Introduction of Microbiology Practical Examination
As you know, practical builds up your confidence level and therefore it is the 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
- 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) nacteria, pure growth of 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 H2Stests, 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, cover slips, 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, bench top discarding jar, gloves
- For parasitoloy examination: Protozoa- cysts and trophozoites, Helminths- egg, larvae, adult worm, proglotid, Stool specimens containing Ascaris lumbricoides, Entamoeba histolytica, Girdia lamblia, hookworm, Taenia species, Hymenolepsis nana, Enterobious vermicularis, etc.- Normal saline, iodine solution, LPCB stain, tissue paper
- Equipment, instruments and glasswares: 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, Pateur 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 flask (flat-sides bottle), HIV western blot positive strip etc.
- For long practical question, 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 AST pattern of the isolate but it depends on your examiner. For this experiment, all the requirements and accessories will be provided like Gram stain kit, AFB stain kit, KOH solution, biochemical test sets (above mentioned, O-F medium, decarboxylase test medium, extra other 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 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 makes 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). Author tried to cover all the basics of medical/ clinical microbiology for Practicals and Viva in Medical Microbiology.
CLSI: Clinical and Laboratory Standards Institute
CLED agar: Cystine–lactose–electrolyte-deficient agar
SDA: Sabouraud Dextrose Agar
MHA: Mueller Hinton Agar
H2S: Hydrogen sulfide
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