Intracranial infections caused by Actinomyces species

Actinomycotic brain abscess

Actinomycosis is caused by Gram-positive filamentous anaerobic organisms of genus Actinomyces, which are commensals of mucosal membranes of the oropharyngeal cavity, and gastrointestinal and genitourinary tracts. Central nervous system involvement is rare and may present as cerebral abscess, meningitis, meningoencephalitis, subdural empyema or epidural abscess. The radiological appearances of actinomycotic brain abscesses are not well recognized. Here, we present the characteristic imaging features of an actinomycotic brain abscess.

Long-term survival in a dog with meningoencephalitis and epidural abscessation due to Actinomyces species

A 2-year-old, female spayed Golden Retriever dog was presented to The Ohio State University Veterinary Medical Center for evaluation of ataxia, cervical pain, 1 episode of acute collapse, dull mentation, and inappetence. Physical examination revealed an elevated temperature of 39.7°C and severe cervical pain. Blood work revealed a mature neutrophilia. Cerebrospinal fluid (CSF) analysis revealed nondegenerative neutrophilic pleocytosis with no infectious agents. A presumptive diagnosis of steroid-responsive meningitis-arteritis was made, and corticosteroid therapy was started. The patient improved initially but experienced a vestibular episode characterized by falling and vertical nystagmus. A magnetic resonance imaging of the brain revealed an epidural abscess in the cervical vertebral canal and diffuse meningeal enhancement in the brain and cranial cervical spine. Abscess drainage revealed degenerate neutrophils and several filamentous, branching organisms. Culture of the initial CSF using an enrichment broth revealed growth of a Gram-positive organism 5 days after fluid collection. The isolate was identified by partial 16S ribosomal DNA sequencing as Actinomyces spp. The patient was successfully treated with long-term antibiotics. Our study reports the long-term survival after medical treatment of bacterial meningoencephalitis and epidural abscessation due to Actinomyces sp. infection in a dog. Bacterial meningoencephalitis should be included as a differential diagnosis in patients with cervical pain and fever, even when a nondegenerative neutrophilic pleocytosis is found on CSF analysis. Culture of the CSF with use of an enrichment broth should be considered in all cases of neutrophilic pleocytosis to rule out infections of the central nervous system.

A case of otitis media complicated by intracranial infection with Actinomyces turicensis

Introduction:

Actinomycosis is a granulomatous suppurative infection caused by filamentous Gram-positive anaerobic bacteria from the family Actinomycetaceae. To our knowledge, this is the first reported case of otogenic brain abscess associated with Actinomyces turicensis.

Case presentation:

We report the case of an immunocompetent 5-year-old boy with recurrent otitis media who re-presented to the emergency department with a 3-week history of otorrhoea, progressive anorexia, vomiting and lethargy. He was admitted with a working diagnosis of otitis media and dehydration, and was treated with intravenous fluids and oral co-trimoxazole. He subsequently developed abnormal posturing with a reduced Glasgow coma score and seizures. Urgent computed tomography revealed a cerebellar abscess with obstructive hydrocephalus for which he underwent urgent neurosurgical intervention. Tissue and aspirate cultures revealed a polymicrobial infection with A. turicensis. The patient has since undergone long-term antibiotic treatment and has made a good recovery.

Conclusion:

This case demonstrates the successful use of long-term antibiotic therapy and neurosurgical intervention to treat otogenic brain abscess associated with A. turicensis infection. To the best of our knowledge, this is the first such documented case. Our report also provides a timely reminder that, despite a reduced incidence in the developed world, intracranial complications of otitis media continue to occur and a high index of suspicion is required.

Actinomycosis: etiology, clinical features, diagnosis, treatment, and management

Actinomycosis is a rare chronic disease caused by Actinomyces spp., anaerobic Gram-positive bacteria that normally colonize the human mouth and digestive and genital tracts. Physicians must be aware of typical clinical presentations (such as cervicofacial actinomycosis following dental focus of infection, pelvic actinomycosis in women with an intrauterine device, and pulmonary actinomycosis in smokers with poor dental hygiene), but also that actinomycosis may mimic the malignancy process in various anatomical sites. Bacterial cultures and pathology are the cornerstone of diagnosis, but particular conditions are required in order to get the correct diagnosis. Prolonged bacterial cultures in anaerobic conditions are necessary to identify the bacterium and typical microscopic findings include necrosis with yellowish sulfur granules and filamentous Gram-positive fungal-like pathogens. Patients with actinomycosis require prolonged (6- to 12-month) high doses (to facilitate the drug penetration in abscess and in infected tissues) of penicillin G or amoxicillin, but the duration of antimicrobial therapy could probably be shortened to 3 months in patients in whom optimal surgical resection of infected tissues has been performed. Preventive measures, such as reduction of alcohol abuse and improvement of dental hygiene, may limit occurrence of pulmonary, cervicofacial, and central nervous system actinomycosis. In women, intrauterine devices must be changed every 5 years in order to limit the occurrence of pelvic actinomycosis.