Why does the antibiotic treatment for osteomyelitis take so long?

Difficult infection: Osteomyelitis is an infection that has burrowed deep though skin and tissues and then into the bone. Antibiotics can be very difficult to get into the bone, which can also have low blood flow into the infected bone. Long courses of weeks of antibiotics may be needed.

See below: Most cases of osteomyelitis in adults need surgery and antibiotics. Because it takes 6 weeks for debrided bone to be covered by soft tissue, and experience that shorter courses of antibiotics have a higher relapse rate, 4-6 weeks of IV antibiotics is recommended. In models of osteomyelitis 4 weeks of antibiotics was more effective in sterilizing bone than 2 weeks.