Review of Microbiology & Immunology Apurba Sankar Sastry, Sandhya Bhat K
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fm1Review of Microbiology and Immunology
Sixth Edition Apurba Sankar Sastry MD (JIPMER) DNB MNAMS PDCR Hospital Infection Control Officer Officer in-charge, HICC Antimicrobial Stewardship Lead Assistant Professor Department of Microbiology Jawaharlal Institute of Postgraduate Medical Education & Research (JIPMER) Puducherry, India Sandhya Bhat K MD DNB MNAMS PDCR Vice Dean (Research) Associate Professor Department of Clinical Microbiology Pondicherry Institute of Medical Sciences (PIMS) Puducherry, India
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Review of Microbiology and Immunology
First Edition: 2011
Second Edition: 2012
Third Edition: 2014
Fourth Edition: 2015
Fifth Edition: 2016
Sixth Edition: 2017
fm3Dedicated to
Our Beloved Parents and Family Members
And above all, Lord Ganesha who gave us the knowledge and inspirationfm4fm5
Preface to the Sixth Edition  
Microbiology is one of the high-scoring sections and, hence, is the key subject for PG entrances.
AIIMS Nov 2016
JIPMER Nov 2016
AIIMS May 2016
JIPMER May 2016
AIIMS Nov 2015
JIPMER Nov 2015
AIIMS May 2015
JIPMER May 2015
PGI Nov 2016
JIPMER Nov 2014
PGI May 2016
APPG 2015
PGI Nov 2015
TNPG 2015
PGI May 2015
MHPG 2015
ALL INDIA 2016 (According to Syllabus)
DNB 2016 (According to Syllabus)
Each Chapter Contains
Changes Done Compared to the Previous Edition
Chapter Review (Theory portion) Part
MCQ Part
One Weapon-Two Targets: 2nd Year MBBS Exams and PG Entrance
This revised edition is prepared in such a manner that it will help the 2nd year MBBS students to prepare for their MBBS exam as well as for the PG entrances. The chapter review part of each chapter is revised and updated in such a way that by studying this book, the students can easily solve the long essays, short notes of MBBS exams as well as MCQs of various PG entrances.
Apurba Sankar Sastry
Sandhya Bhat K
fm6Golden Tips for Your Exam Preparation  
Study Methodology – Antegrade vs Retrograde
Students will always be in a dilemma whether to follow antegrade or retrograde methodology for preparation.
Tips for Your Preparation
Target-oriented Labor
Repeated Revisions
Repeated revisions rather than reading extensively without any revision — Crucial Factor
Survey conducted at various coaching centers and medical colleges:
Performance in Exam
Rank in All India
< 1000
Methods to Improve Your Memory
  • Try to correlate the things and remember rather than purely mugging up
  • Group study or couple study
  • Recalling every night
  • Booster revisions: Should be done before you totally forget the matter (i.e. in short-interval)
  • Mnemonics: Good but should be limited.
Regularly Assess Yourself
Most of the students assess their preparation directly at the exam hall which is absolutely worst method of assessing. You should assess your standard on daily basis and modify your preparation style according to the requirement. You can do that by:
  • Group study: Comparing yourself with your friends.
  • Self-assessment by recalling every night (last two hours post dinner)
  • Grand test: Assess whether studying is reflected in the performance or not. You can compare yourself with students throughout India.
Role of Grand Test
  • Helps in assessing yourself
  • Any trials and errors can be attempted in grand tests and whichever experiment is successful can be executed in main exam
  • To learn time adjustment
  • To enhance guessing ability
  • To improve self-confidence
  • To compare your performance with others.
Weekdays (Self-study) vs Weekend Study (Coaching Center)
  • Coaching institute is the place where you will be trained with the entrance-oriented important aspects of the subjects.
  • However, students attending coaching institutes are getting 50 to 60 days less for their preparation as compared to the other students who prepare at home.
  • fm7You should never waste the time gap (i.e. weekdays) between classes.
  • You will never get time to revise if you have not covered the last subject before the next subject starts.
Last 100 Days
  • Accelerate near the slug overs: Last 100 days of study are very crucial—because the students’ survey has shown that 80% of what you will answer correctly in the exam depends upon the last 2 to 3 months’ study.
  • Never leave any subject: Be master in your area but, at the same time, cover at least average of the uncovered area as MCQs will be asked from all the subjects.
  • Sleeping well the previous night: Increases your efficiency at least by 10%.
  • Do not forget the importance of time: Once lost, it can never be recycled.
Be an Early Riser
As wisely quoted by Benjamin Franklin “Early to bed and early to rise makes a man healthy, wealthy, and wise.”. Remember what you read during early morning (3 am-6 am), will stimulate your memory cells maximum and will be retained longer. More so, there will be no disturbance as compared to late night reading where other friends/TV shows/parties or the whole day tiredness etc. will disturb you a lot.
My Trick to Get up Ealry
  • Sleep early (10 pm)
  • Keep three alarms, 5 min gap
  • Keep alarm away from cot
  • Brush and make tea before go to read
  • Never start a fresh chapter, as you will have starting problem which will induce sleep
  • Always read a chapter continued from yesterday's reading.
While Writing PG Exam ...... The Following Things are to be Kept in Mind
  • Time management
  • Guess ability:
    • By correlating the things
    • By ruling out the options
  • Guess only in 50–50 situation (two or three options are ruled out)
  • Never guess when you can rule out only one or zero options.
Students Choose a PG Seat—either ‘by Choice’ or ‘by Chance’
  • By choice (similar to love marriage): Take your dream PG seat (this happens only when you get a desired rank). Only a few blessed students fall under this category.
  • By chance (similar to arranged marriage): Take the available PG seat (this happens when you get a rank, but not good enough to get your choice subject). Most of the students will fall under this category.
If you have a rank but not good enough to get your choice subject, you have two options:
  • Take what is available
  • Wait for the next year.
This is again a controversial situation. Many have opinions in both the categories.
  • Some say that you can enjoy the subject only if it is your dream subject.
  • Some say that you should not waste time in waiting as there is no guarantee that you will do better in the next exam and in the current online multisession exam pattern, the situation is highly uncertain.
Best Way to Solve this issue is
Try to see the difference between love marriage and arranged marriage.
  • There is no guarantee that in love marriage, you will not fight and you will have a peaceful life.
  • Love is there in arranged marriage also, but it is created after marriage.
Our advice as time is precious:
  • Never wait for long to get your desired subject.
  • Develop interest in the subject that you choose.
  • Do justice with your subject in your three years of PG course.
  • And, in turn, the subject will give you name, fame and prosperity throughout your life.
  • If you dislike the subject, then it will end up in divorce (i.e. you will leave the course or will live throughout).
Keep in touch with us through the FB discussion group and personal touch via FB messanger or mail.
Apurba Sankar Sastry
Sandhya Bhat K
Our efforts bore fruit with the successful completion of this project ‘Review of Microbiology and Immunology’ 5th edition. However, there are many others who share the reward of this effort simply because it would never have been this good without their help. It gives us great pleasure to acknowledge the contribution of those who guided, supported and stood by us through the arduous journey of completing this tedious work.
We also offer our gratitude to some of the students who constantly gave their inputs and support during the correction and editing of the book.
  1. Dr Ramya Raghavan, JIPMER
  2. Dr Prasanna Bhat, JIPMER
  3. Dr Suryaprakash, Stanley Medical College, Chennai
  4. Salman Mapara, Grant Medical College and Sir Jamshedjee Jeejeebhoy Group of Hospitals
  5. Manish Choudhary, Kasturba Medical College, Manipal
  6. Sunil Chillalshetti, Belgaum Institute of Medical Sciences
  7. Akshi Malhotra, JIPMER
  8. Manjula Gunasekaran, PSG Institute of Medical Sciences and Research
  9. Priyanka Patra, SKNMC pune
  10. Praveen G, Melmaruvathur Adhiparasakthi Institute of Medical Sciences and Research, Tamil Nadu
  11. Aarti Chitkara, Sir Maharaja Agrasen Medical College, Haryana
  12. Ashwath Vh, Adichunchanagiri Institute of Medical Sciences, Karnataka
  13. Raja Suman Datta, GSL Medical College, Rajahmundry, Andhra Pradesh
We are grateful to Shri Jitendar P Vij (Group Chairman), Mr Ankit Vij (Group President), Ms Chetna Malhotra Vohra (Associate Director), Ms Payal Bharti (Project Manager), Mr Ravinder (Typesetter), Mr Himanshu Shekhar Lal (Proofreader) and all the other members of Jaypee Brothers Medical Publishers (P) Ltd, New Delhi, India for giving us this wonderful opportunity of writing this book and their excellent support throughout the journey, especially during the editing work on Apurba Sastry's Microbiology discussion.
