Neurocriptococose por Cryptococcus neoformans não capsulado

Lacaz, C. S.; Heins‐Vaccari, Elisabeth Maria; Melo, Natalina Takahashi de; Moreno-Carvalho, Otávio A.; Sampaio, M.L.S.; Nogueira, Lygia Sega; Badaró, R.J.S.; Livramento, José Antônio

doi:10.1590/s0004-282x1993000300019

Cited by 6 publications

(2 citation statements)

References 8 publications

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“…As the capsule appears to be the main virulence factor of this organism, reports of meningeal infection with the nonencapsulated form are rare. 3 Predisposing factors for the non-encapsulated variant of C. neoformans appear to be similar to those of the encapsulated form and include HIV infection, post-transplant immunocompromise, exogenous corticosteroid therapy, sarcoidosis, and collagen vascular diseases. In addition to fungal meningitis, there have also been isolated case reports of nonencapsulated Cryptococcus causing pulmonary infection in an immunocompetent host.…”

Section: Discussionmentioning

confidence: 99%

Treatment of Indolent, Nonencapsulated Cryptococcal Meningitis Associated with Hydrocephalus

Garber

Penar

2012

Clinics and Practice

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Infection with cryptococcal meningitis is uncommon in immunocompetent patients. The major virulence factor is the polysaccharide capsule, while nonencapsulated mutants are generally considered nonpathogenic. The authors present a case of hydrocephalus caused by meningitis from an indolent, nonencapsulated Cryptococcus sp. requiring placement and multiple revisions of a ventriculoperitoneal shunt (VPS). The patient presented with progressively worsening occipital headaches. Computed tomography and magnetic resonance imaging showed significant hydrocephalus with no apparent cause. Her symptoms initially resolved after placement of a VPS, but returned four months later. Cultures of the shunt tubing and cerebrospinal fluid (CSF) showed no bacterial infection. When the symptoms failed to resolve, CSF fungal culture revealed Cryptococcus-like yeast, although the organisms were nonencapsulated, and the cryptococcal antigen was negative. After antibiotic therapy, the symptoms resolved. The unusual clinical presentation delayed the diagnosis, highlighting the importance of understanding the detection, diagnosis, and treatment of meningeal infections caused by C. neoformans.

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Section: Discussionmentioning

confidence: 99%

Treatment of Indolent, Nonencapsulated Cryptococcal Meningitis Associated with Hydrocephalus

Garber

Penar

2012

Clinics and Practice

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“…Several Brazilian authors have related chemocytologic aspects of CFS on cryptococcosis associated or not to AIDS, but a specific pattern of the disease does not exist 24,35,72,73,92,93 . The capsule, a morphologic aspect that distinguishes the genre Cryptococcus sp is considered an important factor of yeast virulence 38 ; however, there are cases described of the disease caused by a non-capsulated agent or by low capsule production 17,37,82 . Other virulence factors such as phenol oxidase production were studied in clinical strains by REZENDE 74 .…”

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confidence: 99%

Cryptococcosis: a review of the brazilian experience for the disease

Pappalardo

Melhem

2003

Rev. Inst. Med. trop. S. Paulo

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SUMMARYCryptococcosis is a systemic mycosis caused by Cryptococcus neoformans. The disease occurs in patients with cellular immunodeficiency. The incidence of cryptococcosis arises with AIDS, and mycosis is one of the opportunistic infections that defines AIDS. After the HAART era the occurrence of cryptococcosis decreased all over the world, but it still continues to be a prevalent disease in Brazil. Thus, we consider this paper to be very important as a result of our reviewing of Brazilian literature regarding some relevant aspects of that disease.

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Capsule enlargement inCryptococcus neoformansconfers resistance to oxidative stress suggesting a mechanism for intracellular survival

Zaragoza¹,

Chrisman²,

Castelli³

et al. 2008

Cellular Microbiology

230

206

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SummaryCryptococcus neoformans is a facultative intracellular pathogen. The most distinctive feature of C. neoformans is a polysaccharide capsule that enlarges depending on environmental stimuli. The mechanism by which C. neoformans avoids killing during phagocytosis is unknown. We hypothesized that capsule growth conferred resistance to microbicidal molecules produced by the host during infection, particularly during phagocytosis. We observed that capsule enlargement conferred resistance to reactive oxygen species produced by H 2O2 that was not associated with a higher catalase activity, suggesting a new function for the capsule as a scavenger of reactive oxidative intermediates. Soluble capsular polysaccharide protected C. neoformans and Saccharomyces cerevisiae from killing by H2O2. Acapsular mutants had higher susceptibility to free radicals. Capsular polysaccharide acted as an antioxidant in the nitroblue tetrazolium (NBT) reduction coupled to b-nicotinamide adenine dinucleotide (NADH)/phenazine methosulfate (PMS) assay. Capsule enlargement conferred resistance to antimicrobial peptides and the antifungal drug Amphotericin B. Interestingly, the capsule had no effect on susceptibility to azoles and increased susceptibility to fluconazole. Capsule enlargement reduced phagocytosis by environmental predators, although we also noticed that in this system, starvation of C. neoformans cells produced resistance to phagocytosis. Our results suggest that capsular enlargement is a mechanism that enhances C. neoformans survival when ingested by phagocytic cells.

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Neurocriptococose por Cryptococcus neoformans não capsulado

Cited by 6 publications

References 8 publications

Treatment of Indolent, Nonencapsulated Cryptococcal Meningitis Associated with Hydrocephalus

Treatment of Indolent, Nonencapsulated Cryptococcal Meningitis Associated with Hydrocephalus

Cryptococcosis: a review of the brazilian experience for the disease

Capsule enlargement inCryptococcus neoformansconfers resistance to oxidative stress suggesting a mechanism for intracellular survival

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