A twelve-year review of central nervous system bacterial abscesses; presentation and aetiology

Neuroinfectious Diseases in Children: Pathophysiology, Outcomes, and Global Challenges

Pathogens with affinity for the central nervous system (CNS) in children are diverse in their mechanisms of infecting and attacking the brain. Infections can reach the CNS via hematogenous routes, transneurally thereby avoiding the blood-brain barrier, and across mucosal or skin surfaces. Once transmission occurs, pathogens can wreak havoc both by direct action on host cells and via an intricate interplay between the protective and pathologic actions of the host's immune system. Pathogen prevalence varies depending on region, and susceptibility differs based on epidemiologic factors such as age, immune status, and genetics. In addition, some infectious diseases are monophasic, whereas others may lie dormant for years, thereby causing a dynamic effect on outcomes. Outcomes in survivors are highly variable for each particular pathogen and depend on the vaccination and immune status of the patient as well as the speed by which the patient receives evidence-based treatments. Given pathogens cause communicable diseases that can cause morbidity and mortality on a population level when spread, the burden is often the greatest and the outcomes the worst in low-resource settings. Here we will focus on the most common infections with a propensity to affect a child's brain, the pathologic mechanisms by which they do so, and what is known about the developmental outcomes in children who are affected by these infections.

Clinical situations for which 3D printing is considered an appropriate representation or extension of data contained in a medical imaging examination: neurosurgical and otolaryngologic conditions

BACKGROUND

Medical three dimensional (3D) printing is performed for neurosurgical and otolaryngologic conditions, but without evidence-based guidance on clinical appropriateness. A writing group composed of the Radiological Society of North America (RSNA) Special Interest Group on 3D Printing (SIG) provides appropriateness recommendations for neurologic 3D printing conditions.

METHODS

A structured literature search was conducted to identify all relevant articles using 3D printing technology associated with neurologic and otolaryngologic conditions. Each study was vetted by the authors and strength of evidence was assessed according to published guidelines.

RESULTS

Evidence-based recommendations for when 3D printing is appropriate are provided for diseases of the calvaria and skull base, brain tumors and cerebrovascular disease. Recommendations are provided in accordance with strength of evidence of publications corresponding to each neurologic condition combined with expert opinion from members of the 3D printing SIG.

CONCLUSIONS

This consensus guidance document, created by the members of the 3D printing SIG, provides a reference for clinical standards of 3D printing for neurologic conditions.

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.

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.

Invasive Aggregatibacter infection: shedding light on a rare pathogen in a retrospective cohort analysis

Introduction. Aggregatibacter are Gram-negative, facultatively anaerobic rods or coccobacilli that are infrequently encountered as pathogens causing infection.Hypothesis/Gap Statement. The range of invasive infection that Aggregatibacter cause is poorly described. The pathogenicity of species such as Aggregatibacter segnis is debated.Aim. To identify invasive infection due to Aggregatibacter species in a large healthcare organization and to characterize clinical syndromes, co-morbidities and risk factors.Methodology. All microbiological samples positive for Aggregatibacter species were identified by conventional culture or 16S rRNA PCR between October 2017 and March 2021. Electronic records for all patients with positive samples were reviewed and the infection syndrome classified for patients with invasive disease.Results. Twenty-seven patients with invasive infection were identified, with a statistically significant difference in species-specific patterns of invasive infection (P=0.02) and a statistically significant association with residence in the 30 % most deprived households in the UK by postcode (P<0.01). The three most common co-morbidities were periodontitis or recent dental work (29.6%), cardiovascular disease (25.9%) and diabetes (18.5 %).Conclusion. We describe a novel association of Aggregatibacter segnis with skin and soft tissue infection. The propensity of the Aggregatibacter species to cause invasive infection at different body sites and be associated with deprivation is reported. Aggregatibacter actinomycetemcomitans bacteraemia was associated with infective endocarditis, and Aggregatibacter aphrophilus was implicated in severe appendicitis and noted to cause brain abscess. Areas warranting future research include exploring the risk-factors required for invasive infection and those that may determine the species-specific differences in patterns of invasive disease.

Case report: Cryptogenic giant brain abscess caused by Providencia rettgeri mimicking stroke and tumor in a patient with impaired immunity

The highly lethal cryptogenic brain abscess can be easily misdiagnosed. However, cryptogenic brain abscess caused by Providencia rettgeri is rarely reported. We present the case of a cryptogenic Providencia rettgeri brain abscess and analyze the clinical manifestations, imaging findings, treatment, and outcome to improve the level of awareness, aid in accurate diagnosis, and highlight effective clinical management. A 39-year-old man was admitted to the hospital after experiencing acute speech and consciousness disorder for 1 day. The patient had a medical history of nephrotic syndrome and membranous nephropathy requiring immunosuppressant therapy. Magnetic resonance imaging revealed giant, space-occupying lesions involving the brain stem, basal ganglia, and temporal-parietal lobes without typical ring enhancement, mimicking a tumor. Initial antibiotic treatment was ineffective. Afterward, pathogen detection in cerebrospinal fluid using metagenomic next-generation sequencing revealed Providencia rettgeri. Intravenous maximum-dose ampicillin was administered for 5 weeks, and the patient's symptoms resolved. Cryptogenic Providencia rettgeri brain abscess typically occurs in patients with impaired immunity. Our patient exhibited a sudden onset with non-typical neuroimaging findings, requiring differentiation of the lesion from stroke and brain tumor. Metagenomic next-generation sequencing was important in identifying the pathogen. Rapid diagnosis and appropriate use of antibiotics were key to obtaining a favorable outcome.

Subdural empyema in adult with recent SARS-CoV-2 positivity case report

Intracranial abscess, including subdural empyema, is a rare central nervous system infectious disease and diagnosis is often delayed due to patient presentation with non-specific neurologic findings. Here we report a 65-year-old male with a recent past medical history of SARS-CoV-2 infection who presented with three weeks of escalating headache in whom MRI imaging revealed a subdural empyema. He subsequently underwent two craniectomies, which resulted in eradication of the abscess and clinical improvement. This report highlights a potential link between SARS-CoV-2 infection and this patient's development of subdural empyema, which has not been documented elsewhere in the literature.

Encephalitis and Brain Abscess

PURPOSE OF REVIEW

This article reviews infections of the brain parenchyma and includes an overview of the epidemiology, pathogenesis, diagnostic approach, and management of infectious encephalitis and brain abscess.

