Samuel is 5 years old and has a 2 day history of watery diarrhoea and fever. He is complaining of abdominal pain and mum has been alarmed today to notice his stools are bloody. There is no history of travel. His mum says a few children have been off school recently with diarrhoea and vomiting.
You have a strong working diagnosis and admit him to hospital. You later check his admitting bloods on the computer system and note that he is anaemic and thrombocytopenic.
Based on the likely diagnosis, which of the below pathogens is most likely to be causative?