Microbial aetiology of brain abscess in a UK cohort: Prominent role of Streptococcus intermedius

Clinical features and outcome of brain abscess after introduction of CT and MRI: A meta-analysis

OBJECTIVE

To describe the clinical features and outcome of brain abscess since introduction of computerized tomography and magnetic resonance imaging.

METHODS

MEDLINE and Embase were searched using "brain abscess" or "cerebral abscess" from 1970 through 2023 and analyses restricted to study populations hospitalized after 1980. Single-variable meta-analyses were done using a random-effects model.

RESULTS

A total of 21,840 patients from 209 studies were included. The mean age was 34 years (95% confidence interval [CI] 30-38) and 11,817/17,406 (66%, 95% CI 64-67) were male. The aetiologies were consistent across time and continents with Streptococcus spp. 2,064/6,393 (32%, 95% CI 28-36), Staphylococcus spp. 1,061/6,393 (14%, 95% CI 12-16), and Gram-negative enteric bacteria 696/6,393 (9%, 95% CI 7-11) as the most common. Predisposing conditions included otitis media/mastoiditis 1,909/6,433 (27%, 95% CI 22-33), immunocompromise 1,022/4,652 (19%, 95% CI 14-24), sinusitis 565/3,725 (16%, 95% CI 12-20), and neurosurgery 745/4,927 (16%, 95% CI 12-20). The case-fatality was 2,444/18,991 (12%, 95% CI 11-14) and good recovery was found in 3,419/5,409 (63%, 95% CI 58-68).

CONCLUSIONS AND RELEVANCE

Brain abscess remains a disease predominantly occurring in men and was caused by contiguous or distant infections. Case fatality and outcome have not improved during recent decades.

Invasive Streptococcus intermedius Infections in Children: Two Cases from a Pediatric Infectious Diseases Unit in Italy

In recent years, an increasing number of reports have described invasive infections caused by bacteria from Streptococcus anginosus group (SAGs). S. intermedius seems to be more related with pleuropulmonary infections and abscess of the brain and deep soft tissues, and it is more likely to cause suppurative and non-bacteremic infections compared to other members of the same genus. We present two clinical cases of invasive S. intermedius infections in pediatric patients: a liver abscess case and a pansinusitis case associated with bilateral otomastoiditis and parapharyngeal abscess complicated by acute mediastinitis, thrombophlebitis of the cavernous sinus, and thrombosis of the cranial tract of the ipsilateral jugular vein. In both cases, prompt broad-spectrum antibiotic therapy and operative drainage of the collections resulted in a good clinical response with full recovery.

Subperiosteal Abscess of the Orbit: Long-term Trends in Bacteriology and Clinical Outcomes and Current Management Recommendations

PURPOSE

To evaluate the impact over time of evolving upper respiratory pathogens, modified microbial terminology, and improved laboratory isolation on the bacteriology and management of sinusitis-related subperiosteal abscess of the orbit.

METHODS

Comparative case series of pediatric patients with bacterial sinusitis-related subperiosteal abscess from 2012 to 2022. Outcomes, culture results, age-specific findings, and antibiotic duration were compared with those in 1977 to 1992, 1988 to 1998, 1999 to 2008, and 2002 to 2012 cohorts at the same institution.

RESULTS

Ninety-one patients met the inclusion criteria. Forty-nine patients (53.8 %) recovered with medical therapy alone; 42 (46.2 %) underwent surgical drainage. There was increased representation in surgical cases of Streptococcus anginosus group (52.4%) and anaerobes (26.2%). Anaerobes were isolated from 2 patients <9 years of age, the youngest age 5; recovery in prior series was limited to patients ≥9 years old. Among 61 of 91 patients <9 years old, 41 (67.2%) were managed medically and 20 (32.8%) underwent surgery. Comparable proportions were 67.5%/32.5%, 85%/15%, and 72%/28% in prior cohorts. Among nonsurgical patients <9 years old, the mean duration of intravenous antibiotics was 4.02 ± 1.2 days. Four patients had multiple admissions. In cases positive for aggressive pathogens, initial findings prompted timely drainage. All patients had favorable visual and systemic outcomes.

CONCLUSIONS

This study extends to 45 years a unique analysis of the bacteriology and clinical course of subperiosteal abscess at a single center with comparatively stable patient demographics and environmental factors, using a relatively uniform treatment algorithm. Despite the increased representation of S. anginosus group and anaerobes, a multifactor protocol with minor modifications remains an effective strategy.

Streptococcus intermedius: an underestimated pathogen in brain infection?

