In severe illness, one of the following is recommended: Penicillin G 1.5 million units IV every 6 hours for 7 days Ampicillin 500 to 1000 mg IV every 6 hours for 7 days Ceftriaxone 1 g IV every 24 hours for 7 days In severe cases, supportive care, including fluid and electrolyte therapy and sometimes renal replacement therapy and / or blood transfusion, is also important.