MCQ 2 – Bacteriology questions with
verified solutions
1. Select the INCORRECT statement about Staphylococci:
A. Anterior nares colonization is common (L4/S24)
B. Organisms can survive on dry surfaces for long periods (L4/S16)
C. Fomite transmission is rare (L4/S16)
D. Risk factors include use of antibiotics that suppress the normal flora - correct answer ✔✔C. Fomite
transmission is rare (L4/S16)
2. Select the INCORRECT combination about patients at risk of specific staphylococcal diseases:
A. Infants/scalded skin syndrome
B. Young children/cutaneous infections
C. Menstruating women/toxic shock syndrome
D. Intravascular catheters/endotoxemia (L4/S19)
E. Antecedent viral respiratory infection/pneumonia - correct answer ✔✔D. Intravascular
catheters/endotoxemia (L4/S19)
3. Select the INCORRECT statement about Staphylococci:
A. Staphylococci form clusters and are catalase positive
B. Coagulase distinguishes S. aureus from other species
C. TSST-‐1 has superantigen and direct effects
D. Superantigens cause massive cytokine release
E. Enterotoxins lose activity after boiling or exposure to digestive enzymes - correct answer ✔✔E.
Enterotoxins lose activity after boiling or exposure to digestive enzymes (L4/S25, they are heat-stable)
4. Toxin-‐mediated diseases caused by Staphylococci include:
A. Food poisoning
,B. Bacteremia
C. Impetigo
D. Carbuncle
E. Endocarditis - correct answer ✔✔A. Food poisoning (L4/S20)
5. Antibiotics of choice for staphylococcal infections are:
A. Penicillinase-‐resistant penicillin
B. Penicillinase-‐sensitive penicillin
C. Oxacillin
D. Both A and C are correct
E. Both B and C are correct - correct answer ✔✔D. Both A and C are correct (L4- S36)
6. Select the INCORRECT statement about hemolytic patterns of Streptococcus pyogenes:
A. Also called group B streptococci
B. Produce pyrogenic exotoxins
C. Responsible for rheumatic fever
D. Antistreptokinase antibodies are a useful marker for infection
E. Can invade into epithelial cells via M and F proteins - correct answer ✔✔A. Also called group B
streptococci (L5)
7. The streptococcal pyrogenic exotoxins:
A. Originally called erythrotoxins
B. Similar to toxin produced by C. diphtheria
C. Are a virulence factor
D. Both A and B are correct
E. All of the above are correct - correct answer ✔✔E. All of the above are correct (L5\S20)
8. Individuals at higher risk of Stretococcal infections include:
A. Children 5-‐15 years (pharyngitis)
, B. Children 2-‐5 yrs with poor hygiene (pyoderma)