Streptococcus intermedius is an oral commensal organism belonging to the Streptococcus anginosus group (SAG). S. intermedius causes periodontitis as well as invasive, pyogenic infection of the central nervous system, pleural space or liver. Compared with other SAG organisms, S. intermedius has a higher mortality as well as a predilection for intracranial infection, suggesting it is likely to possess virulence factors that mediate specific interactions with the host resulting in bacteria reaching the brain. The mechanisms involved are not well described. Intracranial suppuration (ICS) due to S. intermedius infection can manifest as an abscess within the brain parenchyma, or a collection of pus (empyema) in the sub- or extra-dural space. These infections necessitate neurosurgery and prolonged antibiotic treatment and are associated with a considerable burden of morbidity and mortality. The incidence of ICS is increasing in several settings, with SAG species accounting for an increasing proportion of cases. There is a paucity of published literature regarding S. intermedius pathogenesis as well as few published genomes, hampering molecular epidemiological research. This perspective evaluates what is known about the clinical features and pathogenesis of ICS due to S. intermedius and explores hypothetical explanations why the incidence of these infections may be increasing.

Augmented pathogen detection in brain abscess using metagenomic next-generation sequencing: a retrospective cohort study

Brain abscess is a severe infection characterized by the accumulation of pus within the brain parenchyma. Accurate identification of the causative pathogens is crucial for effective treatment and improved patient outcomes. This 10-year retrospective, single-center study aimed to compare the detection performance of conventional culture methods and metagenomic next-generation sequencing (mNGS) in brain abscess. We reviewed 612 patients diagnosed with brain abscess and identified 174 cases with confirmed etiology. The median age was 52 years, with 69.5% males. Culture tests predominately identified gram-positive bacteria, particularly Streptococcus spp. Gram-negative bacteria, including Klebsiella spp., were also detected. However, mNGS revealed a more diverse pathogen spectrum, focusing on anaerobes (e.g., Fusobacterium spp., Parvimonas spp., Porphyromonas spp., Prevotella spp., and Tannerella spp.). mNGS exhibited significantly higher overall pathogen-positive rates in pus samples (85.0% vs 50.0%, P = 0.0181) and CSF samples (84.2% vs 7.9%, P < 0.0001) compared to culture. Furthermore, the detection rates for anaerobes displayed a notable disparity, with mNGS yielding significantly higher positive detections in both pus samples (50.0% vs 10%, P = 0.0058) and CSF samples (18.4% vs 0%, P = 0.0115) when compared to culture methods. The assistance of mNGS in pathogen detection, particularly anaerobes in brain abscess, was evident in our findings. mNGS demonstrated the ability to identify rare and fastidious pathogens, even in culture-negative cases. These results emphasize the clinical value of mNGS as a supplement for brain abscess, enabling more comprehensive and accurate pathogen identification.IMPORTANCEThe accurate identification of pathogens causing brain abscess is crucial for effective treatment and improved patient outcomes. In this 10-year retrospective study, the detection performance of conventional culture methods and metagenomic next-generation sequencing (mNGS) was compared. The study analyzed 612 patients with brain abscess and confirmed etiology in 174 cases. The results showed that culture tests predominantly identified gram-positive bacteria, while mNGS unveiled a broader diverse pathogen spectrum, particularly anaerobes. The mNGS method exhibited significantly higher overall rates of pathogen positivity both in pus and cerebrospinal fluid (CSF) samples, surpassing the culture methods. Notably, mNGS detected a significantly higher number of anaerobes in both pus and CSF samples compared to culture methods. These findings underscore the clinical value of mNGS as a supplement for brain abscess diagnosis, enabling more comprehensive and accurate pathogen identification, particularly for rare and fastidious pathogens that evade detection by conventional culture methods.

Polymicrobial brain abscesses: A complex condition with diagnostic and therapeutic challenges

Brain abscesses (BA) are focal parenchymal infections that remain life-threatening conditions. Polymicrobial BAs (PBAs) are complex coinfections of bacteria or bacterial and nonbacterial pathogens such as fungi or parasites, with diagnostic and therapeutic challenges. In this article, we comprehensively review the prevalence, pathogenesis, clinical manifestations, and microbiological, histopathological, and radiological features of PBAs, as well as treatment and prognosis. While PBAs and monomicrobial BAs have some similarities such as nonspecific clinical presentations, PBAs are more complex in their pathogenesis, pathological, and imaging presentations. The diagnostic challenges of PBAs include nonspecific imaging features at early stages and difficulties in identification of some pathogens by routine techniques without the use of molecular analysis. Imaging of late-stage PBAs demonstrates increased heterogeneity within lesions, which corresponds to variable histopathological features depending on the dominant pathogen-induced changes in different areas. This heterogeneity is particularly marked in cases of coinfections with nonbacterial pathogens such as Toxoplasma gondii. Therapeutic challenges in the management of PBAs include initial medical therapy for possibly underrecognized coinfections prior to identification of multiple pathogens and subsequent broad-spectrum antimicrobial therapy to eradicate identified pathogens. PBAs deserve more awareness to facilitate prompt and appropriate treatment.

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.

Exploring odontogenic brain abscesses: a comprehensive review

INTRODUCTION

Whether in neurology or dentistry, odontogenic brain abscess stands as an ailment demanding undivided attention. The onset of this disease is insidious, with a relatively low incidence rate but a markedly high fatality rate. Moreover, its symptoms lack specificity, easily leading to misdiagnosis, oversight, and treatment delays. Hence, clinicians should maintain heightened vigilance when faced with pathogenic bacteria of dental origin in patients.

