Hello,
I am infecting mice orally with salmonella 1344. I used two doses 10e4 and 10e6. I did fecal CFU on day 3 and day 5 post infection to detect salmonella titre in feces. However, no colonies were formed even with plating from the original tube without dilution.
Anyone can help me figuring out what the problem!
Thanks in advance!
Hello Doaa,
Did you treat mice with antibiotic previous to infection? With antibiotic treatment, you should have plenty Stm in feces even with those inputs!
Otherwise, I usually infect mice orally with 10^8 Stm SL1344 (with or without antibiotic treatment actually). What mice model are you using?
Last thing, for plating Stm SL1344, I use LB supplemented with Streptomycin 200µg/ml. Are you using a similar concentration?
Best,
Thibault
Hi Doaa,
How are you trying to culture the Salmonella from the feces? What we usually do is take a fresh fecal pellet from the mouse and put it directly into 500µL of 1X PBS. We then homogenize the fecal pellet and then do a 1/10 serial dilution down. We spot plate on LB-Strep (200µg/mL like Thibault mentioned). For the neat plate, we plate 100µL.
Have you checked how much you are inoculating your mice with? And via what route? Oral gavage?
--Kyler
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