Etiology, clinical presentation, outcome and the effect of initial management in immunocompromised patients with community acquired bacterial meningitis

Immunocompromised teenager with meningitis caused by Ureaplasma parvum

Infection in the immunocompromised patient is often challenging on multiple levels. It can be difficult to distinguish between manifestations of the underlying disease, infection or malignancy. Symptoms may be vague or even absent, deviations in the common inflammatory parameters discrete, imaging findings scarce and the causative microbe may be a true pathogen as well as opportunistic. Here, we report an immunosuppressed female in her late teens with a purulent meningitis due to Ureaplasma parvum-a very rare cause of infection in the central nervous system of adults. We wish to highlight the relevance of intracellular pathogens and the need to actively search for these microbes, especially when response to broad-spectrum antibiotic treatment is absent. Furthermore, we emphasise the need for adequate molecular microbial diagnostics in search of microbes that are difficult to identify by culture and where serology and antigen tests may be absent or unreliable due to immune suppression.

Polymicrobial Bacterial Meningitis in a Patient with Chronic Suppurative Otitis Media: Case Report and Literature Review

Polymicrobial meningitis is a rare entity in the adult population, especially in the antibiotic era. However, disorders such as chronic suppurative otitis media (CSOM) or even poor oral hygiene are considered risk factors for the development of such cerebral infection. We report a case of polymicrobial meningitis associated with oto-mastoiditis in a 64-year-old female patient known to have CSOM. The patient presented atypical symptoms for community-acquired meningitis, showing subacute evolution of headache, without fever or neck stiffness. The aerobe microorganisms Streptococcus anginosus and Corynebacterium spp., sensitive to beta-lactamines, and the anaerobe Prevotella spp., resistant to penicillin and metronidazole, were isolated from CSF specimens, while Proteus mirabilis and Enterococcus faecalis were identified from the ear drainage. The diversity of pathogens identified in our case led us to the hypothesis of two different sources of meningitis: otogenic and/or odontogenic. Favorable evolution was obtained after a multi-disciplinary approach, combining surgery and broad-spectrum antibiotics. In addition, we performed a literature review that highlights the low incidence of polymicrobial mixed aerobe-anaerobe meningitis.

Human Listeriosis

Listeria monocytogenes is a Gram-positive facultative intracellular pathogen that can cause severe invasive infections upon ingestion with contaminated food. Clinically, listerial disease, or listeriosis, most often presents as bacteremia, meningitis or meningoencephalitis, and pregnancy-associated infections manifesting as miscarriage or neonatal sepsis. Invasive listeriosis is life-threatening and a main cause of foodborne illness leading to hospital admissions in Western countries. Sources of contamination can be identified through international surveillance systems for foodborne bacteria and strains' genetic data sharing. Large-scale whole genome studies have increased our knowledge on the diversity and evolution of L. monocytogenes, while recent pathophysiological investigations have improved our mechanistic understanding of listeriosis. In this article, we present an overview of human listeriosis with particular focus on relevant features of the causative bacterium, epidemiology, risk groups, pathogenesis, clinical manifestations, and treatment and prevention.

Differentiating central nervous system infection from disease infiltration in hematological malignancy

Hematological malignancies place individuals at risk of CNS involvement from their hematological disease and opportunistic intracranial infection secondary to disease-/treatment-associated immunosuppression. Differentiating CNS infection from hematological disease infiltration in these patients is valuable but often challenging. We sought to determine if statistical models might aid discrimination between these processes. Neuroradiology, clinical and laboratory data for patients with hematological malignancy at our institution between 2007 and 2017 were retrieved. MRI were deep-phenotyped across anatomical distribution, presence of pathological enhancement, diffusion restriction and hemorrhage and statistically modelled with Bayesian-directed probability networks and multivariate logistic regression. 109 patients were studied. Irrespective of a diagnosis of CNS infection or hematological disease, the commonest anatomical distributions of abnormality were multifocal-parenchymal (34.9%), focal-parenchymal (29.4%) and leptomeningeal (11.9%). Pathological enhancement was the most frequently observed abnormality (46.8%), followed by hemorrhage (22.9%) and restricted diffusion (19.3%). Logistic regression could differentiate CNS infection from hematological disease infiltration with an AUC of 0.85 where, with OR > 1 favoring CNS infection and < 1 favoring CNS hematological disease, significantly predictive imaging features were hemorrhage (OR 24.61, p = 0.02), pathological enhancement (OR 0.17, p = 0.04) and an extra-axial location (OR 0.06, p = 0.05). In conclusion, CNS infection and hematological disease are heterogeneous entities with overlapping radiological appearances but a multivariate interaction of MR imaging features may assist in distinguishing them.

