Exam 1 Key

MICROBIOLOGY 403: SECOND EXAM KEY

Average score: 76.4%
Maximum score: 96%
Minimum score: 43%

Approximate scale:

96-86 = A
85-78 = B
77-66 = C
65-60 = D
59-43 = F

Section I. Quantitative relationships

Questions numbered 1 through 25 count 2 points each (50 points).

B	1.	(1)	The production of hydrogen peroxide as a consequence of the mechanism of action of the enzyme catalase.
		(2)	The production of hydrogen peroxide as a consequence of the mechanism of action of the enzyme superoxide dismutase.
A	2.	(1)	The incidence of disease in North America that is caused by Treponema pallidum.
		(2)	The incidence of disease in North America that is caused by Treponema pertenue.
A	3.	(1)	The number of strains of S. aureus that contain protein A in the cell wall.
		(2)	The number of strains of S. pyogenes that contain protein A in the cell wall.
A	4.	(1)	The adenylate cyclase activity of the Bacillus anthracis edema factor toxin.
		(2)	The adenylate cyclase activity of the Bacillus anthracis lethal factor toxin.
B	5.	(1)	The ability of botulism toxin to block the release of the neurotransmitter glycine.
		(2)	The ability of tetanus toxin to block the release of the neurotransmitter glycine.
B	6.	(1)	The occurrence of the characteristic spasmatic cough during the catarrhal phase of pertussis.
		(2)	The occurrence of the characteristic spasmatic cough during the paroxysmal phase of pertussis.
A	7.	(1)	The occurrence of meningitis that is due to Haemophilus influenzae in very young children.
		(2)	The occurrence of meningitis that is due to Haemophilus influenzae in adults.
B	8.	(1)	The length of the incubation period for gastroenteritis produced by Salmonella enteritidis.
		(2)	The length of the incubation period for typhoid fever produced by Salmonella typhi.
A	9.	(1)	The frequency of isolation of Bacteroides from various anaerobic infections.
		(2)	The frequency of isolation of Bacillus from various anaerobic infections.
B	10.	(1)	The number of different H-antigens that have been observed in the genus Klebsiella.
		(2)	The number of different H-antigens that have been observed in the genus Escherichia.
B	11.	(1)	The role of anti-capsular antibodies in host defense against S. pyogenes.
		(2)	The role of anti-capsular antibodies in host defense against S. pneumoniae.
C	12.	(1)	The role of crowded, unsanitary conditions in the transmission of dysentery.
		(2)	The role of crowded, unsanitary conditions in the transmission of cholera.
A	13.	(1)	The importance of an animal reservoir in the transmission of Salmonella to humans.
		(2)	The importance of an animal reservoir in the transmission of Shigella to humans.
A	14.	(1)	The frequency of community-acquired urinary tract infections that are due to E. coli.
		(2)	The frequency of community-acquired urinary tract infections that are due to Proteus.
B	15.	(1)	The ability of beta-lactam antibiotics to inhibit bacterial protein synthesis.
		(2)	The ability of macrolide antibiotics to inhibit bacterial protein synthesis.
A	16.	(1)	The probability that an acute infection involving Group A streptococci may progress to glomerulonephritis.
		(2)	The probability that an acute infection involving Group D streptococci may progress to glomerulonephritis.
A	17.	(1)	The ability of piliated strains of Neisseria gonorrhoeae to produce disease.
		(2)	The ability of non-piliated strains of Neisseria gonorrhoeae to produce disease.
B	18.	(1)	The percentage of the oral cavity normal flora that are represented by the genus Staphylococcus.
		(2)	The percentage of the oral cavity normal flora that are represented by the genus Streptococcus.
A	19.	(1)	The level of crosslinking in the peptidoglycan from a Gram-positive cell.
		(2)	The level of crosslinking in the peptidoglycan from a Gram-negative cell.
B	20.	(1)	The role of humoral defenses in preventing disease due to Brucella.
		(2)	The role of cell-mediated defenses in preventing disease due to Brucella.
A	21.	(1)	The association between the organism Borrelia recurrentis and the disease epidemic relapsing fever.
		(2)	The association between the organism Borrelia recurrentis and the disease endemic relapsing fever.
A	22.	(1)	The role of the humoral immune response in host defense against Leptospira.
		(2)	The role of the cell-mediated immune response in host defense against Leptospira.
B	23.	(1)	The role of altered receptors in the mechanism of chloramphenicol resistance.
		(2)	The role of altered receptors in the mechanism of streptomycin resistance.
B	24.	(1)	The ability of Vibrio cholerae to tolerate acidic conditions.
		(2)	The ability of Vibrio cholerae to tolerate alkaline conditions.
A	25.	(1)	The role of fleas in the transmission of Yersinia pestis.
		(2)	The role of ticks in the transmission of Yersinia pestis.