RECENT FINDINGS

The epidemiology of infectious encephalitis and brain abscess has changed in recent years. Vaccination has reduced the incidence of certain viruses associated with encephalitis, while a decrease in fulminant otogenic infections has led to fewer brain abscesses associated with otitis media. However, changes in climate and human population density and distribution have enabled the emergence of newer pathogens and expanded the geographic range of others, and greater adoption of intensive immunosuppressive regimens for autoimmune conditions has increased the risk of opportunistic infections of the brain. The widespread use of early neuroimaging, along with improved diagnostic methodologies for pathogen detection, newer antimicrobial therapies with better brain penetration, and less invasive neurosurgical techniques, has resulted in better outcomes for patients with infectious encephalitis and brain abscess. Novel technologies including metagenomic next-generation sequencing are increasingly being applied to these conditions in an effort to improve diagnosis. Nevertheless, both infectious encephalitis and brain abscess continue to be associated with substantial mortality.

SUMMARY

Infectious encephalitis and brain abscess can present as neurologic emergencies and require rapid assessment, thorough and appropriate diagnostic testing, and early initiation of empiric therapies directed against infectious agents. Close clinical follow-up, proper interpretation of diagnostic results, and appropriate tailoring of therapeutic agents are essential to optimizing outcomes. Diagnosis and management of parenchymal brain infections are complex and often best achieved with a multidisciplinary care team involving neurologists, neurosurgeons, neuroradiologists, infectious disease physicians, and pathologists.

Use of an Intracranial Drain as a Conduit for Treatment of an Intracranial Streptococcus intermedius Abscess

Brain abscesses are difficult to manage clinically and often result in a poor outcome. Although surgical and medical therapeutics have progressed, there are still challenges that make treating intracranial abscesses problematic. One of these treatment barriers is the poor penetration of intravenous antibiotics to the infection source through the blood-brain barrier. In this case report, we will discuss the use of a surgical drain as a conduit for direct antibiotic administration for a rare, recurrent Streptococcus intermedius infection. This technique allows us to bypass the blood-brain barrier while also reducing the systemic effects of antibiotics. When used in conjunction with craniotomy and resection, direct antibiotic administration via a surgical drain proved to be effective at treating our patient’s abscess and preventing recurrence.

Independent risk factors associated with higher mortality rates and recurrence of brain abscesses from head and neck sources

OBJECTIVE

The aim of this study was to identify the features and independent risk factors associated with recurrence and mortality in patients with brain abscesses of head and neck origin.

STUDY DESIGN

We designed a retrospective study of patients diagnosed with a brain abscess at the Massachusetts General Hospital between 1980 and 2017. Inclusion criteria were complete medical records, including medical and surgical history; and radiographic and microbiologic data. Multinomial logistic regression and Gray's test were used to evaluate the independent variables associated with recurrence and mortality.

RESULTS

Eighty-eight cases met the inclusion criteria. Of these, 48 patients (54.5%) were men (mean age 50.5 ± 18.8 years). Significant association between etiology and cultured organisms was found only in cases of neurosurgical intervention with staphylococcal or streptococcal isolates (P < .05). Seizure activity was the only significant predictor of recurrence. Predictors of mortality included advanced age (P = .005); staphylococcal infection (P = .029); low monocyte count (P = .004); hyponatremia (P = .002); elevated blood urea nitrogen (P = .000); elevated creatinine (P = .002); hyperglycemia (P = .023); and status at discharge (P = .000).

CONCLUSIONS

Independent risk factors, such as low monocyte count, hyponatremia, renal dysfunction, and hyperglycemia, were found to be associated with higher mortality rates in patients with brain abscesses of head and neck origin. These abnormalities should be promptly recognized and aggressively treated.

Do brain abscesses have a higher incidence of odontogenic origin than previously thought?

OBJECTIVE

The aim of this study was to answer the following clinical question: "In patients admitted to a tertiary care hospital with a diagnosis of brain abscess, how common is odontogenic etiology?"

STUDY DESIGN

We designed a retrospective study of patients with brain abscesses diagnosed at the Massachusetts General Hospital between 1980 and 2017. Inclusion criteria were complete medical records outlining clinical course, relevant dental history, and radiographic and microbiologic data.

RESULTS

Of 167 intracranial abscesses, 88 (52.7%) originated from a head/neck source, and 12 (13.6%) were of odontogenic etiology. Dental radiographs in 7 cases showed active dental infection. The remaining 5 patients reported recent dental procedures. Frontal lobe localization was the most common (7 of 12 [58.3%]). Presenting signs included headache (66.7%), mental status changes (41.6%), visual deficits (41.6%), and speech difficulties (33.3%). Computed tomography (CT) or magnetic resonance imaging (MRI) confirmed all diagnoses. Drainage via open craniotomy was performed in 6 (50%) of 12 patients, and stereotactic CT-guided drainage in 4 (33.3%). The most common pathogens were Streptococcus milleri (45.5%), Staphylococcus species (27.3%), and Fusobacterium (27.3%). All cases had favorable outcomes. Five had residual neurologic deficits, 4 had persistent visual complaints, and a recurrent abscess developed in 1 case.

CONCLUSIONS

These findings showed a higher subset (13.6%) of brain abscesses that could be attributed to odontogenic etiology than previously reported in the literature and highlight the need to rule out dental sources in cryptogenic cases.

Brain abscess in children, a two-centre audit: outcomes and controversies

OBJECTIVE

The aim of this study was to better characterise clinical presentation, management and outcome in infants and children with brain abscess.

METHODS

The authors conducted a retrospective, multicentre study in two national reference centres over a 25-year period (1992-2017). During this period, 116 children and 28 infants (age <1 year) with brain abscess were treated.

RESULTS

The median age at diagnosis was 101.5 (range: 13-213) months in children and 1 (0-11) month in infants. Significant differences were observed between children and infants. The most common predisposing factor was meningitis in infants (64% of cases vs 3% in children), while it was otolaryngology-related infection in children (31% of cases vs 3.6% in infants). Infants presented more frequently with fever and meningism compared with children. 115 patients were treated with aspiration and 11 with excision. Reoperation was required in 29 children vs 1 infant. The overall mortality rate was 4% (3.4% for children, 7.1% for infants). At 3-month follow-up, the outcome was favourable in 86% of children vs in 68% of infants.

CONCLUSION

There is a clear difference between children and infants with brain abscess in terms of predisposing factors, causative organisms and outcome. Despite surgical drainage and directed antibiotic therapy, 25% of patients with brain abscess require reoperation. Mortality is improved compared with historical series; however, long-term morbidity is significant particularly in the infant population.

