The following figure denotes India ink preparation of bronchialveolar lavage fluid. Which of the following statement is correct about the organism seen here. (1) Infection follows inhalation of arthroconidia from pigeon feces (2) This characteristic appearance in India ink preparation is due to very thick polypeptide capsule (3) Capsule stains positive by Mucicarmine stain and alcian blue.
- (1) and (2) only
- (1) and (3) only
- (2) only
- (3) only
View Explanation
Cryptococcus is yeast like fungus. pathogenic species inclu
1.C neoformans
- C gratti
Infection follows inhalation of dry yeast cells ( NOT ARTHROCONIDIA) It is found in very large numbers in pigeon droppings.
It usually involves CNS and br lungs. Disease manifestation is in immunocompromised individuals.
CNS = Chronic meningoenchephalitis
Lung = Pulmonary cryptoccocosis
Note: Granulomatous pulmonary mass = Cryptoccocomas are formed by C gratti .
Ciypkcoccus neoformans. because of its large polysaccharide capsule (NOT POLYPEPTIDE], can be visualized by the India stain. The capsular polysaccharide regardless of serotype has a similar structure The capsule is composed primarily of two polysaccharides, glucuronoxylomannan (GXM) and galactoxylomannan (GaIXM), in addition to a smaller proportion of mannoproteins (MP) Most of the studies on the composition of the capsule have focused on GXM. which comprises more than 90% of the capsules polysaccharide mass.
Organisms that possess a polysaccharide capsule exhibit a halo around the cell against the black background created by the India.
Modified method employs 2% chromium mercury and India ink This technique allows a clear identification of some external and internal structures of the organism.
The India Ink test may be used in the presumptive identification of C. neoformans. Culture, biochemical and serological testing is recommended for complete identification.
CAPSULE STAINS POSITIVE BY MUCICARMINE AND ALCIAN BLUE BECAUSE OF PRESENCE OF POLYSACCHARIDE.
