Penicillium chrysogenum- An Overview

Figure: Penicillium chrysogenum. Image Source: Pinterest, created using biorender.com

Penicillium chrysogenum is also known as Penicillium notatum, the first Penicillium fungi used for the isolation of penicillin antibiotics, which is used for the treatment of Gram-positive bacteria.
It is also used in the production of other β-lactam antibiotics.
It is an allergen and has pathogenic activity however it is uncommon in causing disease in humans.
Incidences of opportunistic infections by P.chrysogenum have however been reported, causing infections in immune-compromised persons with underlying conditions.
The name penicillium originates from Latin to mean painters brush because of the structure of the conidial spores which are fluffy in appearance.

Table of Contents

Habitat of Penicillium chrysogenum

It is found indoors, in areas that are humid, dump, or having dumped water.
It is also very common in temperate and subtropical areas.
It is found in moist soil and degraded forest vegetation.
It is saprophytic hence it can also grow in the dead decayed matter.
It also grows in stored food and damp building material, hence it is commonly an indoor fungus.
It can also be found on alfalfa leafcutter bees and subglacial ice feeding on sediment-rich basal ice shelves.
It can also be found on fruit causing decay.

Penicillium chrysogenum reproduces by forming dry chains of spores known as conidia, from a thread-like, brush shaped structure known as conidiophore.
Microscopically, P. chrysogenum shows typical filamentous hyphae with conidia, which are the asexual spores of the fungi.
The hyphae are colorless, slender, tubular, branched, and septate hyphae.
The hyphae are formed from several threads of mycelium which can get intertwined into a hyphal network.
Fron the hyphal network, the conidiophores originate as long thick tubes with a swelling at the top, known as vesicles.
The vesicles produce the primary sterigmata from where the secondary sterigmata originate.
The secondary sterigmata form the conidial spores.
The conidia are long, cottony, or fluffy in texture.

Penicillium chrysogenum colonies appear blue-green in color with a yellowish pigment.
Alexander Fleming described it as white fluffy mass” that later turns green then black. A yellow color appears after several days that will diffuse throughout the medium.

Penicillium chrysogenum reproduces asexually by producing asexual spores known as conidia.
The conidial spores are released by wind or water or animals.
They then land on a platform with the right growth and nutrient conditions, they start to germinate.
During germination, they form mycelial threads known as hyphae.
From the hyphae, conidiophore tubes are formed with a bulged vesicle at the top end.
From the vesicles, primary sterigmata originate also known as phialides.
The phialides form the conidial spores.

Penicillium chrysogenum causes disease on rare occasions and of which, if it causes an infection it is opportunistic in people with severely suppressed immune systems such as HIV/AIDS patients.
It has a very low pathogenicity effect and therefore, identifying and detecting it in infection is very low. Symptoms of its infections include:
- Pulmonary infection i.e pneumonia, localized granulomas, fungus balls, and systemic infection.
- Systemic endophthalmitis, an inflammation of the ocular cavity.
- Inducing allergen and asthma, by activating histamine to the epithelial lining of the lungs which causes asthmatic symptoms.

Scientists have exploited the competence of Penicillium chrysogenum in antibiotic production. The fungus produces a hydrophobic β-lactam compound known as penicillin.
Penicillin, an antibiotic has been used in the treatment of gram-positive bacterial infections such as pneumonia, gonorrhea, wounds, staphylococcal infections, bacterial fevers.
Penicillin structural variations classify it into two types, Penicillin G and penicillin V.
Penicillin has also been used in the treatment of crop diseases in apples, trees, grapes, and tomatoes, inducing protective mechanism against infections

Using water to spray off areas where the fungus is growing, to reduce spore spread into the air.
Use bleaches and warm water to clean the walls.