AREAS COVERED

This paper encapsulates the latest research findings on the clinical manifestations and essential treatment points of odontogenic brain abscess. It may offer a crucial reference for prompt diagnosis and improved therapeutic approaches.

EXPERT OPINIONS

Odontogenic brain abscess, an infection of the cerebral parenchyma, usually appears in immunocompromised patients with dental ailments or postdental surgeries. The main pathogenic microorganisms include Streptococcus intermedius, Fusobacterium nucleatum, Streptococcus anginosus, and Millerella. Given the undetectable and nonspecific symptoms in patients, the diagnostic process relies on microbiological methods. Therefore, clinicians should actively investigate and identify the pathogenic microorganisms of odontogenic brain abscess for early detection and selection of appropriate treatment regimens to avoid disease management delays.

Update and approach to patients with brain abscess

PURPOSE OF REVIEW

The epidemiology of brain abscess has changed in recent decades. Moreover, acute and long-term management remains challenging with high risks of mortality and neurological sequelae. This review describes recent advances in epidemiology, diagnosis, and treatment of brain abscess.

RECENT FINDINGS

The incidence of brain abscess is increasing, especially among elderly individuals. Important predisposing conditions include dental and ear-nose-throat infections, immuno-compromise, and previous neurosurgery. Molecular-based diagnostics have improved our understanding of the involved microorganisms and oral cavity bacteria including anaerobes are the predominant pathogens. The diagnosis relies upon a combination of magnetic resonance imaging, neurosurgical aspiration or excision, and careful microbiological examinations. Local source control by aspiration or excision of brain abscess combined with long-term antimicrobials are cornerstones of treatment. Long-term management remains important and should address neurological deficits including epilepsy, timely diagnosis and management of comorbidities, and potential affective disorders.

SUMMARY

A multidisciplinary approach to acute and long-term management of brain abscess remains crucial and source control of brain abscess by neurosurgery should be pursued whenever possible. Numerous aspects regarding diagnosis and treatment need clarification. Nonetheless, our understanding of this complicated infection is rapidly evolving.

A Report of Two Cases of Meningoencephalitis Caused by Streptococcus intermedius

Objective

In this paper, we analyzed the clinical data of patients with meningoencephalitis caused by Streptococcus intermedius to understand better the clinical characteristics of the disease and recommend auxiliary diagnostic mode as well as treatment experience.

Methods

We reviewed the clinical data of two patients admitted to our department in 2019 with meningoencephalitis caused by S. intermedius.

Results

Two female patients were examined, one of whom had a history of radiotherapy for nasopharyngeal carcinoma while the other had no underlying disease. These two patients were admitted with symptoms of meningoencephalitis. Cerebrospinal fluid examinations revealed elevated levels of leukocytes and protein. After treatment with meropenem, the condition improved for a brief time, but then worsened with a decline in mental status and limb movement. Blood and cerebrospinal fluid cultures demonstrated the absence of pathogenic bacteria, while genome sequencing of cerebrospinal fluids revealed the presence of S. intermedius. Cranial magnetic resonance imaging revealed multiple cerebral abscesses (CAs). After coadministration of linezolid as an anti-infective, clinical symptoms gradually improved, and the CAs shrank on follow-up imaging. The condition exhibited a pattern of improvement-deterioration-improvement.

Conclusion

Meningoencephalitis caused by S. intermedius is complex and prone to fluctuation and formation of multiple CAs. The definitive clinical diagnosis of this disease can be aided by genome sequencing technology, and early clarification of the etiology combined with the use of potent antibiotics is effective.

Brain Abscess Caused by Oral Cavity Bacteria: A Nationwide, Population-based Cohort Study

BACKGROUND

Oral cavity bacteria are the most frequent etiology of brain abscess. Yet, data on the clinical presentation and outcome are scarce.

METHODS

We performed a nationwide, population-based study comprising all adults (aged ≥18 years) with brain abscess due to oral cavity bacteria in Denmark from 2007 through 2020. Prognostic factors for unfavorable outcome (Glasgow outcome scale, 1-4) were examined using modified Poisson regression to compute adjusted relative risks (RRs) with 95% confidence intervals (CIs).

RESULTS

Among 287 identified patients, the median age was 58 years (interquartile range, 47-66), and 96 of 287 (33%) were female. Preexisting functional impairment was absent or mild in 253 of 280 (90%), and risk factors for brain abscess included immunocompromise in 95 of 287 (33%), dental infection in 68 of 287 (24%), and ear-nose-throat infection in 33 of 287 (12%). Overall, a neurological deficit was present in 246 of 276 (86%) and in combination with headache and fever in 64 of 287 (22%). Identified microorganisms were primarily the Streptococcus anginosus group, Fusobacterium, Actinomyces, and Aggregatibacter spp., and 117 of 287 (41%) were polymicrobial. Unfavorable outcome occurred in 92 of 246 (37%) at 6 months after discharge and was associated with antibiotics before neurosurgery (RR, 3.28; 95% CI, 1.53-7.04), rupture (RR, 1.89; 95% CI, 1.34-2.65), and immunocompromise (RR, 1.80; 95% CI, 1.29-2.51), but not with specific targeted antibiotic regimens. Identified dental infection was associated with favorable prognosis (RR, 0.58; 95% CI, .36-.93).

