Postoperative Subdural Empyema Caused by Staphylococcus pseudintermedius: A Case Report.

Staphylococcus pseudintermedius is a coagulase-positive staphylococcus that colonizes the skin and mucosal surfaces of dogs. Although human infection remains uncommon, it is increasingly recognized as an emerging zoonotic cause of invasive disease. We report, to our knowledge, the first documented case of postoperative subdural empyema caused by methicillin-resistant Staphylococcus pseudintermedius (MRSP) in a 72-year-old man with household canine exposure. The patient initially underwent hemicraniectomy for evacuation of a traumatic subdural hematoma and subsequently re-presented with progressive neurologic decline requiring repeat neurosurgical intervention. Intraoperative findings revealed purulent material within the subdural space, and nine separate operative cultures yielded MRSP. Despite appropriate surgical source control, prolonged intravenous vancomycin therapy with therapeutic drug monitoring, and radiographic improvement, the patient ultimately died from complications of severe underlying neurologic injury. This case expands the recognized spectrum of invasive human S. pseudintermedius infection and highlights the importance of integrating clinical, radiographic, and microbiologic findings when evaluating postoperative intracranial fluid collections to facilitate timely diagnosis and management.