Risk Factors for Brain Abscess: A Nationwide, Population-Based, Nested Case-Control Study

Undetected permanent dental inflammation as a possible trigger for brain abscesses? A retrospective analysis over the last 2 decades

BACKGROUND

Recently, there is increasing evidence that the proportion of odontogenic brain abscesses is greater than previously known. In this study, we aim to differentiate the oral infections as triggers more precisely and to classify them in the clinical setting.

METHODS

For analysis, we conducted a retrospective single center study. We reviewed patients with brain abscesses who have undergone treatment in the University Hospital of Freiburg, Germany in the period between 2000-2021. Inclusion required two main criteria: 1. The brain abscess must not have an other focus than odontogenic. 2. The microbial spectrum identified in the brain abscess must be consistent with an odontogenic origin.

RESULTS

Of 217 brain abscess patients, 26 met the inclusion criteria. 42% (11 patients) suffered from immunosuppressive conditions. Odontogenic foci were diagnosed in 18 cases (69%). Neurologic deficits included vigilance reduction and hemiparesis. Pathogens of the Streptococcus anginosus group were the most frequent causative agent (21 cases, 81%). Metronidazole (54%) and ceftriaxone (42%) were part of the targeted antibiotic therapy. All brain abscesses were surgically treated. Teeth were extracted in 14 of 17 cases for focus control. 18 cases (72%) showed complete or partial resolution of neurologic symptoms and 3 cases were fatal.

CONCLUSION

Apparently silent or chronic oral infections are sufficient to cause bacterial colonization of the brain, especially in immunocompromised patients. Therefore, special care should be taken to maintain good oral health. An interdisciplinary management should become a standard to prevent and treat the occurrence of brain abscesses.

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.

Pulmonary arteriovenous malformations in patients with previous brain abscess: a cross-sectional population-based study

BACKGROUND AND PURPOSE

Pulmonary arteriovenous malformations (PAVMs) may cause recurrent brain abscess. The primary aim was to determine the prevalence of PAVM amongst survivors of brain abscess. The proportion with cardiac right-to-left shunts was also assessed post hoc.

METHODS

This was a cross-sectional population-based study of adult (≥18 years) survivors of cryptogenic bacterial brain abscess in Denmark from 2007 through 2016. Patients were invited for bubble-echocardiography to detect vascular right-to-left shunting and, if abnormal, subsequent computed tomography thorax for diagnosis of PAVM. Data are presented as n/N (%) or median with interquartile range (IQR).

RESULTS

Study participation was accepted by 47/157 (30%) eligible patients amongst whom two did not appear for scheduled bubble-echocardiography. The median age of participants was 54 years (IQR 45-62) and 19/57 (33%) were females compared with 59 years (IQR 48-68, p = 0.05) and 41/85 females (48%, p = 0.22) in non-participants. Bubble-echocardiography was suggestive of shunt in 10/45 (22%) participants and PAVM was subsequently confirmed by computed tomography in one patient with grade 1 shunting. The corresponding prevalence of PAVM was 2% (95% confidence interval 0.06-11.8) amongst all examined participants. Another 9/45 (20%) were diagnosed with patent in persistent foramen ovale (n = 8) or atrial septum defect (n = 1), which is comparable with the overall prevalence of 25% amongst adults in the Danish background population.

CONCLUSIONS

Undiagnosed PAVM amongst adult survivors of cryptogenic bacterial brain abscess is rare but may be considered in select patients. The prevalence of cardiac right-to-left shunts amongst brain abscess patients corresponds to the prevalence in the general population.

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.

Brain abscess from oral microbiota approached by metagenomic next-generation sequencing: A case report and review of literature

BACKGROUND

Brain abscess is a serious and potentially fatal disease caused primarily by microbial infection. Although progress has been made in the diagnosis and treatment of brain abscesses, the diagnostic timeliness of pathogens needs to be improved.

CASE SUMMARY

We report the case of a 54-year-old male with a brain abscess caused by oral bacteria. The patient recovered well after receiving a combination of metagenomic next-generation sequencing (mNGS)-assisted guided medication and surgery.

CONCLUSION

Therefore, mNGS may be widely applied to identify the pathogenic microorganisms of brain abscesses and guide precision medicine.

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.

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.

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.

