1. SPM – MCQ 26 – Analytical test of choice
2. SPM – MCQ 34 – Best method to compare new test and gold standard test
3. PG Blazer – Online Test Series – Weekly test 1

Histoplasma capsulatum – a dimorphic fungus

(Click on the image to view an enlarged version)

• Fungi which exist in 2 separate morphological forms depending of environmental temperature
  • Yeast form within the body or in cultures at 37C
  • in the soil or in cultures at 22C
• Many fungi causing systemic infections are dimorphic fungi

Examples of dimorphic fungi:

• Histoplasma capsulatum
• Sporothrix schenckii
• Blastomyces dermatitidis
• Coccidioides immitis

1. NEET PG / USMLE – MCQ 8
2. Streptococcus
3. Microbiology – MCQ 77 – Poliovirus

Images: (Mouse over to see thumbnail. Click to see full image – opens in new window)

1. Ancylostoma duodenale and Necator americanus
2. Ancylostoma duodenale – Adult (stained)
3. Necator americanus - Adult (stained)
4. Ancylostoma duodenale – mouth parts
5. Hookworm lifecycle
6. Hookworm egg 400x
7. Cutaneous larva migrans

1. Microbiology – MCQ 59 – Infestation which causes malabsorption
2. Microbiology – MCQ 40 – Parasites causing pulmonary eosinophilia
3. McFadyean’s reaction

1. Pharmacology – MCQ 80 – Antibacterial agents inhibiting cell wall synthesis
2. Pharmacology – MCQ 84 – Antibiotic for MRSA
3. DRACO – the novel broad spectrum antiviral

1. Swine Influenza A pandemic: H1N1 Virus
2. Dermatology – MCQ 6 – Anagen phase of the hair
3. Paediatrics – MCQ 41 – Commonest etiological agent for acute bronchiolitis in infancy

Swine Influenza A manifests with fever, cough, sore throat, body aches, headache, chills, fatigue and sometimes with diarrhea and vomiting. The possibility of Swine Influenza A should be considered in any person who has had contact with cases or travelled to an area with confirmed cases during the preceding 7 days.

Treatment of Swine Influenza A is mainly supportive with rest, fluids, cough suppressants, antipyretics and analgesics. Swine Influenza A (H1N1) virus is susceptible to antivrial agents oseltamivir and zanamivir. Antiviral therapy has to be initiated within 48 hours of onset of symptoms to be effective. Recommended duration of treatment with antiviral agents is for 5 days. Some benefits may be there even if antiviral treatment is started after 48 hours.

The usual influenza vaccine is not effective against Swine Influenza A. Antiviral prophylaxis, both pre exposure and post exposure have been recommended in those at high risk of acquiring the infection.

1. Swine influenza: WHO pandemic alert phase 5
2. Influenza virus was isolated by
3. Human papilloma virus vaccination

Haemophilus influenzae in blood agar

Haemophilus influenzae meningitis

1. Pfeiffer’s bacillus
2. Microbiology – MCQ 73 – 20 year old male with genital ulcer
3. Diseases caused by Haemophilus influenzae

Eaton in 1944 isolated the causative agent of primary atypical pneumonia. It had the capability to pass through bacterial filters and hence was considered to be a virus which was named Eaton agent. Later it was found out that Eaton agent was a bacteria and was named Mycoplasma pneumoniae.

1. Pathology – MCQ 76 – Causes of atypical pneumonia
2. Paediatrics – MCQ 41 – Commonest etiological agent for acute bronchiolitis in infancy
3. Fried egg appearance

Clinical manifestations

• Fever
• headache
• malaise
• sorethroat
• paroxysmal cough
• blood tinged sputum

• Findings on physical examination are minimal
• radiography shows patchy consolidation of lower lobes – starting at hilum, fanning to periphery

Complications

• myringitis bullosa, otitis – common
• rashes
• meningitis
• encephalitis
• hemolytic anemia

Lab diagnosis:

1. Pathology – MCQ 76 – Causes of atypical pneumonia
2. Pathology – MCQ 75 – Viral pneumonia
3. Eaton agent

In bacteriology, it refers to the variation in the structural forms exhibited by a bacteria. Eg: Mycoplasma is a highly pleomorphic bacteria.

