Can air conditioning units spread contamination? - (Nov/17/2008 )

Hi,

I have tried looking on the internet for some answers to this to no avail! What do people think? Can air conditioning units be a bad thing in a cell culture room? We have had a few contamination problems and am currently trying to eliminate or at least limit contamination sources!

Any ideas or opinions on this will be greatly received!

Thanks!

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They certainly can, especially with airborne yeast, etc. Many labs use HEPA type filters over their air exhaust vents in rooms like that to keep them cleaner. I don't know exactly where you would find such a thing, but I know they exist.

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Air conditioning units can without a doubt be a contamination source -- see, for example Legionnaires' disease...

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Ah! Brilliant, thanks for confirming my suspicions! Armed with the evidence I need I am now going to annoy my lab manager some more.....

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As a lab manager I come across this all the time. Yes.....air conditioning units MAY spread contamination, but most of the time the contamination is caused by the end-user/researcher. The simple way I check this is to put "settle plates" in certain areas of the lab. You should always try and do aseptic work in side rooms off a main lab area. Put settle plates in the following areas:

Under the air conditioning outlet
Next to the waterbath
In 6 positions in the class II cabinet
IN THE CO2 NCUBATOR
In any other areas you think you may need to test.

Leave them open for 4 hours. Then incubate them for 24-72 hours. The last time I did this recently, these were the results from the Lab managers jury:

Air con outlet: CLEAR (72hrs)
Waterbath: CLEAR (72hrs)
Cabinet: CLEAR (72hrs)
CO2 Incubator: CONTAMINATED (24hrs only)
other areas: CLEAR (72 hrs)

TAKE HOME MESSAGE FOR THOSE USING THAT AREA: THEY HAVE CONTAMINATED THEIR CO2 INCUBATOR IN A COMPLETELY CLEAN ENVIRONMENT.

This means that probably they have not used "best aseptic technique" ....... i.e.

Use seperate lab coats
Change waterbath water weekly
Change incubator water weekly
Spray all surfaces with PLENTY OF 70% IMS
SPRAY ALL TC FLASK AND DISHES IN AND OUT OF THE INCUBATOR.
Clean the floor weekly
Change the 0.2uM filter in your TC pipettor WEEKLY


All the above little things add up to good technique.

Hope this is useful

Rhombus

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Thanks for all your advice!

Ow, the pain of knowing that; yes, the contamination is probably all down to me! (especially since I am the only person using the culture room right now!)

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