Aspergillus niger: Introduction and Observation of Structures on LPCB Tease Mount

Aspergillus case report

 Introduction of Aspergillus niger

Aspergillus niger is one of the most common and easily identifiable species of the genus Aspergillus, with its white to yellow mat later bearing black conidia. This species is very commonly found in aspergillomas and is the most frequently encountered agent of otomycosis. It is also a common laboratory contaminant and comes under risk group (RG)-1 organism.

Aspergillosis: It is a granulomatous, narcotizing, and cavity disease of the lung. often with hematogenous spread to other organs.

Manifestation

  • Otomycosis and keratitis
  • Toxicity from ingestion of fungal contaminated foods.
  • Allergic manifestation
  • Colonization of fungus in the various body cavities and debilitated tissues
  • The invasive granulomatous disease of the lung with inflammation and necrosis
  • A systemic disseminated disease that is usually fatal if not treated-
  • increased incidence has been seen in
  • Leukemia
  • Diabetic patient
  • AIDS
  • Renal transplantation
  • Cardiac  transplantation

LPCB is a combination of fixative, staining, and clearing agent. Its contents functions are as follows-Lactic acid: It helps in preserving the morphology of the fungal elements. Phenol: It acts as a disinfectant. Cotton blue: It stains the fungal elements and glycerol: Is a hygroscopic agent that prevents drying.

Observation of Aspergillus niger structures On LPCB tease mount

Put a drop of LPCB on a clean grease-free glass slide. Take a small portion of the colony and the supporting agar at a point between the center and the periphery and place it in the drop. With the help of a needle, tease the fungal culture first and spread in the LPCB. Wait for normally 30 minutes .i.e. sufficient time for the structures to take up the stain. Focus on 10 X objective and finally examine at 40 X objective under a microscope. Fungi appear as dark blue stained mycelium.

Aspergillus niger on lactophenol cotton blue (LPCB) mount as shown above picture. To say Aspergillus niger, it should have the following features-

Conidiophore length: 1.5-3.0 mm

Vesicle width (µm):45-75

Phialides: biseriate

Colour of conidia: black and

Diameter of conidia:4.5-5.0 µm.

Further Readings

  1. Medical Mycology. Editors:  Emmons and Binford, 2nd ed 1970, Publisher Lea and Febiger, Philadelphia.
  2. Rippon’s JW: Medical Microbiology. The pathogenic fungi and the Pathogenic Actinomycetes. 3rd ed 1988 Publisher WB Saunder co, Philadelphia.
  3. Clinical Microbiology Procedure Handbook, Chief in editor H.D. Isenberg, Albert Einstein College of Medicine, New York, Publisher ASM (American Society for Microbiology), Washington DC.
  4. A Text-Book of Medical Mycology. Editor: Jagdish Chander.  Publication Mehata, India.
  5.  Practical Laboratory Mycology. Editors: Koneman E.W. and G.D. Roberts, 3rd ed 1985, Publisher Williams and Wilkins, Baltimore.
  6. Topley & Wilsons Medical Mycology. Editors: M.T. Parker & L.H. Collier, 8th ed 1990, Publisher Edward Arnold publication, London.
  7. Textbook of Diagnostic Microbiology. Editors: Connie R. Mahon, Donald G. Lehman & George Manuselis, 3rd edition2007, Publisher Elsevier.
  8. Mackie and Mc Cartney Practical Medical Microbiology. Editors: J.G. Colle, A.G. Fraser, B.P. Marmion, A. Simmous, 4th ed, Publisher Churchill Living Stone, New York, Melborne, Sans Franscisco 1996.
  9. Bailey & Scott’s Diagnostic Microbiology. Editors: Bettey A. Forbes, Daniel F. Sahm & Alice S. Weissfeld, 12th ed 2007, Publisher Elsevier.
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