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MMB621S-MEDICAL MICROBIOLOGY 2B-JAN 2020 |
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NAMIBIA UNIVERSITY
OF SCIENCE AND TECHNOLOGY
Faculty of Health and Applied Sciences
Department of Health Sciences
QUALIFICATION: BACHELOR OF MEDICAL LABORATORY SCIENCES
QUALIFICATION CODE: O8BMLS
LEVEL: 6
COURSE: MEDICAL MICROBIOLOGY 2B
COURSE CODE: MMB621S
DATE: JANUARY 2020
SESSION:
DURATION: 3 HOURS
MARKS: 120
EXAMINER(S)
MODERATOR:
SECOND OPPORTUNITY EXAMINATION QUESTION PAPER
Ms Fredrika Engelbrecht
Prof Sylvester Moyo
INSTRUCTIONS
1. Answer all questions.
Please write neatly and legibly.
3. Donotuse the left side margin of the exam paper. This must be allowed for the
examiner.
4. No books, notes and other additional aids are allowed.
Mark all answers clearly with their respective question numbers.
Permissable material
Non programmable calculator is allowed.
THIS QUESTION PAPER CONSISTS OF 6 PAGES (Excluding this front page)
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Medical Microbiology 2B MMB621S
Second Opportunity Paper 2019
SECTION A (27 MARKS)
QUESTION 1
[10]
Evaluate the statements in each numbered section and select the most appropriate
answer or phrase from the given possibilities. Write the appropriate letter next to the
number of the statement/phrase.
1.1 The reverse CAMP test is used for the identification of:
A)
Clostridium tetani.
B)
Clostridium perfringens.
C)
Clostridium difficile.
D)
Clostridium botulin.
(1)
1.2 The cytokines released during an infection with S. typhi results in:
A)
Leucocytosis.
B)
Inflammatory reaction in the Peyer’s patches.
C)
Spread of the organism to the mesenteric lymph nodes.
D)
Bacteraemia.
(1)
1.3 The causative organism of Lyme disease is:
A)
Leptospirosis icterohaemorrhagie.
B)
Treponema pallidum.
C)
Borrelia burgdoferi.
D)
Borrelia recurrentis.
(1)
1.4 The virulence factors of Shigella dysenteriae that is associated with the diarrhoeal
symptoms are known as:
A)
The shiga toxin.
B)
The invasion plasmid antigens B and C.
C)
The intercellular A and B proteins.
D)
Enterotoxins.
(1)
1.5 Rickettsia rickettsii is the causative organisms of:
A)
Rocky Moutain spotted fever.
B)
Murine typhus.
C)
Boutonneuse fever.
D)
Epidemic typhus.
1.6 The following organism is known to cause pharyngitis:
A)
H. ducreyi.
B)
Mycoplasma spp.
C)
P. aeruginosa.
D)
Group A Streptococcus.
(1)
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Medical Microbiology 2B MMB621S
Second Opportunity Paper 2019
1.7 Which of the following drugs form part of the 2nd generation cephalosporins:
A)
Cefamandole & cefaclor.
B)
Cephalothin & cefazolin.
C)
Amikacin, & streptomycin.
D)
Ceftriaxone & cefotaxime.
(1)
1.8 The following organism ferment lactose when grown on MacConkey agar
A)
N. meningitidis.
B)
E. coli.
C)
P. aeruginosa.
D)
Proteus mirabilis.
(1)
1.9 The Salmonellae Vi antigen:
A)
Is an acidic polysaccharide antigen that overlay the O antigen.
B)
Exhibit the property of diphasic variation.
C)
Is fimbrial antigens.
D)
Is determined by the complete sugar sequence.
(1)
1.10 The causative organism of tick bite fever is:
A)
Treponema pallidum.
B)
Chlamydia trachomatis.
C)
Ureaplasma species.
D)
Rickettsia connori.
(1)
QUESTION 2
[10]
Assess the following statements and decide whether they are true or false. Write only
the number of the question and TRUE for a true statement or FALSE for a false statement
next to the number of the question. IF the statement is FALSE, please give a reason
why you think it is false.
