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MMB711S - MEDICAL MICROBIOLOGY 3 - 1ST OPP - JUNE 2023 |
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nAmIBIA UnIVERSITY
OFSCIEnCEAno TECHnOLOGY
FACULTYOF HEALTH,APPLIEDSCIENCESAND NATURALRESOURCES
SCHOOLOF HEALTHSCIENCES
DEPARTMENTOF CLINICALHEALTHSCIENCES
QUALIFICATION:BACHELOROF MEDICAL LABORATORYSCIENCES
QUALIFICATIONCODE: 08BMLS
LEVEL: 7
COURSECODE: MMB711S
COURSENAME: MEDICAL MICROBIOLOGY 3
SESSION:
JUNE 2023
PAPER:
THEORY
DURATION: 3 HOURS
MARKS:
103
FIRSTOPPORTUNITYEXAMINATION QUESTION PAPER
EXAMINER(S) Ms. V Tjijenda and Dr Markus Schuppler
MODERATOR: Prof R. T. Mavenyengwa
INSTRUCTIONS
1. Answer ALL the questions
2. Write clearly and neatly
3. Number the answers clearly
THIS QUESTION PAPERCONSISTSOF 10 PAGES(Including this front page)
Permissible materials
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SECTIONA {15)
QUESTION 1
[10]
Provide one word/term which best fits the description below. Write only the
number and corresponding term on your answer sheet.
1.1
A strain of Mycobacteria which has been used to immunise susceptible
individuals against tuberculosis
(1)
1.2
A viral infection also known as German Measles
(1)
1.3
Fungal infection characterized by oral thrush.
(1)
1.4
Insect vector that causes African Sleeping sickness
(1)
1.5 Toxins produced by Aspergillusflavus and Aspergillusparasiticus which
grow in soil, decaying vegetation, hay and grains
(1)
1.6
Mention the enzyme that is specific for E. coli and used for their
identifications an "Indicator organism" in drinking water analysis
(1)
1.7
Hepatitis B serum marker which indicates convalescent or immune status (1)
1.8
A patient in a coma is suffering and has exhibited seizure, confusion
and drowsiness and has a history of swimming in a lake
3 days ago
(1)
1.9
Major viral changes in the antigens caused by antigenic reassortment by
two different viral strains.
(1)
1.10 Parasitic ova with a prominent terminal spine and are excreted in urine. (1)
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Question 2
Choose the correct answer and report only the suitable letter next to the
relevant question number.
(5)
2.1.1
2.1.2
2.1.3
2.1.4
2.1.5
What is the main purpose of wastewater treatment?
(1)
A. Elimination of readily degradable carbon *
B. Elimination of pathogens
C. Elimination of heavy metals
D. Elimination of prions
Microbes play a major role in secondary wastewater treatment because: (1)
A. they remove organic matter in the aeration tank
B. they digest complex polymers in the anaerobic sludge digestor
C. they produce methane in the anaerobic sludge digestor
D. All of the above*
Which bacterium is a truly waterborne bacterial pathogen?
(1)
A. Listeriaivanovii
B. Rhone/laaquatilis
C. Shigellaflexneri*
D. Staphylococcus aureus
Why are "indicator organisms" used in drinking water analysis?
(1)
A. It is impractical to screen drinking water for every pathogen*
B. Not all waterborne bacterial pathogens grow on agar plates
C. "Indicator organisms" signal definite presence of pathogens
D. all of the above
Which enzyme is specific for Escherichiacoliand often used for their
(1)
identification as "indicator organism" in drinking water analysis?
A. B-Glucosidase
B. B-Glucuronidase*
C. B-Galactosidase
D. none of the above
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SECTIONB (73)
QUESTION 3
[18]
3.1 A 56-year-old San male reports with 4 weeks of a productive cough, fever,
night sweats and weight loss. A sputum sample was collected and sent for
analysis. The Xpert MTB/RIF results are as follows: MTB +/RIF resistance
3.1.1 What is the diagnosis?
(2)
3.1.2 Motivate the significance of this test in TB control and prevention.
(4)
3.1.3 Below are results obtained from a TB test done following the Xpert
MTB/RIF.
43 2 1
rpoB
rpo8V/T1
rpoBVIT2
rpoBVfT3
rpoBV/Tt.
rpoBVfT5
rpo81/fT6
rpoBVfT7
(p{J8 \\/fT8
rp B MUTT
rpoB MUT2A
rpoB MUT28
rpoB MUT3
inhA
inhAWTl
inhAWT2
inhA MUT
inhA MUT2
inhA MUT3A
inhAMUT3B
3:'.
3.1.3.1
Identify the test done in 3.1.3
(1)
3.1.3.2
Interpret the results for both Patients.
(4)
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3.3 Two types of carbol fuchsin acid fast methods are used to stain Mycobacterium
tuberculosis. Name the two stains and write short notes to differentiate
between them.
(5)
3.4 Name the two first line drugs used for treating Mycobacterium
tuberculosis.
(2)
QUESTION 4
[9]
A 4-year-old male presented to the emergency department with a worsening
skin lesion at the prior intravenous (i.v.) injection site on his left arm. He had
been diagnosed with Acute Lymphoblastic Leukemia (ALL) 10 days prior and
was currently undergoing induction chemotherapy. The lesion was first
noticedby his father 2 days earlier as a dime-sized erythematous papule
with no pain or focal swelling. Physical examination revealed a painful patch
with an irregular erythematous border and central dark bu Ila overlying the
left medial epicondyle. Figure A= Skin lesion; Figure B = Stained tissue
= = biopsy; Figure C Culture and Figure D Microscopy of the fungi from the
culture.
