The laboratory where I work is located in Barranco (Lima, Peru) where there is a lot of humidity (~90%) and our cultures get easily contaminated with molds and yeasts eventhough we are very careful with the handling and cleaning of the laboratory. But I understand that in other laboratories where humidity is notably different people can enter to the cell culture laboratory without much care (some friends told me that this was the case when they were in the US).
My question is if you know, or if you have references, that validate that the climate in the location of a laboratory actually has an effect on cell culture contamination.
Thanks.
The relative humidity inside of the tissue culture incubator is generally meant to be >95% anyways. So it's probably not purely a humidity issue. It's probably got more to do with the fact that your lab probably has lots of spores in the air, especially compared to your friends' labs. Is anyone doing yeast work nearby? Is your tissue culture area blocked off from the rest of the lab by a door or curtain or something?
Try culturing in flasks (T-25, T-75, etc.) with gas-permeable caps instead of dishes and plates if you can...and make sure to wipe the outside of your flasks (especially the neck and cap) with 70% ethanol before they go into an incubator or bio-hood. This way, even if fungal spores get into your incubator, they'll be less likely to actually get into your cultures.
You can also put antimycotics agents in your media. If fungal cells manage to get into your cultures, the antimycotics should prevent their growth. If you are using antimycotics but still getting contamination, make sure you check the expiry of your reagents and keep in mind that most antibiotics rapidly break down in culture media at 37degC. So, if you are pre-heating your media before using it, take out an aliquot and warm that up...don't heat up the whole bottle over and over again. Also, even if the cells aren't confluent or the media hasn't yellowed, it's good practice to completely change the media every 4 days (or less) to replenish nutrients and prophylactic drugs that have spontaneously degraded at 37degC.
If you are seeing a lot of contaminations in your lab, then I think you are asking the wrong question. I believe the better question to address is, what can you do to mitigate the risk of contaminations in your lab in your city?
The environment inside your incubator is more humid than your city, so the environment of your culture room, and the cleanliness of that room and the individuals entering it, should be your primary concern.
it depends how contained your labs are. If they are well opened windows, open door, no temperature control, contaminant in air, than it is concerned.
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