Bacterial Brain Abscesses in a Patient With Transposition of the Great Arteries and Interventricular Communication

Brain abscesses are localized infections in the brain's parenchyma, characterized by inflammation, pus formation, and the development of a surrounding capsule. These lesions typically occur due to underlying factors such as immunosuppression, ear and sinus infections, and contamination during neurosurgery. While brain abscesses are a life-threatening complication of cyanotic heart defects, they are rarely reported, with only sporadic cases previously documented. This article presents the case of an eight-year-old male patient with an uncorrected transposition of the great arteries, who was evaluated for symptoms including headache, fever, and neurological focalization. Diagnostic imaging revealed three lesions consistent with brain abscesses. Furthermore, the causal agents were identified as Streptococcus intermedius and Fusobacterium spp., representing oral microorganisms. Additionally, the patient exhibited poor oral hygiene and dental caries in multiple teeth. This article discusses and integrates the possible pathophysiological mechanisms that allowed a localized dental infection to spread hematogenously and cause brain abscesses in this patient. Prompt management of the infectious source is crucial to prevent a poor prognosis associated with brain abscesses. Therefore, this case emphasizes the importance of regular dental assessments and thromboprophylaxis for patients with underlying cardiomyopathies that cause right-to-left shunting to prevent potential complications.

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.

Cerebral abscess due to Listeria monocytogenes infection in silent diabetes mellitus: Case presentation, treatment and patient outcome

Introduction

Invasive listeriosis most often presents as bacteremia or neurolisteriosis. Cerebral infection mostly manifests as meningitis or meningoencephalitis, but cerebral abscesses are a rare manifestation.

Case presentation

We present the rare case of a 51-year old patient with progressive right sided hemiparesis caused by a cerebral abscess due to Listeria monocytogenes infection. The initially suspected cerebral ischemia or bleeding was ruled out. Magnetic resonance imaging led to the suspected diagnosis of an angiocentric lymphoma. An open cerebral biopsy revealed an intracranial abscess formation. After abscess evacuation and identification of Listeria monocytogenes, anti-infective treatment with ampicillin and gentamicin was started. After repeated cerebral imaging with signs of ongoing tissue inflammation after 6 weeks we chose to prolong the therapy with oral amoxicillin until resolution of signs of intracerebral inflammation after 12 weeks, documented by repeated cerebral magnetic resonance imaging. During hospitalization, the patient was diagnosed with diabetes mellitus type II and treatment was initiated. The patient was discharged without any persistent neurologic deficits.

Discussion

For the treatment of bacterial brain abscesses, 4-6 weeks of intravenous antimicrobial treatment after surgical drainage are recommended. However, first line therapy of invasive cerebral listeriosis is not well established. We decided to use a combined treatment using ampicillin and gentamicin, followed by prolonged oral treatment due to ongoing tissue inflammation.

Conclusion

No evidence-based treatment recommendations are available for brain abscess caused by Listeria monocytogenes. We report a case with favorable outcome after anti-infective ampicillin- and gentamicin-based therapy. Systematic assessment of treatment would be desirable.

Prediction model of central nervous system infections in patients with severe traumatic brain injury after craniotomy

OBJECTIVE

The aim of this study was to develop and evaluate a nomogram to predict CNS infections in patients with severe traumatic brain injury (sTBI) after craniotomy.

METHODS

This retrospective study was conducted in consecutive adult patients with sTBI who were admitted to the neurointensive care unit (NCU) between January 2014 and September 2020. We applied the least absolute shrinkage and selection operator (LASSO) and multivariate logistic regression analysis to construct the nomogram, and k-fold cross-validation (k=10) to validate it. The receiver operator characteristic area under the curve (AUC) and calibration curve were applied to evaluate the predictive effect of the nomogram. The clinical usefulness was investigated by decision curve analysis (DCA).

RESULTS

A total of 471 patients with sTBI who underwent surgical treatment were included, of whom 75 patients (15.7%) were diagnosed with CNS infections. The serum level of albumin, cerebrospinal fluid (CSF) otorrhoea at admission, CSF leakage, CSF sampling, and postoperative re-bleeding were associated with CNS infections and incorporated into the nomogram. The results showed that our model yielded satisfactory prediction performance with an AUC value of 0.962 in the training set and 0.942 in the internal validation. The calibration curve exhibited satisfactory concordance between the predicted and actual outcomes. The model had good clinical use since the DCA covered a large threshold probability.

