final program.qxd - Parallels Plesk Panel

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Complicated Listeria monocytogenes central nervous system (CNS) infection in an
otherwise healthy host. Favorable response to linezolid, notwithstanding early
myelotoxicity
Roberto Manfredi, Sergio Sabbatani, Ginevra Marinacci
Infectious Diseases, University of Bologna, Bologna, Italy
Introduction. CNS listeriosis outside of pregnancy,neonatal period, and immunodeficiency,
is uncommon. Meningitis and especially CNS abscess lead to major diagnostic-therapeutic
concerns. Anecdotal episodes of L.monocytogenes CNS infection were reported from
immunocompetent patients, where diagnosis is hampered by a low clinical suspicion.
Case report. A 50-year-old male with negligible history and no obvious L.monocytogenes
exposure was hospitalized owing to worsening dizziness. A brain CT scan and EEG
detected aspecific abnormalities. Shortly, hyperpyrexia, headache, and vomiting became
evident, with temporal-spatial confusion and head stiffness, thus prompting a lumbar
puncture. CSF studies showed elevated albumin (217 mg/dL), very low glucose levels (4
mg/dL), and 256 leukocytes/µL (60% neutrophils), so that high-dose ceftriaxonechloramphenicol
were started,with dexametazone-mannitole adjuvant therapy. At the 4 th
day,altered mentation and a peripheral facial nerve palsy occurred,and L. monocytogenes
was identified from the CSF, so that chemotherapy was changed towards high-dose (12
g/day) ampicillin and 240 mg/day gentamicin, according to the in vitro susceptibility
testing. Persistingly severe clinical-neurological conditions, and altered CSF assay,
prompted a novel shift of antimicrobial therapy (to rifampicin-cotrimoxazole), 10 days after
hospitalization. Eight days later, a spasmodic torticollis appeared, associated with an left
dysmetria-hypostenia,anisochoria and nistagmus,and difficulty to swallow. A head-neck
MRI showed small, hyperintense roundish focal lesions localized at the left posteriorlateral
portion of the medulla oblongata (Figure 1). The hypointense internal signal, and
the hyperintense peripheral ring of the multiple lesions involving the pons Varolii,the left
cerebellar hemisphere and bulb, were interpreted as multiple bacterial abscesses.
Another change of antimicrobials involved i.v. linezolid (1,200 mg/day), and meropenem
(6 g/day). Although after 6 days of combined linezolid-meropenem treatment an evident
anemia required a RBC transfusion,at the 14th day of therapy the CSF examination
remarkably improved,while fever and other systemic signs-symptoms disappeared.
A persisting anemia prompted another RBC transfusion,and made necessary the
replacement of linezolid with i.v. cotrimoxazole after 21 days. Seven days later our patient
was discharged with a completely normal CSF,and an almost complete recovery of
neurological deficits. Within a 12-month follow-up,no further episodes of anemia occurred
after linezolid suspension,and control MRIs performed confirmed the complete
disappearance of Listeria abscesses. Discussion. Our report of a L. monocytogenes
meningitis complicated by multiple subtentorial abscesses (including rare localizations at
cerebellum,bulb,and pons Varolii), had an evolving and cumbersome clinical presentation
and course. A Listeria cerebellar abscess, and multiple brain stem abscesses seem to
have only one literature equivalent in an otherwise healthy patient, whose diagnosis was
made by surgery [Addas BM, Saudi Med J 2002;23:226]. Despite the demonstrated in
vitro activity of multiple agents,repeated chemotherapy changes became necessary, until
the meropenem-linezolid combination, which was introduced at the appearance of the
most severe neurological complications, and proved very effective,although affected by
relapsing anemia probably attributable to linezolid,and requiring transfusions.
A meningitis and/or multiple CNS L.monocytogenes localizations should be not
overlooked in otherwise healthy individuals without any relevant exposure to this
pathogen,due to the need of a prompt recognition and an effective treatment,to avoid a
possible life-threatening course. Linezolid,thanks to its excellent pharmacokinetic
properties,elevated CSF-brain penetration,and activity against a broad spectrum of CNS
pathogens (including the intracellular L.monocytogenes),is expected to become a key
antimicrobial compound,waiting for randomized controlled trials in this challenging setting.
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