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MMB611S - MEDICAL MICROBIOLOGY 2A - 1ST OPP - JUNE 2022 |
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n Am I BI A u n IVE Rs ITY
OF SCIEnCE Ano TECHnOLOGY
FACULTY OF HEALTH, APPLIED SCIENCES AND NATURAL RESOURCES
DEPARTMENT OF HEALTH SCIENCES
QUALIFICATION: BACHELOR OF MEDICAL LABORATORY SCIENCES
QUALIFICATION CODE: 08BMLS
LEVEL: 6
COURSE CODE: MMB6115
COURSE NAME: MEDICAL MICROBIOLOGY 2A
SESSION:
JUNE 2022
PAPER:
THEORY
DURATION:
3 HOURS
MARKS:
120
FIRST OPPORTUNITY EXAMINATION QUESTION PAPER
EXAMINER(S) Mrs Fredrika Engelbrecht
MODERATOR: Ms Vanessa Tjijenda
INSTRUCTIONS
1. Answer ALL the questions.
2. Write clearly and neatly.
3. Number the answers clearly.
THIS QUESTION PAPER CONSISTS OF 5 PAGES (Including this front page)
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MMB611S MEDICAL MICROBIOLOGY 2A: 1st OPPORTUNITY QUESTION PAPER
JUNE 2022
SECTIONA
(25)
QUESTION 1
[10]
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 and give a reason for calling a statement FALSE.(2 marks allocated to false with a
reason, 1 mark allocated to true)
1.1 70% Ethanol is a more effect antimicrobial agent than 95% ethanol.
1.2 Streptococcus pneumoniae contains active autocatalytic enzymes.
1.3 The declining growth phase of bacteria is the phase in which the bacterial cells die.
1.4 A bacterial urinary tract infection is completely ruled out by a negative nitrite dipstix
result.
1.5 During mixed acid fermentation of bacterial cells, pyruvate is metabolized to a number
of different products.
1.6 DNA-DNA hybridization has been most useful for comparing organisms at or below
specie level.
1.7 Micro-organisms are always causing infection and should be eradicated.
QUESTION 2
[15]
Choose the correct answer and report only the suitable letter next to the relevant question
number.
2.1 End stage kidney disease is associated with the presence of
A) White cell casts.
B) Broad granular casts.
C) Red cell casts.
D) Waxy casts.
[1]
2.2 What organism would you expect to grow in reduced medium?
A) Obligate anaerobes.
B) Organisms that have a requirement for CO2 to grow.
C) Aerobic organisms
D) Organisms with a specific nutrient requirement.
[1]
2.3 Heat resistance of bacterial endospores is believed to be due to
A) Its very resistant cortex.
B) Reduced amounts of water in the core of the spore itself.
C) The shape of the endospore.
D) The structure of the endospore membrane.
[1]
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MMB611S MEDICAL MICROBIOLOGY 2A: 1st OPPORTUNITY QUESTION PAPER
JUNE 2022
2.4 A short course {48hrs) of glycopeptide antibiotic would be used to treat a:
A) 5. aureus infection acquired from an intravenous catheter.
B) Coagulase-negative staphylococcal infection acquired from an intravenous
catheter.
C) Streptococcus infection acquired from an intravenous catheter.
D) E. coli infection acquired from an intravenous catheter.
[1]
2.5 Ketonuria is commonly associated with:
A) Cushing's syndrome.
B)
Liver disease.
C)
Pancreatic disease.
D) Starvation.
[1]
2.6 Bile solubility testing is done by the use of
A) Tryptophanase to check for enzymatic activity.
B) Sodium deoxycholate as check for bile tolerance by the organism.
C) Sodium deoxycholate as bile salt to detect autolytic activity of the
bacteria.
D) Tryptophanase to detect autolytic activity of the bacteria.
[1]
2.7 Extracellular coagulase is tested for by means of
A) Tube coagulase test.
B) Slide coagulase test.
C) Both tube and slide coagulase.
D) Rapid thermonuclease test.
[1]
2.8 Potassium tellurite blood agar is used to identify
A) Enterococcus species.
B) Corynebacterium diphtheria.
C) Haemophillus influenza.
D) Staphylococcus epidermidis.