CONCLUSION

We established a straightforward individualized nomogram for CNS infections in sTBI patients in the NCU, which could help physicians screen high-risk patients to perform early interventions to reduce the incidence of CNS infections in sTBI patients.

Invasive procedures and risk of brain abscess: a nationwide, population-based case-control study

OBJECTIVES

It is unknown whether invasive procedures are associated with brain abscess.

METHODS

Nationwide, population-based, matched case-control study of patients with culture verified brain abscess in Denmark from 1989 to 2016. Exposure was invasive procedures 0-6 months before study inclusion.

RESULTS

We identified 435 patients and 3909 controls. The level of comorbidity was higher among patients with brain abscess than among controls. A total of 48 cases (11%) had one or more invasive procedures 0-6 months before study inclusion (adjusted odds ratios (aOR) of 3.6 (95% confidence interval (CI): 2.5-5.1), a population attributable fractions of 8% (95% CI: 7-9)). In primary care, ear, nose and throat (ENT) procedures were associated with brain abscess (aOR of 4.0 (95% CI: 2.0-8.0)), but gastrointestinal endoscopies were not (aOR of 1.0 (95% CI: 0.3-3.2)). No bronchoscopies were performed in primary care. In the hospital-based setting, ENT procedures, bronchoscopies and gastrointestinal endoscopies were associated with an increased risk of brain abscess (aOR of 14.5 (95% CI: 4.8-43.8), 20.3 (95% CI: 3.8-110.1) and 3.4 (95% CI: 2.0-5.6), respectively).

CONCLUSIONS

The association between invasive procedures and brain abscess was more pronounced in the hospital-based setting than in primary care.

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.

Brain Abscess and Risk of Cancer: A Nationwide Population-Based Cohort Study

Background and objectives:

Underlying occult cancer could potentially explain some of the observed increased long-term mortality among brain abscess patients.

Methods:

Nationwide, population-based healthcare registries were used to examine long-term risks of cancer in brain abscess patients from 1982 through 2016 compared with a population comparison cohort individually matched (10:1) on age, sex, and residence. Cumulative incidences and adjusted cause-specific hazard rate ratios (HRR) with 95% confidence intervals (CIs) for cancer were computed. Potential confounding by family-related factors was explored by comparing cumulative incidences of cancer among siblings of both groups.

Results:

Among 1,384 brain abscess patients (37% female, median age 50 years, IQR 33-63), cancer was observed in 218 (16%) compared with 1,657/13,838 (12%) in the comparison cohort yielding an adj. HRR of 2.09 (95% CI 1.79-2.45). Median time to diagnosis of cancer was 1.8 years (IQR 0.02-9.1) in brain abscess patients and 8.6 years (IQR 3.9-15.9) in comparison cohort. Among brain abscess patients, central nervous system and eye cancer was diagnosed in 59 (4.3%), of which 47/59 (80%) occurred within 90 days of the admission date, metastasizing cancer in 54 (3.9%), respiratory tract cancer in 48 (3.5%), and gastro-intestinal cancer in 36 (2.6%). Results remained consistent in almost all subgroups and in sensitivity analyses. Accounting for competing risk of death, the 1-, 5-, 10-, and 35-year cumulative incidence of cancer was 7% (95% CI 6-8), 11% (95% CI 9-12), 13% (95% CI 11-15), and 24% (95% CI 20-27) in brain abscess patients compared with 0.7% (95% CI 0.6-0.9), 4% (95% CI 4-5), 8% (95% CI 8-9), and 25% (95% CI 23-27) in the comparison cohort. The cumulative incidences of cancer among siblings of brain abscess patients was 10% and 12% among siblings of the comparison cohort.

Discussion:

Brain abscess was associated with substantially increased risk of cancer during the first ten years after diagnosis.

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.

Splenic Abscess in the New Millennium: A Descriptive, Retrospective Case Series

Background

Splenic abscess is a rare infection often resulting from hematogenous spread. Immunocompromised states are commonly comorbid, and the microbiology is heterogeneous.

Methods

We conducted a retrospective review of 33 cases identified by convenience sampling. Cases were treated in our institution’s hospital system between May 2012 and February 2021 and classified as proven or probable based on predetermined criteria.

