Category: Image Based Question

A. It is an exclusive human pathogen.

B. Some strains may cause disseminated disease.

C. Acute urethritis is the most common manifestation in males.

D. All strains are highly sensitive to penicillin.

Correct Answer » D Explanation

Ans:All strains are highly sensitive to penicillin.

The micro-organism shown in the photomicrograph above represents Neisseria gonorrhoea.

Neisseria gonorrhoea

• Gonorrhea is a purulent infection of the mucous membrane surfaces caused by Neisseria gonorrhoeae.

• N gonorrhoeae is spread by sexual contact or through transmission during childbirth. It is an exclusive human pathogen.

• In women, the cervix is the most common site of gonorrhea, resulting in endocervicitis and urethritis, which can be complicated by pelvic inflammatory disease (PID). In men, gonorrhea causes anterior urethritis.

• Gonorrhea can also spread throughout the body to cause

• localized(conjuctivitis,arthritis,endocarditis,meningitis) and disseminated disease(disseminated gonococcal infection (DGI)) .

Morphology :

• Gram-negative cocci that typically appear in pairs with the opposing sides flattened (a “kidney bean” appearance).

Treatment:

• Penicillin is ineffective in treatment of gonorrhoea as most of the strains are resistant to penicillin because penicillnase producing N. gonorrhoeae (PPNG) have spread widely.

• For uncomplicated urogenital, anorectal, and pharyngeal gonococcal infection, a drug regimen using ceftriaxone plus either azithromycin or doxycycline may be used.

A. IgE deficiency

B. HLA b27.

C. Complement deficiency .

D. IgA deficiency.

Correct Answer » C Explanation

Ans:C. Complement deficiency

The micro-organism shown in the photomicrograph above represents Neisseria gonorrhoeae.The female patient is suffering from Gonorrhea.

• Morphology of Neisseria gonorrhoeae: Gram-negative cocci that typically appear in pairs with the opposing sides flattened (a “kidney bean” appearance).

• The complement system is an essential component of the innate immune defence against infection by Neisseria (N. Meningitidis and N. gonorrhoeae).

• People who lack or have a deficiency in complement mediated bactericidal activity are most susceptible to neisserial diseases.

• Vaccinations for encapsulated organisms is crucial for preventing infections in complement deficiencies

A. Zoonotic disease.

B. Man to man transmission possible.

C. Agent for bioterrorism.

D. a and c

Correct Answer » D Explanation

Ans:D. Zoonotic Disease and Agent for terrorism.

The micro-organism shown in the photomicrograph above is Bacillus anthracis.

Anthrax

• It is a zoonotic disease caused by Bacillus anthracis

• It is primarily a disease of herbivorous – goats, sheep, cattle, horses etc.

• Human become infected incidentally by contact with infected animals or their products.

• B. anthracis is among the category A pathogens (ie the highest priority pathogens) for bioterrorism.

• Antibiotic therapy is effective in humans, and ciprofloxacin is recommended for the treatment. For prophylaxis ciprofloxacin or doxycycline should be given.

• Bacillus anthracis is very large, Gram-positive, spore-forming rod .

• Microscopic Features:The cells have characteristic squared ends. The endospores are ellipsoidal shaped and located centrally in the sporangium. The spores are highly refractile to light and resistant to staining.

• Mc Fadyean’s reaction is characteristic of Bacillus anthracis.

A. Clostridium tetani.

B. Clostridium perfirengens.

C. Proteus mirabilis.

D. Bacillus anthracis.

Correct Answer » D Explanation

The micro-organism shown in the photomicrograph above represents Bacillus anthracis as it shows bamboo stick appearance.

Bacillus anthracis, the organism that causes anthrax, derives its name from the Greek word for coal, B anthrakis, because of its ability to cause black, coal-like cutaneous eschars.

Bacillus anthracis, a large Gram positive, aerobic, spore bearing bacillus, 1–1.5 × 3–10 μm in size, is the only obligate pathogen within the genus bacillus.The major virulence factors of B anthracis are encoded on two virulence plasmids pXO1 and pXO2.