IPV and bOPV in India
  • IPV introduced in India: from November 2015
  • Bivalent OPV will be introduced in India: from April 2016
IPV in India
  • Government of India introduced IPV under universal immunization program
  • From November 2015
  • One dose of IPV
  • In a phased manner
  • In the first phase, IPV has been introduced in six high-risk states: Assam, Gujarat, Punjab, Bihar, Madhya Pradesh, and Uttar Pradesh
  • This IPV dose is extra; given over and above the Trivalent OPV.
Indian Government Action Plan: Switchover of tOPV to bOPV and IPV
  • From November 2015 to March 2016: Three doses of trivalent OPV plus one dose of IPV along with the third dose of OPV at 14 weeks.
  • From April 2016: Bivalent OPV three doses plus one dose of IPV along with the third dose of bOPV at 14 weeks.
  • Tuberculosis:
    • TRC: Tuberculosis Research Centre, Chennai
    • LRS Institute of Tuberculosis & Respiratory Diseases, Delhi
    • National Institute of Tuberculosis, Bengaluru
    • National JALMA Institute of Leprosy and Other Mycobacterial Diseases, Agra
  • Leprosy: National JALMA Institute of Leprosy and Other Mycobacterial Diseases, Agra
  • Salmonella:
    • National salmonella reference centre for identification of unusual serotype: Central Research Institute (CRI), Kasauli
    • Reference centre for salmonella of animal origin: Indian Veterinary Institute, Izatnagar
    • Reference centre for phage typing: Lady Hardinge Medical College, Delhi
  • BCG vaccine prepared in India: BCG Vaccine Laboratory, Guindy, Chennai
  • Yellow fever vaccine: Central Research Institute (CRI), Kasauli
  • Plague vaccine: Haffkine Institute, Mumbai
  • Reference centre for phage typing of Staph. auerus in India: Maulana Azad Medical College, Delhi
  • Cholera: National Institute of Cholera and Enteric Diseases (NICED), Kolkata
  • VDRL antigen is prepared in India: Institute of Serology, Kolkata
  • National Institute of Virology, Pune: Prepare diagnostic kits for Hepatitis viruses, JE, Dengue, Chikungunya and Rotavirus
  • NARI (National AIDS Research Institute): Pune
  • Leptospirosis Reference Laboratory: Regional Medical Research Institute (RMRI), Port Blair
MMR + 2Pox
Hepatitis viruses
19 d
15–45 d
P. vivax
14 d
9–90 d
10 d
30–180 d
P. falciparum
12 d
1–14 d
14 d
15–160 d
P. malariae
28 d
2–7 d
12 d
30–180 d
P. ovale
17 d
1–4 wks
15 d
14–60 d
8–16 months
3 d–6 wk
Other viruses
1–4 months
Gas gangrene
5–6 d
1–3 m
Cl. perfringens
10–48 hr
5–6 d
7–14 d
2–6 d
Cl. septicum
2–3 d
3–8 d
10 yrs (Average)
7–14 d
Cl. novyi
5–6 d
Japanese encephalitis
5–15 d
Infectious mononucleosis
4–8 wks
6–10 d
Yellow fever
3–6 d
18–72 hrs
3–5 yrs
Bubonic &
2–7 d
1–2 d
1–3 d
10–14 d
Female: anopheles: Malaria
Aedes: Dengue, Chikungunya, Yellow fever
Culex: JE, Filaria (Lymphatic)
Trench fever (Bartonella quintana),
Epidemic relapsing fever (Borrelia recurrentis),
Epidemic typhus, Pediculosis
Bubonic plague,
Endemic typhus,
Hymenolepis diminuta
Hard Tick
Tick typhus,
Arbo (KFD, RSSE, Crimean-Congo hemorrhagic fever, Colorado tick fever),
Babesia, Tularemia
Soft Tick
Endemic relapsing fever (B. duttoni),
Q-fever (in animals)
Scrub typhus,
Rickettsial pox,
Guinea worm disease,
Fish tapeworm (D. latum)
Black fly
Reduviid bug
Chaga's disease
Enteric pathogens—for Salmonella, Shigella
Hektoen enteric agar (S) Xylose-lysin-deoxycholate agar (S)
Deoxycholate citrate agar (S) Eosin methylene blue agar (S)
MacConkey (D and S) Salmonella Shigella agar (S)
Wilson blair for Salmonella (S) Selenite F broth (En), Tetrathionate broth (En)
Blood culture—for blood-borne pathogens
Castaneda's biphasic media (E): Brain-heart infusion agar slope and broth
Vibrio cholerae (likes alkaline growth medium)
TCBS (Thiosulfate Citrate Bile Sucrose agar) (S)
Mansour's Gelatin Taurocholate Trypticase agar (S)
Alkaline bile salt agar (S)
APW: Alkaline Peptone Water (En)
Mannitol salt agar (S)
Milk salt agar (S)
Ludlam's medium (S)
Crystal violet blood agar (S)
Chocolate agar (E), Thayer-Martin media (S),
Modified New York medium (S)
Loeffler's serum medium (E)
Potassium tellurite agar (S)
Bacillus anthracis
PLET: Polymyxin Lithium EDTA Thallous acetate (S)
Bacillus cereus
MYPA: Mannitol egg yolk phenol red polymyxin agar (S)
Thioglycollate (En)
Robertson cooked meat broth (En)
PALCAM agar (S)
Cetrimide agar (S), King's media (for pigment)
Ashdown's medium
Blood agar with staph streak (E)
Chocolate agar (E)
Levinthal's medium (E), Fildes agar (E)
Regan low media (E)
Bordet Gengou Glycerin potato blood agar (E)
Lacey's DFP media (S)
Lowenstein Jensen, Dorset egg (S)
EMJH (E), Fletcher's (E), Korthof's (E)
Skirrow's, Butzler, Campy BAP (S)
BCYE (Buffered charcoal yeast extract) (E)
Reiter's treponema
Smith Noguchi media
Urinary pathogen
MacConkey agar (D and S)
Cystein Lactose Electrolyte-deficient agar (CLED agar) (D and S)
Transport media
Pike's media
Amies, Stuart's media
VR, Autoclaved sea water, Carry Blair
Enteric pathogen
Carry Blair medium
Shigella, Salmonella
Buffered glycerol saline
Modified Stuart's (with casamino acid)
Mischulow's charcoal agar
Dacron or calcium alginate swab used
fm16Image-Based Questions  
  1. Eminent microbiologists in past:
    1a. Antonie van Leeuwenhoek, 1b. Louis Pasteur, 1c. Robert Koch, 1d. Paul Ehrlich
  2. Cell wall: Differences between Peptidoglycan layer of:
    • 2a. gram-positive cell wall and
    • 2b. gram-negative cell wall. (Refer chapter review 1.1 for detail).