Filifactor alocis brain abscess identified by 16S ribosomal RNA gene sequencing: A case report

We report a clinical case of Filifactor alocis brain abscess in an 85-year-old man who had decayed teeth 1 week prior. In this case, the abscess was surgically drained after empirical antibiotics had been initiated. Although the causative organism could not be identified by culture, F. alocis was detected via 16S ribosomal RNA (16S rRNA) gene sequencing of the pus isolated from the abscess. The patient recovered without serious sequelae after surgical drainage and prolonged antibiotic treatment, including metronidazole, ceftriaxone and meropenem for 8 weeks. The findings in this case emphasize that 16S rRNA gene sequencing allows bacterial diagnosis of brain abscess when phenotypic identification fails, such as in cases where patients are undergoing antimicrobial treatment at the time of sampling or where patients are infected with fastidious organisms.

Brain and Spinal Epidural Abscess

PURPOSE OF REVIEW

Brain abscesses and spinal epidural abscesses are serious, potentially life-threatening infections of the central nervous system. This article outlines the clinical presentation, evaluation, and management of brain abscesses and spinal epidural abscesses, with a specific focus on bacterial infections.

RECENT FINDINGS

The overall incidence of brain abscesses has declined, in part because of fewer brain abscesses associated with otogenic infections. However, emerging patient populations at high risk for brain abscess include those with a history of penetrating head trauma, neurosurgery, or immunodeficiency. Improved mortality rates for brain abscess are attributable to modern diagnostic imaging, stereotactic-guided aspiration, and newer antimicrobials that readily penetrate into the central nervous system and abscesses. Brain MRI is more sensitive than CT for brain abscess, particularly in the early stages, but CT remains more widely available and can adequately identify potential abscesses and confirm response to treatment. With the advent of minimally invasive neurosurgical techniques, surgical excision is often employed only for posterior fossa, multiloculated, or superficial well-circumscribed abscesses. In select clinical scenarios, conservative medical management may be a safe alternative to a combined surgical and medical approach. Unlike brain abscess, the incidence of spinal epidural abscess is on the rise and has been attributed to higher prevalence of predisposing factors, including spinal procedures and instrumentation.

SUMMARY

Successful diagnosis and management of brain abscess and spinal epidural abscess requires a collaborative approach among neurologists, neurosurgeons, radiologists, and infectious disease physicians. The foundation of management of brain abscess includes surgical intervention for diagnostic purposes if a pathogen has not been identified or for decompression of larger abscesses or those with mass effect and significant surrounding edema; appropriate dosing and adequate duration of an antimicrobial regimen tailored to the presumptive source of infection and available culture data, and eradication of the primary source of infection. For spinal epidural abscesses, neurologic status at the time of presentation is directly related to outcomes, underscoring the importance of prompt recognition and intervention.

Multiple brain abscesses treated by extraction of the maxillary molars with chronic apical lesion to remove the source of infection

Background

Brain abscess is a life-threatening condition that occurs due to complications during a neurosurgical procedure, direct cranial trauma, or the presence of local or distal infection. Infection in the oral cavity can also be considered a source of brain abscess.

Case presentation

A 45-year-old male patient was transported with brain abscess in the subcortical white matter. Navigation-guided abscess aspiration and drainage was performed in the right mid-frontal lobe, but the symptoms continued to worsen after the procedure. A panoramic radiograph showed alveolar bone resorption around the maxillary molars. The compromised maxillary molars were extracted under local anesthesia, and antibiotics were applied based on findings from bacterial culture. A brain MRI confirmed that the three brain abscesses in the frontal lobe were reduced in size, and the patient’s symptoms began to improve after the extractions.

Conclusion

This is a rare case report about multiple uncontrolled brain abscesses treated by removal of infection through the extraction of maxillary molars with odontogenic infection. Untreated odontogenic infection can also be considered a cause of brain abscess. Therefore, it is necessary to recognize the possibility that untreated odontogenic infection can lead to serious systemic inflammatory diseases such as brain abscess. Through a multidisciplinary approach to diagnosis and treatment, physicians should be encouraged to consider odontogenic infections as a potential cause of brain abscesses.

Brain abscess in pediatric age: a review

OBJECTIVE

The purpose of the paper is to examine the current state of the art about epidemiology, diagnosis, and treatment of this infection.

METHODS

A review of the literature was performed through a PubMed search of original articles, case reports, and reviews using the key words "brain abscess," "cerebral abscess," "brain infection," "intracranial suppuration," "otogenic brain abscess," "otitis complications," and "sinusitis complications."

RESULTS

Pediatric brain abscess is a rare but serious infection, often involving patients with specific risk factors and burdened by a high risk of morbidity and mortality. Brain abscess incidence and mortality decreased over the years, thanks to improved antibiotic therapy, new neurosurgical techniques, and the wide spread of vaccinations. There are no guidelines for the adequate diagnostic-therapeutic pathway in the management of brain abscesses; therefore, conflicting data emerge from the literature. In the future, multicentric prospective studies should be performed in order to obtain stronger evidences about brain abscesses management. Over the next few years, changes in epidemiology could be observed because of risk factors changes.

Diagnostic Accuracy of Echo-planar Diffusion-weighted Imaging in the Diagnosis of Intra-cerebral Abscess by Taking Histopathological Findings as the Gold Standard

Objective To determine the diagnostic accuracy of echo-planar diffusion-weighted imaging (DWI) in the diagnosis of intra-cerebral abscesses by taking histopathological findings as the gold standard. Subject and methods A retrospective cross-sectional study was performed from July 2014 to June 2015 at a tertiary care hospital in Karachi. A total of 462 patients, who were referred for magnetic resonance imaging (MRI) brain, presenting with clinical suspicion of an intra-cerebral abscess on the basis of clinical signs and symptoms, were included in this study. MR imaging was performed. All patients subsequently underwent surgery. The histopathological findings of these patients were collected and compared with echo-planar diffusion-weighted MRI findings. A proforma was used to record the findings. Results The mean age of the patients was 47.39±13.54 years. The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of echo-planar diffusion-weighted MRI in the diagnosis of intra-cerebral abscesses was 85.64%, 95.88%, 93.82%, 90.14%, and 91.56%, respectively. Conclusion Brain abscesses and necrotic tumors are, most of the time, difficult to differentiate on routine conventional imaging, and prompt diagnosis is important, as an untreated brain abscess could be lethal. Diffusion imaging can aid in the diagnosis and further management plan so as to help in improved patient care. Although this sequence has high sensitivity and specificity, it should be used in addition to conventional imaging and not as a replacement of histopathology.

