In vitro expression of vital virulent genes of clinical and environmental isolates of Cryptococcus neoformans/gattii in endothelial cells of human blood-brain barrier.

BACKGROUND: Evaluation of the pathogenesis of clinical and environmental cryptococcal isolates to the central nervous system is necessary for understanding the risk. This study was designed to determine the in vitro expression of six important virulent genes of Cryptococcus neoformans/gattii in Human Brain Microvascular Endothelial cells (hBMEC). METHODS: The hBMEC were infected with Cryptococcus to determine invasion and survival rate at 3, 12 and 24hours by subsequent colony count of internalized yeasts. The whole RNA of the intracellular Cryptococcus was extracted to quantify the expression of CAP10, PLB1, ENA1, URE1, LAC1, and MATα genes by real-time quantitative PCR for 3 and 12hours of infection. RESULTS: Invasion and survival rates were higher in clinical and standard strains of C. neoformans. A significant difference was observed among the clinical and environmental isolates for the expression of CAP10, ENA1, LAC1, MATα and URE1 at 3hours, and ENA1, LAC1, MATα, PLB1 and URE1 at 12hours. Clinical isolates showed significant upregulation of all the genes except PLB1, which was higher in environmental isolates. Relative expressions at the two time-points showed statistically significant (P=0.043) changes for the clinical isolates and no significance (P=0.063) for environmental isolates. CONCLUSION: The C. gattii (VGI) isolates showed significantly lower invasion and survival than C. neoformans (VNI, and VNII) irrespective of their sources. Clinical isolates exhibited higher expression for the majority of the virulent genes until 12hours of infection, probably due to their better adaptation in the host system and enhanced pathogenicity than the environmental counterparts.

A rare case of multiple brain abscess and probably disseminated phaeohyphomycosis due to Cladophialophora bantiana in an immunosuppressed individual from India.

Cladophialophora bantiana, a dematiaceous neurotropic mold causes rare and lethal brain abscess, commonly in immunocompetent hosts. We report a rare and probably a case of disseminated infection with this black mold in an immunosuppressed individual from India. A 55-year-old diabetic male presented with severe headache, blurred-vision, behavioural abnormalities, eye-pain and ear-discharge. He was undergoing treatment for hypertension, prostatomegaly and obstructive pulmonary disease. He was on steroids for the past six years for uveitis. Haematology reports indicated elevated WBC and platelet count. He was negative for HIV, hepatitis, autoimmune antibodies and tumour markers. CD4 count was within normal limits. Brain magnetic resonance imaging revealed multiple ring-enhancing lesions and oedema in the left tempero-parietal region. Chest X-ray showed irregular consolidations in right paracardiac region and confluence in both lungs. Positron Emission Tomography of whole body revealed multiple lesions in brain, lungs, lymph nodes and C3-vertebrae. Histopathology of the lung lesion showed non-tuberculous infectious pathology and brain lesions showed necrosis with occurrence of pigmented hyphal fungi. The pus aspirated during surgical excision of brain lesions grew black mold, identified as C. bantiana. Although patient was started on intravenous Voriconazole, he succumbed to the infection after 7 days. The lesion was initially suspected to be of tuberculous etiology, and the lesions in lungs were also suggestive of malignancy, which was however ruled out by histopathological examination. Such diagnostic dilemmas are common in the infection caused by Cladophialophora, which can cause treatment delay and death. Early diagnosis is therefore mandatory for the rapid treatment and survival of patients.