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 come under risk group (RG)-1 organism.

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

Manifestation

Otomycosis and keratis

Toxicity from ingestion of fungal contaminated foods.

Allergic manifestation

Colonization of fungus in various body cavity  and debilitated tissues

Invasive  granulomatous disease of the lung with inflammation and necrosis

Systenic 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 disinfectant. Cotton blue: It stains the fungal elements and glycerol: It is a hygroscopic agent that prevents drying.

Oservation 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 centre 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 at 10X objective and finally examine at 40X objective under 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 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.

Reference

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