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.
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.
Morphology of Penicillium chrysogenum
- 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.
Cultural characteristics of Penicillium chrysogenum
- 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.
Life Cycle of Penicillium chrysogenum
- 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.
Pathogenesis of Penicilliun chrysogenum
- 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.
Treatment on Penicillium chrysogenum infection
- Treatment is by surgical removal of the foci of the infection
- Use of oral antifungals such as amphotericin B and itraconazole.
- For systemic endophthalmitis, use of topical amphotericin B or itraconazole
Industrial Applications of Penicillium chrysogenum
- 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
Prevention and Control
- 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.
References and Sources