The pathogenic bacteria of chronic osteomyelitis are often mixed infections of multiple bacteria, but Staphylococcus aureus is still the main pathogen. In addition, Gram-negative bacilli also account for a large proportion. In 1990, Gentry pointed out in an article entitled "Antibiotic Treatment of Osteomyelitis" that 50% of patients with chronic osteomyelitis have Gram-positive bacilli as the pathogenic bacteria. Those caused by sacral bedsores are mostly mixed infections caused by multiple bacteria such as Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Proteus mirabilis. In chronic osteomyelitis caused by artificial joint replacement or other foreign body retention, the pathogenic bacteria are mostly coagulase-negative Staphylococcus. In recent years, fungi have also been reported.