  3. Culture media:
    3a. Peptone water, 3b. Nutrient agar, 3c. Blood agar, 3d. Chocolate agar
  4. Culture media:fm17
    • 4a. Lowenstein–Jensen medium (LJ Medium)
    • 4b. TCBS agar (Thiosulfate-citrate-bile salts-sucrose agar)
  5. Blood culture media:
    • 5a. Brain-heart infusion (BHI) broth (Monophasic medium)
    • 5b. Brain-heart infusion (BHI) broth and agar (Biphasic medium)
  6. Antimicrobial Susceptibility Test
    • 6a. Kirby Bauer Disk diffusion method on Muller Hilton agar
    • 6b. Epsilometer or E-test for MIC detection
  1. Staphylococcus aureus:
    • 7a. Gram stain: Gram positive cocci in cluster
    • 7b. Nutrient agar: Golden yellow pigmentation
    • 7c. Blood agar: Pin head colonies with narrow zone of beta hemolysis
    • 7d. Mannitol salt agar: Yellow colonies due to mannitol fermentation
    • 8a. Catalase positive for all staphylococci (negative for all streptococci)
    • 7e. Tube Coagulase test positive for S.aureus
    • 7f. Slide Coagulase test positive for S.aureusfm18
  2. Staphylococcus saprophyticus:
    • 8a. Catalase positive
    • 8b. Tube Coagulase test negative
    • 8c. Resistant to novobiocin
    • 7f. Slide Coagulase test negative
  3. Streptococcus pyogenes (Group A):
    • 8a. Catalase negative (positive in all staphylococci)
    • 9a. Gram positive cocci in chain
    • 9b. Blood agar: Pin point colonies with wide zone of beta hemolysis
    • 9c. Sensitive to Bacitracin disk
      Streptococcus agalactiae (Group B):
    • 8a. Catalase negative (positive in all staphylococci)
    • 9a. Gram positive cocci in chain
    • 9b. Blood agar: Pin point colonies with wide zone of beta hemolysis
    • 9d. CAMP test positive (Arrow head shaped β hemolysis at junction of S.aureus and S.agalactiae)fm19
  4. Enterococcus
    • 10a. Gram-positive oval cocci in pairs (Spectacle eyed appearance)
    • 10b. Translucent nonhemolytic (γ hemolytic) colonies on blood agar;
    • 10c. Bile aesculin agar (right-positive for Enterococcus, black color due to aesculin hydrolysis, left-negative for other organisms)
  5. Viridans streptococci
    • 11a. Gram-positive cocci in long chains
    • 11b. Alfa hemolytic pin point colonies on blood agar
  6. Streptococcus pneumoniae:
    • 8a. Catalase negative (positive in all staphylococci)
    • 12a. Gram-positive cocci in pair, lanceolate shaped surrounded by a clear halo (capsule)
    • 12b. Alfa hemolytic draughtsman shaped colonies on blood agar
    • 12c. Right tube: Clear in bile indicates Bile soluble (Left tube as negative control: Turbidity indicates bile insoluble)
    • 12d. Sensitive to optochinfm20
  7. Neisseria
    • 13a. Gram-negative diplococci, lens shaped: Indicates Neisseria meningitidis
    • 13b. Gram-negative diplococci, kidney shaped: Indicates Neisseria gonorrhoeae
  8. Corynebacterium diphtheriae:
    • 14a. Albert stain shows dark blue metachromatic granules at the ends of V or L shaped green bacilli arranged in cuneiform pattern (Indicates Corynebacterium diphtheriae)
    • 14b. Palisade arrangement of gram-positive bacilli indicates Diphtheroids (Non diphtheritic Corynebacterium species)
    • 14c. Potassium tellurite agar shows black colonies (selective media for C.diphtheriae)
    • 14d. Loeffler's serum slope (Enriched media for C.diphtheriae)
    • 14e. Grey white Pseudomembrane over tonsils
    • 14f. Bull neck appearance classically seen in diphtheria
  9. Bacillus anthracis:
    • 15a. Malignant pustule seen in Cutaneous Anthrax
    • 15b. Gram stain: Gram-positive bacilli with non-bulging spores (Bamboo stick appearance)
    • 15c. McFadyean reaction: Amorphous purple capsule surrounding blue bacilli (polychrome methylene blue stain)
    • 15d. Medusa head appearance colonies on nutrient agar (10 × magnification)
    • 15e. Non hemolytic dry wrinkled colonies on blood agar
    • 15f. Inverted fir tree appearance on gelatin stab agarfm21
  10. Types of spores (bulging spores) of various clostridia species:
    • 16a. Oval and central spores, (e.g. Clostridium bifermentans)
    • 16b. Subterminal spores, (e.g. Clostridium perfringens)
    • 16c. Spherical and terminal spores (e.g. Clostridium tetani)
    • 16d. Oval and terminal spores (e.g. Clostridium tertium)
  11. Robertson cooked meat broth:
    • 17a. Uninoculated
    • 17b. Pink and turbid (Saccharolytic) (Clostridium perfringens)
    • 17c. Black and turbid (Proteolytic) (Clostridium tetani)
  12. Clostridium difficile
    • 18a. Endoscopic image of pseudomembranous colitis, showing yellow pseudomembranes seen on the wall of the sigmoid colon;
    • 18b. Histopathology (H and E stain) of colonic pseudomembrane in Clostridium difficile colitis
  13. Clostridium perfringens:
    • 19a. Right leg showing Gas gangrene
    • 19b. Gram-positive bacilli without spore
    • 19c. Target hemolysis of Clostridium perfringens: Zone of incomplete hemolysis (blue arrow) and zone of complete hemolysis (black arrow)
    • 19d. Positive Nagler reaction (Opalescence on egg yolk agar due to α toxin which is inhibited by adding anti α toxin antisera to media)
    • 19e. Reverse CAMP test (Arrow head shaped hemolysis at junction of C. perfringens and S. agalactiae pointing towards C. perfringens)fm22
  14. Clostridium tetani:
    • 20a. Sustained spasms of the facial muscles- Risus sardonicus.
    • 20b. Muscular spasms in a patient suffering from tetanus- Opisthotonus
    • 20c. Gram-positive bacilli with drum stick appearance spores (terminal and round bulging spores)
    • 20d. Swarming on blood agar
    • 17c. Robertson's cooked meat broth- growth is indicated by turbidity & blackening of meat particles
  15. Actinomyces:
    • 21a. Actinomycosis (painless, slow-growing, hard mass with cutaneous fistula), caused by A. israelii
    • 21b. Branching gram-positive filamentous bacilli (indicates Nocardia and Actinomyces)
    • 21c. Gomori's stained smear showing sun-ray appearance (Sulfur granules of Actinomyces)
    • 21d. Partially acid fast branching filamentous bacilli indicates Nocardiafm23
  16. Mycobacterium tuberculosis:
    • 22a. Ziehl Neelsen stain (25% sulfuric acid): Long slender, beaded, acid fast bacilli
    • 22b. Auramin phenol stain shows fluorescent acid fast bacilli
    • 22c. Loweinsetin Jensen medium: Rough, tough and buff colonies of M. tuberculosis.
  17. Mycobacterium leprae:
    • 23a. ZN stain (5% sulfuric acid): Shows cigar like bundles of acid fast bacilli arranged in globi
    • 23b. Nodular lesions of lepromatous leporsy
    • 23c. Hypopigmented skin lesions of tuberculoid leprosy (arrows showing)
    • 23d. Deformities seen in untreated lepromatous leprosy: A. Left to right showing Saddle nose deformity; Bony deformity and Corneal opacity
  18. Common biochemical tests:
    • 24a. Catalase test
      • Positive: Bubbles appear when drop of 3% H2O2 is added, e.g. Staphylococcus and family Enterobacteriaceae
      • Negative: No Bubbles on addition of drop of 3% H2O2, e.g. Streptococcus
    • 24b. Oxidase test (positive indicates purple color, negative indicates no color change)-e.g. +ve (Psuedomonas, Vibrio)
    • 24c. Indole test: Cherry red color ring on the top of the broth indicates +ve, yellow colorled ring indicates negative (Following addition of Kovac's reagent)
    • 24d. Citrate test: Positive test indicates medium color is blue in color, negative indicates medium color is green
    • 24e. Urease test: Positive test indicates medium color is pink, negative indicates medium color is pale.fm24
  19. 25. Triple sugar iron test (TSI):
    Reactions in TSI
    No Change in slant/butt (fig 25a)
    Uninoculated media
    Acidic slant/acidic butt
    A/A, gas produced, no H2S (fig 25b)
    ≥ 2 sugars fermented (Glucose plus Lactose and/or Sucrose)
    Examples, Escherichia coli, Klebsiella pneumoniae
    Alkaline slant/acidic butt
    Only glucose fermenter group
    K/A, no gas, no H2S (fig 25c)
    K/A, no gas, H2S produced (small amount), fig 25d
    K/A, no gas, H2S produced (abundant), fig 25e
    Proteus vulgaris
    K/A, gas produced, H2S produced (abundant)
    S. Paratyphi B
    K/A, gas produced, no H2S
    S. Paratyphi A
    Alkaline slant/alkaline butt
    Non fermenters group
    K/K, no gas, no H2S (fig 25f)
    Pseudomonas, Acinetobacter
  20. Escherichia coli:
    • 26a. MacConkey agar: Lactose fermenting pink & flat colonies
    • 26b. ICUT: Indole (positive), Citrate (negative), Urease (negative), TSI: A/A, gas produced, no H2S
  21. 27. Klebsiella pneumoniae:
    • 27a. MacConkey agar: Large, Mucoid, Lactose fermenting pink colonies
    • 27b. ICUT: Indole (negative), Citrate (positive), Urease (positive), TSI: A/A, abundant gas produced, no H2Sfm25
  22. Proteus vulgaris:
    • 28a. Blood agar shows swarming
    • 28b. ICUT: Indole positive (Negative for Proteus mirabilis), Citrate-negative, Urease positive, TSI: K/A, no gas, H2S produced (abundant)
