Linezolid Activity Against Disseminated Listeria monocytogenes Meningitis and Central Nervous System Abscesses: Focus on Early Drug Myelotoxicity

Design

Case presentation

A 50-year-old immunocompetent male developed central nervous system (CNS) listeriosis, manifesting as meningitis and multiple brainstem and cerebellar abscesses. The patient initially presented with dizziness, later progressing to signs indicative of bacterial meningitis, including hyperpyrexia, confusion, vomiting, and meningeal irritation. CSF analysis revealed elevated albumin (217 mg/dL), markedly low glucose (4 mg/dL), and moderate pleocytosis (256 cells/μL, 60% neutrophils). Empiric therapy with intravenous ceftriaxone and chloramphenicol was initiated but proved ineffective. Upon identification of Listeria monocytogenes in the CSF, antimicrobial therapy was escalated to high-dose ampicillin (12 g/day) combined with gentamicin (240 mg/day).

Persistent clinical deterioration and neurologic deficits prompted further therapeutic modifications, including the sequential use of intravenous rifampin, cotrimoxazole, and ultimately, linezolid (1,200 mg/day) in combination with meropenem (6 g/day), following MRI-confirmed diagnosis of multiple subtentorial abscesses involving the medulla, pons, and cerebellum. The introduction of linezolid resulted in rapid clinical and biochemical improvement, as evidenced by normalization trends in CSF glucose and albumin, reduction in leukocyte count, resolution of systemic symptoms, and gradual recovery of neurologic function. Notably, linezolid use was complicated by rapid-onset anemia (hemoglobin nadir 7.5 g/dL) requiring two transfusions, with onset occurring as early as day 6 of therapy. This hematologic adverse event necessitated the discontinuation of linezolid after 21 days, after which anemia resolved. The patient was discharged on oral cotrimoxazole and exhibited full neurologic recovery, with MRI confirmation of radiographic resolution of abscesses at one-month follow-up and sustained remission at six months.

Study Author Conclusions

Listeria Monocytogenes Meningitis in an Immunocompetent Patient

Design

Case presentation

A previously healthy 45-year-old man without identifiable immunosuppressive risk factors presented with Listeria monocytogenes (LM) meningitis in the emergency department, along with a four-day history of diplopia, left ocular medial deviation, and ptosis, but without classical features of meningitis such as fever, neck stiffness, or altered mental status. Initial diagnostic evaluations, including head CT and thoracic imaging, were unremarkable. Due to the atypical presentation and absence of overt systemic signs of infection, the early differential diagnosis included cerebral aneurysm and demyelinating disease, prompting magnetic resonance angiography (MRA), which excluded vascular pathology but showed nonspecific periventricular lesions. On day 3 of hospitalization, the patient developed tremors and diaphoresis, prompting a lumbar puncture. CSF analysis revealed a turbid appearance, elevated protein (125 mg/dL), markedly reduced glucose (<20 mg/dL), elevated lactate, and a predominance of neutrophils.

Rare Gram-positive coccobacilli were identified on microscopy, and empirical antimicrobial therapy was initiated with intravenous ceftriaxone, linezolid (substituted for vancomycin due to a formulary shortage), and dexamethasone. CSF cultures later confirmed sensitivity to ampicillin, amoxicillin-clavulanate, erythromycin, linezolid, tetracycline, and vancomycin. Therapy was modified to include ampicillin and vancomycin, leading to full clinical resolution. The patient was discharged on day 21 with a seven-day course of oral ampicillin and demonstrated complete recovery at follow-up.

Study Author Conclusions

We presented this case to raise awareness about LM as a possible cause for bacterial meningitis in immunocompetent patients with uncharacteristic clinical symptoms and to confirm that linezolid is a viable treatment option for patients with LM meningitis leading to favourable outcomes.

Listeria monocytogenes rhombencephalitis in a patient with multiple sclerosis during fingolimod therapy

Design

Case presentation

Study Author Conclusions

Here, we presented a MS patient who developed L. monocytogenes rhombencephalitis with hydrocephalus during fingolimod treatment. Previously, listeriosis has been reported in MS patients undergoing alemtuzumab therapy and in one patient on dimethyl fumarate. To our knowledge, this is the first reported case of listeriosis in a patient on fingolimod therapy. Clinicians should be aware of listeriosis and implement measures for its prevention.