Section II. Multiple Choice (2 points each, 26 points total).

Questions 26-28. Indicate the SITE OF ACTIVITY listed on the right for each of the ANTIBIOTICS listed on the left. Each lettered choice may be used once, more than once or not at all.

B	26.	Fosfomycin	A.	Integrity of the cell wall
E	27.	Nalidixic acid	B.	Synthesis of the cell wall
D	28.	Erythromycin	C.	Integrity of proteins
			D.	Synthesis of proteins
			E.	Synthesis of nucleic acids
			F.	None of the above
Questions 29-31. Indicate the MOST IMPORTANT HOST DEFENSE MECHANISM listed on the right for each of the DISEASES listed on the left. Each lettered choice may be used once, more than once or not at all.

B	29.	Meningitis	A.	Normal flora
C	30.	Pertussis	B.	Anti-capsular antibodies
A	31.	Pseudomembranous colitis	C.	Anti-toxin antibodies
			D.	Cell-mediated response
			E.	Anatomical barriers
			F.	None of the above
Questions 32-35. Indicate the MOST IMPORTANT VIRULENCE FACTOR listed on the right for each of the ORGANISMS listed on the left. Each lettered choice may be used once, more than once or not at all.

D	32.	Vibrio cholerae	A.	Intracellular growth
A	33.	Brucella suis	B.	Anti-phagocytic capsule
D	34.	Bacillus cereus	C.	Invasion of tissues
A	35.	Legionella pneumophila	D.	Production of toxins
			E.	All of the above
			F.	None of the above
Questions 36-38. Indicate the MOST IMPORTANT CELL SURFACE COMPONENT listed on the right for each of the ORGANISMS listed on the left. Each lettered choice may be used once, more than once or not at all.

F	36.	Neisseria meningitidis	A.	Protein A
	NOTE: Credit was also given for answer C due to an error on the original scoring key.
D	37.	Yersinia pestis	B.	M Protein
B	38.	Streptococcus pyogenes	C.	Protein I
			D.	VW Antigen
			E.	All of the above
			F.	None of the above

Section III. Diagnostic questions (3 points each, 24 points total).
Questions 39 through 46 ask you to presumptively diagnose the etiologic agent of a specific disease scenario based on three facts that include i) patient history, ii) clinical presentation and iii) selected laboratory findings. Respond to each question by choosing the most likely organism from the following list. Each organism may be used once, more than once, or not at all.

A. Bacillus anthracis B. Bacteroides fragilis C. Bordetella pertussis

D. Brucella abortus E. Campylobacter jejuni F. Clostridium botulinum

G. Clostridium tetani H. Escherichia coli I. Haemophilus influenzae

J. Neisseria meningitidis K. Pseudomonas aeruginosa L. Salmonella enteritidis

M. Shigella dysenteriae N. Staphylococcus aureus O. Streptococcus pneumoniae

P. Streptococcus pyogenes R. Vibrio cholerae S. Yersinia pestis

I 39. i) patient is a small child attending day care, ii) patient presents with a high fever, iii) Gram-negative coccobacilli are observed in a smear of cerebrospinal fluid.

