An unusual form of listerial CNS infection.
Abstract: Listeria monocytogenes is a known cause of meningitis, but cerebral abscess formation is exceedingly rare. We describe a patient who presented with an unsteady gait and a small ring-enhancing lesion in the right parietal lobe. Pathologic evaluation demonstrated an abscess with associated microglial nodules, and culture revealed Listeria. In spite of the rarity of this entity, immunosuppression has been noted to be a predisposing factor. Our patient had diabetes mellitus and chronic obstructive pulmonary disease with recent prednisone administration, both very common ailments in the population of West Virginia.
Article Type: Case study
Subject: Central nervous system diseases (Case studies)
Central nervous system diseases (Diagnosis)
Central nervous system diseases (Risk factors)
Listeria (Health aspects)
Brain (Abscess)
Brain (Case studies)
Brain (Diagnosis)
Brain (Risk factors)
Authors: Sedney, Cara L.
Harshbarger, Todd
Gyure, Kymberly
Pub Date: 07/01/2012
Publication: Name: West Virginia Medical Journal Publisher: West Virginia State Medical Association Audience: Academic Format: Magazine/Journal Subject: Health Copyright: COPYRIGHT 2012 West Virginia State Medical Association ISSN: 0043-3284
Issue: Date: July-August, 2012 Source Volume: 108 Source Issue: 4
Geographic: Geographic Scope: West Virginia Geographic Code: 1U5WV West Virginia
Accession Number: 310150679
Full Text: Introduction

Brain abscesses are a well-known entity and can occur in immunocompromised patients. Listerial abscess, however, represents a very rare form of brain abscess, which presents in unusual ways and has unusual pathologic manifestations, and can complicate or delay the diagnosis.

Case Presentation

A 42-year-old woman presented to the emergency room of a referring facility with a history of an unsteady gait for the past 1 1/2 weeks and headaches for the past month which awakened her from sleep. She also noted intermittent neck stiffness, somnolence, and blurry vision. There was no weakness, numbness, or speech problems. Her past medical history was significant for diabetes mellitus, chronic obstructive pulmonary disease (COPD) with exacerbation one month prior to presentation, for which she received IV ceftriaxone for one week and prednisone; cervical cancer in 1988, and a history of smoking 1 1/2 packs per day for 35 years. She had no history of other malignancies or of intravenous drug abuse.

Physical examination revealed her to be alert and oriented with fluent speech and a good memory and fund of knowledge. Her pupils were equally round and reactive to light, cranial nerves were intact, sensation was normal, and reflexes were symmetric. She displayed no pronator drift and had good strength, but she did demonstrate difficulty with tandem walking. Imaging studies revealed a lobulated, ring-enhancing lesion with surrounding edema in the left parietal lobe (Figure 1). Metastatic and infectious work ups were negative.

A stereotactic brain biopsy was performed. Sections from the biopsy demonstrated necrotic brain tissue with an associated neutrophilic inflammatory infiltrate (Figure 2). The surrounding tissue was gliotic and contained a mixed inflammatory infiltrate including perivascular lymphocytes and plasma cells as well as microglial cells with loose microglial nodule formation (Figure 3). Gram stain revealed a Gram-positive bacillus, with subsequent culture confirming Listeria monocytogenes.


Listeria monocytogenes is a Gram-positive bacillus which is facultatively anaerobic and non-spore-forming. It demonstrates "tumbling motility". (1) It is an intracellular pathogen which causes disease in a variety of animals and humans. (2) Ingestion of contaminated food including inadequately chilled salads, meats, and dairy products is considered the main source. (2) One to five percent of humans are asymptomatic intestinal carriers.1 Upon ingestion, the bacteria enter the bloodstream through mesenteric lymph nodes. (1,2,3)

CNS involvement by Listeria has been well-characterized.1 Most commonly CNS involvement manifests as meningitis and it is considered the fourth most common etiology of meningitis. (1) A distinctive form of rhombencephalitis also exists, manifesting as asymmetric cranial nerve palsies, hemiparesis, and coma. (3)

Cerebral abscess formation results from invasion of cerebral capillary endothelium by infected macrophages. (2) This occurs most often in the region of the middle cerebral artery territory and represents a different pathogenesis from that of listerial meningitis, which is caused by entry though the epithelium of the choroid plexus. (2)

Forty reports of listerial brain abscesses have been reported, 30 of which were solitary lesions as in our patient. (2) The majority of these occurred in the frontal or parietal lobes. (3) In these previously reported patients, various forms of immunosuppression were common predisposing factors. Disorders of cell-mediated immunity are considered particularly important. (3) Seven patients had a hematologic malignancy, six had renal or cardiac transplants, six had diabetes mellitus, and three had AIDS. (2) Asthma, sarcoidosis, COPD, hepatic cirrhosis, rheumatoid arthritis, and Crohn's disease were also present. (2,4) Our patient had both diabetes mellitus and COPD as predisposing factors. The mean age of presentation was 44 years of age. In contrast to our case, ninety percent of patients with listerial abscesses were male. (2)