Complex Microbiome in Brain Abscess Revealed by Whole-Genome Culture-Independent and Culture-Based Sequencing

Brain abscess is a severe infectious disease with high mortality and mobility. Although culture-based techniques have been widely used for the investigation of microbial composition of brain abscess, these approaches are inherent biased. Recent studies using 16S ribosomal sequencing approaches revealed high complexity of the bacterial community involved in brain abscess but fail to detect fungal and viral composition. In the study, both culture-independent nanopore metagenomic sequencing and culture-based whole-genome sequencing using both the Illumina and the Nanopore platforms were conducted to investigate the microbial composition and genomic characterization in brain abscess. Culture-independent metagenomic sequencing revealed not only a larger taxonomic diversity of bacteria but also the presence of fungi and virus communities. The culture-based whole-genome sequencing identified a novel species in Prevotella and reconstructs a Streptococcus constellatus with a high GC-skew genome. Antibiotic-resistance genes CfxA and ErmF associated with resistance to penicillin and clindamycin were also identified in culture-based and culture-free sequencing. This study implies current understanding of brain abscess need to consider the broader diversity of microorganisms.

A Clinical Report of Two Cases of Cryptogenic Brain Abscess and a Relevant Literature Review

Brain abscess, a severe intracranial infectious disease, refers to the parenchyma abscess caused by local infection or remote spread. Recently, advancements in modern medicine, especially the wide application of antimicrobial drugs, have contributed to the gradual decrease in the prevalence of this disease. However, cases of cryptogenic brain abscess that feature an unknown origin and atypical symptoms are rising. In this retrospective study, we report and analyze two cases of cryptogenic brain abscess. The first patient was a 30-year-old healthy man who was admitted to our hospital due to 1 week of headache and 3 days of headache aggravation, accompanied by nausea and vomiting. Head MRI shows a circular space-occupying as well as apparently enhanced DWI signals were observed in the right parietal lobe, and the ring wall manifested an apparent increase in signal intensity after enhancement. The patient was diagnosed as a brain abscess before operation and given craniotomy. The postoperative pathology confirmed brain abscess and recovered well after surgery. The second patient was a 45-year-old healthy woman who was hospitalized in a local hospital due to symptoms of headache and right limb weakness for 1 week. Head MRI shows a circular space-occupying lesion in the left basal ganglia, and the ring wall manifested an apparent increase in signal intensity after enhancement. The patient was suspected of glioma at the local hospital and was transferred to our hospital. Twelve hours after hospitalization, the patient was suspected of developing cerebral palsy and thus underwent emergency surgery including lesion resection in the left basal ganglia, resection of the polus temporalis, and a decompressive craniotomy. Postoperative pathology confirmed brain abscess. The patient was eventually conscious, but left the right limb hemiplegia. Hence, when a patient develops the classical triad of fever, headache, and focal neurologic deficits, the possibility of brain abscess should be investigated. Early diagnosis and treatment are crucial to minimize various complications and the number of deaths.

Pyogenic brain abscess and subdural empyema: presentation, management, and factors predicting outcome

PURPOSE

To describe the presentation and management of bacterial brain abscess and subdural empyema in adults treated at two tertiary centers. In addition, to identify factors that may predict a poor clinical outcome.

METHODS

A retrospective analysis of data obtained from clinical records was performed, followed by multivariate regression analysis of patient and treatment-related factors.

RESULTS

113 patients were included with a median age of 53 years and a male preponderance. At presentation symptoms were variable, 28% had a focal neurological deficit, and 39% had a reduced Glasgow coma scale (GCS). Brain abscesses most frequently affected the frontal, temporal, and parietal lobes while 36% had a subdural empyema. An underlying cause was identified in 76%; a contiguous ear or sinus infection (43%), recent surgery or trauma (18%) and haematogenous spread (15%). A microbiological diagnosis was confirmed in 86%, with streptococci, staphylococci, and anaerobes most frequently isolated. Treatment involved complex, prolonged antibiotic therapy (> 6 weeks in 84%) combined with neurosurgical drainage (91%) and source control surgery (34%). Mortality was 5% with 31% suffering long-term disability and 64% achieving a good clinical outcome. A reduced GCS, focal neurological deficit, and seizures at presentation were independently associated with an unfavorable clinical outcome (death or disability).

CONCLUSIONS

Complex surgical and antimicrobial treatment achieves a good outcome in the majority of patients with bacterial brain abscess and subdural empyema. Factors present at diagnosis can help to predict those likely to suffer adverse outcomes. Research to determine optimal surgical and antibiotic management would be valuable.

Whole-Genome Sequencing of Aggregatibacter Species Isolated from Human Clinical Specimens and Description of Aggregatibacter kilianii sp. nov

Aggregatibacter species are commensal bacteria of human mucosal surfaces that are sometimes involved in serious invasive infections. During the investigation of strains cultured from various clinical specimens, we encountered a coherent group of 10 isolates that could not be allocated to any validly named species by phenotype, mass spectrometry, or partial 16S rRNA gene sequencing. Whole-genome sequencing revealed a phylogenetic cluster related to but separate from Aggregatibacter aphrophilus The mean in silico DNA hybridization value for strains of the new cluster versus A. aphrophilus was 56% (range, 53.7 to 58.0%), whereas the average nucleotide identity was 94.4% (range, 93.9 to 94.8%). The new cluster exhibited aggregative properties typical of the genus Aggregatibacter Key phenotypic tests for discrimination of the new cluster from validly named Aggregatibacter species are alanine-phenylalanine-proline arylamidase, N-acetylglucosamine, and β-galactosidase. The name Aggregatibacter kilianii is proposed, with PN_528 (CCUG 70536^T or DSM 105094^T) as the type strain.

Frontal sinusitis complicated by a brain abscess and subdural empyema

A 49-year-old male was brought to the Emergency Department after being found unresponsive. The patient had multiple seizures and was intubated in the prehospital setting. A computed tomography scan showed bilateral paranasal sinus disease, and magnetic resonance imaging showed a right frontal abscess and subdural empyema. Neurosurgery took the patient to the operating room, performed a craniotomy, and drained a large amount of purulent fluid. He was subsequently discharged for acute rehabilitation. Clinicians should consider complicated frontal sinusitis, especially in the undifferentiated patient presenting with neurologic deficits and signs or symptoms of sinus disease.