  23. Serratia marcescens: Produces reddish-orange pigment called prodigiosin.
  24. Yersinia pestis:
    • 30a. Swollen inguinal lymph node (bubo)
    • 30b. Gangrene of the toes, turned the dead digits black (black death)
    • 30c. Wayson stain shows bipolar/safety pin appearance bacilli
    • 30d. Rat flea (Vector for plague)
  25. Vibrio cholerae:
    • 31a. Gram stain shows Coma shaped gram-negative bacilli (Fish in stream appearance)
    • 31b. TCBS media: Media (green colored) with yellow colored colonies due to sucrose fermentation
    • 31c. Blood agar showing hemodigestion
    • 31d. String test positivefm26
  26. Nonfermenters
    • 32a. Blue green pigmentation (diffuse) on nutrient agar: Pseudomonas aeruginosa
    • 32b. Bipolar staining of Burkholderia
    • 32c. Ashdown medium of Burkholderia showing dry wrinkled colonies
  27. Haemophilus influenzae:
    • 33a. Blood agar showing Satellitism: Colonies of H.influenzae are larger adjacent to the streak line of S.aureus
    • 33b. Pleomorphic gram-negative bacilli
    • 33c. Colonies of H. influenzae on chocolate agar
  28. Bordetella pertussis:
    • 34a. Child suffering from whooping cough
    • 34b. Mercury drop colonies on Regan low media
    • 34c. Gram stain shows gram-negative coccobacilli (thumb print appearance)fm27
  29. Syphilis (Manifestations):
    • 35a. Painless indurated hard genital ulcer of primary syphilis
    • 35b. Skin rashes of secondary syphilis
    • 35c. Condylomalata at mucocutaneous junction of secondary syphilis
    • 35d. Mucosal patches of secondary syphilis
  30. Treponema pallidum (Direct Microscopy)
    • 36a. Dark ground microscope
    • 36b. Direct fluorescent antibody staining (DFA-TP)
    • 36c. Fontana stain (Silver impregnation method)
  31. VDRL (Venereal Disease Research Laboratory) test:
    • 37a. VDRL concavity slide
    • 37b. VDRL test interpretation – Presence of clumps indicates reactivefm28
  32. Borrelia and Leptospira:
    • 38a. Giemsa stained peripheral smear showing: Borrelia
    • 38b. Erythema migrans seen in Lyme disease
    • 38c. Dark ground microscopy showing Leptospira (more no. of spirals with hooked ends)
  33. Bartonellosis
    • 39a. Enlarged lymph node of cat-scratch disease
    • 39b. Lesion of Bacillary angiomatosis
    • 39c. Verruga peruana
  34. Chalmydia and Mycoplasma
    • 40a. Chlamydia elementary bodies (coarse granules within vacuoles)
    • 40b. Chlamydia trachomatis inclusion bodies (brown) in a McCoy cell-line culture
    • 40c. Fried egg appearance colony of Mycoplasma
  35. Miscellaneous:
    • 41a. Clue cells (Vaginal epithelial cells studded with numerous coccobacilli) indicates bacterial vaginosis.
    • 41b. H. pylori: Left-Endoscopy shows duodenal ulcer due to H. pylori (arrow showing), Right-Warthin-Starry staining showing H. pylori (black curved rods) colonized on the gastric mucosa
    • 41c. Legionella: Left: Gram-staining; Right. Growth on BCYE agar
    • 41d. Donovanosis: Left-. Beefy red ulcer; Right: Donovan bodies: Cyst-like macrophages filled with deeply stained capsulated bacilli having a safety-pin appearance (Giemsa stain)fm29
  1. Cultivation of virus:
    • 42a. Embryonated egg used for viral cultivation: Routes of inoculation
      • Chorioallantoic membrane (CAM): Used for Vaccinia, variola produce pocks
      • Yolk sac: Used for Arbovirus, Chlamydia, Rickettsia
      • Amniotic sac: Used for culture of Influenza from clinical sample
      • Allantoic cavity: Used for vaccine preparation of Influenza, Yellow fever (17D), Rabies (Flury)
    • 42b. Chorioallantoic membrane showing pock like lesions
    • 42c. Tissue culture flask containing viral culture medium
  2. Viral inclusion bodies:
    • 43a. Negri body (Rabies)
    • 43b. Molluscum body (Molluscum contagiosum virus infection)
    • 43c. Multinucleated giant cell of measles
    • 43d. Tzank smear (Multi nucleated giant cells with faceted nuclei; Suggestive of HSV infection)
    • 43e. Cytomegalic host cell containing characteristic Owl's eye inclusion bodies (CMV)fm30
  3. Electron microscopy picture of:
    • 44a. Rabies, bullet shaped
    • 44b. Rotavirus, wheel shaped
    • 44c. Ebola virus, filamentous shaped
    • 44d. Poxvirus, dumbbell shaped
    • 44e. Adenovirus, space vehicle shaped
    • 44f. Hepatitis B virus, showing three forms: spherical form, tubular form and dane particle
    • 44g. Corona virus showing club shaped peplomers
  4. Schematic Diagram of viruses
    • 45a. Hepatitis B virus
    • 45b. Human Immunodeficiency Virus (HIV)
  5. Clinical Manifestations of Viral diseases
    • 46a. Oral hairy leukoplakia of the tongue
    • 46b. Kaposi sarcoma of the hard palate
    • 46c. Vesicular rashes of smallpox
    • 46d. Vesicular rashes of chickenpox
    • 46e. Molluscum contagiosum lesion: Pearly white wart like nodule with a dimple at the center
    • 46f. Slapped cheek appearance in Parvovirus infection (5th disease)
    • 46g. Parotitis in a mumps virus infected child
    • 46h. Koplik's spot in buccal mucosa (Measles)
    • 46i. Measles Rashes
    • 46j. Deformities in poliomyelitis
    • 46k. Atypical T lymphocytes seen in infectious mononucleosis
  1. Superficial Mycoses
    • 47a and b. Tinea versicolor
      • 47a. Painless noninflammatory, nonpruritic hypopigmented lesions
      • 47b. Scrapping of the lesions show cluster of yeast cells and intervening hyphae giving rise to sphagetti and meatball appearance
    • 47 c and d. Piedra
      • 47c. Arthrospores of Trichosporon beigelii (white piedra)
      • 47d. Black nodule on hair shaft (black piedra)
  2. Dermatophytosis
    • 48a. Favus (Cup like crust formation in scalp)
    • 48b. Kerion (Painful inflammatory boggy lesion of scalp)
    • 48c. Tinea faciei (Infection of the nonbearded area of face)
    • 48d. Tinea pedis (Infection of the web space between the toes)
  3. Dermatophytes (Microscopic picture, LPCB mount):
    • 49a. Trichophyton- Microconidia- plenty, tear drop shaped, Macroconidia- rare, pencil shaped
    • 49b. Microsporum- Microconidia- rare, Macroconidia- plenty, rough walled, spindle shaped
    • 49c. Epidermophyton- Microconidia- absent, Macroconidia- plenty, smooth walled, club shaped.fm33
  4. Mycetoma:
    • 50a. Lesion: Swelling with multiple sinuses in a patient with Actinomycetoma
    • 50b. Eumycetoma: Black grain and cement like substance
    • 50c. Actinomycetoma with branching bacilli at the margin of the grains (H and E staining)
  5. Sporothrix schenckii:
    • 51a. Yeast form: Cigar shaped yeast cells (asteroid body)
    • 51b. Mould form: Hyphae with flower like sporulation
  6. Rhinosporidium: Spherules containing sporangia filled with numerous endospores
  7. Systemic mycoses:
    • 53a and b. Histoplasma: 53a. Yeast form shows 4–6 μm yeast cells with narrow based budding
    • 53b. Mould form shows tuberculate macroconidia
    • 53c. Blastomyces: Yeast form shows 8–15 μm yeast cells with broad based budding (Figure of 8 appearance)
    • 53d and e. Coccidioides: 53d. Yeast form shows Spherules, 53e-Mould form shows fragmented hyphae (arthroconidia)
    • 53f and g. Paracoccidioides: 53f. Yeast form shows Mickey mouse and 53g.Yeast form shows pilot wheel appearance.fm34
  8. Candida albicans:
    • 54a. Phenotypic switching of Candida: Between yeast, pseudohyphae and hyphae
    • 54b and c. Candidiasis, b. Oral thrush, 54c.Onychomycosis
    • 54d. Gram stain: Shows gram-positive budding yeast cells with pseudohyphae
    • 54e. SDA culture: Creamy white dry colonies
    • 54f. CHROM agar showing colonies of various Candida species producing different colors (e.g. light-green color by C. albicans, red arrow)
    • 54g. Candida albicans shows positive germ tube test (arrow showing)
    • 54h. Candida albicans shows thick walled chlamydospores (arrow showing)
  9. Cryptococcus neoformans:
    • 55a. Modified India ink stain showing refractile, delineated and unstained capsule against a black back ground and budding yeast cells.