C. Patients with soft-‐tissue infection (Streptococcal toxic shock syndrome)
D. Patients with prior strep throat (rheumatic fever)
E. All of the above are correct - correct answer ✔✔E. All of the above are correct L5/S260)
9. Select the INCORRECT combination about virulence of S. pneumonia:
A. Ability to colonize oropharynx/surface glycolipids
B. Spread into sterile tissues/pneumolysin, IgA protease
C. Stimulate local inflammatory response/teichoic acid
D. Evade phagocytic killing/polysaccharide capsule
E. Stimulate local inflammatory response/peptidoglycan fragments, pneumolysin - correct answer ✔✔A.
Ability to colonize oropharynx/surface glycolipids L5-33
10. Select the INCORRECT statement about S. pneumonia infections:
A. Most infections are caused by endogenous spread
B. Colonization is highest in young children and their contacts
C. Children and elderly are at greatest risk for meningitis
D. People with hematologic disorders are at risk of fulminant sepsis
E. Person-‐to person through infectious droplets is very common - correct answer ✔✔E. Person-‐to
person through infectious droplets is very common L3-40
11. Select the INCORRECT combination about virulence factors of Enterococci:
A. Aggregation substance/surface adhesion
B. Cytolysin/mediate binding to host cells
C. Antibiotic resistance/multiple plasmid and chromosomal genes
D. Pheromone/chemoattractant for neutrophils
E. Bacteriocin/inihibits growth of gram-‐positive bacteria - correct answer ✔✔B. Cytolysin/mediate
binding to host cells L6-33
12. Diseases caused by Enterococci DOES NOT include:
verified solutions
1. Select the INCORRECT statement about Staphylococci:
A. Anterior nares colonization is common (L4/S24)
B. Organisms can survive on dry surfaces for long periods (L4/S16)
C. Fomite transmission is rare (L4/S16)
D. Risk factors include use of antibiotics that suppress the normal flora - correct answer ✔✔C. Fomite
transmission is rare (L4/S16)
2. Select the INCORRECT combination about patients at risk of specific staphylococcal diseases:
A. Infants/scalded skin syndrome
B. Young children/cutaneous infections
C. Menstruating women/toxic shock syndrome
D. Intravascular catheters/endotoxemia (L4/S19)
E. Antecedent viral respiratory infection/pneumonia - correct answer ✔✔D. Intravascular
catheters/endotoxemia (L4/S19)
3. Select the INCORRECT statement about Staphylococci:
A. Staphylococci form clusters and are catalase positive
B. Coagulase distinguishes S. aureus from other species
C. TSST-‐1 has superantigen and direct effects
D. Superantigens cause massive cytokine release
E. Enterotoxins lose activity after boiling or exposure to digestive enzymes - correct answer ✔✔E.
Enterotoxins lose activity after boiling or exposure to digestive enzymes (L4/S25, they are heat-stable)
4. Toxin-‐mediated diseases caused by Staphylococci include:
A. Food poisoning
,B. Bacteremia
C. Impetigo
D. Carbuncle
E. Endocarditis - correct answer ✔✔A. Food poisoning (L4/S20)
5. Antibiotics of choice for staphylococcal infections are:
A. Penicillinase-‐resistant penicillin
B. Penicillinase-‐sensitive penicillin
C. Oxacillin
D. Both A and C are correct
E. Both B and C are correct - correct answer ✔✔D. Both A and C are correct (L4- S36)
6. Select the INCORRECT statement about hemolytic patterns of Streptococcus pyogenes:
A. Also called group B streptococci
B. Produce pyrogenic exotoxins
C. Responsible for rheumatic fever
D. Antistreptokinase antibodies are a useful marker for infection
E. Can invade into epithelial cells via M and F proteins - correct answer ✔✔A. Also called group B
streptococci (L5)
7. The streptococcal pyrogenic exotoxins:
A. Originally called erythrotoxins
B. Similar to toxin produced by C. diphtheria
C. Are a virulence factor
D. Both A and B are correct
E. All of the above are correct - correct answer ✔✔E. All of the above are correct (L5\S20)
8. Individuals at higher risk of Stretococcal infections include:
A. Children 5-‐15 years (pharyngitis)
, B. Children 2-‐5 yrs with poor hygiene (pyoderma)
C. Patients with soft-‐tissue infection (Streptococcal toxic shock syndrome)
D. Patients with prior strep throat (rheumatic fever)
E. All of the above are correct - correct answer ✔✔E. All of the above are correct L5/S260)
9. Select the INCORRECT combination about virulence of S. pneumonia:
A. Ability to colonize oropharynx/surface glycolipids
B. Spread into sterile tissues/pneumolysin, IgA protease
C. Stimulate local inflammatory response/teichoic acid
D. Evade phagocytic killing/polysaccharide capsule
E. Stimulate local inflammatory response/peptidoglycan fragments, pneumolysin - correct answer ✔✔A.
Ability to colonize oropharynx/surface glycolipids L5-33
10. Select the INCORRECT statement about S. pneumonia infections:
A. Most infections are caused by endogenous spread
B. Colonization is highest in young children and their contacts
C. Children and elderly are at greatest risk for meningitis
D. People with hematologic disorders are at risk of fulminant sepsis
E. Person-‐to person through infectious droplets is very common - correct answer ✔✔E. Person-‐to
person through infectious droplets is very common L3-40
11. Select the INCORRECT combination about virulence factors of Enterococci:
A. Aggregation substance/surface adhesion
B. Cytolysin/mediate binding to host cells
C. Antibiotic resistance/multiple plasmid and chromosomal genes
D. Pheromone/chemoattractant for neutrophils
E. Bacteriocin/inihibits growth of gram-‐positive bacteria - correct answer ✔✔B. Cytolysin/mediate
binding to host cells L6-33
12. Diseases caused by Enterococci DOES NOT include:
