Central nervous system pseudallescheriasis after near-drowning

Pathologic sequelae of vascular cognitive impairment and dementia sheds light on potential targets for intervention

Vascular contributions to cognitive impairment and dementia (VCID) is one of the leading causes of dementia along with Alzheimer's disease (AD) and, importantly, VCID often manifests as a comorbidity of AD(Vemuri and Knopman 2016; Schneider and Bennett 2010)(Vemuri and Knopman 2016; Schneider and Bennett 2010). Despite its common clinical manifestation, the mechanisms underlying VCID disease progression remains elusive. In this review, existing knowledge is used to propose a novel hypothesis linking well-established risk factors of VCID with the distinct neurodegenerative cascades of neuroinflammation and chronic hypoperfusion. It is hypothesized that these two synergistic signaling cascades coalesce to initiate aberrant angiogenesis and induce blood brain barrier breakdown trough a mechanism mediated by vascular growth factors and matrix metalloproteinases respectively. Finally, this review concludes by highlighting several potential therapeutic interventions along this neurodegenerative sequalae providing diverse opportunities for future translational study.

Voriconazole MICs are predictive for the outcome of experimental disseminated scedosporiosis

Background

Scedosporiosis is associated with a mortality rate of up to 90% in patients suffering from disseminated infections. Recommended first-line treatment is voriconazole, but epidemiological cut-off values and clinical breakpoints have not been determined.

Objectives

To correlate voriconazole treatment response in mice suffering from disseminated scedosporiosis with MIC values determined using CLSI broth microdilution, Etest (bioMérieux) and disc diffusion.

Methods

Voriconazole MICs for 31 Scedosporium apiospermum strains were determined using CLSI broth microdilution, Etest and disc diffusion. Groups of mice were challenged intravenously with 1 out of 16 S. apiospermum strains (voriconazole CLSI broth microdilution MIC range: 0.125-8.0 mg/L) and treated with 40 mg/kg voriconazole orally by gavage once daily. Efficacy of voriconazole was evaluated by a statistically significant ( P  <   0.05) reduction in fungal burden in brain.

Results

A categorical agreement of 90.4% was reached for CLSI broth microdilution and disc diffusion and of 93.6% for CLSI broth microdilution and Etest. Correlation of CLSI MICs and in vivo outcome was good, as mice challenged with strains with an MIC ≤2 mg/L responded to voriconazole therapy in 92.3% and those challenged with strains with an MIC ≥4 mg/L responded to voriconazole therapy in 33.3%.

Conclusions

CLSI broth microdilution and Etest deliver comparable results that enable a prediction of in vivo outcome. Our results suggest that voriconazole is able to reduce fungal burden in the brain of 92.3% of all mice challenged with strains with voriconazole CLSI MICs ≤2 mg/L, while mice challenged with strains with CLSI MICs ≥4 mg/L showed limited response to voriconazole treatment.

Management of Brain Abscess

Despite recent advances in neuroimaging techniques, brain abscesses can be difficult to diagnose and may often require surgical intervention. The primary sources of infection are often difficult to locate; hence, even if an abscess is suspected, the organisms may remain unknown. In other patients, the location of the lesion may be in a site of the brain where surgical intervention may not be possible. The types of brain abscesses, their pathophysiology including predisposing conditions, and their characteristic radiologic features are discussed in this review, with particular emphasis on the indications and modes of medical management of brain abscesses. It discusses the use of antimicrobial agents that have the best central nervous system penetration and outlines a strategy for treatment of organisms likely to infect the brain with the different types of predisposing conditions. Also discussed are the indications for empirical therapy, and antimicrobial regimens for this purpose are suggested.

Neuroimaging of pediatric intracranial infection--part 2: TORCH, viral, fungal, and parasitic infections

In the second half of this 2-part review, the neuroimaging features of the most common viral, fungal, and parasitic infections of the pediatric central nervous system are discussed. Brief discussions of epidemiology and pathophysiology will be followed by a review of the imaging findings and potential differential considerations.

Infections due to Pseudallescheria/Scedosporium species in patients with advanced HIV disease--a diagnostic and therapeutic challenge

OBJECTIVES

The aim of this study is to highlight the importance of infections caused by members of the genera Pseudallescheria/Scedosporium in HIV-positive patients.

