"Salmonella Poisoning"

We took our toddler to hospital by ambulance as they had a febrile seizure (as the paramedics described). They had fever of 40.9+for 3 days prior and wasn’t able to keep anything down with severe diarrhoea and vomiting. They had 20 dirty nappies in less than 24 hours.

While we were at the hospital the treating doctor advised us to give our toddler sips of apple juice and water and we were given a piece of paper with a table to monitor frequency of the diarrhoea and vomiting. In the span of 5-6 hours they did 8 dirty nappies and were very unwell. The doctors and nurses never even bothered to ask or check the sheet which they asked us to complete. Either way it was apparent that my child was sick since they were having their nappy changed every time a doctor or nurse was in the room and we ran out of nappies and had to ask a nurse for more. While we were there I asked the doctor on two occasions for our toddler's stool to be tested I could tell something wasn’t right and although the doctor suspected gastro, I just had a hunch that it wasn’t since my partner and I hadn’t contracted it. 

I finally managed to convince a nurse to collect the stool sample but the treating doctor seemed annoyed and they told me that they would consider sending the stool for testing only if symptoms continued but that it wasn’t necessary or their usual process. The doctor also put numbing cream on our toddler in preparation for infusion but they then disappeared and without notice another doctor then took over and instead of infusion our toddler got discharged. At the exact moment we were being discharged our toddler had a big diarrhoea explosion and the doctor told me that it smelt horrible and that I could use the sink to wash my toddler before leaving. I found this very unprofessional! 

After being discharged I had to take our toddler to the GP for care since they were still really unwell. 3 days later I got a call from the hospital doctor to confirm that my toddler had salmonella poisoning. 

I don’t understand why we were discharged, my toddler was clearly ill and I believe the doctors could have at least given them an infusion and some antibiotic for the bacteria and parasites. And why isn’t stool sampling part of the usual process for this type of scenario, why did I have to push so hard to get this done?