I'm just brainstorming here, so please forgive me if I ask some obvious questions, I'm just trying to understand the situation.
If the doctors want to, it might be possible for them to hurry up the test result. But if it has to culture over a specific time period, then they can't.
If it's a virus, why would an antibiotic treat it? I thought ABs can only treat bacteria and fungi?
Assuming a specific AB is the right treatment, do you know which one it is? In some cases, doctors prescribe an AB before test results come back (I;m thinking, less serious, more common, infections). Could they be holding off because the AB would be really rough on your system and not worth the risk unless it is definitely needed?
I think, that if they thought you were at risk of dying in the meantime, they would have you in hospital for observation.
Can a doctor prescribe you a drug to stop the diarrhoea, or would that be too risky?
Based on what I have been reading about HHS, one of the main risk factors is dehydration. If you are having chronic diarrhoea, that would make you at risk of dehydration. Are you managing to drink a lot of water? Do you have any signs of dehydration? Are you passing a lot of urine?
Have you felt increasingly unwell since the last time you had blood tests done at hospital or a clinic? To my mind, that would indicate that they were satisfied with those test results, but they are unaware you are feeling worse.