    • 55b. SDA culture: Creamy white mucoid colonies
  1. Zygomycosis (Clinical Manifestations)
    • 56a. Orbital cellulitis and 56b. proptosisfm35
  2. Zygomycetes- microscopic appearance (Schematic):
    Reveals broad aseptate hyaline hyphae, from which sporangiophore arises and then ending at sporangium which contains numerous sporangiospores. Some species bear a unique root like growth arising from hyphae called
    Rhizoid. Depending on the position of the rhizoid with respect to sporangiophore, members of Zygomycetes can be differentiated.
    • 57a. Rhizopus bears nodal rhizoid
    • 57b. Absidia bears inter-nodal rhizoid
    • 57c. Mucor: rhizoid is absent.
  3. Zygomycetes (SDA culture and LPCB Mount)
    • 58a. SDA culture of Rhizopus- Cottony wooly colonies with salt pepper appearance
    • 58b. LPCB mount of the colonies of Rhizopus (Microscopic appearance)
    • 58c. LPCB mount of the colonies of Mucor (Microscopic appearance)
  4. Hyphae description of Zygomycetes - Histopathology of tissue section shows aseptate broad hyphae (Methenamine silver stain)
60–63 Aspergillus
  1. Hyphae description of Aspergillus (H and E stain): Septate, narrow, with acute angle branching. (However, in LPCB mount appears as hyaline septate hyphae)
  2. Microscopic appearance (Schematic) of various Aspergillus species
  3. SDA Culture: Macroscopic colony appearance of various Aspergillus species
  4. LPCB Mount (Microscopic appearance) of various Aspergillus species
    A. fumigatus
    A. flavus
    A. niger
    Macroscopy of colony
    Smoky green, velvety to powdery, reverse is white
    Yellow green, velvety,
    reverse is white
    Black, cottony type, reverse is white
    Microscopic appearance of colony (LPCB mount)
    Vesicle is conical-shaped.
    Phialides are arranged in single row
    Conidia arise from upper third of vesicle
    Conidia are hyaline
    Vesicle is globular shaped
    Phialides in one or two rows
    Conidia arise from entire vesicle
    Conidia are hyaline
    Vesicle is globular shaped
    Phialides in two rows
    Conidia arise from entire vesicle
    Conidia are black
  5. Penicillium species
    • 64a. Colonies on SDA: Flat colonies with velvety to powdery texture and greenish in color
    • 64b. Microscopic picture (LPCB mount): Hyaline thin septate hyphae with conidia arranged in brush border appearance. Vesicles are absent.
    • 64c. Schematic microscopic picture
  6. Penicillium marneffei
    • 65a. Gomori's Methenamine silver (GMS) staining shows yeast cells with central septations
    • 65b. Red pigmented colony (mould form) on SDA
  7. Pneumocystis jirovecii (GMS stain): Shows black cysts against green back ground.
  8. Fusarium species (LPCB mount): Arrows showing sickle shaped macroconidia, and chlamydospore
  1. Entamoeba:
    • 68a and b. E.histolytica: 68a. Trophozoite (15–20 μm with finger like pseudopodia), 68b. cyst (12–15 μm, 4 nuclei)
    • 68c and d. E. coli: 68c. Trophozoite (20–25 μm with blunt pseudopodia), 68d. cyst (15–25 μm, 1–8 nuclei)
  2. Free living amoeba:
    • 69a and b. Acanthamoeb: 9a. Trophozoite (with thorn like pseudopodia), 69b. cyst (outer wrinkled cyst wall)
    • 69c and d. Naegleria: 69c. Amoeboid Trophozoite and 69d. flagellated trophozoite
  3. Giardia lamblia:
    • 70a and b. Trophozoite: 15–20 μm in Size, contains 2 nuclei, 2 adhesive disk and four pairs (eight flagella), 70a. front view-pear shaped, 70b. lateral view-sickle/spoon shaped
    • 70c and d. Cyst: 70c. 10–14 μm Size, oval, contains axostyle and 4 nuclei. Saline mount, 70d. Iodine mount.
  4. fm38Trichomonas vaginalis: Contains five flagella (4 anterior, 1 recurrent flagella supported by undulating membrane) and 1 nucleus
  5. Leishmania donovani:
    • 72a. LD body: Amastigotes inside macrophage
    • 72b. Promastigotes in culture fluid
  6. Trypanosoma cruzi in blood smear (Trypomastigote form)
  7. Acid fast stain showing Coccidian parasites
    • 74a. Cryptosporidium parvum: 4–6 μm size, round, uniformly acid fast, contains four sporozoites
    • 74b. Cyclospora cayetanensis: 8–12 μm size, round, variably acid fast, contains two sporocysts each bearing two sporozoites
    • 74c. Isospora belli: 23–36 μm size, oval, uniformly acid fast, contains two sporocysts each bearing four sporozoites.
  8. Toxoplasma gondii
    • 75a. Comma shaped tachyzoites in blood smear
    • 75b. Tissue cyst in organ biopsy
  9. Balantidium coli
    • 76a. Mayer's hematoxylin stain shows trophozoite with cilia and macronucleus and micronucleus
    • 76b. Iron hematoxylin stain shows cyst with macronucleus and micronucleus.
77–79 Plasmodium
  1. Plasmodium (Peripheral blood smear)
    • 77a. P. vivax (ring form): Ring form occupies 1/3rd of RBC, parasitized RBC size is enlarged
    • 77b. P. falciparum (ring form): Multiple ring forms, and accolle form, RBC size is normal
    • 77c. P. malariae (ring form): Band forms, RBC size is normal
    • 77d. P. ovale (ring form): RBC size enlarged, oval and fimbrinated margin
    • 77e. P. falciparum (gametocyte form): Banana shaped
    • 77f. Non falciparum (gametocyte form): Round shaped
    • 77g. Schizont of P.vivax: 12-24 merozoites/schizont
  2. fm40Plasmodium (QBC examination) showing 78a. rings forms (brilliant green color dots in side faint RBC) and 78b. gametocytes (banana shaped) of P. falciparum
  3. Morphological forms of various Plasmodium species (Schematic): Refer chapter review 6.4 for details
    Fig. 79: Morphological forms of various Plasmodium species (Schematic)
  4. Cestodes Eggs:
    • 80a. Egg of Taenia: Contains egg shell and oncosphere with three pair of hooklets
    • 80b. Operculated Egg of Diphyllobothrium latum
    • 80c. Egg of Hymenolepis nana: non bile stained, contains polar filaments between two egg shell membranes, oncosphere with three pairs of hooklets.
  5. Taenia saginata vs Taenia solium (For detail, refer chapter review of chapter 6.6)
    • 81a and b-Scolex and segment of Taenia saginata
    • 81c and d-Scolex (with hooklets) and segment of Taenia solium
  6. Cystecerus cellulosae in brain biopsy
  7. Hydatid cyst
    • 83a. Gross specimen of Hydatid cyst
    • 83b and c. Microscopic picture of Hydatid cyst (83b-brood capsule, 83c-trilaminated cyst wall)
  8. Schistosomes (adult worms): The thin female resides in the gynecophoric canal of the thicker male
  9. Trematodes eggs:
    • 85abc. Eggs of Schistosoma: Species differentiation can be done by locating the spine. Terminal spine in S.hematobium (85a), Lateral spine in S.mansoni (85b) and rudimentary lateral spine in S.japonicum (85c)
    • 85d. Operculated Egg of Fasciola hepatica
    • 85e and f. Operculated Egg of Paragonimus: 85e. saline mount, 85f. H & E stain
    • 85g. Flask shaped, Operculated Egg of Clonorchis sinensis
    • 85h. Flask shaped, Operculated Egg of Opisthorchis viverrinifm42
  10. Nematode eggs:
    • 86a. Egg of Trichuris 50–54 μm × 22–23 μm Size, Barrel shaped, mucus plugs at both the ends, bile stained.
    • 86b. Egg of Enterobius 50–60 μm long × 20–30 μm wide Size, planoconvex, bile non stained, contains fully developed larva inside.
    • 86c. Egg of Hookworm 60 × 40 μm Size, oval, segmented ovum with four blastomeres, bile non stained.
    • 86d. Fertilized egg of Ascaris 50–70 μm × 40–50 μm Size, round to oval, surrounded by thick albumin coat, bile stained.