Brain abscess and cervical lymphadenitis due to Paraclostridium bifermentans: A report of two cases

Paraclostridium bifermentans (current nomenclature of Clostridium bifermentans since 2016) is a gram-positive, spore-forming anaerobic bacterium. Here, we describe two cases associated with this organism. The first, primarily a case of tubercular brain abscess where P. bifermentans was isolated as part of a polymicrobial flora, following a neurosurgical procedure for the same and the second, a case of cervical lymphadenitis from which it was isolated as the sole causative agent. There are only a few reported cases of P. bifermentans in literature and these cases illustrate the widening spectrum of infections related to it.

[Intra-optic nerve and chiasmal abscess caused by methicillin-resistant Staphylococcus aureus (a case report and literature review)]

A 27-year-old immunocompetent male with headache, transient polydipsia, and polyuria suddenly developed visual impairment (predominantly in the left eye) and, 2 days later, left-sided amaurosis. MRI in T1, T2, DWI, and FLAIR modes revealed a space-occupying lesion of the left intracranial optic nerve and chiasm. According to the clinical X-ray picture, malignant chiasmal glioma was suspected; another and less likely variant was lymphoma. An open biopsy of the space-occupying lesion of the chiasmal-sellar region revealed purulent-necrotic masses. Material from the operative wound was positive for a Staphylococcus aureus strain. The polymerase chain reaction of a cerebrospinal fluid sample revealed methicillin-resistant Staphylococcus aureus. The patient underwent systemic and intrathecal antibiotic therapy with linezolid and vancomycin, respectively, with a good clinical effect: there was an improvement in the vision in a right single sighted eye and normalization of the cerebrospinal fluid composition.

Use of multiplex PCR based molecular diagnostics in diagnosis of suspected CNS infections in tertiary care setting-A retrospective study

OBJECTIVES

CNS infections like meningitis and encephalitis pose enormous healthcare challenges due to mortality, sequelae and socioeconomic burden. In tertiary setting, clinical, microbiological, cytological and radiological investigations are not distinctive enough for diagnosing microbial etiology. Molecular diagnostics is filling this gap. We evaluated the clinical impact of a commercially available multiplex molecular diagnostic system - SES for diagnosing suspected CNS infections.

PATIENTS AND METHODS

This study was conducted in our tertiary level Neurology ICU. 110 patients admitted during Nov-2010 to April-2014 were included. CSF samples of patients clinically suspected of having CNS infections were subjected to routine investigation in our laboratory and SES test at XCyton Diagnostics. We studied the impact of SES in diagnosis of CNS infections and its efficacy in helping therapeutic management.

RESULTS

SES showed detection rate of 42.18% and clinical specificity of 100%. It had 10 times higher detection rate than conventional tests. Streptococcus pneumoniae and Mycobacterium tuberculosis were two top bacterial pathogens. VZV was most detected viral pathogen. SES results elicited changes in therapy in both positive and negative cases. We observed superior patient outcomes as measured by GCS scale. 75% and 82.14% of the patients positive and negative on SES respectively, recovered fully.

CONCLUSION

Detecting causative organism and ruling out infectious etiology remain the most critical aspect for management and prognosis of patients with suspected CNS infections. In this study, we observed higher detection rate of pathogens, target specific escalation and evidence based de-escalation of antimicrobials using SES. Institution of appropriate therapy helped reduce unnecessary use of antimicrobials.

Expressive aphasia caused by Streptococcus intermedius brain abscess in an immunocompetent patient

Background

Brain abscess is an uncommon but life-threatening infection. It involves a focal, intracerebral infection that begins in a localized area of cerebritis and develops into a collection of pus, surrounded by a well-vascularized capsule. Brain abscess still poses a significant problem in developing countries but rarely in developed countries. Predisposing factors vary in different parts of the world. With the introduction of antibiotics and imaging studies, the mortality rate has decreased between 5% and 15%. If left untreated it may lead to serious neurologic sequelae. The temporal lobe abscess can be caused by conditions like sinusitis, otitis media, dental infections, and mastoiditis if left untreated or partially treated. Additionally, in neurosurgical procedures like craniotomy, the external ventricular drain can get infected, leading to abscess formation.

Case presentation

We present the case study of an elderly female patient who presented with expressive aphasia caused by brain abscess, secondary to Streptococcus intermedius infection. The 72-year-old female with a medical history of hypertension came to hospital for evaluation with word-finding difficulty, an expressive aphasia that began a few days prior to presentation. Computed tomography of the head showed a left temporal lobe mass-like lesion, with surrounding vasogenic edema. The patient was empirically started on courses of antibiotics. The next day, she was subjected to magnetic resonance imaging of the brain, which showed a left temporal lobe septated rim-enhancing mass lesion, with bright restricted diffusion and diffuse surrounding vasogenic edema consistent with abscess. The patient was also seen by the neurosurgery department and underwent stereotactic, left temporal craniotomy, with drainage, and resection of abscess. Tissue culture grew S. intermedius sensitive to ampicillin sulbactam. Subsequently her expressive aphasia improved.

Conclusion

Brain abscess has a high mortality, however a significant proportion of patients with appropriately treated abscess recover completely and can survive without significant neurologic damage. Advanced imaging modalities may yield more accurate methods of differentiation of mass lesions in the brain. Biopsy of brain lesion with early initiation of appropriate antibiotics will change the outcome.

Retrospective analysis of 620 cases of brain abscess in Chinese patients in a single center over a 62-year period

BACKGROUND

Despite advances in laboratory diagnostics, antibiotic regimens, and neurosurgical techniques, brain abscess (BA) remains a potentially fatal infectious disease. This study analyzed clinical and epidemiological aspects of BA in Chinese patients treated at a single center during a 62-year period.

METHOD

We retrospectively analyzed 620 BA patients treated at Tianjin Medical University General Hospital, Tianjin, PR China from 1952 to 2014. Because of the initiation of imaging technology use in 1992, and other specific changes, we analyzed data over three study periods: 1952-1972, 1980-1991, and 2002-2014. Information including incidence, sex, age, community distribution, BA size and location, therapeutic method, prognosis and outcome of BA patients was collected and evaluated.

RESULTS

Our study included 620 BA patients. The percentage mortality significantly decreased from 22.8 % in 1952 to 6.3 % in 2014 (p < 0.001). Although the incidence of BA was higher in males than females, there was no significant change in the male/female incidence ratio over time: 2.5 in 1952-1972, 2.6 in 1980-1991, and 2.2 in 2002-2014. The cryptogenic infection incidence significantly increased over time (p < 0.001). The number of positive bacterial cultures significantly decreased over the three study periods (p < 0.01).

