Penicillium fungi
The genus Penicillium contains over 300 species of fungus. Members of this genus are what produce penicillin.
An electron microscope view
of Penicillium
Penicillium fungi normally grow in soil and prefer cool climates.
However, they are found almost everywhere. They are recognized by their brush-like spore-bearing structures, viewable through a microscope.
Penicillium fungi are often blue. They are responsible for food spoilage, and are commonly known as molds. They are excellent at growing in low humidity environments, while allows for them to remain alive in food storage. Many of these species produce toxins that may cause food poisoning.
However, Penicillium fungi also are of some benefit to humans (besides production of the antibiotic). They are used in the production of certain cheeses, including Roquefort, Brie, Camembert, and Stilton.
A study performed in 2010 showed that Penicillium
spores were among the most prevalent spores in indoor air.
The indoor spore levels were higher even than outdoor
levels.
However, they are found almost everywhere. They are recognized by their brush-like spore-bearing structures, viewable through a microscope.
Penicillium fungi are often blue. They are responsible for food spoilage, and are commonly known as molds. They are excellent at growing in low humidity environments, while allows for them to remain alive in food storage. Many of these species produce toxins that may cause food poisoning.
However, Penicillium fungi also are of some benefit to humans (besides production of the antibiotic). They are used in the production of certain cheeses, including Roquefort, Brie, Camembert, and Stilton.
A study performed in 2010 showed that Penicillium
spores were among the most prevalent spores in indoor air.
The indoor spore levels were higher even than outdoor
levels.
Resistance
When bacteria are subjected to penicillin (either via man-made antibiotics or in nature), some are less susceptible to it than others (due to genetic variation between them). Over time, this has led to the evolution of bacterial resistance. Some bacterial species have become nearly completely resistant to penicillin. There are a variety of different methods used by bacteria to obtain this resistance. A few of them are:
Some examples of penicillin resistant bacterial species are:
the normal flora found in the GI tract. This is the leading cause of pseudomembranous colitis.
Antibiotic resistant bacterial infections are a serious problem. They are usually nosocomial, meaning they are acquired in a hospital. They are long lasting and quite difficult to treat. In some cases, they can be deadly. The medical community is currently struggling to find a solution to this problem. Though early diagnosis, better regulation over isolation precautions, and overall better sanitation within the hospital setting would nearly eliminate the spread of these diseases, it has not happened yet. Hospitals have recognized this, and are attempting to stop the spread of these diseases.
- Inactivation of the penicillin molecule via production of β-Lactamases
- Branched muropeptides (peptides associated with a cell wall) that better protect the cell wall from penicillin
- Alteration of their PBPs (Penicillin Binding Proteins) so that penicillin can no longer bind to them
Some examples of penicillin resistant bacterial species are:
- MRSA:
- VRSA:
- C. diff:
the normal flora found in the GI tract. This is the leading cause of pseudomembranous colitis.
Antibiotic resistant bacterial infections are a serious problem. They are usually nosocomial, meaning they are acquired in a hospital. They are long lasting and quite difficult to treat. In some cases, they can be deadly. The medical community is currently struggling to find a solution to this problem. Though early diagnosis, better regulation over isolation precautions, and overall better sanitation within the hospital setting would nearly eliminate the spread of these diseases, it has not happened yet. Hospitals have recognized this, and are attempting to stop the spread of these diseases.
Image 1 source: http://www.uoguelph.ca/~gbarron/MISCELLANEOUS/penici2.jpg
Image 2 source: http://scientificstate.files.wordpress.com/2011/11/a-fleming.png
Image 3 source: Dennis Kunkel Microscopy. <http://www.ciriscience.org/ph_81-Mold_conidiophores_and_conidia_of_Penicillium_notatum_Copyright_Dennis_Kunkel_Microscopy>
Image 4 source: http://en.wikipedia.org/wiki/File:Contaminated_surfaces_increase_cross-transmission.jpg
Fairs, A., Wardlaw, A.J., Thompson, Pashley, C.H. “Guidelines on Ambient Intramural Airborne Fungal Spores.” Journal of Investigational Allergology and Clinical Immunology. 2010.
Houbraken, J., Frisvad, J.C., Samson, R.A. "Fleming's penicillin producing strain is not Penicillin chryosgenum but P. rubens." <http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3317369/>
Kirk, P.M., Cannon, P.F., Minter, D.W., Stalpers, J.A. Dictionary of the Fungi. 2008.
New Brunswick Museum. Penicillium. <http://website.nbm-mnb.ca/mycologywebpages/Moulds/Penicillium.html>
Streble, Susan. "The Evolution of Resistance to Penicillin." Allegheny College: Webpub. 2001.
Image 2 source: http://scientificstate.files.wordpress.com/2011/11/a-fleming.png
Image 3 source: Dennis Kunkel Microscopy. <http://www.ciriscience.org/ph_81-Mold_conidiophores_and_conidia_of_Penicillium_notatum_Copyright_Dennis_Kunkel_Microscopy>
Image 4 source: http://en.wikipedia.org/wiki/File:Contaminated_surfaces_increase_cross-transmission.jpg
Fairs, A., Wardlaw, A.J., Thompson, Pashley, C.H. “Guidelines on Ambient Intramural Airborne Fungal Spores.” Journal of Investigational Allergology and Clinical Immunology. 2010.
Houbraken, J., Frisvad, J.C., Samson, R.A. "Fleming's penicillin producing strain is not Penicillin chryosgenum but P. rubens." <http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3317369/>
Kirk, P.M., Cannon, P.F., Minter, D.W., Stalpers, J.A. Dictionary of the Fungi. 2008.
New Brunswick Museum. Penicillium. <http://website.nbm-mnb.ca/mycologywebpages/Moulds/Penicillium.html>
Streble, Susan. "The Evolution of Resistance to Penicillin." Allegheny College: Webpub. 2001.