Bacteria have their own protection mechanisms. That being said, your question belies an assumption. Is it not brain-like if it's damaged/attacked? The blood-brain barrier is a structure the human brain has developed that provides a kind of protection. Things still get through and affect the human brain. So the idea of "protection" is a matter of vector, intensity, and the nature of the interaction being "protected". e.g. If a pain receptor is no longer registering due to an opiate, has the brain been disrupted?