An update on bacterial brain abscess in immunocompetent patients

Case report: Analysis of the efficacy and safety of anti-infectious treatment for brain abscess caused by oral anaerobes

Anaerobic meningitis is relatively rare, and the positivity rate of cerebrospinal fluid (CSF) cultures is exceedingly low, particularly in light of the limited research data regarding bacterial meningitis caused by oral anaerobes. This report presents a case involving a 24-year-old woman who developed fever and headache 32 days after undergoing a cesarean section. The symptoms persisted for 2 weeks, and enhanced nuclear magnetic resonance (NMR) scanning confirmed the suspicion of a brain abscess. Additionally, metagenomic next-generation sequencing (mNGS) of cerebrospinal fluid (CSF) identified several microbial species, including Porphyromonas gingivalis, Prevotella heparinolyticus, Fusobacterium nucleatum, Parvimonas micra and Filifactor alocis. Bacterial culture of CSF revealed the growth of Prevotella heparinolyticus. Following bilateral ventricular external drainage, intracranial lesion resection, and the implantation of an Ommaya reservoir in the right lateral ventricle, cranial decompression treatment was performed. Antimicrobial therapy administered successively over a period of 6 weeks, including vancomycin, meropenem, metronidazole, polymyxin B and ceftazidime, resulting in significant control of the infection. Clinical pharmacists engaged in comprehensive discussions with clinicians regarding the antimicrobial drug regimens and recommended a combined regimen of meropenem and metronidazole. An individualized anti-infective treatment protocol was developed based on therapeutic drug monitoring (TDM), which is anticipated to yield valuable insights for the management of brain abscesses resulting from oral anaerobic bacteria.

Safe early switch to oral antibiotics in immunocompetent adults with intracranial bacterial suppurations: Retrospective of a 25-year experience in a tertiary care centre

BACKGROUND

Switching antibiotic therapy from intravenous to oral route (IVOS) has become the standard of care for many deep-seated infections. IVOS seems applicable to intracranial bacterial suppurations (ICBS) with a good safety profile but remains debated and has shown insufficient evidence to be recommended in the latest guidelines. We hypothesize that early IVOS is not associated with a poorer neurological prognosis.

MATERIAL

We conducted a single-center retrospective cohort study in a French tertiary hospital between October 1998 and June 2022. We included adult patients neuro-surgically treated for ICBS, who survived early hospitalization. The primary endpoint was to determine if outcome was associated with the duration of intravenous antibiotic therapy prior to IVOS. Secondary endpoints were total duration of antibiotic treatment, adverse effects and safety parameters.

RESULTS

We analysed data for 190 patients of whom 91 % underwent IVOS, after a median 9 days (IQR 5-15) of intravenous route. Patients with a favourable 6-month outcome (Glasgow Outcome Scale Extended ≥ 7) were more likely to receive shorter intravenous treatment (8 (IQR 5-15) versus 13 (IQR 5-23) days, p = 0.035). Patients having undergone early IVOS had fewer surgical revisions (p = 0.002). Treatment side effects did not differ between groups.

CONCLUSION

In patients with intracranial bacterial suppurations who have undergone surgery and are adequately monitored, switching from intravenous to oral antibiotics was not associated with a worse outcome, even when performed early. The absence of association between IVOS and death or poorer outcome requires confirmation in further studies.

Primary Cutaneous Nocardiosis (Lymphangitic Type) in an Immunocompetent Patient: A Case Report

Cutaneous nocardiosis is an uncommon bacterial infection caused by Nocardia spp.; Nocardia brasiliensis is the agent involved in most cases. This infection is acquired through the direct traumatic inoculation of soil, plants, or other substrates where the bacteria are found. Clinically, it usually manifests as an erythematous ulcerated nodule. In one-third of cases, nodules or gummas are distributed over the lymphatic pathways that resemble lymphocutaneous sporotrichosis. Its manifestations vary and can present acutely or more frequently with a latent clinical picture over time. Diagnosis is established mainly by Gram staining, biopsy, exudate culture, and molecular biology. Nocardia infections can recur, implying that antimicrobial therapy must be prolonged (between 6 and 12 months) and involve monitoring patients for at least 6 months after the end of treatment. Early diagnosis and targeted treatment may reduce patient mortality rates. We report the case of an 82-year-old woman who presented with four nodules with a lymphangitic spread on her left hand and forearm, one week after the trauma. Molecular identification was performed using 16S rDNA gene sequencing, and Nocardia brasiliensis was identified.

Brain abscess mimicking a brain tumor only realized during surgery: A case report in a resource strained environment

Background

Diagnosis of brain tumors increased in sub-Saharan Africa since the advent of computed tomography (CT)-scans and magnetic resonance imaging (MRI) in these regions, enabling easy diagnosis. However, some histological types of brain tumors can be confusing, especially on CT-scan, simulating other pathologies such as inflammatory granulomas or pyogenic abscesses. MRI, in this instance, with its diffusion-weighted imaging, susceptibility weighted imaging, or perfusion imaging, is important to help with accurate diagnosis. The down side of these imaging facilities, however, is that less and less importance is accorded to proper and detailed history taking. Such a care-free attitude to history taking can be costly, especially in resource strained environments.

Case Description

We report the case of a 06-year-old child who presented with seizures associated with headaches and vomiting. In this case, proper history taking following the surgical intervention revealed a history of head trauma after a fall with a scalp wound, which was suppurated but later progressed well. The CT scan showed a solid cystic lesion. The first component is a ring enhanced portion (hyperdense ring with the hypodense center, surrounded by edema) with central calcification located in the frontal region, and the second component is a cystic portion located in the temporal region. This lesion with dual component was more suggestive of a tumoral lesion on imaging than an abscess. The child did not benefit from further imaging due to unavailability in the region as well as the socioeconomic status of the family making them incapable of going elsewhere to do it. A decision to surgically excise the lesion was made, and during surgery, we found a well-circumscribed yellowish lesion associated with an arachnoid cyst. The capsule of the lesion was very thick, and after opening it, the content was pus combined with debris. The child did well on antibiotic therapy post-surgery. The follow-up was unremarkable.

Conclusion

Brain MRI is essential to differentiate some pyogenic brain abscesses from tumors. However, meticulous history taking is important to gather as much information as possible about any medical pathology, which would then be corroborated with the physical examination findings and imaging to increase diagnostic accuracy and minimize misdiagnosis.

Patterns of abnormal magnetic susceptibility in the brain: an image-based review

PURPOSE

This article is designed to facilitate a systematic approach to formulating a radiologic differential diagnosis based on the pattern of abnormal magnetic susceptibility on MRI. Susceptibility-weighted imaging (SWI) is a three-dimensional sequence with excellent spatial resolution and superior contrast resolution. It originated from and has largely replaced two-dimensional T2* weighted sequences. Currently, SWI refers to any high-spatial resolution susceptibility-enhanced sequence from different MR vendors.

METHODS

There are many entities that have specific patterns unique on SWI. We chose both entities that are commonly encountered in the clinical practice and unusual entities that may present as challenges in making the diagnosis. Each entity is discussed in detail, focusing on salient imaging features seen with SWI and key differences highlighted from other entities.

RESULTS

In the first category, lesions with randomly distributed susceptibility abnormalities are described. Further classification is made based on the presence of foci of susceptibility located diffusely through the brain (e.g. diffuse axonal injury) noting the subtleties of the shape, size, and preferential distribution of these foci. Special attention is also directed toward entities that, while random in location, are associated with a specific lesion (e.g. abscess). Finally, clues to correctly diagnose the various pathologies are provided. In the second category, the focus is on lesions that can be classified based upon anatomic locations whether peripheral (e.g. sulcal hemosiderin) versus central distribution.

