Listeria monocytogenes is now the second most common cause of acute bacterial meningitis in elderly adults and remains a less frequent but important cause of meningitis in neonates and immunocompromised patients. Unlike other causes of acute bacterial meningitis, Listeria meningitis might be complicated by true encephalitis with extension of microorganisms and inflammatory cells into the brain parenchyma; the brainstem is the typical site of involvement, and the syndrome of Listeria rhombencephalitis carries considerably higher morbidity and persistent neurologic impairment than simple meningitis. We report a case of an elderly woman with a fatal case of Listeria sepsis complicated by meningitis and rhombencephalitis with autopsy examination that was limited to the brain. In addition, we discuss the commonplace contamination of the food supply by Listeria, the pathogenesis of acute Listeria infection, and some of the factors in the cell‐mediated immune response that are responsible for ultimate control of infection.

Listeria monocytogenes is a facultative anerobic, gram-positive bacillus that is isolated from the soil, vegetables, and wild or domestic animals. Listeria infection is usually found in the older adults, immunocompromised patients, pregnant women, and newborns, whereas it is rare in healthy infants and children. Listeria monocytogenes may cause meningitis, meningoencephalitis, brain abscess, pyogenic arthritis, osteomyelitis, and liver abscess in children. The course of meningoencephalitis by Listeria is often severe and even fatal. Complications such as acute hydrocephalus, brain abscess, and spine abscess can develop, and the mortality associated with listeriosis is significantly high. We present a case of a previously healthy 7-year-old boy who developed Listeria monocytogenes meningitis.

Spinal symptoms in acute bacterial meningitis are rare. In a series of 10 cases of neurolisteriosis, we observed 2 spinal complications, one due to an acute intramedullary abscess, the other caused by chronic spinal arachnoiditis. Therefore, if spinal symptoms develop in acute bacterial meningitis,Listeria monocytogenes infection should be considered and early adequate antibiotic treatment be implemented.

Meningitis and meningoencephalomyelitis caused by Listeria monocytogenes were experimentally established in mice. The pathological changes in brain and spinal cord resulting from the infection resemble those observed in man and domestic animals. The efficacy of 24 antibiotics in treating this experimental infection was determined. Minocycline and chlortetracycline were the most efficacious antibiotics followed by amoxicillin, which was 2- to 4-fold less active than the former. However, the acute toxicity of amoxicillin to the murine central nervous system was at least 10-fold lower than that of the tetracyclines. Since parenteral amoxicillin may be of value in the management of listerial meningitis and meningoencephalomyelitis in man and domestic animals, clinical trials seem warranted.

Acute bacterial meningitis (ABM) is a potentially life‐threatening neurological emergency. An agreed protocol for early, evidence‐based and effective management of community‐acquired ABM is essential for best possible outcome. A literature search of peer‐reviewed articles on ABM was used to collect data on the management of ABM in older children and adults. Based on the strength of published evidence, a consensus guideline was developed for initial management, investigations, antibiotics and supportive therapy of community‐acquired ABM. Patients with ABM should be rapidly hospitalized and assessed for consideration of lumbar puncture (LP) if clinically safe. Ideally, patients should have fast‐track brain imaging before LP, but initiation of antibiotic therapy should not be delayed beyond 3 h after first contact of patient with health service. In every case, blood sample must be sent for culture before initiating antibiotic therapy. Laboratory examination of cerebrospinal fluid is the most definitive investigation for ABM and whenever possible, the choice of antibiotics, and the duration of therapy, should be guided by the microbiological diagnosis. Parenteral therapy with a third‐generation cephalosporin is the initial antibiotics of choice in the absence of penicillin allergy and bacterial resistance; amoxicillin should be used in addition if meningitis because of Listeria monocytogenes is suspected. Vancomycin is the preferred antibiotic for penicillin‐resistant pneumococcal meningitis. Dexamethasone should be administered both in adults and in children with or shortly before the first dose of antibiotic in suspected cases of Streptococcus pneumoniae and H. Influenzae meningitis. In patients presenting with rapidly evolving petechial skin rash, antibiotic therapy must be initiated immediately on suspicion of Neisseria meningitidis infection with parenteral benzyl penicillin in the absence of known history of penicillin allergy.

The killing of bacteria gaining access to the central nervous system is insufficient and requires bactericidal antibiotics for treatment. The inefficient host response in cerebrospinal fluid (CSF) is thought to be due to impaired phagocytosis in CSF, and low local concentration of antibody and complement. In addition, the CSF may contain inhibitors, disabling phagocytes to eliminate bacteria. We have assessed the bactericidal activity of macrophages in the presence of CSF from mice infected intracerebrally with Listeria monocytogenes (LM). Pretreatment of J774A.1 macrophages with interferon gamma (IFN-gamma) resulted in high levels of nitric oxide-dependent intracellular killing of LM. CSF taken from mice 24 h after infection (CSF-LM 24) contained IFN-gamma and induced killing of LM by macrophages. However, pulsing J774A.1 cells with IFN-gamma in the presence of CSF obtained from mice at later time points (48 h) rendered macrophages partly permissive for intracellular Listeria growth. The inhibitor detected in CSF-LM 48 was identified as IL-10 since: (a) IL-10 dose dependently impaired the listericidal activity of IFN-gamma-activated macrophages; (b) anti-IL- 10 antibodies abrogated the bacterial growth permissive effect of CSF- LM 48; and (c) IL-10 was detected in CSF-LM 48 but not in CSF-LM 24 or CSF of mock-injected animals (CSF-Co). Likewise, IL-10 was found in the CSF of 95% of patients with bacterial meningitis.