A 32-year-old woman from Delhi presents to the emergency department with acute onset fever (39.2°C), severe headache, neck stiffness, and photophobia for 6 hours. On examination, Kernig's sign is positive. A lumbar puncture is performed and cerebrospinal fluid (CSF) is sent for Gram stain and culture. The Gram stain shows gram-negative diplococci with a kidney bean or coffee bean morphology. What is the most likely organism?