Review Question - QID 210642

A 7-day-old infant boy presents to an emergency department due to poor feeding. His parents are recent immigrants to the United States. He was born in a traditional home birth and has never seen a medical provider. Mom had no prenatal care, has no medical issues, and is unvaccinated. The baby had been breastfeeding well until 24 hours ago when mom noticed he started having trouble latching. In the last 12 hours, he has completely refused to feed. He has had a decreased number of wet diapers and has stooled twice in the last 24 hours. His temperature is 98.6°F (37.0°C), pulse is 180/min, respirations are 52/min, and blood pressure is 70/50 mmHg. On exam, the infant has increased tone, a clenched jaw, no head lag, and clenched hands. Initial screening bloodwork is normal. What is the most likely organism causing this infant's presentation?