This is the cycle of the pathogenesis of chronic OM, the key element is the entering of the organisms into a dormant state – this means that because they divide very slowly antibiotics are essentially ineffective. Also because of the unique properties of the biofilm in dead tissue, sensitivity testing on agar plates is useless as the microbes have different properties on the agar plate than they do on the devitalised bone tissue.
The transition from acute to chronic Osteomyelitis is poorly understood, there are numerous complex intercellular signalling molecules that organise the dormant state and biofilm formation. The key thing is to intervene during the acute phase of osteomyelitis with antibiotics before bone devitalisation and biofilm formation has been established in a way to avoid the extensive debridement and wound management needed in later stages of the disease.
Abx is only effective before biofilm / dead bone is established after which surgical debridement and wound care is needed to remove devitalised tissue and prevent spread to adjacent bone.
There are really 2 types of OM: acute and chronic. Acute Osteomyelitis needs to be recognised early and aggressively treated with antibiotics to prevent it from developing into a chronic form of OM. Its likely that there will be a mixture of Chronic and Acute OM present and treating with Abx can reduce the pathogenic payload, if you will, that with good wound care, identification of the source of infection and management of that source (Wound care, ebridement, removing teeth, Maxfax input etc) is key to getting a good result.
Ostemyelitis is a holistic disease in the sense that in order to get a really good outcome you need primary interventions, abx cover and also community input, lifestyle management and woundcare guidance that is multi disciplinary in nature. For more complex cases it is also worthwhile getting plastics involved as unsightly wounds that are difficult to take care of may lead the patient down a spiral that can cause a remission of OM.