CONCLUSIONS

Brain abscess due to oral cavity bacteria often occurred in previously healthy individuals without predisposing dental infections. Important risk factors for unfavorable outcome were rupture and immunocompromise. However, outcome was not associated with specific antibiotic regimens supporting carbapenem-sparing strategies.

European society of Clinical Microbiology and Infectious Diseases guidelines on diagnosis and treatment of brain abscess in children and adults

SCOPE

These European Society of Clinical Microbiology and Infectious Diseases guidelines are intended for clinicians involved in diagnosis and treatment of brain abscess in children and adults.

METHODS

Key questions were developed, and a systematic review was carried out of all studies published since 1 January 1996, using the search terms 'brain abscess' OR 'cerebral abscess' as Mesh terms or text in electronic databases of PubMed, Embase, and the Cochrane registry. The search was updated on 29 September 2022. Exclusion criteria were a sample size <10 patients or publication in non-English language. Extracted data was summarized as narrative reviews and tables. Meta-analysis was carried out using a random effects model and heterogeneity was examined by I2 tests as well as funnel and Galbraith plots. Risk of bias was assessed using Risk Of Bias in Non-randomised Studies - of Interventions (ROBINS-I) (observational studies) and Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) (diagnostic studies). The Grading of Recommendations Assessment, Development and Evaluation approach was applied to classify strength of recommendations (strong or conditional) and quality of evidence (high, moderate, low, or very low).

QUESTIONS ADDRESSED BY THE GUIDELINES AND RECOMMENDATIONS

Magnetic resonance imaging is recommended for diagnosis of brain abscess (strong and high). Antimicrobials may be withheld until aspiration or excision of brain abscess in patients without severe disease if neurosurgery can be carried out within reasonable time, preferably within 24 hours (conditional and low). Molecular-based diagnostics are recommended, if available, in patients with negative cultures (conditional and moderate). Aspiration or excision of brain abscess is recommended whenever feasible, except for cases with toxoplasmosis (strong and low). Recommended empirical antimicrobial treatment for community-acquired brain abscess in immuno-competent individuals is a 3rd-generation cephalosporin and metronidazole (strong and moderate) with the addition of trimethoprim-sulfamethoxazole and voriconazole in patients with severe immuno-compromise (conditional and low). Recommended empirical treatment of post-neurosurgical brain abscess is a carbapenem combined with vancomycin or linezolid (conditional and low). The recommended duration of antimicrobial treatment is 6-8 weeks (conditional and low). No recommendation is offered for early transition to oral antimicrobials because of a lack of data, and oral consolidation treatment after ≥6 weeks of intravenous antimicrobials is not routinely recommended (conditional and very low). Adjunctive glucocorticoid treatment is recommended for treatment of severe symptoms because of perifocal oedema or impending herniation (strong and low). Primary prophylaxis with antiepileptics is not recommended (conditional and very low). Research needs are addressed.

Early switch to oral antimicrobials in brain abscess: a narrative review

BACKGROUND

Early switch to oral antimicrobials has been suggested as a treatment strategy in patients with brain abscess, but the practice is controversial.

OBJECTIVES

This review aimed to summarize the background, current evidence, and future perspectives for early transition to oral antimicrobials in patients with brain abscess.

SOURCES

The review was based upon a previous systematic review carried out during the development of the ESCMID guidelines on diagnosis and treatment of brain abscess. The search used 'brain abscess' or 'cerebral abscess' as text or MESH terms in PubMed, EMBASE, and the Cochrane Library. Studies included in the review were required to be published in the English language within the last 25 years and to have a study population of ≥10 patients. Other studies known by the authors were also included.

CONTENT

In this review, the background for some experts to suggest early transition to oral antimicrobials in patients with mild and uncomplicated brain abscess was clarified. Next, results from observational studies were summarized and limitations discussed. Indirect support for early oral treatment of brain abscess was described with reference to other serious central nervous system infections and general pharmacological considerations. Finally, variations within and between countries in the use of early transition to oral antimicrobials in patients with brain abscess were highlighted.

IMPLICATIONS

Early transition to oral antimicrobials in patients with uncomplicated brain abscess may be of benefit for patients due to convenience of treatment and potential decreased risks associated with prolonged hospitalization and intravenous lines. The strategy may also confer a more rational allocation of healthcare resources and decrease expenses. However, the benefit/risk ratio for this strategy remains unresolved at present.

Clinical features of Streptococcus intermedius infection in children: a case series study

Introduction

Streptococcus intermedius is an opportunistic pathogen associated with prolonged hospital stays and high mortality rates in adults. However, little is currently known about the clinical features of Streptococcus intermedius infection in children.