CONCLUSION

Knowledge of the patterns of susceptibility on SWI and the physics behind this technique are essential for facilitating MR interpretation.

Cerebral Abscess Mimicking Intracerebral Hemorrhage: A Case Report

Hemorrhagic pyogenic cerebral abscesses are a rare clinical entity that can present diagnostic challenges and lead to treatment delays. We report a case of a 46-year-old female who initially presented with a sudden onset of focal neurological deficits, raising a suspicion of a cerebrovascular etiology. Further diagnostic workup revealed a hemorrhagic pyogenic brain abscess. The patient was managed successfully with a conservative approach, receiving medical treatment after declining surgical intervention, and was discharged with only minimal neurological residuals. Although hemorrhagic pyogenic brain abscesses are uncommon, maintaining a high index of suspicion, supported by comprehensive history taking and targeted diagnostic testing, is imperative for early detection and effective management to mitigate potential morbidity and mortality.

Clinical outcomes of neuroendoscopic resection of brain abscess guided by electromagnetic navigation among patients presenting at Jieyang People's Hospital in China

Background

The treatment of brain abscesses presents certain difficulties. How to enhance the surgical effect and the positive rate of bacterial culture has always been our objective.

Aim

This study explored the surgical outcome of neuroendoscopic resection of brain abscess under the guidance of electromagnetic navigation and how to increase the positive rate of bacterial culture.

Methods

From June 2018 to December 2023, a total of 5 cases of neuroendoscopic resection of brain abscess under the guidance of electromagnetic navigation were conducted in our hospital. After admission, enhanced head MR layer scans were carried out. The imaging data were imported into the neuronavigation system. After successful registration, the abscess wall was cauterized with bipolar under the guidance of electromagnetic navigation, and the abscess wall was taken for bacterial culture and drug sensitivity test. We calculated the positive rate of bacterial culture, that is, the positive rate of bacterial culture is the number of positive cases of bacterial culture divided by the total number of cases sent for culture. After the operation, sensitive antibiotics were intravenously administered according to the bacterial culture and drug sensitivity test.

Results

The headache symptoms of the 5 patients were significantly alleviated, and there was no residual limb dysfunction. Reexamination of the head MR indicated that the abscess was significantly reduced. Five cases were all subjected to bacterial culture, among which bacteria were cultured in three cases, and the positive rate of bacterial culture was 60 %. The abscess clearance rate after the operation was all greater than 80 %.

Conclusion

Neuroendoscopic resection of brain abscess under the guidance of electromagnetic navigation has a favorable effect.This surgical method increases the positive rate of bacterial culture and holds significant reference significance for the subsequent intravenous administration of antibacterial drugs.

Detection of Gram-positive and Gram-negative bacteria in brain abscesses by 16S rRNA in situ hybridization

In situ hybridization (ISH) staining of bacterial 16S ribosomal RNA (rRNA) is an alternative to standard histological stains (eg, Gram, Warthin-Starry), and may improve the diagnosis of bacterial brain abscesses. To evaluate the utility of 16S rRNA ISH, a 10-year retrospective cohort was assembled from a large academic medical center. Results of histological stains, cultures, and 16S rRNA sequencing were extracted from reports, and new Gram and 16S rRNA ISH stains were performed. Histologically identifiable bacteria were present in 40/63 (63%) cases and 38/57 (67%) were associated with positive cultures. Overall, 16S rRNA ISH was positive in 18/63 (29%) cases, including 16/37 (43%) with positive Gram stains, 12/38 (32%) positive by culture, and 4/8 (50%) positive by sequencing. 16S rRNA ISH highlighted bacteria in 14/40 (35%) cases with Gram-positive organisms and 9/17 (53%) with Gram-negative organisms (including 6 polymicrobial cases). Compared to a composite gold standard of Gram stain and culture, the sensitivity and specificity of 16S rRNA ISH were 35% and 93%, respectively. While sensitivity is relatively low, 16S rRNA ISH may be useful for distinguishing real organisms from artifacts and for identifying brain abscess cases suitable for 16S rRNA sequencing.

Spontaneous brain abscess formation: challenge of a shifting pathogen spectrum over the last 21 years - a single center experience

BACKGROUND

Spontaneous intracerebral abscess formation is a rare condition presenting with a disabling sequela. The origin of infection can either be primary or secondary to an infection at another location. The site of primary infection - due to the proximity, often the oral cavity, the sinuses, and the orbit - determines the causative pathogens. Treatment often combines surgical and antimicrobial therapies. To determine the microbiology and respective changes and treatment outcome, we performed this retrospective monocentric cohort study of patients requiring surgical treatment of brain abscesses.

METHODS

Patients undergoing surgical treatment of a primary intracranial abscess between January 2000 and January 2021 in the Department of Neurosurgery, Freiburg University Hospital were included. Demographic, clinical and imaging data were extracted from patients' medical records and databases. Treatment approaches were also analyzed, and surgical therapy and antibiotic therapy were reported. Outcome was assessed by the modified Rankin score (mRS) and was dichotomized into good (mRS 0-3) and poor (mRS 4-6) outcome.

RESULTS

We included 65 patients with spontaneous intracerebral abscess that were treated with neurosurgical intervention at our institution. Analysis of the causative pathogens showed an increasing dominance of rare pathogens such as fungi, parasites, mycobacteria and anaerobes. Outcome measured by the mRS was similar from 2005 to 2021.

CONCLUSIONS

The pathogen spectrum of spontaneous intracerebral abscess at our institution is shifting with rarer pathogens being increasingly detected. This retrospective analysis highlights the need for microbiological diagnosis and of combined surgical and antibiological treatment.

Characterization of Disease Patterns in Children with Intracranial Abscesses for Enhanced Clinical Decision-Making

BACKGROUND

Intracranial suppurative infections in pediatric patients, while rare, pose a significant risk to patient mortality. Early recognition and fast initiation of diagnosis and treatment are crucial to prevent fatal outcomes. Between December 2022 and May 2023, a significant cluster of nine cases emerged, each necessitating neurosurgical intervention. This series highlights an important trend in clinical outcomes and raises questions about underlying factors contributing to this pattern. The need for surgical procedures in all instances suggests a commonality in severity, warranting further investigation into potential causes and preventative measures. This retrospective monocentric study aims to explore the clinical features associated with these cases to identify specific disease patterns that can expedite management in clinical practice.

METHODS

Cramer's V effect size was employed to evaluate combinations of clinical features, followed by Fisher's exact test applied to a constructed contingency table. A p-value was assessed for significance analysis, with combinations achieving a Cramer's V value of 0.7 or higher being classified as exhibiting very strong correlations.

RESULTS

The analysis revealed distinct patterns of clinical features among children diagnosed with intracranial abscesses. Significant associations were identified, including correlations between sinusitis and Streptococcus pyogenes, and fever accompanied by affected temporal, frontal, and frontobasal lobe regions.

CONCLUSIONS

Despite the generally limited statistical analysis of pediatric intracranial abscesses in the existing literature, this study provides meaningful significant associations between clinical features, delineating specific disease patterns for children with intracranial abscesses. By addressing this gap, the findings contribute valuable insights and offer a framework that could enhance clinical decision-making and support timely disease management in pediatric cases.

Innumerable Culture-Negative Intracranial Abscesses in an Immunocompetent Young Male Diagnosed by 16s rRNA Gene Sequencing

Here, we present a case of a healthy young man with an initial presentation concerning for infectious encephalitis later found on neuroimaging to have extensive intracranial lesions. Pathological analysis of these lesions was consistent with a bacterial intraparenchymal abscess; however, cultures were negative for a causative organism. Results of gene sequencing from an abscess sample were consistent with Streptococcus intermedius infection. Streptococcus intermedius, a β-hemolytic gram-positive species of the Streptococcus anginosus group (SAG), is known to possess several virulence factors that promote abscess formation.