[1]
2.9 Lithotrophic bacteria can be classified as
A) Bacteria that is unable to use CO2as their sole source of carbon.
B) Requires an organic form of carbon.
C) Use CO2as its sole source of carbon.
D) Bacteria that only survive in aquatic environments.
[1]
2.10 The stationary phase of bacterial growth is when
A) The growth ceases because of exhaustion of essential nutrients.
B) The number of viable cells has plateaued, and the number of new
organisms produced is equal to the number of cells dying.
C) The cells begin to lyse and die.
D) The growth and cell division occur at its maximum rates.
[1]
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MMB611S MEDICAL MICROBIOLOGY 2A: 1st OPPORTUNITY QUESTION PAPER
JUNE 2022
2.11 The Slayer of a bacterial cell
A) Inhibit phagocytosis.
B) Are associated with cell wall stability.
C) Chelate small ions needed for cell function.
D) Determine the bacterial cells competence.
[1]
2.12 The cord factor of mycobacteria is
A) Lipoaabinomannan.
B) A soluble lipid.
C) The muein layer of the cells.
D) A unique mycolic acid.
[1]
2.13 Enriched media can be defined as:
A) Media that suppress the growth of specific bacteria.
B) Media supporting the growth of obligate anaerobes.
C) Media to which additional growth factors have been added.
D) Media supporting the growth of different organisms with morphologically
distinct colonies.
[1]
2.14 Sanitization can be described as:
A) Reduction of the microbial population to levels set by public health
authorities.
B) The prevention of sepsis.
C) The process by which micro-organisms are killed.
D) The process by which microbial spores are destroyed.
[1]
2.15 The mode of action employed by quaternary ammonium compounds is:
A) Inactivation of essential metabolic compounds.
B) Modifying of bacterial DNA.
C) Disrupting of bacterial cell membranes.
D) Denaturing of bacterial proteins.
[1]
.SECTIONB
(39)
QUESTION 3
3.1 Match the following: (1 mark each)
3.1.1 Urinoid odour
3.1.2 Ammoniac odour
3.1.3 Urine with faecal smell
3.1.4 Pungent odour
[11]
A) Alkaline fermentation
B) UTI infection
C) Normal urine
D) Gastointestinal-bladder fistulas
[4]
3.2 Compare in a table form, the functions of selective, differential and enriched media.
[4]
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MMB611S MEDICAL MICROBIOLOGY 2A: 1st OPPORTUNITY QUESTION PAPER
JUNE 2022
3.3 Show, with a drawing, what you would expect to see under the microscope for the
following:
3.3.1 Gram negative diplococci.
[1/2 X 2 = 1]
3.3.2 Gram positive bacilli.
[1/2 X 2 = 1]
3.3.3 Gram variable coccobacilli.
[1/2 X 2 = 1]
QUESTION 4
[10]
4.1 You need to culture a gastro-intestinal specimen for the most commonly isolated
potential pathogens from this site.
4.1.1 Propose a medium that should be used.
[1]
4.1.2 Classify the type of medium you proposed.
[2]
4.1.3 Defend why the medium have these properties.
[7]
QUESTION 5
[18]
5.1 Discuss bacterial nitrate reactions.
[8]
5.2 Explain the principle and the significance of the bile aesculin agar.
[10]
SECTION C
(56)
QUESTION 6
[20]
6.1 Categorise the following media under indicator, selective and/or differential media.
6.1.1 Cystine Lactose Electrolyte Deficient media.
6.1.2 Mannitol Salt agar.
6.1.3 Nagler medium.
6.1.4 Potassium tellurite blood agar.
[7]
6.2 Propose universal safety precautions that need to be considered when working
in a diagnostic medical laboratory.
[8]
6.3 Evaluate the necessity of transmembrane proteins in bacterial cells.
[5]
QUESTION 7
[36]
7.1 Predict how a pathogenic organism can evade the defence systems of the host. [6]
7.2 Defend why Thiosulphate Citrate Bile Sucrose agar is a selective and differential
culture media.
[7]
7.3 Compose a diagram with labels to illustrate the sporulation process.
[12]
7.4 Formulate a standard operating procedure for the preparation of sterile blood
agar plates.
[11]
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TOTAL: 120 MARKS