Methods

This retrospective case series study included 40 children diagnosed with Streptococcus intermedius, confirmed through bacterial cultures or high-throughput sequencing. Antibiotic resistance was assessed through susceptibility testing. The site and clinical manifestations were evaluated for all patients.

Results

The common infection sites were the abdominal cavity, skin and soft tissue, intracranial, and invasive pulmonary, with the abdominal cavity being the most frequently affected. The drug susceptibility test showed 100% sensitivity to ceftriaxone, levofloxacin, chloramphenicol, vancomycin, and linezolid, 92.6% sensitivity to penicillin, 73.3% resistance to erythromycin, and 76.7% resistance to clindamycin. Besides antibiotic therapy, surgical intervention or pus drainage was often necessary. Lung imaging of four patients revealed pulmonary abscesses, nodules, or encapsulated pleura. Two cases yielded positive culture results, while three were identified as positive through high-throughput nucleotide sequencing of pleural effusion.

Discussion

In children with Streptococcus intermedius infection, emphasis should be placed on the risk of pus or abscess formation. In cases of pulmonary abscess and pleural effusion, especially in male children, Streptococcus intermedius should be suspected even if the culture is negative. Improvements in high-throughput nucleotide sequencing are required to reduce misdiagnosis rates.

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.

Clinical and radiological characteristics of brain abscess due to different organisms in hospitalized patients: A 6-year retrospective study from China

Background

Brain abscess (BA) is a rare but life-threatening infection. Early identification of the pathogen is helpful to improve the outcomes. This study aimed to describe the clinical and radiological features of patients with BA caused by different organisms.

Methods

A retrospective, observational study of patients with known etiologic diagnosis of BA in Huashan Hospital Affiliated to Fudan University in China between January 2015 and December 2020 was conducted. Data on patient demographics, clinical and radiological presenting features, microbiological results, surgical treatment, and outcomes were collected.

Results

Sixty-five patients (49 male, 16 female) with primary BAs were included. Frequent clinical presentations included headache (64.6%), fever (49.2%) and confusion (27.3%). Streptococcus viridans was associated with thicker wall of abscesses (6.94 ± 8.43 mm for S. viridans versus 3.66 ± 1.74 mm for other organisms, P = 0.031) and larger oedema (89.40 ± 15.70 mm for S. viridans versus 74.72 ± 19.70 mm for other organisms, P = 0.023). The independent factor associated with poor outcome identified by multivariate analysis was confusion (Odds ratio 6.215, 95% confidence interval 1.406-27.466; P = 0.016).

Conclusions

Patients with BAs caused by Streptococcus species had nonspecific clinical signs, but specific radiological features, which might be helpful for early diagnosis.

Cerebral abscesses with odontogenic origin: a population-based cohort study

Objectives

Recent studies have indicated that cerebral abscess (CA) patients with odontogenic origin are on the rise. However, CA patients are often poorly characterized and with an unknown etiologic background. The purpose of this study is to identify and characterize CA patients that may have an odontogenic origin based on microbiologic, radiographic, and/or clinical findings.

Materials and methods

This is a population-based cohort study analyzing retrospective and prospective data from CA patients. Radiographic examinations of panoramic radiographs (PRs) or computed tomography (CT) scans were conducted. CA patients characterized with odontogenic origin required the fulfilment of the following criteria on admission: (1) Oral pathologic conditions were the only bacterial infections present, (2) oral microorganisms were isolated in the purulent exudate from the brain, and (3) radiographically and/or clinical recordings of oral pathologic conditions.

Results

A total of 44 patients could be included in this study of which 25 (57%) were characterized as having CA with a likely odontogenic origin. Type two diabetes (T2D) (p = 0.014) and microorganisms of the Streptococcus anginosus group (SAG) (p < 0.01) were overrepresented in patients with CAs of odontogenic origin.

Conclusions

Odontogenic infections may cause CAs to a greater extent than previously assumed. T2D was overrepresented among patients with odontogenic CA. When microorganisms of the SAG were isolated from the brain pus, CA patients had a predisposing odontogenic or sinus infection.

Clinical relevance

The identification of patients with a likely odontogenic CA will contribute to understanding the etiology of the infectious disease and highlighting the importance of preserving oral health.

Septic Arthritis of the Atlanto-Occipital Joint Caused By S. Intermedius in a 5-Year-Old Girl: A Case Report

Septic arthritis of the atlanto-occipital joint caused by Streptococcus intermedius is extremely rare. We present the first case report of this entity in a fully immunocompetent 5-year-old girl. The magnetic resonance imaging and blood tests were consistent with septic arthritis, so she started empirical antibiotic therapy. Septic arthritis should be excluded in children with torticollis, fever and neck pain.

Concomitant brain abscess and spinal cord abscess in an immunocompetent teenage male: illustrative case

BACKGROUND

Multiple bilateral brain abscesses occur rarely in immunocompetent patients. Hematogenous spread to the central nervous system (CNS) allows suppuration and abscess formation in the privileged immune environment of the CNS; hematogenous spread to the spinal cord is extremely rare and the combination of multifocal brain abscesses and intramedullary abscesses has not been reported. This report presents a rare presentation and diagrams a treatment algorithm involving iterative minimal access surgeries and prolonged medical management.