Results

The median age was 57 years, and 58% were men. Common underlying diseases included diabetes mellitus (30%), pancreatic disease (30%), and hematological malignancy (15%). The most common mechanism of pathogenesis was hematogenous spread (n = 13). Escherichia coli, enterococcal spp., and anaerobes were frequently implicated. One case was discovered at autopsy and excluded from subsequent analyses. The median duration of antimicrobial therapy (range) was 45 (5–525) days, and the median length of index hospitalization was 20 days. Percutaneous drainage by interventional radiology was common (17 of 32; 53%), and 6 patients underwent splenectomy. Treatment success was achieved in 14 of 32 cases (44%), with clinical stability in 3 of 32 cases (9%). Failures occurred in 13 of 32 (41%) cases, 2 of whom died from splenic abscesses. Two patients (2 of 32) were lost to follow-up.

Conclusions

To our knowledge, this is the largest North American series since the turn of the century and the first to distinguish between proven and probable cases. As reflected in our series, patients with splenic abscess may require prolonged hospitalizations and courses of antimicrobial therapy. Improvements in management are needed.

Dentist's visits and risk of brain abscess: a nationwide, population-based case control study

BACKGROUND

Brain abscesses are frequently caused by oral cavity bacteria, but whether dental status and invasive dental procedures are important risk factors is unknown.

METHODS

A nationwide, population-based, case-control study examined the association between dentist's visits and invasive dental procedures and risk of brain abscess caused by oral cavity bacteria from 1989-2016. Date of brain abscess diagnosis was considered the index date. Using risk-set sampling, 10 population controls per case were individually matched by age, sex, and residential area. Conditional logistic regression was used to compute odds ratios (OR) with 95% confidence intervals (CIs), adjusted for comorbidity (aOR).

RESULTS

We identified 362 patients with culture-proven brain abscess caused by oral cavity bacteria. The median age was 53 years (IQR 39 - 65) and 220/362 (61%) were male. Invasive dental procedures within six months before the index date was observed in 21/362 (6%) brain abscess patients and 179/3257 (5%) population controls yielding an aOR of 1.07 (95% CI 0.67-1.70). A total of 213/362 (59%) brain abscess patients had visited their dentist within one year before the index date compared with 1944/3257 (60%) of population controls corresponding to an aOR of 0.99 (95% CI 0.77-1.26). Using no dentist's visits as reference, we observed aOR's of 0.95 (95% CI 0.64-1.40) for 1-2 visits within three years of the index date and 1.01 (95% CI 0.76-1.35) for 3 or more visits.

CONCLUSIONS

Recent invasive dental procedures and number of dentist's visits were not associated with culture verified brain abscess caused by oral cavity bacteria.

Diagnostics with clinical microbiome-based identification of microorganisms in patients with brain abscesses-a prospective cohort study

Brain abscesses are often polymicrobial and of unclear primary origin. Here, we compare the use of next-generation sequencing (NGS) technology with classical microbiological diagnostics for identification of clinically relevant microorganisms and describe the microbiome profiling with respect to the primary source of brain abscess. Thirty-six samples from 36 patients, with primary brain abscesses, were subjected to both culture- and 16S/18S rRNA Sanger sequencing-based diagnostics ("standard methods") and compared to a 16S/18S amplicon-based NGS, which were also subjected to a microbiome diversity analyses. Forty-seven species were identified with "standard methods" compared to 96 species with NGS, both confirming and adding to the number of species identified (p < 0.05). The variation of the brain abscess microbiome diversity was not continuous but could be stratified comparing the presumable origin of infection ("dental," "sinus," "disseminated," or "unknown"). Alpha diversity did not differ (p > 0.05) between groups while beta diversity differed significantly (p = 0.003) comparing disseminated vs the other presumable origin of infection. Interesting, clustering was also detected between "dental" and "sinusitis," although not significantly (p = 0.07). Microbiome-based diagnostics can increase sensitivity without losing specificity. The bacterial beta diversity differed between the presumably origin of the brain abscess and might help to clarify the primary source of infection.

Epidemiology of patients with central nervous system infections, mainly neurosurgical patients: a retrospective study from 2012 to 2019 in a teaching hospital in China

BACKGROUND

Central nervous system (CNS) infections are relatively rare but are associated with high mortality worldwide. Empirical antimicrobial therapy is crucial for the survival of patients with CNS infections, and should be based on the knowledge of the pathogen distribution and antibiotic sensitivities. The aim of this study was to investigate the features of pathogens in patients with CNS infections in North China and evaluate the risk factors for mortality and multi-drug-resistant (MDR) bacterial infections.