1. Eaton agent
2. Fried egg appearance
3. RGUHS Karnataka PGET 2011 – MCQ 168

Mycoplasma colonies:

• biphasic – distinct central and peripheral zones
• central zone – opaque, granular – growth extending into the depth of the medium
• peripheral zone – translucent, flat

Click here to view ‘Fried egg colonies of Mycoplasma’ – Image from an external source – Opens in new window

1. Draughtsman appearance
2. Carrom coin appearance
3. Pneumoccus – cultural characteristics

1. Fried egg appearance
2. Obstetrics & Gynaecology – MCQ 68 – Smallest diameter of true pelvis
3. Eaton agent

1. Wool sorters disease
2. Microbiology – MCQ 11 – A person working in an abattoir presented with a papule on hand, which turned into an ulcer.
3. Safety pin appearance is seen in

Typhus group:

• Epidemic typhus / Classic typhus / louse borne typhus / gaol fever – Rickettsia prowazekii
• Edemic typhus / murine typhus / fleaborne typhus – Rickettsia typhi

Spotter fever group:

• Rocky mountain spotted fever – Rickettsia rickettsii
• Oriental spotted fever – Rickettsia japonica
• Rickettsial pox – Rickettsia akari

1. Weil Felix Reaction
2. Brill-Zinsser disease
3. Medicine – MCQ 149 – Causes of palpable purpura

Invasive diseases are usually caused by capsulated strains. The bacilli are protected from phagocytes by the capsule and spread through blood. The various invasive infections are:

• Meningitis – most common
• conjunctivitis
• laryngoepiglottitis
• pneumonia
• pericarditis
• endocarditis
• arthritis
• bacteremia

Non invasive diseases usually occur as superadded infections and are often caused by non capsulated strains. It spreads locally in the mucous membranes and are associated with respiratory infections. The various conditions include:

• otitis media
• sinusitis
• acute exacerbation of chronic bronchitis, bronchiectasis

1. Diseases caused by Clostridium perfringens
2. Haemophilus influenzae
3. SPM – MCQ 89 – Herd Immunity for infectious diseases

1. Oxidation pond
2. DEC (diethylcarbamazine) provocation test
3. Pleomorphism

1. Swine Influenza A pandemic: H1N1 Virus
2. Orthopaedics – MCQ 35 – Subtrochanteric fractures of femur
3. Swine influenza: WHO pandemic alert phase 5

Wayson stain of Yersinia pestis showing characteristic safety pin appearance

Wayson stain is a modified methylene blue stain used to demonstrate Yersinia pestis for diagnosis of bubonic plague.

1. Safety pin appearance is seen in
2. Causative organism of plague
3. Types of plague

1. Diseases caused by Clostridium perfringens
2. Microbiology – MCQ 43 – Clostridium perfringens spores
3. Surgery – MCQ 16 – Most common complication after ERCP

1. Clostridium welchii
2. Biliary tract infections caused by Clostridium perfringens
3. Microbiology – MCQ 43 – Clostridium perfringens spores

1. Obstetrics & Gynaecology – MCQ 82 – Most common cause of secondary amenorrhoea in India
2. Paediatrics – MCQ 60 – Most common renal cystic disease in infants
3. AIIMS November 2011 – MCQ 132

Clostridium perfringens

Previous name of Clostridium prefringens, an anaerobic, spore forming, gram positive bacilli. It causes many conditions such as gas gangrene, food poisoning, gangrenous appendicitis and necrotising enteritis.

1. Diseases caused by Clostridium perfringens
2. Microbiology – MCQ 43 – Clostridium perfringens spores
3. Organisms producing gas gangrene

Warthin Starry stain demonstrating H.pylori in the gastric mucosa

A silver nitrate stain used as a special stain for demonstrating organisms such as H.Pylori and spirochetes. It is also called Warthin Starry’s silver.

1. Bartonella henselae
2. Pathology – MCQ 40 – Amyloid stain
3. Wayson stain

1. Bartonella
2. Oroya fever
3. Brill-Zinsser disease

1. Warthin Starry stain
2. Surgery – MCQ 29 – A patient has carcinoma of right tongue on its lateral border
3. Bartonella

1. SPM – MCQ 113 – Types of power in management
2. Symptoms of infant botulism
3. Aphakia – Causes, Optics, Clinical features and Treatment

1. Bartonella
2. Rickettsial diseases
3. Trench fever

1. Oroya fever
2. Bartonella
3. Medicine – MCQ 112 – Infective dose of Salmonella typhi

It is also called Carrion’s disease, in honour of Daniel Carrion, a Peruvian medical student who identified the common etiology of verruga peruana and oroya fever.

1. Verruga peruana
2. SPM – MCQ 90 – Child with a history of cough and fever for 4 days
3. Causative organism of Q fever

1. Oroya fever
2. Bartonella
3. Types of skin lesions