It’s a systemic mycoses( involvement of deep tissue and organs) caused by fungus-like bacteria. The clinical picture is a chronic suppurative and granulomatous disease, wooden or lumpy lesions, and multiple draining sinuses (cervicofacial, thoracic, abdominal). I assume a culture was performed which confirmed the docs’ diagnosis. Usually the drug of choice if culture identifies as Actinomyces israelii is Penicillin G or Tetracycline. As a clinical microbiologist please check with your physician for laboratory testing ( anaerobic culture ) if one has not been performed. Good luck!