    • 86e. Unfertilized egg of Ascaris 90 μm × 45 μm Size, rectangular and elongated, albumin coat is thin/lost, bile stained.
  11. Rhabditiform Larva of Strongyloides: 250 μm long × 16 μm width. They have a short mouth (buccal cavity), a double bulb esophagus and prominent, large genital primordium.fm43
  12. Microfilaria:
    • 88a. Microfilaria of Wuchereria bancrofti: 240–300 μm long, sheathed, tail tip is pointed and free of nuclei.
    • 88b. Microfilaria of Brugia malayi: 220 μm long, sheathed, tail tip is blunt and nuclei extended till the tail tip and two widely spaced nuclei are present at the tail tip.
  1. WHO's Five Moments of Hand Hygiene
  2. Biomedical Waste related images: Biohazard Symbol, Cytotoxic Hazard Symbol, Biomedical Waste Bags
  3. Steps of Hand rub and Handwash
Fig. 89: WHOs five moments of hand hygiene
Fig. 90: Biomedical Waste related images
Fig. 91: Steps of Hand rub and Handwash
fm44Image Based Questions 2016
  1. In the following Gram stained specimen, identify the bacteria seen?        (AIIMS Nov 2016)
    1. Neisseria gonorrhoeae
    2. Staphylococcus aureus
    3. Streptococcus pyogenes
    4. Hemophilus influenzae
    Ans. (a) (Neisseria gonorrhoeae) Ref: Apurba Sastry's Essentials of Medical Microbiology/p240
    • Intracellular Gram negative kidney shaped diplococcic- Suggestive of gonococci
  2. A 15 year old boy presented with fever and chills for 3 days. On examination he was found to have delayed skin pinch time and dry oral mucosa. A peripheral blood smear revealed the following picture. Identify the pathogen involved?        (AIIMS Nov 2016)
    1. Plasmodium falciparum
    2. Babesia
    3. Plasmodium vivax
    4. Plasmodium ovale
    Ans. (a) (P.falciparum) Ref: Apurba Sastry's Essentials of Medical Parasitology/p106
    • History of fever with and chills, along with peripheral blood smear showing multiple ring forms and double dot ring forms inside RBCs- Suggestive of falciparum malaria.
  3. The following are images of an intestinal nematode. Which of these are true about it?     (AIIMS Nov 2016)
    1. Filariform larvae is infective for humans as shown in the diagram
    2. Transmitted usually through contaminated food and water
    3. Females of these species show parthenogenesis
    4. Triclabendazole is the drug of choice
    Ans. (b) (Transmitted usually through contaminated food and water) Ref:Apurba Sastry's Essentials of Medical Parasitology/p225
    This is a picture of adult male and female worms of Trichuris.
    • Trichuris is transmitted by consumption of food and water contaminated with eggs.
    • Mebendazole or albendazole is safe and moderately effective for treatment of trichuriasis.
  4. A patient with benign hypertrophy of prostate was admitted in the hospital for 3 weeks. He subsequently developed suspected catheter associated-urinary tract infection. The tip of the catheter was sent for culture and was grown on blood agar. After 24 hours, the blood agar shows the following appearance. What is the likely causative agent for the UTI? (AIIMS Nov 2016)
    1. Proteus mirabilis
    2. Pseudomonas
    3. Escherichia coli
    4. Klebsiella pneumoniae
    Ans. (a) (Proteus mirabilis) Ref: Apurba Sastry's Essentials of Medical Microbiology/p309
    Blood agar with swarming motility is suggestive of Proteus.
  5. What Treponema is seen in the silver impregnation micrograph below:       (AIIMS Nov 2016)
    1. Borrelia burgdorferi
    2. Leptospira interrogans
    3. Treponema pallidum
    4. Ehrlichia chaffeensis
    Ans. (b) (Leptospira interrogans) Ref: Apurba Sastry's Essentials of Medical Microbiology/p385
    • Spirally coiled bacilli with hooked ends and more no. of spirals (tightly coiled spirals)- suggestive of Leptospira.
  6. Egg with single knob, hooks polar filaments. What is the correct statement?         (AIIMS MAY 2016)
    1. Treatment of choice is albendazole
    2. Disease transmitted by uncooked pork
    3. Both adult and larva stages of parasite are seen in host
    4. Transient diarrhoea cured spontaneously
    Ans. (c) (Both adult and larva…) Ref: Apurba Sastry's Essentials of Medical Parasitology/p186
    • H.nana transmission occurs to man by Ingestion food and water contaminated egg → egg develops to larva → Larva develops to adult → adult undergoes self fertilization and produce eggs→ Eggs are released in feces
    • Both adult and larval stages are seen in human intestine. (Correct statement).
    • H.nana infection is not self-limiting. Treatment is needed.
    • Drug of choice for this condition is Praziquantel and Niclosamide
  7. A 23 year old male presented with abdominal pain and bloody diarrhoea of one week duration. The following colonoscopic biopsy is diagnostic of infection with:        (AIIMS MAY 2016)
    1. Giardiasis
    2. Amoebiasis
    3. Enterobius
    4. Severe bacterial infection
    Ans. (b) (Amoebiasis) Ref: Apurba Sastry's Essentials of Medical Parasitology/p32
    History of bloody diarrhoea, tiny round trophozoites seen in colonoscopic biopsy confirms the diagnosis as Intestinal amoebiasis.
  8. fm46A 40 year HIV positive male patient comes with odynophagia and watery diarrhoea. An endoscopy reveals esophageal and gastric candidiasis. A wet mount of the stool of the patient reveals following picture: What is true about this helminth?(AIIMS MAY 2016)
    1. Filariform larvae is infective for humans as shown in the diagram
    2. Usually transmitted through contaminated food and water
    3. Females of these species show parthenogenesis
    4. Drug of choice is Triclabendazole
    Ans: (c) (Females of these species shows parthenogenesis) Ref: Apurba Sastry's Essentials of Medical Parasitology/p239-241
    The stool mount above is showing severe infestation with Strongyloides Rhabditiform Larvae.
    The infective stage is Filariform larvae only.
    It is usually transmitted through skin (skin penetration)
    In human intestine, male Strongyloides do not exist, only females exist who reproduce asexually by parthenogenesis.
    Drug of choice of strongyloidiasis is Ivermectin.
  9. The following pap smear shows infestation by:
    1. Trichomonas         (AIIMS MAY 2016)
    2. Candida
    3. Herpes simplex virus Type II
    4. Actinomyces
    Ans. (d) (Actinomyces) Ref: Apurba Sastry's Essentials of Medical Microbiology/p292-93
    Pelvic actinomycosis is a rare complication of use of intrauterine devices, presented in PAP smear as ball- like clusters of branching bacilli, which have radiating filaments.
  10. A 23 year old female presents with fever and altered sensorium for two days with the following rash on legs. Her BP is 70/50 mm Hg and neck stiffness is present. Lumbar puncture reveals cloudy turbid CSF with 4200 cells/uL, Protein level 168 and Glucose of 21 mg/dL. Which of the following correctly describes the organism causing this condition? (AIIMS MAY 2016)
    1. Gram Negative Diplococci (kidney shaped), Oxidase positive
    2. Gram Negative Diplococci, ferments glucose and maltose
    3. Gram Positive cocci catalase negative, bacitracin sensitive
    4. Gram Positive Diplococci (lanceolate), catalase negative, optochin sensitive
    Ans. (b) (Gram Negative diplococcic, ferments glucose and maltose) Ref: Apurba Sastry's Essentials of Medical Microbiology/p236
    The clinical history of meningitis with a typical purpuric rash is seen in Meningococcal infection. Meningococci are Gram Negative diplococci, ferment glucose and maltose both, in contrast to gonococci which ferment only glucose.
  11. Gram stain shows most likely which organism:
    1. Neisseria meningitidis      (AIIMS MAY 2016)
    2. Staphylococcus aureus
    3. Streptococcus pneumoniae
    4. Streptococcus pyogenes
    Ans. (c) (S.pneumoniae) Ref: Apurba Sastry's Essentials of Medical Microbiology/p232,15
    Gram positive cocci in pair, lanceolate shaped with a halo (i.e. capsule) is suggestive of Streptococcus pneumoniae.
fm47Image Based Questions 2015
  1. Which of the following structures is required in the microscope for taking this type of image?
            (AIIMS May 2015)
    a. Dark field condenser
    b. Phase plate
    c. Dichroic mirror
    d. Cathode ray tube
    Ans. (c) (Dichroic mirror) Ref: Apurba Sastry's Essentials of Medical Microbiology 1/e p 12
    • The given image is a Fluorescence microscopy photograph. The components of a fluorescence microscope are a light source (e.g. mercury lamp), the excitation filter, the dichroic mirror and the emission filter.
