As mentioned you suffered from serraita marcescens and was put on bactrim
according to culture report and later you became symptomatically better n report also showed no serraita marcescens infection anymore . You were put on Augmentine though very good anti microbial which itself causes gastric upset n probably caused multiple loose stools . But chances of food poisoning
can't be denied . Later you were put on ciprofloxacin
and now symptomatically better.
So in my opinion you don't require any treatment it happened coz u continuasly changed doc and accordingly was on multiple medication which later caused its side effect . Try to maintain healthy habits like normal exercise , maintain hygiene ; healthy diet like fruits and vegetables , avoid junk food oily n spicy food ; drink plenty of fluids; avoid sedentary habits .These thing will increase your immune system n fight against infection .
If you still want to visit a doc then follow as you pediatrician
adviced but follow wat he suggests n don't change him.
Hope this ll help
Thanks n regards