Development of a murine model of cerebral aspergillosis.
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Central nervous system (CNS) Aspergillus infection has a mortality rate in humans that approaches 95%. Because no animal models are available for studying this infection, we sought to develop a murine model of CNS aspergillosis. Inconsistent data were obtained for nonimmunosuppressed CD-1, C57BL/6, and DBA/2N mice after infection by midline intracranial injection of Aspergillus fumigatus. CD-1 mice given cyclophosphamide to produce immunosuppression had continuous pancytopenia. Dose-finding studies in CD-1 mice showed that infection with 5 x 106 conidia/mouse consistently caused 100% mortality by day 5-8; no mice died before day 3. Histologic examination of samples of brain tissue showed focal abscesses containing Aspergillus hyphae. Fungus burdens in brain were higher than those in other organs, although Aspergillus disseminated to the kidneys and the spleen. The model we established provides an opportunity to study immune responses to and therapeutic options for CNS disease in an immunologically defined, genetically manipulable, and inexpensive species. (+info)
Isolation of Nocardia paucivorans from the cerebrospinal fluid of a patient with relapse of cerebral nocardiosis.
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Nocardia paucivorans represents a new species of the genus Nocardia that has recently been isolated from bronchial secretions of a patient with chronic lung disease. Here, we report on the course of a disseminated infection caused by this species: i.e., cerebral and subsequent meningeal manifestations, isolation from the cerebrospinal fluid, and in vitro susceptibility to various antimicrobial agents. (+info)
Brain abscess and glioblastoma identified by combined proton magnetic resonance spectroscopy and diffusion-weighted magnetic resonance imaging--two case reports.
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The differential diagnosis between brain abscesses and necrotic tumors such as glioblastomas is sometimes difficult to establish by conventional computed tomography and magnetic resonance imaging. Combined proton magnetic resonance spectroscopy (1H-MRS) and diffusion-weighted magnetic resonance imaging (DWI) were used to establish the preoperative diagnosis of brain abscess and glioblastoma. DWI visualized the brain abscess as a homogeneous hyperintense lesion and 1H-MRS revealed the presence of acetate, lactate, and amino acids and the absence of the normal brain components. DWI sometimes shows glioblastoma as a hyperintense lesion, but 1H-MRS reveals markedly increased lactate and decreased N-acetyl-aspartate. Combined DWI and 1H-MRS findings can distinguish brain abscess and glioblastoma. (+info)
Successful non-surgical treatment of brain abscess and necrotizing fasciitis caused by Bacillus cereus.
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Musculoskeletal and central nervous system infections caused by Bacillus cereus are very rare. Only a few cases have been reported, whose clinical courses strongly suggested that surgical procedures combined with appropriate antimicrobial therapy are necessary to cure these infections. A 60-year-old man with severe neutropenia due to myelodysplastic syndrome, developing necrotizing fasciitis and brain abscess caused by Bacillus cereus is reported. Without performing any surgical procedures, the patient was successfully treated with systemic antimicrobial therapy combined with granulocyte colony stimulating factor, which contributed to the increase in the neutrophil count. (+info)
Brain abscess and necrotic brain tumor: discrimination with proton MR spectroscopy and diffusion-weighted imaging.
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BACKGROUND AND PURPOSE: Discriminating pyogenic brain abscesses from cystic or necrotic tumors is sometimes difficult with CT or MR imaging. We compared findings of proton MR spectroscopy ((1)H-MRS) with those of diffusion-weighted imaging to determine which technique was more effective for this differential diagnosis. METHODS: Fourteen patients (necrotic or cystic tumor [n = 7]; pyogenic abscess [n = 7]) who underwent 1.5-T (1)H-MRS and diffusion-weighted imaging and had findings of ring-shaped enhancement after contrast agent administration were enrolled in this study. Diffusion-weighted imaging was performed with a single-shot spin-echo echo-planar pulse sequence (b = 1000 s/mm(2)). The apparent diffusion coefficient and ratio were also measured. RESULTS: Spectra for two patients were unacceptable because of either poor shimming conditions or contamination from neighboring fat. Spectra in three of five patients with abscess had lactate, amino acids (including valine, alanine, and leucine), and acetate peaks; one of the three spectra had an additional peak of succinate. In one patient with abscess treated by antibiotics, only lactate and lipid peaks were detected. Spectra for four of seven patients with cystic or necrotic tumors showed only lactate peaks. Lactate and lipids were found in three patients with tumors. Hyperintensity was seen in all the pyogenic abscess cavities and hypointensity in all the cystic and necrotic tumors on diffusion-weighted images. CONCLUSION: (1)H-MRS and diffusion-weighted imaging are useful for differentiating brain abscess from brain tumor, but the latter requires less time and is more accurate than is (1)H-MRS. (1)H-MRS is probably more limited in cases of smaller peripheral lesions, skull base lesions, and treated abscesses. (+info)
Dialister pneumosintes associated with human brain abscesses.
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In this report, we review two cases of brain infection due to Dialister pneumosintes in previously healthy patients. The bacterium was isolated from the first patient by blood culture and directly from a brain abscess in the second patient. In both cases, the infection was suspected to be of nasopharyngeal or dental origin. The patients had favorable outcomes following surgical debridement and antibiotic treatment. After in vitro amplification and partial sequencing of the 16S rRNA gene, two strains were classified as D. pneumosintes. However, traditional biochemical tests were not sufficient to identify the bacteria. In addition to causing periodontal and opportunistic infections, D. pneumosintes, contained in mixed flora, may behave as a clinically important pathogen, especially in the brain. In addition to phenotypic characterization, 16S rRNA partial sequencing was used to identify D. pneumosintes definitively. (+info)
PRESENTATION: We report a case of a 68-year-old man who suffered ischemic strokes in the left middle cerebral artery territory and three months later, following urosepsis, developed a cerebral abscess in the infarcted area. DISCUSSION: A literature search found only eight other cases. We discuss herein the common clinical aspects of brain abscess complicating strokes, the co-existent diseases, and point out the possibility of underreporting this rare but treatable complication. CONCLUSION: Cerebral abscess should be suspected in patients with a previous brain infarction or haemorrhage, who develop bacteremia and impaired consciousness without a clear explanation to their condition. Advanced age, and medical conditions known adversely to affect immunological competence reinforce the clinical suspicion. (+info)
Successful treatment of listerial brain abscess: a case report and literature review.
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Listerial brain abscess is extremely rare; only two cases have been reported in Japan. We encountered a female patient with immunoblastic lymphadenopathy, who developed listerial brain abscess after 8 years of treatment with antineoplastic agents and corticosteroids. Brain MRI revealed multiple space occupying lesions, suggesting abscesses which were possibly caused by hematogenous spread of the bacteria. Immediate blood culture enabled early diagnosis, and she entered into complete remission with high-dose ampicillin. Blood culture and brain imaging seem to play a crucial role in making an early diagnosis, and the administration of high dose of antibiotics is recommended for improvement of this disease. (+info)