The organism responsible for this illness is

NEET PG Microbiology
#1

The photomicrograph shown below fresh sputum after 10% KOH digestion from a patient presenting with chronic indolent pneumonia with fever, weight loss, productive cough and haemoptysis. The patient also had veruccous skin lesion over right forearm. The organism responsible for this illness is

image

  1. Histoplasmosis
  2. Blastomycosis
  3. Coccidiodomycosis
  4. Candida

View Explanation

It presents as lung + skin involvement It causes ostemyelitis in 25 % cases and show CNS disease in 40 % of the patients.

Lung : It can present as acute pulmonary infection but most of the patients present with chronic indolent pneumonia with fever. weight loss. productive cough and hemoptysis.

Skin: The patient can have veruccous skin lesion over right forearm Less commonly ulcerative lesion may also be present .

Diagnosis: The easiest and most rapid method of diagnosis is examination of expectorated sputum or aspirated pus after 10% KOH digestion. The characteristic large organism( 8-20 micron) with double retractile thick wall and multiple nuclei can be seen. The yeast is single budding with broad base.

The figure above shows a cell with broad base budding + multiple nuclei + double refractile cell wall So it is blastomycosis.

Some important points

  1. INFECTIOUS FORM OF

a) Histoplasma = microconidia(spiked spherical)

b) Coccidioidomycosis(VAL.LEY FEVER) = arthroconidia

c) Blastomycosis = conidia

d) Cryptococcosis = dessicated spore or basidiospore

  1. Histoplasma has small 2-5 micron narrow budding yeast whereas yeast form in blastomycosis is 8 -15 micron thick walled ,multinucleate , reproduce by single broad base bud

  2. SPHERULES are unique to coccidioides which develop from arthroconidia in human body. these spherules contain unicellular ENDOSPORES

4.NECROTISING GRANULOMA is formed in coccidioidomycosis