The drugs are available. The treatment that's typically used by doctors who specialize in this field consists of multiple types of antibiotics, often used in combination.
There are two reasons. One is that doctors have not been educated on the existence of treatment guidelines that explain how to treat an infection that can be persistent and disseminated. As well, many doctors feel like they can't. They are concerned that they will be stigmatized, harassed, or sanctioned if they go past the current guideline of two to three weeks of antibiotics.