A
·.'.\\•.:.."-..,",·,.,...*,...
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;•• , ... •:
--c
?. :..,-\\.:.-
:•J:
:r
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4.1.1 Identify the stain used in figure B
(1)
4.1.2 Identify the fungi identified in Figure D
(1)
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4.1.3 Identify the test done in Figure D and explain the principle of the test. (4)
4.2
4.2.1
4.2.2
4.2.3
The clinical infections caused by dermatophytes are generally referred
to as ringworm or tin ea. Name Tinea species which affects the following
body parts:
(3)
Foot
Nails
Beard
QUESTION 5
[21]
5.1.1 Give another name for the following parasites:
(5)
(a) Whip worm
(b) Thread worm
(c) Pin worm
(d) Pork tape worm
(e) Hookworms
5.1.2 Which of the above parasites (a), (b), (c), (d) or (e) has an intermediate
host.
(1)
5.1.3 In which of the above parasites (a), (b), (c), (d) or (e) do eggs hatch in
the soil.
(1)
5.1.4 In which of the above parasites (a), (b), (c), (d) or (e) does larval migration
occur?
(2)
5.1.5 In which of the above parasites (a), (b), (c), (d) or (e) is the cellulose Tape
(scotch tape) preparation the recommended diagnostic test.
(1)
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5.2
An adult man, an immigrant from El Salvador (Central America), went to the
Emergency Room of a U.S. hospital with fever and confusion that did not respond
to antibiotic treatment. A CTscan showed a brain lesion. The patient was HIV-positive
and his last visit to El Salvador was one year earlier. A spinal tap showed low glucose
and high protein levels in the CSF.In addition, the organisms shown in Figures A
below is found in the CSF(size approximately 20 micrometers: Giemsa stain).
Figure A
5.2.1 Identify the organism to species level.
(1)
5.2.2 What stage of the parasite is this?
(1)
5.2.3 Mention the disease associated with this pathogen.
(1)
5.2.4 Summarize the life cycle of this pathogen.
(8)
QUESTION 6
[25]
6.1
A 15-year-old girl, who is presumed to have been perinatally infected with
HIV presents to the clinic. She is classified as WHO stage Ill and is aware of ·
her status and is started on ARVs.She is a maternal orphan; her mother
having passed away 4 years ago. She is currently in the care of an aunt who
receives her Care Dependency Grant (COG)on her behalf. They live in a
hostel, with inadequate accessto good nutrition. After 8 months she returns
to the clinic, alone, she is underweight and sick. She is referred to the wards
and is admitted. Her CD4 count has decreased and her viral load has increased.
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6.1.1 Explain what is meant by 'perinatal infection'.
(2)
6.1.2 Compare the use of ELISAand DNA-PCRin monitoring perinatal infection.(4)
6.1.3
Discuss the significance of the low CD4 count and increased viral load in
HIV patient management and propose a reason for what might have led
to it.
(3)
6.1.4 Describe the pathogenesis of HIV-1 virus.
(8)
6.2
Complete the table below
(3)
Virus
;,
Hepatitis B
Hepatitis A
Genome
5.2.1
5.2.4
Mode of transmission
5.2.2
5.2.5
Diagnostic Marker
5.2.3
5.2.6
6.3 Discuss the pathogenesis of varicella Zoster infection.
(6/2 = 3)
(5)
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SECTION C (15)
QUESTION7
[15]
7.1 Assessthe following statements and decide whether they are true or false.
Write only the number of the question and next to it TRUEfor a true
statement and FALSEfor a false statement
(10)
7.2.1 Cereulide is the heat labile emetic-type toxin of Bacillus cereus, which is
produced during growth of the bacteria in food.
7.2.2 The diarrhea-type toxins of Bacillus cereus are produced during growth of the
bacteria in the small intestine of the host.
7.2.3 Typical symptoms of botulism are: double vision, droopy eyelids, wet
mouth and difficulty in swallowing.
7.2.4 The food most likely to be contaminated with Clostridium botulinum
neurotoxins (BoNTs) is home-canned foods.
7.2.5 BoNTs prevent the release of acetylcholine from the nerve end by cleavage
of the acetylcholine receptor.
7.2.6 Infections with Campylobacter jejuni can trigger an autoimmune response
that leads to damage of nerves and may result Guillain-Barre syndrome (GBS).
7.2.7 Non-typhoidal Salmonella are worldwide the leading cause of bacterial
food-borne diarrheal disease.
7.2.8 The Stx toxins of enterohemorrhagic f. coli (EHEC)act as a
rRNA-N-glycosidase leading to ribosome damage that results in shut down
of protein synthesis, apoptosis and cell death.
7.2.9 Enterohemorrhagic f. coli (EHEC)use a type Ill secretion system to inject
virulence factors into eukaryotic host cells.
7.2.10 All known bacteriophage contain dsDNA as genetic material.
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7.3 Name the steps and the required pathogenicity factors of Listeria
monocytogenes in the order they are required along the infection process. (5)
1.
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END OF EXAMINATION