OBSERVATIONS

The authors present a case of an 18-year-old male with numerous multifocal and bilateral intraparenchymal abscesses and a medically resistant C5 intramedullary spinal cord abscess. The symptomatic patient had a left oculomotor palsy and left hemiparesis, ultimately undergoing ultrasound-guided aspiration of abscesses in the left frontal and left cerebral peduncle. Following transient motor improvement, he evolved tetraparesis prompting spinal cord imaging and emergent ultrasound-guided needle aspiration of an occult C5 intramedullary spinal cord abscess. The patient received appropriate medical therapy, completed inpatient rehabilitation, and made a full recovery.

LESSONS

Needle- and ultrasound-guided catheter drainage of CNS abscesses should be considered for symptomatic lesions. Following the neurological examination closely is extremely important; if the expected neurological improvement is delayed or regresses, then expanded imaging is warranted.

Oral microbes and the formation of cerebral abscesses: A single-centre retrospective study

OBJECTIVE

Intracranial abscesses are relatively uncommon, but can result in significant mortality and morbidity. Whilst many potential causes of brain abscesses are recognised, in many cases the origin of infection remains clinically unidentified. Our objective was to investigate the role of bacteria found in the oral cavity in the development of brain abscesses.

METHODS

A retrospective analysis was performed using data from 87 patients admitted to a single UK neurosurgical unit with brain abscesses over a 16-year period. Using microbiological data obtained from abscess sampling and peripheral cultures, species of bacteria were categorised in patients where no primary source of infection was identified (NSI) for their brain abscess (n = 52), or where an infective source (ISI) was identified. The microbiological data was then screened to identify common oral bacteria in each group.

RESULTS

Brain abscesses from the ISI group (n = 35) demonstrated a significantly lower preponderance of oral bacteria (n = 8), than the NSI group (n = 29) (p < 0.05). Brain abscesses from the NSI group also had significantly higher counts of Streptococcus anginosus compared to ISI (p < 0.05), with brain abscesses being most common in the frontal and parietal lobes for both ISI and NSI.

CONCLUSIONS

These findings suggest that the oral cavity could be considered as a source of occult infection in cases of brain abscess where no clear cause has been identified. Future studies should include oral screening and microbiome analysis to better understand the mechanisms involved and develop approaches for prevention.

CLINICAL SIGNIFICANCE STATEMENT

Oral bacteria may be an under-recognised cause of brain abscesses. Careful review of oral health in brain abscess patients may help establish causation, particularly in patients with no cause for their abscess identified. Good levels of oral health may help prevent the development of brain abscesses in some individuals.

Retrospective review of the epidemiology, microbiology, management and outcomes of intra-cranial abscesses at a neurosurgical tertiary referral centre, 2018-2020

BACKGROUND

Intracranial abscesses are rare but serious, and are associated with significant morbidity and mortality. Due to both the rarity and severity of these infections, well-controlled trials have not been reported in the literature, and optimal management is a matter for expert opinion. Advances in surgical management have improved outcomes and increased rates of microbiological diagnosis. However, the approach to antimicrobial chemotherapy varies considerably, including the choice of antibiotic, the duration of treatment, and the timing of oral switch.

METHODS

We conducted a retrospective review of 43 cases of intracranial abscesses from a large, tertiary neurosurgical centre in London, UK, between 2018 and 2020, including 29 primary intra-parenchymal abscesses, 11 subdural abscesses and 3 extradural abscesses.

RESULTS

The majority of cases had surgical intervention; 6/43 (14%) required repeat intervention (all intra-parenchymal abscesses). A microbiological diagnosis was made in 83% of cases. Intravenous antibiotics were given for a median of 33 days (IQR 23-44 days), with a variable duration of oral follow-on antibiotics. Total duration of antibiotic treatment ranged from 0 to 467 days. Only three patients from our cohort are known to have died.

CONCLUSION

Shorter courses of intravenous antibiotics for brain abscesses were not associated with increased mortality. In the absence of well-controlled trials, a national registry of intracranial abscesses would provide invaluable data to inform optimal treatment.

Development of posttraumatic frontal brain abscess in association with an orbital roof fracture and odontogenic abscess: A case report

Background:

Brain abscess is a potentially fatal condition. Orbital fractures caused by penetrating injury may be associated with intracranial infection. Such complication associated with blunt trauma, orbital roof fractures, and odontogenic abscesses is exceedingly rare.

Case Description:

We report the case of a 40-year-old transgender female with a frontal abscess presenting several weeks following a motor vehicle crash from which she suffered multiple facial fractures and an odontogenic abscess. On computed tomography scan, the patient had multiple right-sided facial fractures, including a medial orbital wall fracture and a right sphenoid fracture extending into the superior orbital roof. There was hemorrhage notable in the right frontal lobe. Communication with the ethmoid sinuses likely provided a conduit for bacterial spread through the orbit and into the intracranial and subdural spaces.