Profiles of primary brain abscesses and their impact on survival: An international ID-IRI study

OBJECTIVES

This study of 331 primary brain abscess (PBA) patients aimed to understand infecting agents, predisposing factors, and outcomes, with a focus on factors affecting mortality.

METHODS

Data were collected from 39 centers across 16 countries between January 2010 and December 2022, and clinical, radiological, and microbiological findings, along with their impact on mortality, were analyzed.

RESULTS

The patients had a mean ± SD age of 46.8 ± 16.3 years, with a male predominance of 71.6%. Common symptoms included headache (77.9%), fever (54.4%), and focal neurological deficits (53.5%). Gram-positive cocci were the predominant pathogens, with Viridans group streptococci identified as the most frequently isolated organisms. All patients received antimicrobial therapy and 71.6% underwent interventional therapies. The 42-day and 180-day survival rates were 91.9% and 86.1%, respectively. Significant predictors of 42-day mortality included intravenous drug addiction (HR: 6.02, 95% CI: 1.38-26.26), malignancy (HR: 3.61, 95% CI: 1.23-10.58), confusion (HR: 2.65, 95% CI: 1.19-5.88), and unidentified bacteria (HR: 4.68, 95% CI: 1.76-12.43). Significant predictors of 180-day mortality included malignancy (HR: 2.70, 95% CI: 1.07-6.81), confusion (HR: 2.14, 95% CI: 1.11-4.15), temporal lobe involvement (HR: 2.10, 95% CI: 1.08-4.08), and unidentified bacteria (HR: 3.02, 95% CI: 1.49-6.15).

CONCLUSION

The risk of death in PBA extends beyond the infection phase, with different factors influencing the 42-day and 180-day mortality rates. Intravenous drug addiction was associated with early mortality, while temporal lobe involvement was associated with late mortality.

Unveiling the Intricate Link Between Anaerobe Niche and Alzheimer Disease Pathogenesis

Dysbiosis within microbiomes has been increasingly implicated in many systemic illnesses, such as cardiovascular disease, metabolic syndrome, respiratory infections, and Alzheimer disease (Ad). The correlation between Ad and microbial dysbiosis has been repeatedly shown, yet the etiologic cause of microbial dysbiosis remains elusive. From a neuropathology perspective, abnormal (often age-related) changes in the brain, associated structures, and bodily lumens tend toward an accumulation of oxygen-depleted pathologic structures, which are anaerobically selective niches. These anaerobic environments may promote progressive change in the microbial community proximal to the brain and thus deserve further investigation. In this review, we identify and explore what is known about the anaerobic niche near or associated with the brain and the anaerobes that it is harbors. We identify the anaerobe stakeholders within microbiome communities and the impacts on the neurodegenerative processes associated with Ad. Chronic oral dysbiosis in anaerobic dental pockets and the composition of the gut microbiota from fecal stool are the 2 largest anaerobic niche sources of bacterial transference to the brain. At the blood-brain barrier, cerebral atherosclerotic plaques are predominated by anaerobic species intimately associated with the brain vasculature. Focal cerebritis/brain abscess and corpora amylacea may also establish chronic anaerobic niches in direct proximity to brain parenchyma. In exploring the anaerobic niche proximal to the brain, we identify research opportunities to explore potential sources of microbial dysbiosis associated with Ad.

Acute infections of the central nervous system in children and adults: diagnosis and management

Central nervous system infections are due to different microorganisms such as viruses, bacteria, mycobacteria, fungi, amoebas, and other parasites. The etiology depends on multiple risk factors, and it defines the infection location because some microorganisms prefer meninges, brain tissue, cerebellum, brain stem or spinal cord. The microorganisms induce diseases in the nervous system through direct invasion, neurotoxin production, and the triggered immune response. To determine the infection etiology, there are several diagnostic tests which may be conducted with cerebrospinal fluid, blood, respiratory and stool samples. These tests include but are not limited to direct microscopic examination of the sample, stains, cultures, antigenic tests, nucleic acid amplification tests, metagenomic next-generation sequencing, immunologic biomarker and neuroimaging, especially contrast-enhanced magnetic resonance imaging. The treatment may consist of specific antimicrobial treatment and supportive standard care. Since viruses have no specific antiviral treatment, antimicrobial treatment is mainly targeted at non-viral infections. This article will focus on diagnosis and treatment of acute acquired infections of the central nervous system beyond the neonatal period. The discussion defines the disease, provides the clinical presentation, explains the etiology and risk factors, and briefly mentions potential complications. This updated review aims to provide the reader with all the elements needed to adequately approach a patient with a central nervous system infection. Mycobacterium tuberculosis infection, Cryptococcus spp. infection and vaccines are not within the scope of this article.

Geriatric nutritional risk index has a prognostic value for recovery outcomes in elderly patients with brain abscess

Background

The Geriatric Nutritional Risk Index (GNRI) is a straightforward and objective tool for nutritional screening in older patients and has been demonstrated to possess prognostic predictive value in several diseases. Nonetheless, there is a lack of research on the nutritional risk associated with brain abscess in the older. This study aimed to evaluate the prevalence of nutritional risk among these patients by GNRI and to investigate its potential prognostic value for clinical outcomes.

Materials and methods

From August 2019 to April 2023, 100 older patients diagnosed with brain abscess were enrolled in this single-center prospective cohort study, which evaluated the prognostic value of the Geriatric Nutritional Risk Index (GNRI) in elderly brain abscess patients. Data collected included demographic, and clinical characteristics at admission and calculated the GNRI, and the Glasgow Outcome Scale (GOS) score 6 months post-discharge. A GOS score of 5 was considered indicative of a good recovery, whereas scores ranging from 1 to 4 were classified as poor recovery.

Results

The results revealed that 48% of older brain abscess patients were at risk of malnutrition according to the GNRI. These patients had significantly higher post-admission C-reactive protein (CRP) levels (p = 0.017), more comorbidities (p < 0.001), and higher age-adjusted Charlson Comorbidity Index (aCCI) scores (p < 0.001) compared to those without nutritional risk. Spearman correlation analysis showed that GNRI scores were negatively correlated with CRP levels, comorbidities, and aCCI scores, and positively correlated with Glasgow Outcome Scale (GOS) scores (Spearman's ρ = 0.624, p < 0.001). Multivariate logistic regression revealed that lower GNRI values were linked to reduced GOS levels (OR = 0.826, 95% CI: 0.775-0.880). ROC analysis determined a GNRI threshold of 97.50 for predicting poor recovery, with 90.57% sensitivity and 87.23% specificity.

Conclusion

The older brain abscess patients exhibited a high malnutrition risk. GNRI showed an important predictive value for recovery in older patients, which could be helpful in clinical intervention and rehabilitation.

Brain Abscesses in Domestic Ruminants: Clinicopathological and Bacteriological Approaches

Brain abscesses in ruminants often arise from primary infection foci, leading to an unfavorable prognosis for affected animals. This highlights the need for comprehensive studies on brain abscesses across different ruminant species. We retrospectively investigated medical records of epidemiological, clinical, neuroimaging, anatomopathological, and bacteriological findings in six ruminants (three goats, two cows, and one sheep) diagnosed with brain abscesses. All animals studied were female. Apathy (50%), compulsive walking (33%), decreased facial sensitivity (33%), head pressing (33%), seizures (33%), semicomatous mental status (33%), strabismus (33%), unilateral blindness (33%), and circling (33%) represented the most common neurologic signs. Leukocytosis and neutrophilia were the main findings in the hematological evaluation. Cerebrospinal fluid (CSF) analysis revealed predominant hyperproteinorrachia and pleocytosis. In three cases, computed tomography or magnetic resonance imaging were used, enabling the identification of typical abscess lesions, which were subsequently confirmed during postmortem examination. Microbiological culture of the abscess samples and/or CSF revealed bacterial coinfections in most cases. Advanced imaging examinations, combined with CSF analysis, can aid in diagnosis, although confirmation typically relies on postmortem evaluation and isolation of the causative agent. This study contributes to clinicopathological aspects, neuroimages, and bacteriological diagnosis of brain abscesses in domestic ruminants.

