Microbiology Interview Preparation Guide Download PDF
Microbiology Interview Questions and Answers will guide us now that Microbiology is the study of microorganisms, which are unicellular or cell-cluster microscopic organisms. This includes eukaryotes such as fungi and protists, and prokaryotes. Viruses, though not strictly classed as living organisms, are also studied. So learn more about Microbiology with the help of this Microbiology Interview Questions with Answers guide
124 Microbiology Questions and Answers:
Table of Contents
1 :: All Enterobacteriaceae share all of the following characteristics EXCEPT?
* A. Ferment glucose
* B. Reduce nitrates to nitrites
* C. Oxidase positive
* D. Gram negative
* E. Rod-shaped (bacilli)
Correct Answer: C
* B. Reduce nitrates to nitrites
* C. Oxidase positive
* D. Gram negative
* E. Rod-shaped (bacilli)
Correct Answer: C
2 :: What is the O antigen of Enterobacteriaceae?
* A. Cell surface polysaccharide
* B. A channel controlling substance taken into the organism.
* C. A flagellar protein
* D. A peptidoglycan matrix important for cellular rigidity
* E. Cell wall lipopolysaccharide
Correct Answer: E
* B. A channel controlling substance taken into the organism.
* C. A flagellar protein
* D. A peptidoglycan matrix important for cellular rigidity
* E. Cell wall lipopolysaccharide
Correct Answer: E
3 :: Which of the following statements about the 23-valent pneumococcal vaccine is not correct?
* A. It is a protein-conjugated, polysaccharide vaccine.
* B. It is poorly immunogenic in young children and immuno compromised hosts.
* C. It is routinely recommended for immune competent adults and children >2 yrs. of age at risk for serious pneumococcal disease.
* D. It protects against the major serotypes of pneumococci causing infection.
* E. An adult with asplenia would be a candidate for this vaccine.
Correct Answer: A
* B. It is poorly immunogenic in young children and immuno compromised hosts.
* C. It is routinely recommended for immune competent adults and children >2 yrs. of age at risk for serious pneumococcal disease.
* D. It protects against the major serotypes of pneumococci causing infection.
* E. An adult with asplenia would be a candidate for this vaccine.
Correct Answer: A
4 :: Which of the following statements about Group B a streptococcus (Streptococcus agalactiae) is not correct?
* A. They are important causes of toxic strep syndrome.
* B. They are frequent colonizers of the female genital tract.
* C. Screening for this pathogen during pregnancy has reduced the incidence of neonatal sepsis.
* D. These organisms are b-hemolytic.
* E. They are important causes of urinary tract infections and bacteremia in elderly and diabetic adults.
Correct Answer: A
* B. They are frequent colonizers of the female genital tract.
* C. Screening for this pathogen during pregnancy has reduced the incidence of neonatal sepsis.
* D. These organisms are b-hemolytic.
* E. They are important causes of urinary tract infections and bacteremia in elderly and diabetic adults.
Correct Answer: A
5 :: A 12 year old boy presents with acute onset of sore throat, fever to 38.9 degrees C and painful anterior cervical lymphadenopathy. On exam the pharynx is red and swollen and the tonsils are covered with yellow-white exudates. The child also has halitosis. Which of the following non-suppurative complications are of concern?
* A. Sinusitis
* B. Acute rheumatic fever alone
* C. Acute glomerulonephritis alone
* D. Acute rheumatic fever and acute glomerulonephritis
* E. Scarlet fever alone
Correct Answer: D
* B. Acute rheumatic fever alone
* C. Acute glomerulonephritis alone
* D. Acute rheumatic fever and acute glomerulonephritis
* E. Scarlet fever alone
Correct Answer: D
6 :: All of the following statements about the M-protein of Group A- Streptococci are correct EXCEPT?
* A. The amino terminal portion (distal portion) is variable, accounting for over 80 distinct serotypes.
* B. M proteins allow streptococci to resist phagocytosis.
* C. Antibodies to M protein confer type-specific immunity.
