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Introduction of Microbiology Practical Examination

As you know, practical builds up your confidence level and therefore it is an integral part of your course of study. The Microbiology Practical Examination will cover the topics from all the parts of microbiology like bacteriology, parasitology, virology, mycology, and immunology. The contents of this examination are given below as requirements. It includes viva voce ( oral examination) and spots or objective structured practical examinations (OSPE).

Requirements for Microbiology Practical Examination

• Chocolate agar
• blood agar
• MacConkey agar
• CLED agar
• SDA
• Robertson’s cooked meat medium
• MHA ( Note- All agar mentioned above should be uninoculated.)
• Blood agar plates having Haemodigestion, hemolysis ( α, ß, and γ),
• CLED agar plates with no growth, non-significant growth (NSG), significant growth (SG), growth of lactose fermenter( LF) bacteria, non-lactose fermenter (NLF) bacteria, pure growth of the organism, mixed growth of organisms
• MacConkey agar plates with lactose fermenter (LF) bacteria, Non-lactose fermenter (NLF) bacteria, late-lactose fermenter (LLF) bacteria
• Sabouraud Dextrose Agar (SDA): Growth of Candida albicans
• Lowenstein-Jensen (LJ) Medium: Growth of Mycobacterium tuberculosis ( avirulent stain)
• Robertson’s cooked medium (RCM): Growth of organisms showing proteolytic ( black), saccharolytic (pink) and non-pigmented
• Gram-stained smear slides- Gram-positive bacilli/rods (GPB/GPR), Gram-negative bacilli or rods (GNB/ GNR), Gram-positive cocci (GPC), Gram-negative cocci (GNC), Gram-stained slide of Candida albicans
• Antimicrobial Susceptibility Testing (AST) plates having growth of following organisms-ATCC 25922 Escherichia coli, ATCC 25923 Staphylococcus aureus, ATCC 27853 Pseudomonas aeruginosa, ATCC 29212 Enterococcus faecalis
• MHA plate having Multidrug-Resistant( MDR) Bacteria
• MHA plate having Multidrug-Resistant( MDR) Bacteria
• MHA plate having Extended-Spectrum Beta-Lactamase-(ESBL)-Producing Bacteria
• MHA plate having growth of Metallo-β-Lactamase (MBL)-Producing bacteria
• MHA plate having Modified Hodge Test (MHT) positive
• Antimicrobial Susceptibility Testing (AST) plates according to CLSI
• Biochemical test set: Triple sugar iron (TSI) agar- Uninoculated, Negative control and positive control for A/A, K/A, K/NC, H₂S, aerogenic ( formation of gas), Sulphide indole motility (SIM) medium- Uninoculated, NC and PC for motility, indole, and H₂S tests, Citrate medium- Uninoculated, NC, PC and test, Urea agar- Uninoculated, NC, PC and test, Oxidase test- oxidase disk, bamboo sticks, Catalase test- 3%H₂O₂(hydrogen peroxide), bamboo sticks, Coagulase test- Fresh plasma, normal saline, clean and grease-free slides, coverslips, dropper.
• A set of biochemical tests for E. coli and Klebsiella pneumoniae.
• Serology/Immunology: Rapid plasma reagin (RPR) test kit-NC, PC, test ( if possible  use positive sample), C-reactive protein (CRP) test kit- NC, PC, test ( if possible  use positive sample), Antistreptolysin O  (ASO) Test kit-NC, PC, test ( if possible use positive sample), Rheumatoid factor (RF) test kit- NC, PC, test ( if possible use positive  sample), HIV rapid test kit-NC, PC, test, HBsAg rapid test kit-NC, PC, test and HCV test kit-NC, PC, test-Micropipettes, tips, tissue paper, benchtop discarding jar, gloves
• For parasitology examination: Protozoa- cysts and trophozoites, Helminths- egg, larvae, adult worm, proglottid, Stool specimens containing Ascaris lumbricoides, Entamoeba histolytica, Giardia lamblia, hookworm, Taenia species, Hymenolepsis nana, Enterobius vermicularis, etc.- Normal saline, iodine solution, LPCB stain, tissue paper
• Equipment, instruments, and glassware: Autoclave, Hot air oven, Bunsen burner, McIntosh-Filde’s jar, Seitz filter, Candle ajar, microtiter plate, latex agglutination tile, Durham tubes, incubator, Universal container, Bijou bottle, Mc Cartney bottle, Pasteur pipette, Tissue culture bottle, LAF chamber, Safety cabinet, NIH swab, Electrophoresis tank, Electrophoresis combs, thermocycler, microscope, densitometer, ELISA reader, RPMI 1640 medium,  etc.
• Miscellaneous- AFB stained slide, MP slide, L-D bodies slide, oocysts of coccidian parasite slide (e.g. oocyst of Cryptosporidium parvum), Fungus, Grocott Methenamine Silver (GMS) Stained slide, viral growth in the flask (flat-sides bottle), HIV western blot positive strip, etc.
• For long practical questions, you will get a specimen either sputum or urine, blood or  CSF, or pus from which you have to isolate and identify the organism. Also, you have to find out the AST pattern of the isolate but it depends on your examiner. For this experiment, all the requirements and accessories will be provided like a Gram stain kit, AFB stain kit, KOH solution, biochemical test sets (above mentioned, O-F medium, decarboxylase test medium, extra others you need), culture plates, antimicrobial disks, and so on.
• Long question sample- A broth is given to you, isolate and identify the organism and also produce its antibiotics sensitivity profile by …. Please do not proceed with another experiment before showing the result of your experiment to your examiner.

Preparation of Microbiology Practical Examination

Microbiology itself is a vast subject, however, tricks and tips make it easier. The above contents are useful for both graduate and post-graduate students ( mainly) of medical microbiology as well as related subject students ( e.g.  MBBS, B.Sc. Nursing, B.Sc. MLT). The author tried to cover all the basics of medical/ clinical microbiology for Practicals and Viva in Medical Microbiology.

Abbreviations

CLSI: Clinical and Laboratory Standards Institute

CLED agar: Cystine–lactose–electrolyte-deficient agar

SDA: Sabouraud Dextrose Agar

MHA: Mueller Hinton Agar

H₂S: Hydrogen sulfide

A: Acid

K: Alkaline

NC: Negative control

PC: Positive control

HIV: Human immunodeficiency virus

HBsAg: Hepatitis B surface antigen

HCV: Hepatitis C virus

LPCB: Lactophenol Cotton Blue

LAF: Laminar Air Flow

NIH: National Institutes of Health

ELISA: Enzyme-linked immunosorbent assay

RPMI: Roswell Park Memorial Institute

AFB: Acid-fast bacilli

MP: Malarial parasite

L-D: Leishmania donovani

KOH: Potassium hydroxide

CSF: Cerebrospinal fluid

O-F: Oxidation fermentation