Conclusion:

Skull base fractures that communicate with a sinus, whether it be frontal, ethmoid, or sphenoid may increase the risk of brain abscess, especially in patients who develop an odontogenic abscess. Surgical repair of the defect is essential, and treating patients prophylactically with antibiotics may be beneficial.

Brain complications from odontogenic infections: A systematic review

PURPOSE

Odontogenic infections can spread through different routes to more remote anatomical areas, such as the brain. Brain abscesses have an incidence of 0.3-1.3 / 100,000 population and only 2-5% are of dental origin. The main objective is to research brain complications derived from odontogenic infections. Secondary objectives were to identify the most common symptoms in brain abscess, to describe the microbiology involved in these infectious processes, report which parts of the brain complex are most commonly affected and report the sequelae of this patients.

METHODS

A systematic review following the PRISMA Guide and the Joanna Briggs Institute (JBI) Critical Appraisal Checklist for Case Reports was carried out in PubMed, Scopus and Web of Science. The search terms were: Brain infection, brain abscess, oral health oral origin, odont* infect*.

RESULTS

The database search identified a total of 1000 articles. A total of 18 publications were identified after applying inclusion and exclusion criteria. A total of 38 patients were analyzed. Mean age was 49.64±18.80 years.

CONCLUSION

The most common symptoms of patients with brain abscess are neurological affectations first and then fever and headache second, without necessarily presenting as a symptomatological triad. Microbiological diagnosis is key to determining the origin of the infection. Anaerobic pathogens such as Streptococcus (F. Milleri), Fusobacterium Nucleatum and Porfiromonas Gingivalis families are common bacterial agents. The frontal lobe is the most frequently affected, followed by the parietal and temporal lobe. The most frequent brain complications are neurological disorders. However, most patients with brain abscesses recover without sequelae.

Focal Neurological Symptoms at Initial Presentation Could Be a Potential Risk Factor for Poor Prognosis Among Patients With Multiple Brain Abscesses by Streptococcus anginosus Group: A Case Report With Literature Review

Streptococcus anginosus group (SAG) is one of the most common microbes of brain abscesses. Brain abscesses caused by SAG have often delayed diagnosis since both blood and cerebrospinal fluid cultures are negative in half of the cases. A 68-year-old man developed persistent fever, headache, and myalgias for two weeks and visited our department. He was treated with oral antibiotics without laboratory work. Although examination showed no focal neurological symptoms, a careful interview revealed a history of unusual behavior for a few minutes on the previous day. Whole body contrast-enhanced computed tomography (CT) and head magnetic resonance imaging (MRI) showed two ring enhancements close to the bilateral ventricles, which were consistent with a diagnosis of the brain abscesses. An emergent surgical puncture for the larger abscess with intravenous antimicrobial therapy quickly improved his condition, and he was discharged on day 36 with no sequelae. We retrospectively reviewed works of literature on cases with multiple brain abscesses by SAG to assess potential prognostic factors for neurological sequelae. Statistical analyses of 12 cases, including 11 cases from the literature review and the current case, were performed between groups with or without poor prognosis. Among potential risk factors of age, sex, focal neurological symptoms, duration from onset to treatment, abscess formation of other organs, presence of surgical drainage, and positive for blood culture, only focal neurological symptoms at the initial presentation were significantly associated with poor prognosis (no poor prognosis, 1/4 cases vs poor prognosis group, 8/8 cases; p=0.01). Careful interviews and detailed examinations should be conducted to assess the possibility of brain abscesses among patients with fever of unknown etiology. Otherwise, a delayed diagnosis might result in poor prognoses such as death or neurological sequelae due to this disease's nature, which has few specific symptoms in the early stages.

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.

Cerebral abscess with Streptococcus intermedius as a complication of pelvic inflammatory disease in the setting of intrauterine device use

A 43-year-old healthy female with no significant medical problems except for recently diagnosed pelvic inflammatory disease presented to our hospital with acute onset, severe head and neck pain. Brain imaging revealed a rim-enhancing lesion consistent with an abscess. The patient underwent successful surgical removal of the abscess and its capsule. Intraoperative cultures grew Streptococcus intermedius and she was discharged with a plan for four weeks of intravenous ceftriaxone.

Case Report: Subtherapeutic Vancomycin and Meropenem Concentrations due to Augmented Renal Clearance in a Patient With Intracranial Infection Caused by Streptococcus intermedius

Streptococcus intermedius occasionally causes brain abscesses that can be life-threatening, requiring prompt antibiotic and neurosurgical treatment. The source is often dental, and it may spread to the eye or the brain parenchyma. We report the case of a 34-year-old man with signs of apical periodontitis, endophthalmitis, and multiple brain abscesses caused by Streptococcus intermedius. Initial treatment with meropenem and vancomycin was unsuccessful due to subtherapeutic concentrations, despite recommended dosages. Adequate concentrations could be reached only after increasing the dose of meropenem to 16 g/day and vancomycin to 1.5 g × 4. The patient exhibited high creatinine clearance consistent with augmented renal clearance, although iohexol and cystatin C clearances were normal. Plasma free vancomycin clearance followed that of creatinine. A one-day dose of trimethoprim–sulfamethoxazole led to an increase in serum creatinine and a decrease in both creatinine and urea clearances. These results indicate that increased tubular secretion of the drugs was the cause of suboptimal antibiotic treatment. The patient eventually recovered, but his left eye needed enucleation. Our case illustrates that augmented renal clearance can jeopardize the treatment of serious bacterial infections and that high doses of antibiotics are needed to achieve therapeutic concentrations in such cases. The mechanisms for regulation of kidney tubular transporters of creatinine, urea, vancomycin, and meropenem in critically ill patients are discussed.