Update on Focal Infection Management: A Czech Interdisciplinary Consensus

BACKGROUND

The focal infection theory has been used to explain several chronic systemic diseases in the past. Systemic diseases were thought to be caused by focal infections, such as caries and periodontal diseases, and dentists were held responsible for these diseases due to the spread of oral infections. As knowledge of the interrelationship between oral microorganisms and the host immune response has evolved over the last few decades, the focal infection theory has been modified in various ways. The relationship between oral and systemic health appears to be more complex than that suggested by the classical theory of focal infections. Indeed, the contribution of the oral microbiota to some systemic diseases is gaining acceptance, as there are strong associations between periodontal disease and atherosclerotic vascular disease, diabetes, and hospital-associated pneumonia, amongst others. As many jurisdictions have various protocols for managing this oral-systemic axis of disease, we sought to provide a consensus on this notion with the help of a multidisciplinary team from the Czech Republic.

METHODS

A multidisciplinary team comprising physicians/surgeons in the specialities of dentistry, ear-nose and throat (ENT), cardiology, orthopaedics, oncology, and diabetology were quetioned with regard to their conceptual understanding of the focal infection theory particularly in relation to the oral-systemic axis. The team also established a protocol to determine the strength of these associations and to plan the therapeutic steps needed to treat focal odontogenic infections whenever possible.

RESULTS

Scoring algorithms were devised for odontogenic inflammatory diseases and systemic risks, and standardised procedures were developed for general use.

CONCLUSIONS

The designed algorithm of the oral-systemic axis will be helpful for all health care workers in guiding their patient management protocol.

Brain abscess caused by Actinomyces turicensis in a non-immunocompromised adult patient: a case report and systematic review of the literature

BACKGROUND

Actinomyces turicensis is rarely responsible of clinically relevant infections in human. Infection is often misdiagnosed as malignancy, tuberculosis, or nocardiosis, therefore delaying the correct identification and treatment. Here we report a case of a 55-year-old immunocompetent adult with brain abscess caused by A. turicensis. A systematic review of A. turicensis infections was performed.

METHODS

A systematic review of the literature was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The databases MEDLINE, Embase, Web of Science, CINAHL, Clinicaltrials.gov and Canadian Agency for Drugs and Technology in Health (CADTH) were searched for all relevant literature.

RESULTS

Search identified 47 eligible records, for a total of 67 patients. A. turicensis infection was most frequently reported in the anogenital area (n = 21), causing acute bacterial skin and skin structure infections (ABSSSI) including Fournier's gangrene (n = 12), pulmonary infections (n = 8), gynecological infections (n = 6), cervicofacial district infections (n = 5), intrabdominal or breast infections (n = 8), urinary tract infections (n = 3), vertebral column infections (n = 2) central nervous system infections (n = 2), endocarditis (n = 1). Infections were mostly presenting as abscesses (n = 36), with or without concomitant bacteremia (n = 7). Fever and local signs of inflammation were present in over 60% of the cases. Treatment usually involved surgical drainage followed by antibiotic therapy (n = 51). Antimicrobial treatments most frequently included amoxicillin (+clavulanate), ampicillin/sulbactam, metronidazole or cephalosporins. Eighty-nine percent of the patients underwent a full recovery. Two fatal cases were reported.

CONCLUSIONS

To the best of our knowledge, we hereby present the first case of a brain abscess caused by A. turicensis and P. mirabilis. Brain involvement by A. turicensis is rare and may result from hematogenous spread or by dissemination of a contiguous infection. The infection might be difficult to diagnose and therefore treatment may be delayed. Nevertheless, the pathogen is often readily treatable. Diagnosis of actinomycosis is challenging and requires prompt microbiological identification. Surgical excision and drainage and antibiotic treatment usually allow for full recovery.

A Rare Case of Cerebral Abscess due to Fusobacterium nucleatum with Native Aortic Valve Infective Endocarditis and Pyogenic Liver Abscess

Fusobacterium nucleatum is a commensal pathogen typically found in the oral cavity, digestive tract, and urogenital system which has been associated with Lemierre's syndrome, periodontal diseases, sinusitis, endocarditis, and intra-abdominal and brain abscesses. Our case is of a 62-year-old male who presented with headaches, nausea, and vision loss. Brain imaging identified a right occipito-parietal brain abscess. Following surgery and abscess drainage, Fusobacterium nucleatum was isolated from intraoperative cultures, and the infectious disease service was consulted for antibiotic recommendations. Additional history uncovered that he had also been experiencing night sweats, generalized weakness and 40-pound weight loss for 2 months, and had a prior history of colon polyps and diverticulitis. Furthermore, the patient disclosed having substandard oral hygiene practices, particularly in relation to the care of his dental appliances. Despite negative blood cultures, suspicion for hematogenous seeding was high. Imaging ruled out periodontal disease, but identified a colovesical fistula and liver abscesses, indicating potential translocation of bacteria via portal circulation to his liver. Echocardiogram workup revealed a 1-cm mobile vegetation on the aortic valve. His course was complicated by breakthrough seizures, renal failure, and drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome, and he ultimately completed 16 weeks of antibiotics. This case illustrates an uncommon presentation of brain abscess in an immunocompetent adult, with a prior episode of diverticulitis as the probable primary infection source, leading to development of a colovesical fistula and bacterial dissemination to the liver, heart, and brain. It highlights the importance of a comprehensive diagnostic approach, including consideration of atypical pathogens in immunocompetent adults.

Brain Abscesses in the Tropics

Purpose of Review

This review aims to elucidate the etiologies of brain abscesses in the tropics. Despite the similarities in causes of brain abscesses across global regions, tropical settings manifest distinguishing characteristics, prominently observed on computed tomography or magnetic resonance imaging.

Recent Findings

In tropical climates, the leading conditions predisposing individuals to brain abscesses are polymicrobial bacterial infections originating from paranasal sinuses, dental sources, and otitis media. However, the tropics present unique etiologies to be aware of, including Trypanosoma cruzi (Chagas disease), free-living amoebas like Balamuthia mandrillaris, infections from Burkholderia pseudomallei (melioidosis), fungi such as Talaromyces marneffei, and Mycobacterium tuberculosis. Given the differential diagnoses, which include neoplastic, inflammatory, and demyelinating diseases, a stereotactic biopsy coupled with a microbiological assessment remains valuable for accurate diagnosis.

Summary

In tropical regions, brain abscesses are a concern when confronted with mass-occupying or other types of brain lesions. Successful clinical management of brain abscesses typically combines surgical intervention and extended anti-microbial treatment. However, specific parasitic invasions like Chagas disease, free-living amoebas, and Entamoeba histolytica necessitate targeted anti-parasitic therapies. Furthermore, international policy efforts should focus on prevention measures in resource limited regions with heightened risks and disease burden.

Is Metagenomics the Future Routine Diagnosis Tool for Brain Abscesses? About a Case

Shotgun metagenomics (SMg) usefulness for brain abscess diagnosis is not known. We describe a case of brain abscess diagnosed with SMg and provide a review of the literature. A 70-year-old woman was diagnosed with multiple brain abscesses. Standard culture techniques and 16S rRNA gene sequencing of abscess samples remained negative. SMg finally revealed the presence of sequences from Streptococcus anginosus and Fusobacterium nucleatum, leading to antimicrobial treatment adaptation and corticosteroids initiation. The patient finally recovered. A literature review retrieved fifteen other cases of brain abscesses diagnosed with SMg. SMg results led to changes in patient management in most cases. The existing literature about the performances of SMg, its advantages, future evolutions, and limitations is then discussed. SMg place in routine should be evaluated and defined through prospective studies.

