Microbial Sources

[Magick]

(I don't know if it would be more suited for homework help).

 

I did an exercise, using settle plates and swabs, to monitor microbial contamination at various surfaces/locations in a laboratory. And the amount of bacteria retrieved was far higher than fungi. Any particular reason for this?

 

At locations, such as a spectrophotometer, I have pinned this down to personnel interactions (hair/skin cells etc.). I am wondering of any other possible causes of bacteria and fungi. Why would fungi be found, for example, on a working table top but not other locations?

 

Thanks.

Edited November 8, 2013 by Magick

[CharonY]

Well, there are a lot of factors that determine contaminants, which may include airflow and humidity. Another thing to thing about is also what kind of plates and growth conditions are being used and whether they are slightly selective for either one. What you grow is not necessarily the only thing being on site. For example, if you have a fast growing bacterium but a slow growing fungus, there is a big chance that initially you will only see bacteria, whereas it may take a while until the fungi start growing visibly,

[Magick]

Thanks for the reply.

 

The agars used were Malt and TSA.

 

In terms of the microbes that didn't grow, I don't think the exercise was much about that because I am suppose to be comparing the levels of bacteria and fungi that DID grow. I have stated the obvious about open windows/doors/personnel activity, I am thinking are there any others I might have missed?

 

Fair point about the slow growing fungus, didn't think of that. Out of interest, are there slow growing bacteria that could be possibly found in a lab?

 

On another unrelated scenario, I have a 15-day bacteria count for a bench top. There are two days with high spikes in the counts which reduce dramatically by the next day. I'm think here possible spillage near the plates that was cleaned up? It wouldn't happen twice though...

Edited November 12, 2013 by Magick