Cryptococcus. var. gattii, var. neoformans and var. grubii.

It details information regarding fungal disease. Cryptococcus is encapsulated yeast, found in soil contaminated with pigeon droppings or eucalyptus trees and decaying wood.
Cryptococcus neoformans grows easily in pigeon feces, however the birds are not naturally infected. Among these, Cryptococcus neoformans is the only species that is pathogenic to humans.
Other species are Cryptococcus albidus, Cryptococcus laurentii, Cryptococcus terreus, Cryptococcus uniguttulatus, Cryptococcus luteolus and Cryptococcus gastricus.
It has four serotypes (A to D). Serotyping is based on capsular agglutination reactions. The two varieties, neoformans and gattii are morphologically similar, except that basidiospores of var. neoformans are round and those of var. gattii are more elliptical in shape.
Cryptococcus neoformans serotype A is responsible for the majority of human cases. Major virulence factors- The polysaccharide capsule
The phenoloxidase enzyme
The organism's ability to grow at 37°C
Phospholipase enzymes
It produces urease.
Cryptococcosis or European blastomycosis or Torulosis or Busse-Buschke’s disease. The clinical types of cryptococcosis are pulmonary, CNS, visceral, osseous, cutaneous and mucocutaneous. Patients with AIDS, carcinoma, leukemia, collagen vascular disease, Hodgkin’s disease, sarcoidosis and those undergoing immunosuppressive therapy are at increased risk of cryptococcosis.

1. Cryptococcus

2. Cryptococcus
Cryptococcus is encapsulated yeast, found in
soil contaminated with pigeon droppings or
eucalyptus trees and decaying wood.
Cryptococcus neoformans grows easily in
pigeon feces, however the birds are not
naturally infected.

3. Speciation
•The genus Cryptococcus includes around 37 species.
•Among these, Cryptococcus neoformans is the only species that
is pathogenic to humans.
•Other species are Cryptococcus albidus, Cryptococcus
laurentii, Cryptococcus terreus, Cryptococcus uniguttulatus,
Cryptococcus luteolus and Cryptococcus gastricus.
•It has four serotypes (A to D). Serotyping is based on capsular
agglutination reactions.
•It includes three varieties;
•var. gattii, var. neoformans and var. grubii.
•The two varieties, neoformans and gattii are morphologically
similar, except that basidiospores of var. neoformans are round
and those of var. gattii are more elliptical in shape.
•Cryptococcus neoformans serotype A is responsible for the
majority of human cases.

4. Morphology
A characteristic polysaccharide capsule of variable
thickness (1-30μm) surrounds these yeasts.
In its natural environment the capsule is thinner and the
yeast smaller, while thicker capsules tend to be found from
infected tissues.
The capsules stain pink by the Meyer’s mucicarmine
technique.

5. Transmission
•Inhalation
–Via environment
•Reactivation of latent infection
•Fomites
–Mastitis in cattle
•Contaminated syringes, cannulas, etc.
•Animal-to-human and human-to-human
transmission very rare

6. Major Virulence factors
The polysaccharide capsule
The phenoloxidase enzyme
The organism's ability to grow at 37°C
Phospholipase enzymes
It produces urease

7. •Cats
•Cattle
•Dogs
•Ferrets
•Guinea Pigs
•Horses
•Foxes
•Mink
•Cheetahs
•Sheep
•Goats
•Llamas
Species Affected

8. Disease
•Cryptococcosis or European blastomycosis or
Torulosis or Busse-Buschke’s disease
•In 1894, It was isolated from tibial lesion of human
patient by Busse and Buschke in Germany
•It developed following inhalation of the organism
•Cryptococcosis is considered an opportunistic
infections as it affects mainly immunosupressed
individuals
•The clinical types of cryptococcosis are pulmonary,
CNS, visceral, osseous, cutaneous and
mucocutaneous

9. Clinical types of Cryptococcosis
Pulmonary,
CNS,
Visceral,
Osseous,
Cutaneous
Mucocutaneous

10. The course of the infection is usually subacute or chronic.
In healthy individuals, the disease is primarily pulmonary and is
asymptomatic.
CNS cryptococcosis such as meningitis and brain abscess are
commonly seen in acute settings.
Cutaneous and mucocutaneous cryptococcosis is the result of
disseminated disease.
In osseous cryptococcosis, cranial bones and vertebrae are
commonly affected.
Visceral cryptococcosis follows dissemination of fungus to any
organ or tissue of the body, most commonly heart, testis, prostate
and eye.
Patients with AIDS, carcinoma, leukemia, collagen vascular disease,
Hodgkin’s disease, sarcoidosis and those undergoing
immunosuppressive therapy are at increased risk of cryptococcosis.
Contin….

11. Laboratory Diagnosis
•Detection in tissues or fluids
–Methods
•Direct microscopy
•Culture
•Imaging (CT, MRI, X-ray)
–Specimens
•CSF, blood, sputum, urine, others
–Yeast characteristics
•Encapsulated, round to oval, clear halo

12. Globose yeast cells are seen in most clinical materials,
such as CSF and pulmonary tissue mounted in 10% KOH.
A capsule may or may not be present.
The capsule is best visible in India ink preparations.
Aspirates and tissues are inoculated onto Sabouraud
dextrose agar.
Colonies of C. neoformans are fast growing, soft,
glistening, smooth, usually mucoid, and cream to
yellowish brown in color.
 It usually takes 48 to 72 hours.
Laboratory Diagnosis

13. It grows well at 25°C as well as 37°C.
Ability to grow at 37°C is one of the features that differentiates
C. neoformans from other Cryptococcus spp.
C. neoformans produces phenoloxidase enzyme that results in
production of melanin and thus a brown to black discoloration
of the colony when it is grown on caffeic acid agar or bird seed
agar.
Detection of cryptococcal antigens, particularly polysaccharide
capsular antigen by latex-agglutination is helpful in diagnosis.
Cryptococcus neoformans differs from Candida by hydrolysing
urea and not forming pseudohyphae.
Laboratory Diagnosis

14. Treatment
•Anti-fungals in humans
–Amphotericin B, fluconazole
–Long term therapy may be required in AIDS patients
•C. neoformans var gattii
–Infections respond slowly to treatment
•Anti-fungals in animals
–Amphotericin B
–Flucytosine
–Itraconazole
–Fluconazole

15. Prevention and Control
•Environmental exposures
–Difficult to prevent
•C. neoformans var neoformans
–Avoid pigeon droppings
•C. neoformans var gattii
–Avoid eucalyptus trees