Clinical Features and Diagnosis of Intramedullary Spinal Cord Abscess in Adults: A Systematic Review

BACKGROUND AND OBJECTIVES

Intramedullary spinal cord abscess (ISCA) was described 200 years ago but remains poorly understood and is often mistaken for immune-mediated or neoplastic processes. We present a systematic review of ISCA in adults, describing the clinical presentation, diagnostic features, treatment strategies, and outcomes.

METHODS

Database searches for intramedullary abscess were performed on April 15, 2019, and repeated on February 9, 2022, using PubMed and EMBASE with 2 unpublished cases also included. Publications were independently reviewed for inclusion by 2 authors followed by adjudication. Data were abstracted using an online form and then analyzed for predictors of disability.

RESULTS

A total of 202 cases were included (median age 45 years [interquartile range 31-58]; 70% male). Thirty-one percent of those affected had no identified predisposing condition. The most common symptom was weakness (97%), and the median symptom duration before presentation was 10 days (interquartile range 5-42). An MRI showed restricted diffusion in 100% of 8 cases where performed and enhancement in 99% of 153 cases where performed. The most common organisms were Mycobacterium tuberculosis (29%), Streptococcus sp. (13%), and Staphylococcus sp. (10%). All patients received antimicrobial therapy; surgical drainage was performed in 65%. At follow-up (median 6 months), 12% had died, 69% were ambulatory, and 77% had improved compared with clinical nadir. Of those who underwent operative intervention, surgery within 24 hours of diagnosis was associated with an increased likelihood of being ambulatory at follow-up compared with surgery after 24 hours (odds ratio 4.44; 95% CI 1.26-15.61; p = 0.020).

DISCUSSION

ISCA is important to consider in any patient presenting with acute-to-subacute, progressive myelopathy. Immunocompromise and typical signs of infection (e.g., fever) are often absent. Diffusion restriction and gadolinium enhancement on MRI seem to be sensitive. Antimicrobial therapy with surgical drainage is the most common therapeutic approach, but morbidity remains substantial. If performed, urgent surgery may be more beneficial.

[Actinomyces europaeus (Gleimia europaea) associated with brain abscess: A report of three cases]

A brain abscess is a focal infection characterized by a collection of pus in the brain parenchyma. It is a life-threatening condition that should be diagnosed and treated as soon as possible. We report here three cases of patients with otogenic brain abscesses of polymicrobial origin that had in common the isolation of Actinomyces europaeus, which has not been previously described in this location. A. europaeus was identified by the conventional methodology, matrix-associated laser deionization-time of flight mass spectrometry (MALDI-TOF MS) and 16S rRNA gene sequencing. Antibiotic susceptibility was evaluated by the epsilometric method, and all isolates showed sensitivity to penicillin, vancomycin and linezolid, whereas susceptibility to clindamycin and erythromycin was variable. MALDI-TOF MS identification allowed a quick and reliable species level identification in order to provide a rapid and effective response to avoid treatment delay that could lead to increased morbidity and even mortality.

Treatment of septic encephalopathy and encephalitis - a critical appraisal

INTRODUCTION

The central nervous system is frequently involved during severe sepsis. Patients either develop septic encephalopathy characterized by delirium and coma or focal neurological signs as a consequence of septic-embolic or septic-metastatic encephalitis.

AREAS COVERED

In this review, a summary of currently available literature on established and some promising experimental treatment options for septic encephalopathy and encephalitis is provided, with a focus on the clinical utility of published studies.

EXPERT OPINION

Treatment relies on proper identification of the causative pathogen and rapidly initiated adequate empirical or (after identification of the pathogen) tailored antibiotic therapy, fluid and electrolyte management. In the presence of brain abscess(es) or mycotic aneurysm(s), surgery or interventional neuroradiology must be considered. Pharmacological approaches to prevent delirium of different etiology include the use of dexmedetomidine and (with limitations) of melatonin and its derivatives. In the absence of a specific pharmacological treatment, non-pharmacological bundles of interventions (e.g. promotion of sleep, cognitive stimulation, early mobilization and adequate therapy of pain) are of proven efficacy to prevent delirium of different etiology including sepsis. Experimental promising therapies include the use of non-bacteriolytic antibiotics and the reduction of the toxic effects of microglial activation.

Actinomyces israelii and Fusobacterium nucleatum brain abscess in an immunocompetent patient: case report

Introduction

Brain abscess is the most common focal infectious neurological injury. Until the nineteenth century this condition was fatal, however the development of neuroimaging for early diagnosis, neurosurgery and antibiotic therapy in the twentieth century has led to new therapeutic strategies decreasing mortality from 50 % in the 1970s to less than 10 % nowadays. In this context we report a case of brain abscess with a dental origin.

Case report

A immunocompetent man without any addiction presented to the emergency department with dysarthria and frontal headache at home. The clinical examination was normal. Further investigations revealed a polymicrobial brain abscess as a consequence of an ear, nose or throat (ENT) infection with locoregional extension with a dental starting point involving Actinomyces israelii and Fusobacterium nucleatum . In spite of a rapid diagnosis and a neurosurgical management associated with an optimal treatment by a dual therapy made of ceftriaxone and metronidazole the patient unfortunately died.

Conclusion

This case report shows that despite a low incidence and a good prognosis following the diagnosis, brain abscesses can lead to patient's death. Thereby, when the patient's condition and urgency allow, a thorough dental examination of patients with neurological signs following the recommendations would improve the diagnosis made by the clinician. The use of microbiological documentation, the respect of pre-analytical conditions, the interaction between the laboratory and the clinicians are indispensable for an optimal management of these pathologies.

Methodological comparison of bronchoalveolar lavage fluid-based detection of respiratory pathogens in diagnosis of bacterium/fungus-associated pneumonia in critically ill patients

Background

Bacterium/fungus-associated pneumonia (BAP/FAP) is the prominent cause of high mortality and morbidity with important clinical impacts globally. Effective diagnostic methods and proper specimen types hopefully facilitate early diagnosis of pneumonia and prevent spread of drug-resistant bacteria/fungi among critically ill patients.

Methods

In the present study, 342 bronchoalveolar lavage fluid (BALF) samples were collected from critically ill patients with pulmonary infections between November 2020 and March 2021. The BALF materials were comparatively employed to screen BAP/FAP through microscopy, culture, antigenic marker and PCR-based methods. The limit of detection (LOD) of cultures and PCR for bacteria/fungi was determined by serial dilution assays. Specimen slides were prepared with Gram staining for microscopic examinations. Microbial cultures and identifications underwent routine clinical protocols with the aid of mass spectrometry. (1,3)-β-D-glucan and galactomannan tests with BALF were carried out accordingly. Direct detection of pathogens in BALF was achieved through PCR, followed by sequencing and BLAST in GenBank database for pathogenic identification. The subjects' demographic and clinical characteristics were well evaluated.

Results

BAP/FAP was identified in approximately 47% of the subjects by the BALF-based PCR. The PCR-based diagnostic methods showed improved detection performance for fungi with good LOD, but performed similarly for bacteria, when compared to the cultures. There was poor agreement among traditional microscopy, culture and PCR assays for bacterial detections (kappa value, 0.184 to 0.277). For overall bacterial/fungal detections, the microscopy showed the lowest detecting rate, followed by the cultures, which displayed a slightly higher sensitivity than the microscopy did. The sensitivity of PCR was much higher than that of the other means of interest. However, the traditional cultures rather than antigenic marker-based approaches were moderately consistent with the PCR-based methods in fungal species identification, particularly for Candida and Aspergillus spp. Our findings further revealed that the age, length of hospital stay, invasive procedures and cerebral diseases were likely considered as main risk factors for BAP/FAP.