Brain abscess of odontogenic origin in patients with malignant tumors: A report of two cases

Background

Oral infection and dental manipulations can lead to the development of brain abscesses, a rare but potentially life-threatening condition. Herein, we report patients undergoing cancer treatment who developed brain abscesses of odontogenic origin at our hospital.

Case Description

Two patients developed brain abscesses during cancer treatment. Both underwent neurosurgical aspiration, and the causative microorganism was identified as Streptococcus intermedius of the Streptococcus anginosus group, which is a part of the normal bacterial flora in the oral cavity. There was clinical and radiographic evidence of dental infection in one of the patients diagnosed with a brain abscess of odontogenic origin. No infectious foci were found in the other patient during hospitalization for the abscess. However, the patient had undergone extraction of an infected tooth approximately 3 months before admission for the abscess, suggesting origination from an oral infection or dental manipulation. The patients' cancers rapidly worsened because cancer treatment in both patients was interrupted for several months to treat the brain abscess.

Conclusion

Oral infections can cause severe infections, such as brain abscesses, particularly during the treatment of malignant tumors. Improving the oral environment or treating oral infections before initiating treatment for malignant tumors is highly recommended. In addition, the possibility of odontogenic origin should always be considered as a potential etiology of brain abscesses.

Neuroradiology of infectious diseases

PURPOSE OF REVIEW

Early diagnosis of central nervous system (CNS) infections is crucial given high morbidity and mortality. Neuroimaging in CNS infections is widely used to aid in the diagnosis, treatment and to assess the response to antibiotic and neurosurgical interventions.

RECENT FINDINGS

The Infectious Diseases Society of America (IDSA) guidelines have clear recommendations for obtaining a computerized tomography of the head (CTH) prior to lumbar puncture (LP) in suspected meningitis. In the absence of indications for imaging or in aseptic meningitis, cranial imaging is of low utility. In contrast, cranial imaging is of utmost importance in the setting of encephalitis, bacterial meningitis, ventriculitis, bacterial brain abscess, subdural empyema, epidural abscess, neurobrucellosis, neurocysticercosis, and CNS tuberculosis that can aid clinicians with the differential diagnosis, source of infection (e.g., otitis, sinusitis), assessing complications of meningitis (e.g., hydrocephalus, venous sinus thrombosis, strokes), need for neurosurgical interventions and to monitor for the response of therapy. Novel imaging techniques such as fast imaging employing steady-state acquisition (FIESTA), susceptibility-weighted imaging (SWI), and chemical exchange saturation transfer (CEST) contrast are briefly discussed.

SUMMARY

Though the radiological findings in CNS infections are vast, certain patterns along with clinical clues from history and examination often pave the way to early diagnosis. This review reiterates the importance of obtaining cranial imaging when necessary, and the various radiological presentations of commonly encountered CNS infections.

Microbiology of orbital cellulitis with subperiosteal abscess in children: Prevalence and characteristics of Streptococcus anginosus group infection

Purpose: To evaluate the predominant pathogens and clinical course in pediatric patients with orbital cellulitis (OC) complicated by subperiosteal abscess (SPA).Methods: This is a single-center retrospective chart review evaluating pediatric patients with OC complicated by SPA treated at a tertiary care center in the Pacific Northwest. Data were analyzed for characteristics, rates of infection, and antibiotic resistance of the predominant pathogens in pediatric patients.Results: Twenty-seven children were identified with OC complicated by SPA and bacterial cultures drawn. The average age (SD) of the patients was 9.2 years (4.8), median 9.6; 15 range 5 months to 17.2 years. Seventeen (63.0%) were male. Sinusitis was present in all patients. Streptococcus species were the most common pathogen accounting for 52% (17/33) of isolates. Streptococcus anginosus group (SAG) was the predominant species and were isolated in 10 out of 27 (37%) children in the study. Twenty-one (78%) patients required surgery for the treatment of SPA. Among surgically treated patients, females tended to be younger than males (p = .068). Pediatric patients with SAG infections required more surgery than children without this isolate, 100% and 65%, respectively (p = .030). Female patients tended to have SAG infections more often than males (p = .063).Conclusions: Orbital infections caused by SAG require surgical management more often than those caused by other pathogens. Our results suggest a difference in pathogenic organisms in male and female patients with SPA. SAG is one of the most common pathogens isolated in orbital cellulitis complicated by SPA in children.