Samuel is 5 years old and has a 2 day history of watery diarrhoea and fever. He is complaining of abdominal pain and mum presents to A&E with him today since noticing 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.
Blood tests done on admission show he is anaemic and thrombocytopenic.
Based on the likely diagnosis, which of the below pathogens is most likely to be causative?