Conclusion

Screening for BALF in critically ill patients with suspected pneumonia pertaining high risk factors using combined PCR-based molecular detection strategies would hopefully contribute to early diagnosis of BAP/FAP and improved prognosis of the patients.

Spontaneous empyema and brain abscess in an intensive care population: clinical presentation, microbiology, and factors associated with outcome

BACKGROUND

Data on critically ill patients with spontaneous empyema or brain abscess are limited. The aim was to evaluate clinical presentations, factors, and microbiological findings associated with the outcome in patients treated in a Neurocritical Care Unit.

METHODS

In this retrospective study, we analyzed 45 out of 101 screened patients with spontaneous epidural or subdural empyema and/or brain abscess treated at a tertiary care center between January 2012 and December 2019. Patients with postoperative infections or spinal abscess were excluded. Medical records were reviewed for baseline characteristics, origin of infection, laboratory and microbiology findings, and treatment characteristics. The outcome was determined using the Glasgow outcome scale extended (GOSE).

RESULTS

Favorable outcome (GOSE 5-8) was achieved in 38 of 45 patients (84%). Four patients died (9%), three remained severely disabled (7%). Unfavorable outcome was associated with a decreased level of consciousness at admission (Glasgow coma scale < 9) (43% versus 3%; p = 0.009), need of vasopressors (71% versus 11%; p = 0.002), sepsis (43% versus 8%; p = 0.013), higher age (65.1 ± 15.7 versus 46.9 ± 17.5 years; p = 0.014), shorter time between symptoms onset and ICU admission (5 ± 2.4 days versus 11.6 ± 16.8 days; p = 0.013), and higher median C-reactive protein (CRP) serum levels (206 mg/l, range 15-259 mg/l versus 17.5 mg/l, range 3.3-72.7 mg/l; p = 0.036). With antibiotics adapted according to culture sensitivities in the first 2 weeks, neuroimaging revealed a progression of empyema or abscess in 45% of the cases.

CONCLUSION

Favorable outcome can be achieved in a considerable proportion of an intensive care population with spontaneous empyema or brain abscess. Sepsis and more frequent need for vasopressors, associated with unfavorable outcome, indicate a fulminant course of a not only cerebral but systemic infection. Change of antibiotic therapy according to microbiological findings in the first 2 weeks should be exercised with great caution.

Neuroimaging Patterns of Intracranial Infections: Meningitis, Cerebritis, and Their Complications

Neuroimaging provides rapid, noninvasive visualization of central nervous system infections for optimal diagnosis and management. Generalizable and characteristic imaging patterns help radiologists distinguish different types of intracranial infections including meningitis and cerebritis from a variety of bacterial, viral, fungal, and/or parasitic causes. Here, we describe key radiologic patterns of meningeal enhancement and diffusion restriction through profiles of meningitis, cerebritis, abscess, and ventriculitis. We discuss various imaging modalities and recent diagnostic advances such as deep learning through a survey of intracranial pathogens and their radiographic findings. Moreover, we explore critical complications and differential diagnoses of intracranial infections.

Intramedullary spinal cord abscess with brain abscess due to subacute infective endocarditis

BACKGROUND

Intramedullary spinal cord abscesses (ISCA) are rare, even more so in association with brain abscesses. Infective endocarditis is an uncommon cause of ISCA. In this case study, we report a patient with intramedullary abscesses and multiple brain abscesses due to subacute infective endocarditis.

CASE PRESENTATION

A 54-year-old man presented with a 7-day history of head and neck pain and numbness in both lower limbs. Intramedullary abscess combined with multiple brain abscesses was diagnosed based on blood culture, head and spinal magnetic resonance imaging (MRI), contrast-enhanced MRI, and magnetic resonance spectroscopy. Echocardiography revealed vegetations on the mitral valve and severe mitral regurgitation, which the authors believe was caused by subacute infective endocarditis. With ceftriaxone combined with linezolid anti-infective therapy, the patient's symptoms and imaging was improved during follow-up.

CONCLUSIONS

This case hopes to raise the vigilance of clinicians for ISCA. When considering a patient with an ISCA, it is necessary to complete blood culture, MRI of the brain and spinal cord, and echocardiography to further identify whether the patient also has a brain abscess and whether the cause is infective endocarditis.

Brain Abscess Caused by Nocardia brevicatena in an Immunocompetent Patient: A Case Report

Nocardia brain abscess is relatively rare and generally occurs in immunodeficient patients. Here, we present the first case of brain abscess due to Nocardia brevicatena in an immunocompetent patient, with unknown origin. In this case, a 49-year-old man was admitted to our hospital with limb twitching and complained of a history of intermittent headache. He was diagnosed with brain abscess through brain imaging and cured after craniotomy for abscess excision and targeted antibiotic treatment. Surgical specimens were sent for further detection. The causative organism was identified by weak acid-fast staining, culture and metagenomic next-generation sequencing (mNGS). We hope this case could provide a reference for incoming patients as well as their clinical management.

Surgical management of an abscess of the insula

Background

Mass lesions within the insular are diagnostically and surgically challenging due to the numerous critical cortical, subcortical, and vascular structures surrounding the region. Two main surgical techniques - the transsylvian approach and the transcortical approach - provide access to the insular cortex. Of the range of pathologies encountered, abscesses in the insula are surprisingly rare.

Case Description

A 34-year-old patient was admitted for surgical resection of a suspected high-grade glioma in the insula of the dominant hemisphere. A rapid clinical decline prompted emergent neurosurgical intervention using a transsylvian approach. Surprisingly, abundant purulent material was encountered on entering the insular fossa. Pathological analysis confirmed an insular abscess, although a source of infection could not be identified. The patient required a second evacuation for reaccumulation of the abscess and adjuvant corticosteroids for extensive cerebral edema.

Conclusion

An abscess located in the insular cortex is an incredibly rare occurrence. Surgical management using the transsylvian approach is one option to approach this region. Familiarity with this approach is thus extremely beneficial in situations requiring emergent access to the dominant insula when awake mapping is not feasible. In addition, treatment of abscesses with adjuvant corticosteroids is indicated when extensive, life-threatening cerebral edema is present.

COVID-19 Co-Infection May Promote Development of Sinusitis Complication in Children

BACKGROUND

The olfactory dysfunction that occurs during a COVID-19 infection has sparked much debate about its similarity to sinusitis. Up to 65% of COVID-19 pediatric patients may be asymptomatic; however, when symptoms are observed, fever and cough are the most common. Nasal congestion and discharge as well as headaches can also be seen, which makes both entities, i.e., COVID-19 and sinusitis, similar to each other.

METHODS

In this review, we present the clinical case of a teenager with a history of acute sinusitis and COVID-19 co-infection followed by purulent meningoencephalitis. We aim to summarize available findings on the association between COVID-19, sinusitis, and possible common complications of both diseases.

RESULTS

Differentiating between COVID-19 and sinusitis can be confusing because presented symptoms may overlap or mimic each other. Increased risk of complications, especially in patients with bacterial sinusitis co-infected with SARS-CoV-2, should prompt physicians to monitor young patients and inform parents about disturbing symptoms and possible complications.

CONCLUSIONS

Acute sinusitis and COVID-19 co-infection may lead to numerous complications and should be included among the factors predisposing to worse prognosis. It is especially related to patients with high risk factors and even more important in children as they often pass the infection asymptomatically and its complications can lead to loss of health or life.