* D. M protein is the major virulence factor of Group A streptococci
* E. M protein is the major constituent of the capsule of Group A streptococci
Correct Answer: E
* B. M proteins allow streptococci to resist phagocytosis.
* C. Antibodies to M protein confer type-specific immunity.
* D. M protein is the major virulence factor of Group A streptococci
* E. M protein is the major constituent of the capsule of Group A streptococci
Correct Answer: E
7 :: Which of the following extracellular enzymes produced by Group A-streptococci is called “spreading factor”, an enzyme important in skin and soft tissue infection?
* A. Streptokinase
* B. Hyaluronidase
* C. M Protein
* D. Deoxyribonuclease C
* E. None of the above
Correct Answer: D
* B. Hyaluronidase
* C. M Protein
* D. Deoxyribonuclease C
* E. None of the above
Correct Answer: D
8 :: The diagnosis of septicemia should be considered in patients who are at increased risk of blood stream infection (often secondary to local disease, such as urinary tract infection or pneumonia). All of the following are factors predisposing patients to septicemia except?
* A. Underlying diseases that appear to compromise host defenses, such as diabetes, lymphoma, etc
* B. Patients with a polymorphonuclear leukocyte count less than 1000/mm3
* C. Patients with polymorphonuclear leukocyte counts of 10,000 to 20,000
* D. Long term therapy with broad-spectrum antimicrobials.
Correct Answer:
* B. Patients with a polymorphonuclear leukocyte count less than 1000/mm3
* C. Patients with polymorphonuclear leukocyte counts of 10,000 to 20,000
* D. Long term therapy with broad-spectrum antimicrobials.
Correct Answer:
9 :: Physical findings and other factors that should suggest the presence of septicemia in a particular patient are all of the following except?
* A. Shaking chills, spiking fevers
* B. Conjunctivitis
* C. Nausea, vomiting, diarrhea
* D. in elderly patients, decreased urine output or mental changes (confusion)
Correct Answer: B
* B. Conjunctivitis
* C. Nausea, vomiting, diarrhea
* D. in elderly patients, decreased urine output or mental changes (confusion)
Correct Answer: B
10 :: It is extremely difficult to eradicate staphylococcal infection in the presence of a foreign body. Thus, infected artificial joints and infected intravenous lines often must be removed in conjunction with optimal intravenous anti-staphylococcal therapy with oxacillin or nafcillin (sometimes in combination with rifampin) in order to eradicate such staphylococcal infections (and these attempts are not always successful). Staphylococcal infection of bone may persist for many years despite what should be optimal antimicrobial therapy. The most likely reason for this tenacity of staphylococcal osteomyelitis is:?
* A. The Staphylococcal pilus gene is up-regulated by oxacillin
* B. Fragments of dead bone, called "involucrum" may act as a foreign body, and may have to be removed for optimal eradication of the staphylococcal infection.
* C. Staphylococci may be perceived by the patient's immune system as a positive factor, because the staphylococci produce an extracellular enzyme, obtundokinase, which makes the patient more alert.
* D. Staphylococci are such an integral part of our normal flora that they are treated as "self" rather than "non-self", and no immune reaction to them occurs.
Correct Answer: B
* B. Fragments of dead bone, called "involucrum" may act as a foreign body, and may have to be removed for optimal eradication of the staphylococcal infection.
* C. Staphylococci may be perceived by the patient's immune system as a positive factor, because the staphylococci produce an extracellular enzyme, obtundokinase, which makes the patient more alert.
* D. Staphylococci are such an integral part of our normal flora that they are treated as "self" rather than "non-self", and no immune reaction to them occurs.
Correct Answer: B
11 :: A 42 year old woman who was complaining of shaking chills and fever went to the Salt Lake City Homeless clinic. She had enlarged lymph nodes in the right axilla. Upstream from the enlarged nodes was an ulcer on the top of the patients right hand. When carefully questioned, the patient said she remembered being bitten there by an insect resembling a horsefly, but with yellow stripes on its abdomen; Its what we used to call a deerfly, she added laconically. The patient denied any contact with rats or fleas. The patients disease was most likely to be:?