Treatment of Brain Abscess Caused by Listeria monocytogenes in a Patient with Allergy to Penicillin and Trimethoprim-Sulfamethoxazole

Design

Case presentation

A 63-year-old man with a known diagnosis of multiple myeloma was admitted due to fever and altered mental status. On physical examination, the most notable finding was neck stiffness, though no focal neurological deficits were observed. Cerebrospinal fluid (CSF) analysis revealed a leukocyte count of 158 cells/mm³ with a predominance of neutrophils (71%), a glucose level of 46 mg/dL, and a markedly elevated protein level of 151 mg/dL. Cultures of both blood and CSF grew Listeria monocytogenes (L. monocytogenes), which was susceptible to ampicillin and trimethoprim-sulfamethoxazole (TMP-SMZ). Intravenous ampicillin therapy was promptly initiated.

On the 13th day of hospitalization, the patient developed motor aphasia. A computed tomography (CT) scan of the brain suggested an abscess in the left basal ganglia, which was confirmed by biopsy. TMP-SMZ was added to his treatment regimen, but within 24 hours, he developed a rash attributed to the drug. The TMP-SMZ was discontinued, and he continued on ampicillin monotherapy. After 37 days of inpatient care, the patient was discharged to continue intravenous ampicillin at home. However, 39 days later, he developed another rash consistent with a drug allergy, prompting discontinuation of ampicillin.

A follow-up CT scan at that time revealed a persistent but reduced brain abscess. The treatment strategy was switched to an oral regimen of linezolid (600 mg twice daily) and rifampin (300 mg twice daily), which was continued for an additional 107 days. This revised therapy was well tolerated, and the patient ultimately achieved full clinical recovery with complete radiographic resolution of the abscess.

Study Author Conclusions

Linezolid and dexamethasone experience in a serious case of Listeria rhombencephalitis

Design

Case presentation

A 63-year-old immunocompromised female with Takayasu’s arteritis developed Listeria monocytogenes rhombencephalitis. The patient, chronically treated with methotrexate and corticosteroids, presented with fever, headache, nausea, and vomiting. Although initial neuroimaging via cranial CT yielded no abnormalities, cerebrospinal fluid (CSF) analysis revealed pleocytosis with lymphocytic predominance, elevated protein levels (337 mg/dL), and decreased glucose concentrations (37 mg/dL). L. monocytogenes was isolated from the CSF culture, confirming the diagnosis. Empirical antiviral and broad-spectrum antibacterial therapies, acyclovir and ceftriaxone, were promptly discontinued, and first-line treatment with penicillin G plus gentamicin was initiated.

On the second day of antimicrobial therapy, intravenous linezolid (600 mg twice daily) was added due to deteriorating consciousness. Methylprednisolone was continued at a reduced dose due to immunosuppressive concerns, and intravenous dexamethasone was introduced during ICU admission when MRI revealed progressive pontine and periaqueductal signal changes, correlating with evolving brainstem dysfunction. The patient developed complications including respiratory failure, necessitating mechanical ventilation, Acinetobacter baumannii ventilator-associated pneumonia, and methicillin-resistant Staphylococcus haemolyticus bacteremia. Linezolid was discontinued on day 19 of antimicrobial therapy due to hematuria and thrombocytopenia. Gentamicin was also discontinued upon evidence of nephrotoxicity. Meropenem and colistin were added to address the nosocomial infections, but subsequently stopped as targeted therapy durations concluded. Despite the lengthy hospitalization (71 days total), serial CSF analyses showed gradual improvement in cellular and protein profiles, and the patient was successfully extubated. MRI at discharge revealed persistent but non-progressive pontine lesions. Seizures developed late in the clinical course and were managed with levetiracetam.

Study Author Conclusions

In the treatment of Listeria rhombencephalitis, the first-line antibiotic therapy is essential, although dexamethasone and linezolid can be added to firstline therapy for severe clinical forms.