METHODS

A retrospective study was conducted with patients with positive cerebrospinal fluid (CSF) cultures in a teaching hospital from January 2012 to December 2019. The following data were collected: demographic characteristics, laboratory data, causative organisms and antimicrobial sensitivity results. Data were analyzed with SPSS 16.0. Univariate analysis and binary logistic regression analyses were performed to identify the risk factors for mortality and MDR bacterial infections.

RESULTS

A total of 72 patients were diagnosed with CNS infections, and 86 isolates were identified. The proportions of Gram-positive bacteria, Gram-negative bacteria and fungi were 59.3, 30.2 and 10.5%, respectively. The predominant Gram-positive bacteria was Coagulase-negative Staphylococci. Acinetobacter baumannii, Escherichia coli and Klebsiella spp. were the predominant Gram-negative bacteria. Compared to 2012-2015 years, the proportion of Gram-negative bacteria increased markedly during 2016-2019 years. Coagulase-negative Staphylococci, Streptococcus pneumoniae and Enterococcus faecium had 100% sensitivity to vancomycin, teicoplanin and linezolid. Acinetobacter baumannii and Klebsiella pneumoniae were 100% sensitive to tigecycline. Escherichia coli had 100% sensitivity to amikacin, meropenem and imipenem. The overall mortality rate in the 72 patients was 30.6%. In multivariate analysis, age > 50 years, pulmonary infections and CSF glucose level < the normal value were associated with poor outcomes. CSF adenosine deaminase level > the normal value and the presence of external ventricular drainage/lumbar cistern drainage were associated with MDR bacterial infections.

CONCLUSIONS

The mortality rate due to CNS infections reached 30.6% in our study. The proportion of Gram-negative bacteria has increased markedly in recent years. We should give particular attention to patients with risk factors for mortality and MDR bacterial infections mentioned above.

Brain abscess associated with ventricular septal defect and Eisenmenger syndrome: A case report

INTRODUCTION AND IMPORTANCE

Brain abscess is a potentially fatal neurological infection, despite the development of new antimicrobial agents and modern neurosurgical techniques.

CASE PRESENTATION

We present an uncommon case where a large brain abscess was treated successfully in a patient with Eisenmenger syndrome. He was underwent neurosurgical treatment and eventually recovered.

CLINNICAL DISCUSSION

The etiology of a brain abscess in patients with congenital cyanotic heart disease has multiple aspects. In this patient population was high risk for developing perioperative complications.The preoperative evaluation, intraoperative management and postoperative care are important steps in the treatment of cardiac patients undergoing noncardiac surgery, and essential for patient's safe and fast recovery.

CONCLUSIONS

We highlight the importance of the diagnosis and management of Eisenmenger syndrome to help us further understand this rare and fatal disease.

Brain abscess – A rare complication of endovascular treatment for acute ischemic stroke

Background:

Brain abscess is a neurosurgical emergency, which can arise through direct bacterial seeding or hematogenous spread. Rarely, brain abscess formation has been reported following ischemic stroke. An increasingly utilized therapy for stroke is mechanical thrombectomy, and within this report, we present a case of brain abscess formation following this procedure.

Case Description:

A 78-year-old female presented to our center with a right total anterior circulation stroke (TACS) secondary to terminal internal carotid artery occlusion. An emergent mechanical thrombectomy was performed and the patient’s initial postoperative recovery was good. In the 3^rd week after the procedure, however, the patient became more confused and following the onset of fever, an MRI brain was performed, which demonstrated an extensive multiloculated right-sided brain abscess. Burr hole drainage of the abscess was subsequently undertaken and pus samples obtained grew Proteus mirabilis, presumed secondary to a urinary tract infection, and the patient was started on prolonged antibiotic therapy. To date, the infection has been eradicated and the patient survives albeit with persistent neurological deficits.

Conclusion:

To the best of our knowledge, this is the first reported UK case of brain abscess following mechanical thrombectomy for stroke. Endovascular interventions can lead to increased incidence of ischemia-reperfusion injury in stroke with increased blood–brain barrier damage and risk of microbial seeding. This case highlights the need for rigorous asepsis and proactive treatment of systemic infections in the acute phase following endovascular treatment and consideration of brain abscess in all patients who present with new-onset confusion and unexplained fever following stroke.