* A. Brucellosis
* B. Ulcero-glandular tularemia
* C. Pneumonic plague
* D. Relapsing fever
Correct Answer: B
* B. Ulcero-glandular tularemia
* C. Pneumonic plague
* D. Relapsing fever
Correct Answer: B
12 :: Which of the following diseases are not transmitted by ticks?
* A. Ulceroglandular tularemia
* B. Bubonic plague
* C. Relapsing fever
* D. Lyme disease
Correct Answer: B
* B. Bubonic plague
* C. Relapsing fever
* D. Lyme disease
Correct Answer: B
13 :: A 20 year old patient comes to the homeless clinic with a skin abscess on the right arm. A swab from the intact skin overlying this abscess grows coagulase negative staphylococci. An aspirate obtained sterilely with a needle and syringe grows Staphylococcus aureus. About these 2 organisms in this patient you can say?
* A. Both are normal flora and contaminated the specimens sent to the lab
* B. The staph aureus is a pathogen and the coagulase negative staph is not
* C. The coagulase negative staphylococcus is a pathogen
* D. The coagulase negative staphylococcus is an opportunistic pathogen
Correct Answer: B
* B. The staph aureus is a pathogen and the coagulase negative staph is not
* C. The coagulase negative staphylococcus is a pathogen
* D. The coagulase negative staphylococcus is an opportunistic pathogen
Correct Answer: B
14 :: A person who has a normal healthy immune system acquires a new strain of E. coli that now lives in his gastrointestinal tract. This individual is not ill. A second person with an acute leukemia and no white blood cells acquires the same organism, develops diarrhea followed by hypotension, bacteremia, sepsis, and death. This organism is?
* A. Normal flora for both individuals
* B. A pathogen for both individuals
* C. An opportunistic pathogen for both individuals
* D. One with a low degree of virulence
Correct Answer: D
* B. A pathogen for both individuals
* C. An opportunistic pathogen for both individuals
* D. One with a low degree of virulence
Correct Answer: D
15 :: A 25 year old woman has a 4 year old son who is now recovering from Group A strep pharyngitis. Out of curiosity, the pediatrician does a throat culture on the mother which is positive for Group A strep even though she doesnt have a sore throat. The pediatrician also does an ASO titer and anti DNAse B assay on her both of which are negative. At this point we would say that she?
* A. Has asymptomatic infection
* B. Has opportunistic infection
* C. Is a carrier
* D. Is immunosuppressed
Correct Answer: C
* B. Has opportunistic infection
* C. Is a carrier
* D. Is immunosuppressed
Correct Answer: C
16 :: Characteristics of a bacterial capsule include?
* A. All bacteria have one
* B. It is composed of peptidoglycan
* C. It is an important mechanism for protecting a bacteria against ingestion by PMNs
* D. It is what causes the gram stain reaction
Correct Answer: C
* B. It is composed of peptidoglycan
* C. It is an important mechanism for protecting a bacteria against ingestion by PMNs
* D. It is what causes the gram stain reaction
Correct Answer: C
17 :: As a budding basic scientist you work in a research laboratory and discover a chemical that removes the cell wall from bacteria but leaves the organism undamaged otherwise. Things that the bacteria will lose because of this include?
* A. The ability to stain gram positive: all will look gram negative
* B. The ability to move
* C. The ability to have a gram stain result
* D. The ability to attach to other cells
Correct Answer: C
* B. The ability to move
* C. The ability to have a gram stain result
* D. The ability to attach to other cells
Correct Answer: C
18 :: Under the electron microscope you keep at home next to your MP3 player you look at a single bacterium living in your mouth. You see a single polar flagellum stretching off from one end looking very much like a tail. A characteristic of this organism should be?