CONCLUSIONS

The prognosis of patients with BA has gradually improved over the past 62 years in Tianjin, China. This may be because improvements in neurosurgical techniques, cranial imaging, and antimicrobial regimens have facilitated less invasive and more precise neurosurgical procedures.

[Pyogenic brain abscesses in adults]

Pyogenic brain abscesses (BA) are rare and their diagnosis may be difficult because of the absence of specific clinical or biological signs. However, the use of diffusion-weighted brain MRI sequences has modified the management of BA, as they are highly sensitive and specific to differentiate pyogenic brain abscesses from necrotic tumors, which are the most frequent differential diagnosis in case of ring-enhancing lesions on CT scan. This new tool allows for a rapid diagnosis and should be followed by a CT-guided aspiration of BA. This safe procedure should be performed if possible before starting antibiotics in order to optimize microbiological diagnosis. Recent epidemiological changes include an increase in the numbers of immunocompromised patients and a decrease in the traditional causes of BA (direct inoculation, ear nose and throat infections, etc.). In consequence, a wider range of bacterial species may be involved, making it all the more necessary to obtain a microbiological diagnosis. Many uncertainties remain in terms of the duration of antibiotic treatment, the optimal radiological follow-up and the place for associated treatments such as corticosteroids and anticonvulsive therapy. BA remain severe infections with high mortality and morbidity rates; the factor most regularly associated with a poor prognosis is the patients neurological status at diagnosis.

Retrospective analysis of multiplex polymerase chain reaction-based molecular diagnostics (SES) in 70 patients with suspected central nervous system infections: A single-center study

Background:

Central nervous system (CNS) infections present a grave health care challenge due to high morbidity and mortality. Clinical findings and conventional laboratory assessments are not sufficiently distinct for specific etiologic diagnosis. Identification of pathogens is a key to appropriate therapy.

Aim:

In this retrospective observational study, we evaluated the efficacy and clinical utility of syndrome evaluation system (SES) for diagnosing clinically suspected CNS infections.

Materials and Methods:

This retrospective analysis included inpatients in our tertiary level neurointensive care unit (NICU) and ward from February 2010 to December 2013. Cerebrospinal fluid (CSF) samples of 70 patients, clinically suspected of having CNS infections, were subjected to routine laboratory tests, culture, imaging, and SES. We analyzed the efficacy of SES in the diagnosis of CNS infections and its utility in therapeutic decision-making.

Results:

SES had a clinical sensitivity of 57.4% and clinical specificity of 95.6%. Streptococcus pneumoniae and Pseudomonas aeruginosa were the top two bacterial pathogens, whereas Herpes simplex virus (HSV) was the most common viral pathogen. Polymicrobial infections were detected in 32.14% of SES-positive cases. SES elicited a change in the management in 30% of the patients from initial empiric therapy. At discharge, 51 patients recovered fully while 11 patients had partial recovery. Three-month follow-up showed only six patients to have neurological deficits.

Conclusion:

In a tertiary care center, etiological microbial diagnosis is central to appropriate therapy and outcomes. Sensitive and accurate multiplex molecular diagnostics play a critical role in not only identifying the causative pathogen but also in helping clinicians to institute appropriate therapy, reduce overuse of antimicrobials, and ensure superior clinical outcomes.

MRSA in Croatia: prevalence and management

Infections caused by methicillin-resistant Staphylococcus aureus (MRSA) are associated with increased morbidity, mortality and length of hospital stay. MRSA is a major pathogen in hospitals and an important pathogen in community infections with few severe and fatal cases. However, MRSA causes the majority of skin and soft tissue infections in the US. The burden of community MRSA is much smaller in Europe, but there are reports of livestock-associated MRSA (LA-MRSA) isolated from pigs and cattle causing significant infections in the people who are connected to these farms. MRSA has been present in Croatia for more than 45 years, and it exerts a different impact on health-care infections. A remarkable increase in MRSA percentage was noted in primarily sterile samples in 2002 (37%) in comparison to 2001 (31%). This percentage remained quite high until 2008, when the first signs of a reduced trend were observed. The lowest percentage was 22% in 2012.

Staphylococcus aureus infection of the optic nerve

A 71-year-old woman presented with painful vision loss in the right eye followed by ophthalmoplegia. Magnetic resonance imaging demonstrated optic nerve sheath enlargement and enhancement. Biopsy of the optic nerve sheath revealed purulent and necrotic material that was positive for methicillin-sensitive Staphylococcus aureus. The patient underwent enucleation of the right eye and was treated with systemic antibiotics with clinical stabilization. Imaging, pathological and treatment aspects of optic nerve sheath abscess are discussed.

Cerebral Abscess Presenting as a Complex Febrile Seizure

Currently, there is no standardized approach to the management of complex febrile seizures in children and there are no published practice guidelines for the procurement of neuroimaging. Presented is a 2-year-old female patient who experienced a 3- to 5-minute episode of staring and unilateral mouth twitching associated with high fever. On initial presentation, the patient appeared well and had a normal neurological examination. No focus of infection was identified, and she was diagnosed with complex febrile seizure. The patient was discharged home with close neurology and primary care follow-up but returned the following day with altered mental status, toxic appearance, and right lower extremity weakness. Magnetic resonance imaging of the brain revealed left-sided cranial empyema and the patient was managed with antibiotics and surgical drainage. A literature review to answer the question "Do children with complex febrile seizures require emergent neuroimaging?" yielded a small number of retrospective reviews describing the utility of computed tomography, magnetic resonance imaging and lumbar puncture in the work-up of febrile seizures. Current evidence indicates that neuroimaging is not indicated in an otherwise healthy child who presents with complex febrile seizure if the patient is well appearing and has no evidence of focal neurological deficit on examination. As this case demonstrates, however, serious conditions such as meningitis and brain abscess (though rare) should be considered in the differential diagnosis of complex febrile seizure and physicians should remain aware that the need for neuroimaging and/or lumbar puncture may arise in the appropriate clinical setting.

