Reg Doc usually... But sometimes you may need the expertise of an infectious diseases specialist if the infection doesn't go away. You might be dealing with a resistant bug, a difficult situation where the antibiotic interacts with medications, or if an underlying condition makes medical management more complex- your regular doctor can determine this.
No specialist needed. Your primary care physician should be able to take care of your e. Coli infection and prescribe the appropriate antibiotic once the strain of bacteria is identified. But if you are very ill, you should seek immediate attention in the emergency room, as fatalities from this type of bacterial infection occasionally occur.