    • The exciting rays then get reflected by a dichromatic mirror in such a way that they fall on the specimen which is priorly stained by fluorescent dye. Then the specimen is focused under the microscope.
    • Other options:
      • Dark field condenser- required for Dark field microscope
      • Phase plate-required for Phase contrast microscope
      • Cathode ray tube- required for Electron microscope.
  2. Image depicted below belongs to which of the following?         (AIIMS Nov 2015)
    a. Brugia malayi
    b. Wuchereria bancrofti
    c. Loa loa
    d. Onchocerca
    Ans (a) (Brugia malayi) Ref: Apurba Sastry's Essentials of Medical Parasitology 1/e p264
  3. Which is the mode of transmission and infective form of the parasite whose egg picture is given below?
    1. Ingestion of uncooked/raw beef (AIIMS Nov 2015)
    2. Ingestion of egg contaminated in water
    3. Penetration by filariform larva
    4. Penetration by rhabditiform larva
    Ans. (b) (Ingestion of egg contaminated in water) Ref: Apurba Sastry's Essentials of Medical Parasitology 1/e p226
    This is the egg of Trichuris trichiura. It spreads by ingestion of egg contaminated in water.
  4. Histopathological image given below belongs to which of the following fungus?      (AIIMS Nov 2015)
    a. Blastomyces
    b. Histoplasma
    c. Coccidioides
    d. Paracoccidioides
    Ans. (a) (Blastomyces) Ref: Apurba Sastry's Essentials of Medical Microbiology 1/e p564
    Yeast cells with Broad based budding (Figure of 8 appearance) is seen in yeast form of Blastomyces.
  5. A female with pruritus and vaginal discharge. Identify the organism shown in the wet mount of vaginal discharge?      (AIIMS Nov 2015)
    a. Gonorrhea
    b. Chlamydia
    c. Gardnerella vaginalis
    d. Trichomonas vaginalis
    fm48Ans. (c) (Gardnerella vaginalis) Ref: Apurba Sastry's Essentials of Medical Microbiology 1/e p368
    This image belongs to clue cell (vaginal epithelial cells studded with numerous coccobacilli). These cells are seen in bacterial vaginosis caused by Gardnerella vaginalis
  6. The image given below belongs which of the following organism?       (AIIMS Nov 2015)
    a. Cryptococcus
    b. Candida
    c. Histoplasma
    Ans. (a) (Cryptococcus) Ref: Apurba Sastry's Essentials of Medical Microbiology 1/e p570
    It is a negative staining (India ink) showing capsule of Cryptococcus neoformans.
  7. The insect given in the image below is vector of which of the following disease?       (AIIMS Nov 2015)
    a. JE
    b. Trypanosomiasis
    c. KFD
    d. Visceral leishmaniasis
    Ans. (d) (Visceral Leishmaniasis) Ref: Apurba Sastry's Essentials of Medical Parasitology 1/e p317
    This photograph belongs to Sandfly and it is the vector of Leishmaniasis
    Identification features of Sandfly:
    • Head contains pair of long, slender and hairy antennae, palpi and a proboscis
    • Thorax contains pair of wings and three pair of legs
    • Abdomen has ten segments. Body and wings are covered by dense hair
    • Though winged, they only hop about and do not fly, have longer legs
    • They bite during night and only female bite; the males live on fruit juices.
    Diseases transmitted by sandfly:
    • Visceral leishmaniasis
    • Sand-fly fever (Papatasi fever/3 days fever)
    • Oriental sore
    • Oroya fever (Carrion's disease).
  8. A 30-year-lady with 3 months history of progressive breathelessness and dyspnea was evaluated. Chest X ray showing cavitary lesion in lower lobe of lung. Lobectomy was done and histopathology shows the following image, identify the agent and how many layers it will have?         (AIIMS Nov 2015)
    1. Echinococcus with 2 layers
    2. Entamoeba with 1 layer
    3. Lung fluke with 1 layer
    4. Strongyloides with 2 layers
    Ans (a) (Echinococcus with 2 layers) Ref: Apurba Sastry's Essentials of Medical Parasitology 1/e p181
    • This is picture of hydatid cyst. The cyst wall of hydatid cyst is bilayered (ectocyst and endocyst).
    • There is also a host derived outer pericyst layer.
  9. The life cycle given below is shown by which of the following virus?         (AIIMS Nov 2015)
    1. JE (Japanese encephalitis) virus
    2. Swine flu virus
    3. West nile virus
    4. Hendra virus
    fm49Ans. (a) (JE virus) Ref: Apurba Sastry's Essentials of Medical Microbiology 1/e p488
    JE virus has two transmission cycles:
    • Pigs → Culex → Pigs
    • Ardeid birds → Culex → Ardeid birds
  10. The schematic image of peripheral blood smear belongs to which of the following Plasmodium species?         (AIIMS Nov 2015)
    1. Plasmodium vivax
    2. Plasmodium falciparum
    3. Plasmodium ovale
    4. Plasmodium malariae
    Ans. (a) (Plasmodium vivax) Ref: Apurba Sastry's Essentials of Medical Parasitology 1/e p99
    Features in favour of P. vivax include: Enlarged RBC, enlarged ring form which turns amoeboid shape in late trophozoite stage, schizont containing 12–24 merozoites.
  11. The gram stain image given below belongs to which of the following organism?      (AIIMS Nov 2015)
    a. Nocardia
    b. Streptococcus
    c. Corynebacterium
    d. Mycobacterium tuberculosis
    Ans. (b) (Streptococcus) Ref: Apurba Sastry's Essentials of Medical Microbiology 1/e p227
    The image shows pus cells and gram-positive cocci in chain: Suggestive of Streptococcus.
  12. The gram stain image given below belongs to which of the following organism?       (AIIMS Nov 2015)
    a. Nocardia
    b. Streptococcus
    c. Corynebacterium
    d. Mycobacterium tuberculosis
    Ans. (a) (Nocardia) Ref: Apurba Sastry's Essentials of Medical Microbiology 1/e p295
    Branching Gram positive bacilli: Suggestive of Nocardia.
  13. A patient prsents with genital ulcer. Ulcer biopsy reveals the following image. Which is the causative organism:         (AIIMS Nov 2015)
    a. Klebsiella granulomatis
    b. Haemophilus ducreyi
    c. Chlamydia trachomatis L1-L3
    d. N. gonorrheae
    Ans. (a) (Klebsiella granulomatis) Ref: Apurba Sastry's Essentials of Medical Microbiology 1/e p367
    This picture shows Donovan body (macrophage filled with bipolar stained bacilli). This forms are seen in donovanosis which is caused by Klebsiella granulomatis.
  14. Women presented with dome-shaped warty lesions with a dimple at center on forehead since 2 months, similar lesions noticed in her daughter (image given) causative agent?         (AIIMS Nov 2015)
    a. Poxvirus (Molluscum contagiosum)
    b. Human Herpes virus 6
    c. Papilloma virus
    d. Coxsackie virus
    Ans. (a) Poxvirus (Molluscum contagiosum) Ref: Apurba Sastry's Essentials of Medical Microbiology 1/e p454
    Dome shaped warty lesions with a dimple at centre is suggestive of Molluscum contagiosum.
  15. An athlete complains of itching and redness in the groin region. The clinical photograph is given below. All of the following can be cause Except?
             (AIIMS Nov 2015)
    a. Trichophyton
    b. Microsporum
    c. Epidermophyton
    d. Aspergillus
    Ans. (d) (Aspergillus) Ref: Apurba Sastry's Essentials of Medical Microbiology 1/e p555
    It is a case of dermatophyte infection (tinea cruris).
  16. Based on the picture depicted above, the following are True statements EXCEPT:       (APPG 2015)
    1. The patient would have a past history of varicella
    2. Commonest and most troublesome complication is neuralgia
    3. Early treatment with valaciclovir 1 gram TID is helpful
    4. Ramsay Hunt syndrome includes similar lesions on the ophthalmic division of V nerve and cornea
    Ans. (d) (Ramsay Hunt syndrome..) Ref: ApurbaSastry's Essentials of Medical Microbiology 1/e p439
    • The vesicular rashes shown in the picture could be suggestive of zoster.
    • Zoster patient will have a past history of varicella and the commonest complication seen is neuralgia.
