Persistence of Cutibacterium acnes for Nine Years in a Host With a Cranial Implant
Emily White1, Sharon Whitney1, William Curry2, April Eichler1, Sandra Nelson3, Shibani Mukerji1
1Neurology, 2Neurosurgery, 3Infectious Disease, Massachusetts General Hospital
Objective:
To share a case illustrating the elusive nature of C. acnes as a pathogen in chronic meningitis, especially in those with cranial implants.
Background:
Cutibacterium (formally Propionibacterium) acnes are fastidious, slow-growing gram-positive anaerobes, abundantly found on human skin and associated with biofilm-related infections, including meningitis. While chronic meningitis is often immune-mediated, indolent infections remain a key consideration in the differential diagnosis.
Results:
A 43-year-old man with history of a recurrent 4th ventricular anaplastic ependymoma requiring three resections between 1996 and 2010, radiation therapy, and years of oral low-dose etoposide chemotherapy, developed nine years of recurrent headaches. These were associated with nonspecific upper respiratory illnesses and meningitis, notably with cell counts up to 1,100 cells/uL, protein of 250 mg/dL, and hypoglycorrhachia. Despite cerebrospinal fluid (CSF) microbiological and autoantibody testing, including bacterial cultures for 14 days, PCR for bacterial, fungal, and mycobacterial pathogens, and serum/CSF autoimmune encephalopathy panels, no etiology was identified. His positive response to steroids was attributed to an immune-mediated process, prompting initiation of oral methotrexate (MTX) as a steroid-sparing agent. In 2019, he developed increasing fluctuance at his surgical site, and a long-standing space-filling implant, previously missed by MRI, was detected on CT. Although infection was unconfirmed, his multidisciplinary team proceeded with the removal of the implanted hardware and previous duraplasty. Intraoperatively, there was no evidence of dural disruption. Three cultures of the hardware, wound, and dura rapidly returned positive for C. acnes, strongly suggesting true infection rather than contamination. He was treated with Ceftriaxone for six weeks, weaned off steroids/MTX, and remained headache-free without meningitis for two years.
Conclusions:
A high index of suspicion for chronic infections, including C. acnes and other biofilm-forming bacteria, is essential in patients with cranial implants, along with the need for cultures obtained near the implants to definitively confirm infection.
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