2.1 C. diphtheria is only pathogenic when it is infected with the tox gene via a
bacteriophage.
2.2 Bacillus species is cause infectious and are always harmful to society.
2.3 Citrate utilization should be incubated anaerobically for accurate results.
2.4 Bacteroides fragilis is an aerobic organism usually responsible for conjunctivitis.
2.5 Clostridium perfringens is the causative organism of Bubonic plaque.
2.6 The anthrax toxin causes an increase in vascular permeability resulting in shock.
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Medical Microbiology 2B MMB621S
Second Opportunity Paper 2019
QUESTION 3
[7]
3.1 Pictures of specimen A and B below were taken from a low power microscopic
field.
(6x
Evaluate the quality of the respiratory specimens seen on slides A and B,
Y=
and explain your answer.
3)
Specimen A
Specimen B
3.2 Match the following organisms with their associated disease.
3.2.1 Enterotoxigenic E.coli
A)
Bloody diarhoea in all ages.
3.2.2. Vero cytotoxin-producing E.coli B)
Dysentery-like disease in all
ages.
3.2.3. Enteroinvasive E.coli
C)
Diarhoea in infants, rarely in
adults.
3.2.4 Enterpathogenic E.coli
D)
Infant and adult watery
diarhoea
(4)
SECTION B (29 MARKS)
[29]
QUESTION 4
4.1 Discuss how you will handle a positive blood culture, once the blood culture machine
has flagged it as being positive.
(5)
4.2 Outline the main criteria used for bacterial identification.
(10)
4.3 Discuss the transmission of Epidemic typhus.
(8)
4.4 Explain the step-by-step procedure for diagnosing typhoid fever.
(6)
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Medical Microbiology 2B MMB621S
Second Opportunity Paper 2019
SECTION C (64 MARKS)
QUESTION 5
[28]
5.1 Compare the pathogenesis and clinical manifestations of primary and secondary
syphilis.
(10)
5.2 Distinguish in a table format between C. perfringens and C. tetani using the
following criteria:
A)
Gram reaction and microscopic morphology.
B)
Spore.
C)
Motility.
D)
Lecithinase production.
E)
Indole production.
F)
Glucose fermentation.
G)
Lactose fermentation.
(18
H)
Maltose fermentation.
X A=
9)
5.3 A doctor requests a diagnosis for Cholera.
A)
What specimen from the patient would you ask the doctor to submit?
(1)
B)
Suggest the culture media and incubatory conditions required to grow
the suspected pathogen causing Cholera?
(3)
C)
Explain what you would expect to see if you have a positive growth on
the culture media and justify why you would see this growth.
(2)
D)
What is the causative agent of Cholera?
(1)
E)
Descirbe the gram characteristics of the expected pathogen causing
Cholera.
(2)
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Medical Microbiology 2B MMB621S
Second Opportunity Paper 2019
QUESTION 6
[36]
6.1
A 44-year-old male developed gas gangrene following an open fracture. Bacteriological
studies of the case and the results are presented together with the clinical pictures.
Despite adequate treatment of the open fracture of his right femur and tibia, he
developed gas gangrene with typical signs such as severe myonecrosis, subcutaneous
vesicles and crepitus, erythematous changes of the skin and with symptoms of toxemia.
Gram stained smears and cultures of the exudate and tissue fragments from the lesion
yielded the following results.
Gram stained slide:
a aS l‘in AN
Bo are India ink stain:
x
Anaerobic Growth on blood agar:
A) Analyse and interpret the information received for this case study, and use
it to identify the causative pathogen in this case.
(2)
B) Justify how you’ve identified the pathogen in A.
(8)
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Medical Microbiology 2B MMB621S
Second Opportunity Paper 2019
6.2 Assess the virulence factors of B. pertussis and discuss how it causes clinical
symptoms in the patient.
(10)
6.3 A patient is presenting with a very sore throat. The doctor submits a throat swab to
the diagnostic medical microbiology laboratory.
A) Discuss how you would go about processing this sample and justify your
suggestions.
(6)
B) Name the expected pathogen?
(1)
C) Illustrate, by means of a flow chart, how you would identify this organism. (9)
END OF PAPER