B 40. i) patient is a 62-year old woman, ii) patient reports to the emergency room with a high fever and abdominal tenderness, iii) surgery reveals a ruptured appendix and intra-abdominal infection having a very foul odor.

L 41. i) patient is a 28-year old man, ii) patient reports having nausea, vomiting and diarrhea about 2 days after eating some poorly cooked chicken, iii) Gram-negative, hydrogen sulfide-producing bacteria were isolated from the feces.

A 42. i) patient is a cattle farmer, ii) patient presents with a small, black, necrotic lesion on the forearm, iii) Gram-positive rods are observed in smear of the lesion material.

N 43. i) patient is an SIU student, ii) patient complains of vomiting, diarrhea and abdominal pain about 4 hours following ingestion of an "old" ham sandwich, iii) the patient recovered completely in about 24 hours and no pathogenic bacteria were cultured from the feces.

O 44. i) patient is an elderly man who recently had influenza, ii) patient now reports to the emergency room with severe chills and a productive cough, iii) catalase-negative, Gram-positive cocci are isolated from the patient's sputum.

K 45. i) patient is a fireman who was severely burned, ii) despite topical antibiotic therapy, the wounds became infected, iii) Gram-negative rods that produced a greenish-pigment were isolated from the wounds.

H 46. i) patient is a 53-year old man who is in the hospital for a routine surgical procedure, ii) patient suddenly develops a high fever, iii) Gram-negative bacteria that ferment lactose are isolated from the patient's blood.

BONUS QUESTION:

47. What is the name of the antibiotic shown in the figure to the right? (3 points)

Tetracycline tet

A.	Bacillus anthracis	B.	Bacteroides fragilis	C.	Bordetella pertussis
D.	Brucella abortus	E.	Campylobacter jejuni	F.	Clostridium botulinum
G.	Clostridium tetani	H.	Escherichia coli	I.	Haemophilus influenzae
J.	Neisseria meningitidis	K.	Pseudomonas aeruginosa	L.	Salmonella enteritidis
M.	Shigella dysenteriae	N.	Staphylococcus aureus	O.	Streptococcus pneumoniae
P.	Streptococcus pyogenes	R.	Vibrio cholerae	S.	Yersinia pestis

I	39.	i) patient is a small child attending day care, ii) patient presents with a high fever, iii) Gram-negative coccobacilli are observed in a smear of cerebrospinal fluid.
B	40.	i) patient is a 62-year old woman, ii) patient reports to the emergency room with a high fever and abdominal tenderness, iii) surgery reveals a ruptured appendix and intra-abdominal infection having a very foul odor.
L	41.	i) patient is a 28-year old man, ii) patient reports having nausea, vomiting and diarrhea about 2 days after eating some poorly cooked chicken, iii) Gram-negative, hydrogen sulfide-producing bacteria were isolated from the feces.
A	42.	i) patient is a cattle farmer, ii) patient presents with a small, black, necrotic lesion on the forearm, iii) Gram-positive rods are observed in smear of the lesion material.
N	43.	i) patient is an SIU student, ii) patient complains of vomiting, diarrhea and abdominal pain about 4 hours following ingestion of an "old" ham sandwich, iii) the patient recovered completely in about 24 hours and no pathogenic bacteria were cultured from the feces.
O	44.	i) patient is an elderly man who recently had influenza, ii) patient now reports to the emergency room with severe chills and a productive cough, iii) catalase-negative, Gram-positive cocci are isolated from the patient's sputum.
K	45.	i) patient is a fireman who was severely burned, ii) despite topical antibiotic therapy, the wounds became infected, iii) Gram-negative rods that produced a greenish-pigment were isolated from the wounds.
H	46.	i) patient is a 53-year old man who is in the hospital for a routine surgical procedure, ii) patient suddenly develops a high fever, iii) Gram-negative bacteria that ferment lactose are isolated from the patient's blood.

BONUS QUESTION:
47.	What is the name of the antibiotic shown in the figure to the right? (3 points) Tetracycline