Aspiration Surgery with Appropriate Antibiotic Treatment Yields Favorable Outcomes for Bacterial Brain Abscess

BACKGROUND

Even in the era of advanced medical treatment, brain abscess still has a high mortality rate. At our institution, brain abscess has been treated mainly using stereotactic or echo-guided aspiration followed by relatively long-term antibiotic treatment, achieving favorable outcomes. To evaluate the efficacy of our strategy involving less-invasive aspiration surgery and long-term selective antibiotic administration for brain abscess, a single-institution series of cases was investigated.

METHODS

We retrospectively reviewed and analyzed the medical records of 25 cases of brain abscess treated at Saitama Medical University Hospital between 2008 and 2021. The patients comprised 16 men and 9 women aged between 39 and 85 years (median 62 years). Neurosurgical intervention was performed for 23 (92.0%) of the patients and the remaining 2 received antibiotics alone.

RESULTS

Among the neurosurgery patients, 22 (95.7%) underwent echo-guided or stereotactic aspiration, and only 1 underwent craniotomy. Anaerobic bacteria were detected in 11 patients. In the surgical and conservative groups, the median duration of antibiotic treatment was 16 weeks and 23 weeks, respectively. Since 2014 when metronidazole first became available, it has replaced meropenem to cover anaerobic bacteria. The overall mortality rate was 4.0% and a favorable outcome (Glasgow Outcome Scale 4 or 5) was achieved in 76% of the patients. There was no surgical mortality or morbidity.

CONCLUSIONS

Most patients underwent aspiration surgery and achieved favorable outcomes. Along with antibiotic treatment for a sufficiently long period to cover anaerobes, this approach can be expected to yield good results.

5-Aminolevulinic acid fluorescence in brain non-neoplastic lesions: a systematic review and case series

Fluorescence-guided surgery with 5-aminolevulinic acid (5-ALA) is used to assist brain tumor resection, especially for high-grade gliomas but also for low-grade gliomas, metastasis, and meningiomas. With the increasing use of this technique, even to assist biopsies, high-grade glioma-mimicking lesions had misled diagnosis by showing 5-ALA fluorescence in non-neoplastic lesions such as radiation necrosis and inflammatory or infectious disease. Since only isolated reports have been published, we systematically review papers reporting non-neoplastic lesion cases with 5-ALA according with the PRISMA guidelines, present our series, and discuss its pathophysiology. In total, 245 articles were identified and 12 were extracted according to our inclusion criteria. Analyzing 27 patients, high-grade glioma was postulated as preoperative diagnosis in 48% of the cases. Microsurgical resection was performed in 19 cases (70%), while 8 patients were submitted to biopsy (30%). We found 4 positive cases in demyelinating disease (50%), 4 in brain abscess (80%), 1 in neurocysticercosis (33%), 1 in neurotoxoplasmosis, infarction, and hematoma (100%), 4 in inflammatory disease (80%), and 3 in cortical dysplasia (100%). New indications are being considered especially in benign lesion biopsies with assistance of 5-ALA. Using fluorescence as an aid in biopsies may improve procedure time, number of samples, and necessity of intraoperative pathology. Further studies should include this technology to encourage more beneficial uses.

An Eight Year Clinico-Microbiological Retrospective Study on Brain Abscesses in India

Background:

Intracranial abscesses have been a diagnostic and therapeutic challenge since time immemorial for both the microbiologists and the neurosurgeons. There is paucity of detailed studies documenting the infecting organism causing brain abscesses in South India.

Aims:

The study aimed at identifying and assessing the prevalence of aerobic, anaerobic bacteria and fungi associated with brain abscesses at a tertiary care hospital in South India.

Methods and Material:

Eight years data was collected from the records of culture reports from 2007 to 2010 and 2013 to 2018. The corresponding clinical case records were retrieved for the assessment of risk factors. Risk factors of brain abscess development were assessed based on clinical cases records.

Results:

Data from 140 brain abscess cases obtained over a period of 8 years were analyzed. Out of the 140 samples, 66 (47.14%) were culture positive in which 33 (50%) had single aerobic/facultative anaerobic bacteria, 20 (30.3%) had mixture of more than one aerobic/facultative anaerobic bacteria, 12 (18.18%) had single obligate anaerobic bacteria and 1(1.5%) sample had Mycobacterium tuberculosis isolated. Among the total 92 isolates, Pseudomonas aeruginosa (21/92, 23%) and Staphylococcus aureus (20/92, 22%) predominated. Bacteroides fragilis group was the most common obligate anaerobe isolated. There were no fungal isolates. As there were various isolates isolated, hence there is heterogeneity of isolates detected Neuroanatomically, parietal lobe (45/140, 32%) was the most common location. Otogenic infection was the major risk factor for parietal and temporal lobe abscess (P value < .05).

Conclusions:

It has become essential for the microbiologists to be aware of unusual isolates from brain abscess and its complex nature. Obscurity and difficulty in their microbiological diagnosis calls for more such detailed studies.

Brain abscess in immunocompetent patients: recent findings

PURPOSE OF REVIEW

We conducted a systematic review of the literature to update findings on the epidemiology and the management of cerebral abscesses in immunocompetent patients.

RECENT FINDINGS

Observational studies suggest that the overall prognosis has improved over the last decades but mortality rates remain high. Several parameters may contribute to a better prognosis, including the identification of common risk factors for brain abscess, the systematic use of brain MRI at diagnosis, the implementation of appropriate neurosurgical and microbiological techniques for diagnosis, the optimization of the antibacterial treatment based on epidemiology and pharmacokinetic/pharmacodynamic studies, and a long-term follow-up for detection of secondary complications. Outcome research on brain abscess is mainly based on observational studies. Randomized controlled trials have yet to be performed to identify clinically relevant interventions associated with improved patient-centered outcomes.

SUMMARY

Our review highlights the importance of a multidisciplinary approach to optimize brain abscess management both at the acute phase and in the long-term. Randomized controlled studies are urgently needed to identify interventions associated with improved outcomes.

Application of metagenomic next-generation sequencing for the diagnosis of intracranial infection of Listeria monocytogenes

Background

Intracranial infection of Listeria monocytogenes (LM) can lead to various manifestations, including meningitis, meningoencephalitis, brainstem encephalitis, and brain abscess, which often have a poor prognosis. Metagenomic next-generation sequencing (mNGS) is a promising new tool for the diagnosis of intracranial infection of LM. We describe the typical clinical manifestations of LM intracranial infection and highlight its rarity and severity to help physicians better understand the disease characteristics.

Methods

Six cases of severe LM intracranial infection were diagnosed by mNGS. We conducted a retrospective analysis of the data on disease progression, diagnostic tools, treatments, and outcomes, and summarized the findings. We compared the differences in diagnostic accuracy and timeliness between mNGS and etiological cultures.

Results

Among the 6 patients, 5 were males and 1 was female (age range 32–83). Three patients had a history of immunosuppressive therapy. Common symptoms included fever (100%) and a stiff neck (100%). Coma occurred early in severe patients (66%). Two healthy young patients had previously developed with meningitis, while coma occurred in 3 immunosuppressed patients and 1 elderly patient. Three immunosuppressed patients presented with brain abscess, brainstem encephalitis, and meningitis. 1 elderly patient presented with meningitis. Two patients developed septic shock complications early. Laboratory data showed normal or slightly increased leukocytes, neutrophils, and procalcitonin, and cerebrospinal fluid (CSF) tests were consistent with bacterial CSF infection. All 6 patients were examined for blood culture and CSF culture. The positive rate of blood culture and CSF culture was 50% and 16%. The average time from admission to positive culture findings was 91 h. All 6 patients were examined for CSF mNGS. Two were also examined for whole-blood mNGS. The positive rate for CSF mNGS and whole-blood mNGS results was 100%. The mean time from admission to positive mNGS report was 47 h. After diagnosis and treatment with sensitive antibiotics, 1 patient with brain abscess developed neurological sequelae, while the other 5 patients completely recovered.

