When making DMEM (Dulbecco's Modified Eagle Medium) why do we add 2 % penicillin – streptomycin (PS) to cell culture?
Actually PS helps again the bacteria. To protect from fungi growth better to use Nystatin and amphotericin B. Some of commercially available antibiotic mix already contain all mentioned components.
If your question was related to Why penicillin, streptomycin (but not other even more effective) - then answer will be - because of long history of using these antibiotics and well characterized effects in almost all cell cultures.
Although we culture our cells in the sterilized apparatus/system, to avoid any possibility of the fungal and/or bacterial infection during handling we used these combination with DMEM.
To prevent contamination by bacteria and fungi. It is not required. Typically, it is added to an 1% concentration.
Agree with the others. 1% is the typical amount we use. Only to prevent contamination by bacteria and fungi.
Actually PS helps again the bacteria. To protect from fungi growth better to use Nystatin and amphotericin B. Some of commercially available antibiotic mix already contain all mentioned components.
If your question was related to Why penicillin, streptomycin (but not other even more effective) - then answer will be - because of long history of using these antibiotics and well characterized effects in almost all cell cultures.
Adding penicillin – streptomycin depends on your experiment's design. Some experiments need to culture cells without antibiotics such as transfection. Normally we add antibiotics but if your cells are sensitive against antibiotics or antibiotics are not required in your experiments, you don't need to add antibiotics.
Hello,
Sorry to add my query here, I just thought it was quite relevant to the question asked.. My cells seem to be resistant to the effect/ strength of PS in the media i.e., I am having repeated contamination in my mESC and MEF cultures.. Can anyone please advice an alternated/ supplementation to the media? Considering I need to maintain the similar conditions for all experiments (1% PSQ) addition to DMEM, what would be the best way to go about it? I have already established many mESCs using this concentration, but unable to proceed with any experiments due to the recurrent contamination issues.
I wondered if anyone could also perhaps suggest a kit for earliest detection of bacteria/ fungal infections- to help detect if my established lines' frozen aliquots are already contaminated.
Any advice would be much appreciated.
Many thanks.
Pooja.
Dear. Khurana
I'm sorry to hear that. But, best way is removing all samples related contaminated vial and estabilishing new mESC and clean all of equipment such as water bath, CO2 incubator, liquid nitrogen tank etc. I know it is very laborious but it is one method to prevent spreading contamination. Adding antibiotics is effective to prevent contamination and supress bateria(or fungal) not removal. Even antibiotics can remove origin of contatination, do you believe your experiment's results? Detecting kit will be purchased in life science vender. I searched contamination detect kit in ThermoFisher scientific(cat. C7028) You can search other companies. Or you can design PCR primer and run PCR.
P.S What does PSQ mean?
I agree the best method is to exclude the source of contamination. Even if you cure your cultures it will come back again if source persist in lab. or used equipment.
Antibiotics is good than you start primary cultures from nonsteril materials but not obligatory during next steps.
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