METHODS

We describe a case of a fatal scedosporiosis in a treatment-naïve HIV patient and review all previously reported cases of pseudallescheriosis/scedosporiosis from a search of the PubMed and Deutsches Institut für Medizinische Dokumentation und Information (DIMDI) databases, applying the terms 'Pseudallescheria', 'Scedosporium', 'Allescheria', 'Monosporium', 'Petriellidium', 'boydii', 'prolificans', 'inflatum', cross-referenced with 'HIV' and 'AIDS'.

RESULTS

Detection of Scedosporium and Pseudallescheria species has been reported in 22 HIV-positive patients. Fourteen isolates belonged to the Pseudallescheria boydii complex and eight to Scedosporium prolificans. Invasive scedosporiosis (IS) was proven in 54.5% of the patients. Among them dissemination was observed in 66.7%. Pseudallescheria/Scedosporium species were mainly isolated from male individuals. Patients with proven IS showed CD4+ cell counts <100/μl and a higher co-infection rate as compared to colonized patients. Patients with central nervous system (CNS) manifestations showed CD4+ cell counts <50/μl. The mortality rate for patients with proven IS was 75% and was 100% for patients with dissemination/CNS manifestations. The fatality rate for patients treated with antifungal drugs plus surgery was lower compared to patients treated with antimycotic agents alone.

CONCLUSIONS

IS only occurred in HIV-positive patients with a strongly impaired immune system. The survival rates of patients with advanced HIV disease and invasive scedosporiosis can be improved by rapid diagnosis by biopsy and requires complex therapy with a combination of active antifungal drugs, surgery and supportive immune augmentation.

Invasive mycoses following trauma

Invasive fungal infection may afflict people with trauma in two ways: either by entry into tissue via penetrating trauma or by haematogenous spread in critically ill people with polytrauma. Penetrating injury allows the advance of ubiquitously present fungi into the human body. Miniscule foreign material fosters the establishment and growth of fungi within the traumatically changed tissue. The seriousness of the infection depends upon the type of injury, the body area and the person's general condition. Usually, the infection is confined to the cutis and subcutis; the fascia, muscles and bones are rarely affected. In the presence of immunocompromise, however, the fungus may spread rapidly and cause systemic disease. The following overview will focus on fungal infection associated with open wounds and fractures, particularly eye injury and with near-drowning, tropical mycetoma and nosocomial conditions. Post-traumatic invasive fungal infections are rare, but the surgeon should be alert to this possibility in cases with chronic inflammation and deferred healing of injuries, with or without systemic inflammatory response.

Treatment of scedosporiosis with voriconazole: clinical experience with 107 patients

The efficacy of voriconazole in 107 patients with scedosporiosis was analyzed. Principal infection sites were the lungs/sinuses (24%), central nervous system (CNS) (20%), and bone (18%), while 21% of patients had disseminated infection. Solid organ transplantation (22%), hematological malignancy (21%), and surgery/trauma (15%) were the predominant underlying conditions. A successful therapeutic response was achieved in 57% of patients (median, 103 therapy days), with > 98% of those responding receiving > or = 28 days of therapy. Patients receiving primary therapy showed a 61% response versus 56% for the others. The best therapeutic responses were seen for skin/subcutaneous (91%) or bone (79%) infections, and the lowest for CNS infections (43%). Patients without major immune suppression (72%) or those with solid organ transplantation (63%) or various hematological conditions (60%) showed the best responses by underlying condition. Median known survival time was 133 days (therapy successes, 252 days; failures, 21 days). In all, 43 (40%) patients died, 73% due to scedosporiosis. Patients with Scedosporium prolificans infection had significantly reduced survival times (P = 0.0259) and were more likely to die from fungal infection (P = 0.002) than were Scedosporium apiospermum-infected patients. In a subset of 43 patients where voriconazole baseline MICs were available, response to voriconazole was higher for S. apiospermum-infected patients (54% response; MIC(50), 0.25 microg/ml) than for S. prolificans-infected patients (40% response; MIC(50), 4.0 microg/ml). Voriconazole demonstrated clinically useful activity in the treatment of both S. apiospermum and S. prolificans infections and was well tolerated.