An 18-year-old-male present to an urgent care facility for evaluation of diarrhea and abdominal pain. The patient noticed mild tenderness and abdominal discomfort and three loose bowel movements per day a week ago. Two days ago, he started having intermittent, crampy lower abdominal pain. He denied drinking well water, fever, blood in the stool, or relation of the pain while eating. He also had no urinary complaints and no blood or pain upon urination. On examination, the patient was afebrile and had normal vital signs. They noted mild abdominal tenderness. The stool examination demonstrated a greenish, watery stool that was negative for occult blood. Laboratory results showed normal CBC findings. Examination of the stool indicated WBC’s present in the stool. The stool was cultured and grew the following organism on special selective media along with a gram stain from the plate. what is the likely cause of this patient’s infection? What does the presence of WBC’s in the stool indicate? Explain your answer.