Spreading of multiple Listeria monocytogenes abscesses via central nervous system fiber tracts: case report

Abstract

Animal studies have shown that Listeria monocytogenes can probably access the brain through a peripheral intraneural route, and it has been suggested that a similar process may occur in humans. However, thus far, its spreading through the central nervous system (CNS) has not been completely elucidated. The authors present a case of multiple L. monocytogenes cerebral abscesses characterized by a pattern of distribution that suggested spread along white matter fiber tracts and reviewed the literature to identify other cases for analysis. They elected to include only those cases with 3 or more cerebral abscesses to make sure that the distribution was not random, but rather followed a pattern. In addition, they included those cases with abscesses in both the brainstem and the cerebral hemispheres, but excluded cases in which abscesses were located solely in the brainstem. Of 77 cases of L. monocytogenes CNS abscesses found in the literature, 17 involved multiple abscesses. Of those, 6 were excluded for lack of imaging and 3 because they involved only the brainstem. Of the 8 remaining cases from the literature, one was a case of bilateral abscesses that did not follow a fiber tract; another was also bilateral, but with lesions appearing to follow fiber tracts on one side; and in the remaining 6, to which the authors added their own case for a total of 7, all the abscesses were located exclusively in the same hemisphere and distributed along white matter fiber tracts. The findings suggest that after entering the CNS, L. monocytogenes travels within the axons, resulting in a characteristic pattern of distribution of multiple abscesses along the white matter fiber tracts in the brain. This report is the first description suggesting intraaxonal CNS spread of L. monocytogenes infection in humans following its entry into the brain. This distinct pattern is clearly seen on imaging and its recognition may be valuable in the diagnosis of listeriosis. This finding may allow for earlier diagnosis, which may improve outcome.

Listeria monocytogenes Brain Abscess: Controversial Issues for the Treatment—Two Cases and Literature Review

“…A recent animal study suggests that once the bacteria have gained access to the CNS via the peripheral nervous system, the infection can spread along the axons, producing additional lesions by traveling within the axons of the trigeminal nerve [ 14 – 16 ]. According to Bojanowski et al, once inside the CNS, the bacterium may travel along the white fiber tracts of the brain, resulting in a distinct anatomical imaging thus enabling early diagnosis [ 17 ]. The spreading of multiple listeria brain abscess within the cerebral nervous system through the intrassonal pathway justified their specific pattern and why they have more detrimental effects than bacterial brain abscess.…”

“…To the best of our knowledge, only 73 cases of brain abscess caused by L. monocytogenes were reported in the literature between 1968 and 2017. We report further two cases ( Table 1 ) [ 1 , 13 , 17 , 21 – 23 ].…”

Distinct Neurotoxicity Profile of Listeriolysin O from Listeria monocytogenes

“…A specific feature that pathologically differentiates this type of meningitis is the frequent involvement of brain parenchyma (including brain abscesses) and hematogenic dissemination [ 32 ]. Evidence for multiple abscesses along interconnected projection areas of the brain implies a possibility for distribution via white matter fiber tracts [ 33 ]. LLO is known to be critical for the development of listerial disease: LLO is required to release bacteria from the endosomal compartment in host cells, and toxin deficiency renders bacteria highly non-virulent [ 34 ].…”

Serial magnetic resonance imaging findings of intracerebral spread of listeria utilising subcortical U-fibres and the extreme capsule

“…3,6,8,9 Our case exquisitely depicts a less well-recognised feature of listerosis brain abscesses, namely the propensity for the bacteria to spread to distant sites within the CNS utilising white-matter fibre tracts as conduits. 4 A recent literature review by Bojanowski et al. found that eight of the nine reported cases of supratentorial cerebral listeria abscesses followed a white-matter tract pattern of dissemination, and the majority of cases were limited to a single cerebral hemisphere.…”

“…1–3 There are few reported cases of L. monocytogenes cerebral infection spreading along white-matter fibre tracts, and a paucity of evidence documenting the serial imaging appearance following antimicrobial treatment. 4 We present a unique case of L. monocytogenes cerebral abscesses with intracerebral spread via the subcortical U-fibres and the extreme capsule, and review the microbiological literature to discuss mechanisms of bacterial mobility which may account for these neuroimaging findings.…”