Existing Data Sources for Clinical Epidemiology: The Danish Study Group of Infections of the Brain Database (DASGIB)

Central nervous system (CNS) infections are rare diseases that are associated with considerable morbidity and mortality. Increased knowledge based on contemporary data is a prerequisite for improved management and prevention of these serious conditions. Yet, population-based databases of patients hospitalized with CNS infections remain scarce. The Danish Study Group of Infections of the Brain (DASGIB) has prospectively registered information on all adults ≥18 years of age admitted with CNS infections at departments of infectious diseases in Denmark since 2015. The main variables collected are baseline demographics, blood and cerebrospinal fluid tests, imaging results, and outcome using the Glasgow Outcome Scale score. To investigate important aspects for each type of CNS infections, additional variables are included specifically for bacterial meningitis, viral meningitis, encephalitis, brain abscess, neurosyphilis, and Lyme neuroborreliosis. From 2015 to 2020, a total of 3579 cases of CNS infections have been recorded in the DASGIB database. Using the unique civil registration number assigned to all Danish residents, the database can be unambiguously linked with nationwide healthcare registries at the individual level. This enables researchers to conduct detailed population-based and longitudinal observational studies of risk and prognosis of CNS infections and to compare them with matched population cohorts. The database is well-suited for epidemiological research and the DASGIB network forms a solid infrastructure for future national and international collaborations.

Listeria Monocytogenes Brain Abscesses in a Patient with Disseminated Non-Small Cellular Lung Cancer: MRI Findings

Brain abscesses caused by Listeria monocytogenes (LM) are very rare and carry a high mortality risk. We present a patient with disseminated non-small cellular lung cancer (NSCLC) and multiple unusual LM brain abscesses. These abscesses have multiple elongated peripherally enhancing lesions in a characteristic formation that is "worm or tramtrack-like" following the white matter fiber tracts.

Enterovirus Meningitis in Adults: A Prospective Nationwide Population-Based Cohort Study

OBJECTIVE

To test the hypothesis that enterovirus meningitis (EM) is a frequent and self-limiting condition, the epidemiology of EM in adults was examined.

METHODS

Using a prospective, nationwide, population-based database, all adults with EM confirmed by PCR of the CSF from 2015 to 2019 were included. Unfavorable outcome was defined as Glasgow Outcome Scale scores of 1-4 at discharge. Modified Poisson regression was used to compute adjusted relative risks (RRs).

RESULTS

A total of 419 cases of EM in 418 adults (46% female, median age 31 years [interquartile range (IQR) 27-35]) yielded an incidence of 1.80/100,000/year. Admission diagnoses included CNS infection 247/397 (62%), other neurologic conditions 89/397 (22%), and cerebrovascular diseases 33/397 (8%). Genotype was available for 271 cases, of which echovirus 30 accounted for 155 (57%). Patients presented with headache 412/415 (99%), history of fever 303/372 (81%), photophobia 292/379 (77%), and neck stiffness 159/407 (39%). Fever (≥38.0°C) was observed in 192/399 (48%) at admission. The median CSF leukocyte count was 130 10⁶/L (range 0-2,100) with polymorphonuclear predominance (>50%) in 110/396 (28%). Cranial imaging preceded lumbar puncture in 127/417 (30%) and was associated with non-CNS infection admission diagnoses and delayed lumbar puncture (median 4.8 hours [IQR 3.4-7.9] vs 1.5 [IQR 0.8-2.8], p < 0.001). Unfavorable outcome occurred in 99/419 (24%) at discharge; more often in female patients (RR 2.30 [1.58-3.33]) and less frequent in echovirus 30 (RR 0.67 [0.46-1.00]) in adjusted analyses. Outcome remained unfavorable in 22/379 (6%) after 6 months.

CONCLUSIONS

EM is common among young, healthy adults. Although the long-term prognosis remains reassuring, a substantial proportion have moderate disability at discharge, especially female patients.

Neuroimaging of CNS infection in haematological malignancy: important signs and common diagnostic pitfalls

Patients with haematological malignancy are at increased risk of developing central nervous system (CNS) infections, which are associated with significant morbidity and mortality. Neuroimaging plays a pivotal role in the diagnostic pathway of these patients; however, layers of complexity are added to image interpretation by the heterogeneity in imaging manifestations of haematological malignancies in the CNS, overlapping imaging features of CNS infection, treatment-related parenchymal changes and the presence of intracranial comorbidity. In this article, we review important intracranial findings of CNS infection cases accrued in 1,855 studies over more than a decade at a specialist tertiary centre. We offer schema to identify common and important neuroimaging features, discuss key differential diagnoses and frequent diagnostic pitfalls.