Pediatric intracranial abscesses

Intracranial infections in children are a relatively rare, but potentially severe condition. Because of the potential for rapid deterioration, timely diagnosis and treatment are necessary. These infections are categorized based on their intracranial location: epidural abscess, subdural empyema, and brain abscess. They largely arise from direct extension of adjacent infection, hematogenous seeding, or trauma. Clinical presentations of intracranial infections also vary. However, common signs and symptoms include headache, fever, nausea and vomiting, altered mental status, focal neurologic deficits, and seizures. In general, MRI demonstrates a peripherally enhancing lesion with high signal on diffusion weighted imaging (DWI). Bacterial isolates vary, but most commonly are a single pathogen. Successful treatment requires a multidisciplinary team approach including such modalities as antibiotic therapy and surgical drainage. When possible, open surgical evacuation of the abscess is preferred, however, in cases of deep-seated lesions, or in unstable patients, aspiration has also been performed with good results.

Bacterial brain abscess

Significant advances in the diagnosis and management of bacterial brain abscess over the past several decades have improved the expected outcome of a disease once regarded as invariably fatal. Despite this, intraparenchymal abscess continues to present a serious and potentially life-threatening condition. Brain abscess may result from traumatic brain injury, prior neurosurgical procedure, contiguous spread from a local source, or hematogenous spread of a systemic infection. In a significant proportion of cases, an etiology cannot be identified. Clinical presentation is highly variable and routine laboratory testing lacks sensitivity. As such, a high degree of clinical suspicion is necessary for prompt diagnosis and intervention. Computed tomography and magnetic resonance imaging offer a timely and sensitive method of assessing for abscess. Appearance of abscess on routine imaging lacks specificity and will not spare biopsy in cases where the clinical context does not unequivocally indicate infectious etiology. Current work with advanced imaging modalities may yield more accurate methods of differentiation of mass lesions in the brain. Management of abscess demands a multimodal approach. Surgical intervention and medical therapy are necessary in most cases. Prognosis of brain abscess has improved significantly in the recent decades although close follow-up is required, given the potential for long-term sequelae and a risk of recurrence.

Risk factors associated with poor outcomes in patients with brain abscesses

OBJECTIVE

The purpose of this study was to describe the clinical characteristics, treatment outcomes, and prognostic factors in patients with brain abscesses treated in a single institute during a recent 10-year period.

METHODS

Fifty-one patients with brain abscesses who underwent navigation-assisted abscess aspiration with antibiotic treatment were included in this study. Variable parameters were collected from the patients' medical records and radiological data. A comparison was made between patients with favorable [Glasgow Outcome Scale (GOS) ≥4] and unfavorable (GOS <4) outcomes at discharge. Additionally, we investigated the factors influencing the duration of antibiotic administration.

RESULTS

The study included 41 male and 10 female patients with a mean age of 53 years. At admission, 42 patients (82%) showed either clear or mildly disturbed consciousness (GCS ≥13) and 24 patients (47%) had predisposing factors. The offending microorganisms were identified in 25 patients (49%), and Streptococcus species were the most commonly isolated bacteria (27%). The mean duration of antibiotic administration was 42 days. At discharge, 41 patients had a favorable outcome and 10 had an unfavorable outcome including 8 deaths. The decreased level of consciousness (GCS <13) on admission was likely associated with an unfavorable outcome (p=0.052), and initial hyperglycemia (≥140 mg/dL) was an independent risk factor for prolonged antibiotic therapy (p=0.032).

CONCLUSION

We found that the level of consciousness at admission was associated with treatment outcomes in patients with brain abscesses. Furthermore, initial hyperglycemia was closely related to the long-term use of antibiotic agents.

Community-acquired intracranial suppurative infections: A 15-year report

Background:

The aim of this study was to retrospectively evaluate the characteristics, treatment, and prognosis of patients with intracranial suppurative infection (ISI) by review of clinical, radiological, and laboratory findings.

Methods:

The data collected from all patients who had been diagnosed with ISI and followed up at the Infectious Diseases and Clinical Microbiology Department of the study site between 1998 and 2013 were reviewed.

Results:

Of the 23 ISI patients identified, the mean age was 38.21 ± 12.61 years (range: 19–67 years, median: 34) and mean symptom duration was 22.25 ± 20.22 days. Headache was the most common symptom, the frontal lobe the most common localization of ISI, and mastoiditis due to chronic suppurative otitis media the most common source of infection causing ISI. Proteus mirabilis, Pseudomonas spp., Peptostreptococcus spp., Enterococcus avium, Mycobacterium tuberculosis complex, and Toxoplasma gondii were isolated from the specimens collected from 6 (37.5%) of the 16 patients who underwent invasive procedures. Of these 16 patients, 2 underwent craniotomy, 12 burr hole aspiration, and 2 stereotactic biopsy. The rate of recurrence was 0% and the rates of sequelae and fatality were both 8%.

Conclusions:

ISI should be considered in male patients presenting with headache and neurological signs and symptoms, whether with or without fever, on admission for early diagnosis and provision of timely, adequate therapy and, if required, surgical intervention to reduce mortality and sequelae rates.

A curious case of confusion

Delirium secondary to pneumonia is expected in the elderly, but when persistent and incongruent with expectation, cerebral abscess should be considered.

Parietal subdural empyema as complication of acute odontogenic sinusitis: a case report

Introduction

To date intracranial complication caused by tooth extractions are extremely rare. In particular parietal subdural empyema of odontogenic origin has not been described. A literature review is presented here to emphasize the extreme rarity of this clinical entity.

Case presentation

An 18-year-old Caucasian man with a history of dental extraction developed dysarthria, lethargy, purulent rhinorrhea, and fever. A computed tomography scan demonstrated extensive sinusitis involving maxillary sinus, anterior ethmoid and frontal sinus on the left side and a subdural fluid collection in the temporal-parietal site on the same side. He underwent vancomycin, metronidazole and meropenem therapy, and subsequently left maxillary antrostomy, and frontal and maxillary sinuses toilette by an open approach. The last clinical control done after 3 months showed a regression of all symptoms.

Conclusions

The occurrence of subdural empyema is an uncommon but possible sequela of a complicated tooth extraction. A multidisciplinary approach involving otolaryngologist, neurosurgeons, clinical microbiologist, and neuroradiologist is essential. Antibiotic therapy with surgical approach is the gold standard treatment.

