Which part of the brain looks like a swollen extension of the spinal cord?

The brain stem. The brain stem is a continuation of the spinal cord but much larger then this. It is still part of the brain and it controls the most simple and primitive functions of the human brain. Lesions on this structures are usually fatal.

This bacteria must be very strong as it has a large amount on antibiotic targeting it. this bacteria could be one of many different types and it is very hard to tell which one with out more information.