Presentation of patients is most often due to rapid onset of symptoms, with 88% of reported cases having symptoms for two weeks or less. (3) This is consistent with our patient's complaints of gait difficulty for 1 1/2 weeks prior to presentation. Most have had fevers, and all have had abnormal neurologic findings. (3) Although our patient presented with classic headaches suggesting an intracranial mass lesion, headache was a less common presenting symptom among patients with listerial abscesses than in those with other brain abscesses. (3) It has been demonstrated that blood cultures are more often positive in these patients than in other patients with brain abscesses. (1,2,3,5) In one series, 86% had positive blood cultures. (3)

Prognosis in these patients is guarded, with an approximately 40% mortality rate attributed to the infection. (2) Of the survivors, 61% in previous series have had residual neurologic deficits. (3) Most reported deaths due to listerial abscesses occurred within a month of diagnosis and while the patient was taking appropriate antibiotics. (3) Only one patient who died from a listerial abscess had a neurosurgical procedure, which likely points to the importance of surgical drainage of these lesions. (3)



Treatment often includes neurosurgical drainage of lesions greater than 2.5 cm in size. (3) Antimicrobial therapy must also be initiated, with the most effective treatment reported in the literature being ampicillin with gentamycin. (1,2,3,4,5) Relapse in one patient was attributed to treatment with ampicillin alone, although two reported patients were successfully treated with this regimen. (1) Second-line agents include vancomycin and Bactrim. (1,2,3) Duration of therapy has been reported from two weeks to 14 months. (3) Due to the toxicity of gentamycin, it was decided to treat our patient with an 8 week course of ampicillin alone. She did well with this treatment and follow up MRI demonstrated resolution of the lesion, and her symptoms did not return.

The pathology of listerial abscesses has not been well-characterized, however several studies have examined the pathological appearance of listerial rhombencephalitis in both humans and ruminants. (6,7) Listerial rhombencephalitis is thought to occur through a unique mechanism of infection through injured oral mucosa with retrograde axonal transport along cranial nerves. (6) Pathological studies of these cases have revealed microglial cells as well as microabscesses with neutrophils and macrophages. (6,7) Occasional necrotic neurons and neuronophagia were also present. (6,7) Significant to our case, microglial nodules were seen in several cases, consisting of microglial cells and T-lymphocytes. (6) Microglial nodules are rare in brain abscesses due to other infectious etiologies.


Listerial brain abscesses are an unusual neurologic manifestation of Listeria infection. These infections may have a complicated clinical and pathological picture. The propensity to occur in the immunocompromised host has been recognized, and in particular, this infection can occur in the settings of diabetes mellitus and COPD, two common predisposing conditions found in West Virginia.


(1.) Mylonakis E, Hohmann EL, Calderwood SB. Central nervous system infection with Listeria monocytogenes: 33 years' experience at a general hospital and review of 776 episodes from the literature. Medicine 1998; 77: 313-36.

(2.) Cone LA, Leung MM, Byrd RG, et al. Multiple cerebral abscesses because of Listeria monocytogenes: Three case reports and a literature review of supratentorial listerial brain abscesses. Surgical Neurology 2003; 59: 320-8.

(3.) Eckburg PB, Montoya JG, Vosti KL. Brain abscess due to Listeria moncytogenes: Five cases and a review of the literature." Medicine 2001; 80: 223-35.

(4.) Cone LA, Somero MS, Qureshi FJ, et al. Unusual infections due to Listeria monocytogenes in the southern California desert. International Journal of Infectious Diseases 2008; 12: 578-81.

(5.) Soares-Fernandes JP, Beleza P, Cerqueira JJ, et al. Simultaneous supratentorial and brainstem abscesses due to Listeria monocytogenes. Journal of Neuroradiology 2008; 35: 173-6.

(6.) Antal EA, Loberg EM, Dietrichs E, at al. Neuropathological findings in 9 cases of Listeria monocytogenes brain stem encephalitis. Brain Pathology 2005; 15:187-91.

(7.) Oevermann A, Zurbriggen A, Vandevelde M. "Rhombencephalitis caused by Listeria monocytogenes in humans and ruminants: A zoonosis on the rise? Interdisciplinary Perspectives on Infectious Disease 2010. 1-22.

Cara L. Sedney, MD

Todd Harshbarger, MD

Kymberly Gyure, MD

West Virginia University Departments of

Neurosurgery and Pathology
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