Brain infection with Staphylococcus aureus leads to high extracellular levels of glutamate, aspartate, γ-aminobutyric acid, and zinc

Staphylococcal brain infections may cause mental deterioration and epileptic seizures, suggesting interference with normal neurotransmission in the brain. We injected Staphylococcus aureus into rat striatum and found an initial 76% reduction in the extracellular level of glutamate as detected by microdialysis at 2 hr after staphylococcal infection. At 8 hr after staphylococcal infection, however, the extracellular level of glutamate had increased 12-fold, and at 20 hr it had increased >30-fold. The extracellular level of aspartate and γ-aminobutyric acid (GABA) also increased greatly. Extracellular Zn(2+) , which was estimated at ∼2.6 µmol/liter in the control situation, was increased by 330% 1-2.5 hr after staphylococcal infection and by 100% at 8 and 20 hr. The increase in extracellular glutamate, aspartate, and GABA appeared to reflect the degree of tissue damage. The area of tissue damage greatly exceeded the area of staphylococcal infiltration, pointing to soluble factors being responsible for cell death. However, the N-methyl-D-aspartate receptor antagonist MK-801 ameliorated neither tissue damage nor the increase in extracellular neuroactive amino acids, suggesting the presence of neurotoxic factors other than glutamate and aspartate. In vitro staphylococci incubated with glutamine and glucose formed glutamate, so bacteria could be an additional source of infection-related glutamate. We conclude that the dramatic increase in the extracellular concentration of neuroactive amino acids and zinc could interfere with neurotransmission in the surrounding brain tissue, contributing to mental deterioration and a predisposition to epileptic seizures, which are often seen in brain abscess patients.

Central nervous system syndromes in solid organ transplant recipients

Solid organ transplant recipients have a high incidence of central nervous system (CNS) complications, including both focal and diffuse neurologic deficits. In the immunocompromised host, the initial clinical evaluation must focus on both life-threatening CNS infections and vascular or anatomic lesions. The clinical signs and symptoms of CNS processes are modified by the immunosuppression required to prevent graft rejection. In this population, these etiologies often coexist with drug toxicities and metabolic abnormalities that complicate the development of a specific approach to clinical management. This review assesses the multiple risk factors for CNS processes in solid organ transplant recipients and establishes a timeline to assist in the evaluation and management of these complex patients.

Multiple brain abscesses in an immunocompetent patient after undergoing professional tooth cleaning

BACKGROUND

Dental disorders and dental treatment are among the variety of causes of brain abscess.

CASE DESCRIPTION

The authors present the case of a patient who developed multiple brain abscesses after undergoing professional tooth cleaning. The results of a diagnostic work-up ruled out an underlying immunodeficiency. After receiving neurosurgical intervention and intensive care treatment by means of local and intravenous antibiotics for 24 days, the patient was transferred to another hospital for rehabilitation. Six months after the treatment, the patient still had moderate residual paresis of the left leg.

PRACTICAL IMPLICATIONS

Although it happens rarely, professional tooth cleaning may be considered a cause of brain abscesses even in otherwise healthy patients.

Classification, identification, and clinical significance of Haemophilus and Aggregatibacter species with host specificity for humans

The aim of this review is to provide a comprehensive update on the current classification and identification of Haemophilus and Aggregatibacter species with exclusive or predominant host specificity for humans. Haemophilus influenzae and some of the other Haemophilus species are commonly encountered in the clinical microbiology laboratory and demonstrate a wide range of pathogenicity, from life-threatening invasive disease to respiratory infections to a nonpathogenic, commensal lifestyle. New species of Haemophilus have been described (Haemophilus pittmaniae and Haemophilus sputorum), and the new genus Aggregatibacter was created to accommodate some former Haemophilus and Actinobacillus species (Aggregatibacter aphrophilus, Aggregatibacter segnis, and Aggregatibacter actinomycetemcomitans). Aggregatibacter species are now a dominant etiology of infective endocarditis caused by fastidious organisms (HACEK endocarditis), and A. aphrophilus has emerged as an important cause of brain abscesses. Correct identification of Haemophilus and Aggregatibacter species based on phenotypic characterization can be challenging. It has become clear that 15 to 20% of presumptive H. influenzae isolates from the respiratory tracts of healthy individuals do not belong to this species but represent nonhemolytic variants of Haemophilus haemolyticus. Due to the limited pathogenicity of H. haemolyticus, the proportion of misidentified strains may be lower in clinical samples, but even among invasive strains, a misidentification rate of 0.5 to 2% can be found. Several methods have been investigated for differentiation of H. influenzae from its less pathogenic relatives, but a simple method for reliable discrimination is not available. With the implementation of identification by matrix-assisted laser desorption ionization-time of flight mass spectrometry, the more rarely encountered species of Haemophilus and Aggregatibacter will increasingly be identified in clinical microbiology practice. However, identification of some strains will still be problematic, necessitating DNA sequencing of multiple housekeeping gene fragments or full-length 16S rRNA genes.

Brain abscess: Current management

Brain abscess (BA) is defined as a focal infection within the brain parenchyma, which starts as a localized area of cerebritis, which is subsequently converted into a collection of pus within a well-vascularized capsule. BA must be differentiated from parameningeal infections, including epidural abscess and subdural empyema. The BA is a challenge for the neurosurgeon because it is needed good clinical, pharmacological, and surgical skills for providing good clinical outcomes and prognosis to BA patients. Considered an infrequent brain infection, BA could be a devastator entity that easily left the patient into dead. The aim of this work is to review the current concepts regarding epidemiology, pathophysiology, etiology, clinical presentation, diagnosis, and management of BA.

The correlation of microbiology growth between subperiosteal orbital abscess and affected sinuses in young children

BACKGROUND

Subperiosteal orbital abscess (SPOA) typically presents as a collection of pus in the space between the periorbit and the lamina papyracea adjacent to the infected paranasal sinuses. The aim of this study was to investigate the simultaneous microbiological growth from an SPOA and the paranasal sinuses in the same children.

METHODS

A retrospective study was performed on cultures obtained from involved sinuses and surgically drained abscesses in young children with SPOA from January 1992 to March 2009.

RESULTS

Twenty-two children with a mean age of 5.9 years were included. Results of the microbiological studies were available from the sinuses of 17 children (77.2%) and from the SPOA in 18 children (81.8%). High rates of staphylococci bacteria and Streptococcus viridans were observed compared with lower-than-expected upper respiratory tract infection pathogens. Both groups showed scarce anaerobic and polymicrobial growth. In 13 children (59%), both sinus and abscess culture results were available with correlation found in only 4 (30.7%) of these children.

CONCLUSION

In this study we report the results of bacteriological studies of nasal sinuses and SPOAs in young children, with a low rate of correlation between both sites and low rates of anaerobic growth, but high rates of staphylococcal growth in the SPOA cultures. These observations might be related to the trend toward conservative treatment in children.