides fragilis ✅
C. Escherichia coli
D. Klebsiella pneumoniae
A. Proteus mirabilis
B. Bacteroides fragilis ✅
C. Escherichia coli
D. Klebsiella pneumoniae
1699. Acute glomerulonephritis is a non-suppurative complication that follows infection by which one of the following organisms?
A. Enterococcus faecalis
B. Streptococcus pyogenes ✅
C. Streptococcus agalactiae
D. Streptococcus pneumoniae
A. Enterococcus faecalis
B. Streptococcus pyogenes ✅
C. Streptococcus agalactiae
D. Streptococcus pneumoniae
1700. A 9-year-old child develops glomerulonephritis a week after she was treated for a sore throat. The causal agent is identified by serotyping of the:
A. Teichoic acids
B. M proteins ✅
C. Capsule
D. Pili
A. Teichoic acids
B. M proteins ✅
C. Capsule
D. Pili