    • When geniculate ganglion of facial nerve (VIIth cranial nerve) gets affected in patients with Zoster which leads to Ramsay Hunt syndrome (rash of the skin of the ear canal, auricle and/or oropharynx mucosa)
  17. Identify this organism:         (APPG 2015)
    a. Sarcoptes scabei
    b. Trichinella spiralis
    c. Trichomonas vaginalis
    d. Malassezia furfur
    Ans. (a) (Sarcoptes scabei) Ref: Apurba Sastry's Essentials of Medical Parasitology 1/e p 319
    Identification features of Itch mite/Sarcoptes scabei:
    • Very small in size, body is rounded above and flattened below
    • The body surface is covered with short bristles
    • It has two pairs of legs in front, and two pairs behind
    • The front legs have suckers at the end and the hind legs have long bristles
    • Disease caused: scabies.
  18. Which one of the following is most likely diagnosis of the picture of cervix depicted above in this woman with leukorrhea?         (APPG 2015)
    a. Carcinoma cervix
    b. Gardnerella infection
    c. Candidal infection
    d. Trichomonas vaginalis infection
    Ans. (d) (T. vaginalis infection) Ref: Apurba Sastry's Essentials of Medical Parasitology 1/e p56
    The depicted picture is Strawberry appearance of vaginal mucosa (Colpitis macularis) is observed
    in 2% of patients infected with Trichomonas vaginalis. It is characterized by small punctate hemorrhagic spots on vaginal and cervical mucosa.
  19. This patient came with this complaint one month after an extramarital sexual contact. He has no pain and is indurated. Which one of the following statements is TRUE?       (APPG 2015)
    1. He is likely to develop arthritis of the knee
    2. A single dose of 2.4 million units of benzathine penicillin IM is the treatment
    3. It is caused by Hemophilus ducreyi
    4. fm51Examination of the groin will reveal a characteristic Groove Sign
    Ans. (b) (A single dose..) Ref: Apurba Sastry's Essentials of Medical Microbiology 1/e p373
    H/o extramarital sexual contact, pain less and indurated genital ulcer- is suggestive of primary syphilis:
    • Syphilis is caused by Treponema pallidum (Haemophilus ducreyi causes Chancroid)
    • Benzathine penicillin (IM, single dose) is the treatment of choice in primary syphilis
    • Arthritis of the knee is a complication of gonococcal infection
    • Groove Sign is seen in LGV
  20. Identify this mosquito?         (APPG 2015)
    a. Mansonoides
    b. Anopheles
    c. Culex
    d. Aedes
    Fig. 110:
    Ans. (b) (Anopheles) Ref: Apurba Sastry's Essentials of Medical Parasitology 1/e p316, Vector Control WHO manual, 1997, 425 p.
    Points in favor of Anopheles are: (i) Eggs laid singly, (ii) larva resting parallel to water surface, (iii) adult- proboscis and body are at same straight line
  21. Features of Anopheles mosquito:        (PGI Nov 2014)
    1. Spots on wings
    2. Lay eggs in cluster
    3. Body at angle
    4. Palpi as long as proboscis
    Ans. (a) (c) (d) (Spots on wings, Body at angle, Palpi as long as proboscis) Ref: Apurba Sastry's Essentials of Medical Parasitology 1/e p316
    • Culexlay eggs in clusters called rafts where a Anopheles eggs are laid singly.
    • The maxillary palpi of Anopheles- are as long as proboscis
    • The body of Anopheles- rests at an angle to the surface
    • Anopheles has dark spots on wings.
    • Identification features of Anopheles, Culex, and Aedes mosquitoes
      Identification features
      Anopheles mosquito
      Culex mosquito
      Aedes mosquito
      General identification features of mosquito
      Body is slender and rests with an angle to the surface
      Body rests parallel to the surface
      Head is slightly bent downward and body shows a hunch back at rest
      Have dark spots
      Unspotted and has white markings on legs and abdomen (hence named as tiger mosquito)
      Hind legs
      Held outstretched
      Curled up over the back
      Held curled upwardfm53
      Proboscis and body
      Proboscis and body is in same straight line
      Proboscis is and body at an angle to one another.
      Proboscis and body at an angle to one another
      Maxillary palpi
      Maxillary palpiare as long as proboscis (both sexes)
      Maxillary palpi are shorter than proboscis (females)
      Maxillary palpi are shorter than proboscis (females)
      Tip of the abdomen
      Biting time
      Each species has specific peak biting hours and there are also variations in their preferences for biting indoors or outdoors.
      Day time
      Important species
      A culiofacies,
      A fluviatis, A minimus,
      A stephensi
      C. fatigans,
      C. tritaeniorhyachurs
      C. tarsalis
      A. aegypti
      Vector of diseases
      Malaria encephalitis
      Bancroftian filariasis
      West Nile fever
      Japanese encephalitis
      Yellow fever
      Chikungunya fever
      Rift Valley fever
Image Based Questions 2016
  1. An immunosupressed patient is presented with features of encephalopathy. Blood smear examination reveals the image given below. Indentify the parasite?
    1. Toxoplasma         (Recent Question 2013)
    2. Sarcocystis
    3. Plasmodium
    4. Trypanomsoma
    Ans. (a) (Toxoplasma) Ref: Paniker's parasitology 7/e p91, Apurba Sastry's Essentials of Medical Parasitology,p/123-4
    Clue for diagnosis:
    • Immunosupressed patient, features of encephalopathy.
    • Blood smear shows coma shaped tachyzoites
  2. A 3-year-child with malnutrition, chronic diarrhoea and malabsorption. Stool examination shows the parasite as given in the picture.        (Recent MCQ 2013)
    1. Ascairs
    2. Giardia lamblia trophozoite
    3. Necator americanus
    4. Entameoba histolytica
    Ans. (b) (Giardia lamblia trophozoite) Ref: Paniker's parasitology 7/e p31, Apurba Sastry's Essentials of Medical Parasitology, p50-52
    Clue for diagnosis:
    • Child with malnutrition, chronic diarrhoea and malabsorption. Stool examination shows- tear drop shaped trophozoites with two sucking disk and two nuclei and eight flagella.
  3. A 25-year-old man with painless ulcer on penis. He has h/o contact with commercials sex worker. Dark ground microscopy of the discharge from the lesion has be shown in the picture. Identify the disease.
            (Recent Question 2103)
    a. Chancre
    b. Chancroid
    c. Herpes
    d. Granuloma inguinale
    Ans. (a) (Chancre) Ref: Ananthanarayan 9/e p372, 373
    Clue for diagnosis:
    • Painless ulcer on penis, h/o contact with commercial sex worker, Dark ground microscopy showing spirally coiled bacilli......... Suggestive of Treponema pallidum
  4. Urethral smear from a 30-year-old male is cultured and the following colonies are grown. Identify the agent?        (Recent Question 2013)fm54
    a. Mycoplasma
    b. Chlamydia
    c. Mobilincus
    d. Trichomonas
    Ans. (a) (Mycoplasma) Ref: Ananthanarayan 9/e p387
    Clue for diagnosis:
    • Case of urethritis, fried egg colonies on culture.
  5. A patient has diarrhea for 3 days. Acid fast stained smears made from stool samples as given in the picture. Identify the pathogen?  (Recent Question 2013)
    a. Cyclospora
    b. Isospora
    c. Cryptosporidium
    d. Cryptococcus
    Ans. (b) (Isospora) Ref: Paniker's parasitology 7/e p94, Apurba Sastry's Essentials of Medical Parasitology p134
    Clue for diagnosis- Acid fast stained of stool sample shows oval oocysts of Isospora of 20-30μm size.
  6. A patient has painful tiny vesicular ulcers on lips. Tzank smear was made from the scrapping of the lesion. Identify the pathogen?   (Recent MCQ 2013)
    1. Varicella zoster
    2. Herpes simplex
    3. Parvovirus
    4. HPV
    Ans. (b) (Herpes simplex) Ref: Ananthanarayan 9/e p470
    Clue for diagnosis- Painful tiny vesicular ulcers on lips, Tzank from the scrapping of the lesion shows multinucleated giant cells.
  7. A patient has suddenly developed agitation, anger and hyperactive after weeks of dog bite. The dog was found dead, brain biopsy of the dog is shown in the picture. Identify.    (Recent MCQ 2013)
    1. Negri body
    2. Molluscum body
    3. Torres body
    4. Paschen body
    Ans. (a) (Negri bodies) Ref: Ananthanarayan 9/p 534
    Clue for diagnosis- Patient has suddenly developed agitation, anger and hyperactive after weeks of dog bite.............. Suggestive of suspicion of Rabies.
    Brain biopsy from the Dog- shows Negri bodies