Conclusions

mNGS can improve accuracy in the diagnosis of LM intracranial infection and reduce the delay in diagnosis. Intracranial infection of Listeria monocytogenes responds well to the timely use of appropriate antibiotics.

Can MRI differentiate between ring-enhancing gliomas and intra-axial abscesses?

Gliomas of the brain may appear as expansile ring-enhancing masses in MRI studies, mimicking the appearance of intra-axial abscesses. The aims of this study were to compare the MRI features of ring-enhancing gliomas and intra-axial brain abscesses in dogs and cats and to identify the characteristics that might help differentiate them. For this multicenter, retrospective, and observational study, the inclusion criteria were as follows: (a) a definitive diagnosis of glioma or abscess based on cytological or histopathological examination following CSF collection or surgical biopsy/necropsy, respectively; (b) MRI study performed with a high- or low-field MRI scanner, including a same plane T1W pre- and postcontrast, a T2W and a T2 FLAIR sequence in at least one plane. If available, delayed T1W postcontrast, T2*W GE, DWI/ADC, and SWI sequences were also evaluated. Sixteen patients were diagnosed with ring-enhancing gliomas, and 15 were diagnosed with intra-axial abscesses. A homogenous signal on T1W (P = 0.049) and T2W (P = 0.042) sequences, a T2W (P = 0.005) or T2*W GE (P = 0.046) peripheral hypointense halo, and an even enhancing capsule (P = 0.002) were significantly associated with brain abscesses. A progressive central enhancement on delayed T1W postcontrast sequences was correlated with ring-enhancing gliomas (P = 0.009). The combination of the following features was suggestive of brain abscess: homogeneous T1W or T2W signal intensity, a T2W or T2*W GE peripheral hypointense halo and an evenly enhancing capsule. Central progression of enhancement on delayed T1W postcontrast sequences was suggestive of glioma.

Brain Abscess Caused by Eikenella corrodens in an Immunocompetent Child: Case Report and Literature Review

Objective Eikenella corrodens is a slow-growing, fastidious, non-motile, facultative anaerobic, Gram-negative bacillus that is commonly found in the human oropharynx. Although many cases have been reported in the adult population, only few cases of brain abscesses caused by E.corrodens have been reported in children so far.

Methods Here, we reported the case of a 29-month-old female with complaints of weakness in the right leg twice in the past 3 weeks. Imaging studies revealed a brain abscess in the left parietofrontal lobe. The patient underwent surgery for abscess drainage, microbiological samples were obtained and empirical antibiotic treatment was started. Abscess culture showed the growth of E.corrodens. The bacteria were found to be sensitive to ceftriaxone; hence, the therapy was continued for 46 days with ceftriaxone. A final computed tomography showed the resolution of the abscess. The patient's clinical condition improved and she was discharged without any sequelae.

Conclusion Brain abscess should be considered when patients present with neurological deficits. As far as we know, there are only six reported cases of brain abscesses only due to E.corrodens in the pediatric population. Since it is a slow-growing pathogen, early diagnosis and treatment are crucial for patient survival. This case supports the combination of surgical drainage and antibiotics for treatment.

Robot-assisted stereotactic multiple brain abscesses' puncture: technical case report

We report a case of multiple brain abscesses' puncture, employing the ROSA™ Brain surgical robot (Zimmer Biomet) and the O-arm® O2 Imaging System (Medtronic). A 51-year-old man was diagnosed with multiple supratentorial ring enhancing cystic lesions consistent with brain abscesses. A neurological deterioration occurred despite broad spectrum antibiotic therapy, due to mass effect of the abscesses. Stereotactic aspiration was performed using the described technique, allowing a single stage puncture of the cerebral lesions. In this case, the robot-assisted and image-guided procedure permitted an accurate, quick, and efficient targeting of the multiple abscesses for drainage.

Spontaneous intramedullary abscesses caused by Streptococcus anginosus: two case reports and review of the literature

BACKGROUND

Intramedullary abscesses are rare infections of the spinal cord. Intramedullary abscesses often have a complex presentation, making a high index of suspicion essential for prompt diagnosis and management.

CASE PRESENTATION

We present two cases of intramedullary abscesses referred to and ultimately managed at our institution. Delayed diagnosis occurred in both instances due to the rarity of intramedullary abscesses and their propensity to mimic other pathologies. For both patients, prompt surgical management and the rapid institution of broad-spectrum antibiotics were critical in preventing further neurological decline.

CONCLUSIONS

Although rare, it is critical to consider intramedullary abscesses on the differential for any MRI lesions that are hyperintense on T2 and peripherally enhancing on T1 post-contrast sequences, as even short delays in treatment can lead to severe neurological damage.

Systematic Review of the Pharmacological Evidence for the Selection of Antimicrobials in Bacterial Infections of the Central Nervous System in Dogs and Cats

Bacterial meningitis in dogs and cats is a rare disease associated with a high lethality rate. The spectrum of causative bacteria includes a diverse set of gram positive, gram negative and anaerobic species. Currently, no veterinary medicinal product is approved for this indication in these species in Europe. The objective of this review was to collect the available pharmacokinetic data for antibiotics approved in dogs and cats to enable a preliminary analysis of their potential effectiveness for the treatment of bacterial meningitis. This analysis yielded data for 13 different antibiotics in dogs and two in cats. Additionally, data about frequently recommended cephalosporines not approved in dogs and cats were included. The collected data was used to assess the potential of the respective antibiotics to attain certain simple pharmacokinetic-pharmacodynamic (PK-PD) indexes in the cerebrospinal fluid (CSF). A more sophisticated investigation using modern methods was not possible due to the limited data available. For this purpose, data about the sensitivity of four bacterial species commonly associated with meningitis in dogs and cats to these antibiotics were included. The analysis provided evidence for the potential effectiveness of ampicillin, doxycycline, enrofloxacin, ceftriaxone and cefoxitin against bacteria frequently detected in bacterial meningitis in dogs. Data were not available or insufficient for the assessment of several antibiotics, including frequently recommended substances like metronidazole and trimethoprim-sulphonamide. Little evidence is available for the use of antibiotics in cats afflicted with this disease, highlighting the need for further research to obtain data for evidence based therapeutic recommendations.

Sequential Intravenous-Oral Therapy for Pediatric Streptococcus anginosus Intracranial Infections

Background

Streptococcus anginosus group is a common cause of pediatric intracranial infections but treatment recommendations, including use of oral therapy, are poorly defined.

Methods

We performed a retrospective review from 2004 to 2019 of all patients with S anginosus group pyogenic intracranial infections at Children's Hospital Colorado, highlighting patients transitioned to oral therapy. The primary endpoint was worsening infection necessitating intravenous antibiotics or a source control procedure after transition to oral therapy.

Results

Of 107 patients with S anginosus intracranial infections, 61 were transitioned to exclusive oral therapy after a median intravenous duration of 37 days, overwhelmingly with a levofloxacin-based regimen. Only 1 treatment failure was noted in a patient who did not fill their prescription. Patients with epidural infections were more likely to be transitioned to oral therapy within the first 28 days of treatment (defined as "early"). Patients with parenchymal infections, bacteremia, co-pathogens, higher inflammatory markers, and requiring >1 source control procedure were less likely to be transitioned early to oral therapy. Complications of a central catheter and/or intravenous medications contributed to 56% of oral transitions.

Conclusions

Levofloxacin-based oral regimens were effective and well tolerated. Patients with less severe infections were more likely to be transitioned early to oral therapy. Criteria for transitioning patients to oral antibiotics for intracranial infections should be established to minimize risks inherent with central catheters.