I need a transport media to hold swabs potentially containing E. coli strains for latter lab processing. It must be viable for at least 36 hours. Have you guys got any advice on the matter?
Hello, 36 hours are not so critical for E.coli, you can use each media you want, even peptone water. After you can use selective media for identification.
Thirty six hours are enough to develop metallic sheen on Eosin Methylene Blue agar (EMB) characteristic of E. coli. Note that there is no certainty that the bacterium is in your sample. Therefore if you are transporting for 36 h, then you should be certain that E. coli is present in the sample for you to proceed with further analysis. It saves time and resources.
You can use tryptone soy agar (TSA) or broth (TSB), both are working. After that you need to plate it on selective media as Eosine Methylene Blue (EMB).
It isn't the media so much, E. coli will last for many days just in saline. What is important is that it does not dry out.
E. coli can grown every where so nutrient agar more than enough especially the is long time keeping
I put my swabs into Amies medium and keep on ice packs or at 4 degrees C between the field and the lab. It's a minimal and buffered media so it shouldn't cause any bacteria in the sample to grow until you process it in the lab, particularly if you're worried about non-targets growing and/or outcompeting your target E. coli between sample collection and lab processing. Then when you process it, you can directly select for your E. coli and have less background growth than if you stored it in/on a normal growth medium. If your sample may also contain Gram-positives, include novobiocin at 20mg/L to reduce their growth on your E. coli selective plates. That makes a BIG difference for me!
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