A. Cl welchii.

B. Cl septicum.

C. Cl novyi.

D. Cl histolyticum.

Correct Answer » A Explanation

The condition shown in the picture above represents gas gangrene.

Most common cause of gas gangrene is Cl perfringens (Cl welchii) causing 80% of cases of gas gangrene.

Other causes are Cl septicum, Cl novyi and Cl histolyticum.

A. Cl welchii.

B. Cl novyi.

C. Cl histolyticum.

D. Klebsiella pneumoniae.

Correct Answer » D Explanation

The micro-organism shown in the photomicrograph above is Klebsiella pneumoniae.

Klebsiella pneumoniae is a Gram-negative, nonmotile, encapsulated, lactose-fermenting, facultative anaerobic, rod-shaped bacterium.

A. E.coli.

B. Klebsiella Pneumoniae.

C. Shigella.

D. Salmonella typhi.

Correct Answer » B Explanation

The test shown in the picture above represents Voges-Proskauer test.

Voges–Proskauer or VP is a test used to detect acetoin in a bacterial broth culture. The test is performed by adding alpha-naphthol and potassium hydroxide to the Voges-Proskauer broth which has been inoculated with bacteria.It is most commonly seen in cases of Klebsiella Pneumoniae.

A. Haemophilus.

B. Streptococcus.

C. Klebsiella.

D. Proteus.

Correct Answer » A Explanation

The phenomenon marked by a white arrow in the picture above represents satellitism,

Satellitism refers to the phenomenon in which certain bacterial species like Haemophilus influenzae grows more vigorously in the immediate vicinity of the colonies of other unrelated species like Staphylococcus aureus which synthesize factor V.

It demonstrates the dependence of H influenzae on the V factor, which is available in high concentrations near the staphylococcal growth and only in smaller quantities away from it.

H influenzae can be isolated on chocolate agar enriched with factor X and V.
The blood used in chocolate agar is heated to inactivate nonspecific inhibitors of H. influenzae growth.

Definitive identification is made by Quellung reaction.

Additional means of identifying encapsulated strains include fluorescent-antibody staining of the organism and counter immunoelectrophoresis or latex agglutination tests, which detect the capsular polysaccharide

A. HemoPhilus influenzae.

B. Bordetella Pertussis.

C. Brucella melitensis.

D. MYcobacterium tuberculosis.

Correct Answer » B Explanation

Bordetella Pertussis is an organism which shows Bisected pearls/ Mercury drops appearance of colonies on Regan-Lowe medium as shown in the photograph above.

B. pertussis is a very small Gram-negative aerobic coccobacillus that appears singly or in pairs. Its metabolism is respiratory, never fermentative, and taxonomically, Bordetella is placed among the “Gram-negative Aerobic Rods and Cocci” in Bergey’s Manual. Bordetella is not assigned to any family.

The bacteria are nutritionally fastidious and are usually cultivated on rich media supplemented with blood. They can be grown in synthetic medium, however, which contains buffer, salts, an amino acid energy source, and growth factors such as nicotinamide (for which there is a strict requirement). Even on blood agar the organism grows slowly and requires 3-6 days to form pinpoint colonies.

Bordetella pertussis colonizes the cilia of the mammalian respiratory epithelium. Generally, it is thought that B. pertussis does not invade the tissues, but some recent work has shown the bacterium in alveolar macrophages.

The bacterium is a pathogen for humans and possibly for higher primates, and no other reservoir is known. Whooping cough is a relatively mild disease in adults but has a significant mortality rate in infants. Until immunization was introduced in the 1930s, whooping cough was one of the most frequent and severe diseases of infants.

A. Granuloma inguinale.

B. Chancroid.

C. Lymphogranuloma venereum.

D. Herpes genitalis.

Correct Answer » B Explanation

Haemophilus ducreyi produce “school of fish”appearance in stained smears.

Haemophilus ducreyi is a fastidious gram-negative coccobacillus bacteria, which causes the sexually transmitted disease chancroid, a major cause of genital ulceration in developing countries characterized by painful sores on the genitalia.