Major Constituents of Skin Microflora

lalala

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14 years ago

As title said, does anyone know the major constituents of skin microflora?

I need to design an experiment to identify them as well. Pls assist. Thanks.

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bio_man

wrote...

Educator

14 years ago

Do you mean bacteria?

The bacteria Staphylococcus epidermidis, Staphylococcus aureus, and Micrococcus luteus; moreover, Corynebacteria and Mycobacteria are also found.

Coagulase-negative staphylococci (S. epidermidis and other species), the principle constituents of skin microflora, are the predominant etiological agents, followed by S. aureus and group D streptococci (enterococcal and nonenterococcal).

So I suppose you can take swabs of your skin (i.e. underneath a subject's armpit) and other areas and try to identify the pathogen that grows?

You can start you lab report like this:

There are microbes that are indigenous to our body and in particular, our skin. Regardless of pathogenicity, commensal even, these micro-organisms survive the skin-secreted antimicrobial substances and relative dryness to exist symbiotically. Among these microorganisms, Staphylococcus epidermidis and Corynebacteria are found almost 100 percent of the time on the skin. In addition, a potential pathogen, Staphylococcus Aureus is also commonly found on the skin together with Mycobacteria. Although rarely found on skin, there is another microbe, Streptococcus pyogene, which is also a pathogen.

Good luck Slight Smile

Bio_man 8)

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lalala Author

wrote...

14 years ago

Well, i think I need a list of them before I decide how I can go about doing it. What are the species of mycobacteria commonly found on the human skin? Which species of Streptococcus are commonly found? Enterococcus arent usually found on the skin, they are more on the inside of the body right?

Same for Corynebacteria. What are the major species grown on the skin?

Please assist, thanks.

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bio_man

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Educator

14 years ago

Depending on your level of study (I'm guessing third-year microbiology Undecided

), I would mostly focus on two main species, namely staphylococci (Staphylococcus epidermidis and Staphylococcus aureus), which are the principle constituents of skin flora. We know that skin variety provides a rich and diverse habit for bacteria; there is no doubt about that, but literature mainly focuses on these two species of bacteria. My advice, don't complicate things Slight Smile

. Nevertheless, Propionibacteria and Staphylococci species are the main species found in sebaceous areas. In moist places on the body, Corynebacteria together with Staphylococci dominate. In dry areas, there is a mixture of species but b-Proteobacteria and Flavobacteriales; they are dominant. Ecologically, sebaceous areas has greater species richness than moist and dry places.

Made a little chart for you on the bottom Slight Smile

Hope it helps.

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lalala Author

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14 years ago

It sure does, thanks. Because the question set to me was to introduce major constitutents of microflora in skin and identify them. So, I have to make sure that I can account for almost most of the major constituents in the skin before I can go into identifying through catalase, oxidase test etc.

Would be nice if you can also recommend some tests for me to identify some of them =).

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bio_man

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Educator

14 years ago

Yes, absolutely. I did something like this years ago. I have a protocol you can use. I will attach it for you. First, check out this website:

http://www.jlindquist.net/generalmicro/102bactid.html [Almost all you need to know is in there].

See attachments - These will show you how to do the experiments. Also, I have the Bergey's manual if you'd like it.

Tell me if you need further assistance.

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lalala Author

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14 years ago

Thanks.

The chart is a little bit confusing. There are 2 coccus (cluster), I am not really sure whats that use for. I have a couple of Staphylococcal species, so I dont think those oxidase tests are going to be useful.

Does the Bergey's manual tell the major constitutent of skin microflora?

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bio_man

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Educator

14 years ago

Here, I created a chart for you, tests you can use. Slight Smile

Tell me if it's helpful.

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Staphylococcus Identification.pdf (50.91 KB)

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bio_man

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Educator

14 years ago

For Bergeys, go to this link:

http://tiny.cc/bioforums3

Then scroll down a page.

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lalala Author

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14 years ago

Great. Now I can use it to check for S. Aureus and Epidermis. As for the 3rd species, is it readily found in our skin?

BTW, is Propionibacteria the ones that causes acne? If that is, I think I have to have that in. I know Corynebacteria and mycobacteria are also found the human skin but do not know what special trait they have. Can you help me in identifying them?

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bio_man

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#10

Educator

14 years ago

Yes, as in P. acnes, the common skin disease acne vulgaris. However, species of Propionibacteria can be found all over the body.

Corynebacteria are small, generally nonmotile, Gram-positive, non-sporulating (although they have club-like ends), pleomorphic bacilli. Due to their snapping type of division, cells often lie in clusters resembling chinese letters. Corynebacteria are chemoorganotrophic, aerobic, or facultatively anaerobic, and they exhibit a fermentative metabolism (carbohydrates to lactic acid) under certain conditions. They are fastidious organisms, growing slowly on even an enriched medium. The best method for isolating and cultivating Corynebacteria is to use sheep blood agar plus one selective medium as the primary plating media. Selective media commonly used are Cystine-Tellurite blood agar or Tinsdale medium. The plates should be ready after 18 to 24 hours of incubation at 37 degrees Celsius in a 5% carbon dioxide-enriched atmosphere.

Skip Mycobacteria because that requires acid-fast staining. Have you performed acid-fast before? Besides, it's not as common as the other ones.

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lalala Author

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#11

14 years ago

I have checked through the requirements, I need to go to species level. I have to have a list of the bacteria that are found on the Skin Microflora. I have since compiled a list, please see if you can add to it

S. epidermis
S. aureus
S. pyogenes
M. luteus
P. acnes
P. aeruginosa
Corynebacteria (no specific species identified yet)
Acinebacteria (no specific species identified yet)

I am sure there are more Staph and Strep to add on to it; which would increase the number of steps for identification.

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bio_man

wrote...

#12

Educator

14 years ago

Wow, that's a comprehensive list! Person Raising Both Hands in Celebration

A major nonhuman skin flora is Batrachochytrium dendrobatidis - if you want, you can talk about that.

Also, some more to add...

Staphylococcus warneri
Streptococcus mitis
Acinetobacter johnsonii

Can you talk about fungi?

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lalala Author

wrote...

#13

14 years ago

I was told to limit to the tests used and they were all tests for bacteria.

Tests:
Denitrification
MV-PR
Glucose-Fermentation
Methyl Red
Kovac Reagent
Oxidase
Catalase

Do you think I can identify all of them using the above methods?

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