* A. An ability to stay in one place for a very long time
* B. An ability to move in the direction opposite the flagellum
* C. An ability to avoid ingestion by PMNs
* D. An ability to induce a large antibody response
Correct Answer: B
* B. An ability to move in the direction opposite the flagellum
* C. An ability to avoid ingestion by PMNs
* D. An ability to induce a large antibody response
Correct Answer: B
19 :: On the same day the clinical laboratory identifies two strains of the same bacterial species. One of these strains has pili on the surface; the other does not. In terms of the clinical status of the two patients it is likely that?
* A. Patient with the piliated strain is ill, the other patient is not
* B. Patient with the piliated strain is not ill, the other patient is
* C. Both patients are ill since pili do not correlate with virulence
* D. Patient with the piliated strain is a child, the other patient is an adult
Correct Answer: A
* B. Patient with the piliated strain is not ill, the other patient is
* C. Both patients are ill since pili do not correlate with virulence
* D. Patient with the piliated strain is a child, the other patient is an adult
Correct Answer: A
20 :: Infections caused by anaerobes are?
* A. Usually confined to the abdomen
* B. Never seen in the lung because of its excellent blood supply
* C. Mixed
* D. Rapidly progressive
Correct Answer: C
* B. Never seen in the lung because of its excellent blood supply
* C. Mixed
* D. Rapidly progressive
Correct Answer: C
21 :: The laboratory reports that both blood cultures that are drawn from a 15 year old girl are growing Bacteroides fragilis. She was admitted to the hospital because of acute abdominal pain. You should be concerned that?
* A. She has acute gastroenteritis and the organism is entering the blood from the inflamed bowel endothelial surface
* B. She has a bowel perforation and intraabdominal tissue destruction with impaired vascular flow
* C. She has gram negative sepsis and the Bacteroides is a contaminant
* D. She has pelvic inflammatory disease with gonorrhea, a sexually transmitted disease, and the Bacteroides is a contaminant
Correct Answer: B
* B. She has a bowel perforation and intraabdominal tissue destruction with impaired vascular flow
* C. She has gram negative sepsis and the Bacteroides is a contaminant
* D. She has pelvic inflammatory disease with gonorrhea, a sexually transmitted disease, and the Bacteroides is a contaminant
Correct Answer: B
22 :: Anaerobic infections are?
* A. Often continuous to mucosal surfaces
* B. Associated with highly vascularized tissue
* C. Gram negative
* D. Most likely to occur in the lung with its high oxygen level
Correct Answer: A
* B. Associated with highly vascularized tissue
* C. Gram negative
* D. Most likely to occur in the lung with its high oxygen level
Correct Answer: A
23 :: Specific organisms that are considered strict anaerobes include?
* A. E. coli and Streptococcus pneumoniae
* B. Bacteroides and Klebsiella
* C. Fusobacterium and Clostridium
* D. Peptostreptococcus and Nocardia
Correct Answer: C
* B. Bacteroides and Klebsiella
* C. Fusobacterium and Clostridium
* D. Peptostreptococcus and Nocardia
Correct Answer: C
24 :: The single most important characteristic of diarrhea caused by Vibrio cholera is?
* A. Profound watery diarrhea
* B. Severe abdominal pain
* C. Massive bloody diarrhea
* D. Renal insufficiency
Correct Answer: A
* B. Severe abdominal pain
* C. Massive bloody diarrhea
* D. Renal insufficiency
Correct Answer: A
25 :: A 15 year old boy comes in to clinic with pain in his right ear. He is on his school swim team and spends about 2 hours per day in the pool. Along with the pain in his ear, he has watery drainage coming from the ear canal. On exam his vital signs are normal, and he appears healthy, but his left external ear looks quite red and there is copious watery, slightly green drainage coming from the ear. The organism mostly likely causing this is?
* A. Staph aureus
* B. Viridans group streptococci
* C. Streptococcus pneumoniae
* D. Pseudomonas aeruginosa
Correct Answer: D
* B. Viridans group streptococci
* C. Streptococcus pneumoniae
* D. Pseudomonas aeruginosa
Correct Answer: D