Two specific strains of Histoplasma capsulatum causing mucocutaneous manifestations of histoplasmosis: preliminary analysis of a frequent manifestation of histoplasmosis in southern Brazil.

OBJECTIVES: Skin lesions, uncommon in US cases (<10%), occur in 38-85% of cases reported from Latin America. Although these differences may reflect reporting bias, delayed diagnosis, or differences in host immune response among different ethnic groups, they also could result from genetic differences changing the pathobiology of the organism. It is possible that genetic differences among strains of H. capsulatum may influence the pathogenesis and clinical manifestations of histoplasmosis. METHODS: We examined the clinical features of patients with mucocutaneous manifestations of histoplasmosis and performed genetic analysis based on nucleotide sequence variations in the internal transcribed spacer regions of rRNA genes of H. capsulatum isolates of patients. Two pairs of PCR primers were designed to develop and amplify the ITS regions of H. capsulatum, 5'-TACCCGGCCACCCTTGTCTA-3' and 5'-AGCGGGTGGCAAAGCCC-3'. These primers were based on the ITS sequence of Ajellomyces capsulatus, the ascomycetous teleomorph form of H. capsulatum, deposited in the GenBank (accession number U18363). Eight patients attending a tertiary-care hospital in southern Brazil were enrolled into the study. All case patients had skin cultures growing H. capsulatum at the mycology laboratory. RESULTS: Six of eight (75%) patients were HIV-positive and presented involvement of multiples organs by H. capsulatum. Two HIV-negative patients did not present evidence of involvement of other organs besides mucosa and skin. ITS sequencing of a DNA H. capsulatum fragment of 485-bp from isolates of 8 patients revealed two distinct strains. The 2 distinct fragments (Hc1, Hc2) differed from each other at 7 positions in the ITS regions. They were identical to strains of H. capsulatum isolated in patients from Colombia and Argentina, but different from strains isolated in US. Hc1 and Hc2 were isolated in 5 patients and 3 patients, respectively, with mucocutaneous manifestations of histoplasmosis. Both Hc1 and Hc2 strains were isolated in HIV-infected and non-HIV-infected patients. CONCLUSIONS: Mucocutaneous manifestations of histoplasmosis, which are frequently seen in Brazilian patients were caused by 2 specific strains in our institution. Those strains have been isolated in patients with these particular clinical features of histoplasmosis in Latin America. Our study suggests that unique pathogenic characteristics among the Latin American species of H. capsulatum might explain its increased dermatotropism.

Cutaneous cryptococccosis due to Cryptococcus gattii in immunocompetent hosts: case report and review.

Cutaneous cryptococcosis caused by C. gattii, in immunocompent patients is a rare manifestation of disease, and may be one of the first manifestations of disseminated cryptococcosis. We report a case of disseminated cryptococcosis caused by Cryptococcus gattii presenting as cutaneous lesions in an immunocompetent patient. Previously to our report, only five cases of cutaneous involvement by Cryptococcus gattii in immunocompetent patients have been reported in the literature. Risk factors for C. gattii infection included exposure to the eucalypt reservoirs in tropical and subtropical areas. Skin involvement corresponded to the disseminated form of cryptococcosis in the majority of patients, and commonly affected the face and neck with different morphologies including papules, pustules, plaques, ulcers, subcutaneous masses, cellulitis or acneiform lesions. Due to the severity of this infection and the life threatening condition that it represents, clinicians must be aware that cutaneous involvement may be one of the first manifestations of disseminated cryptococcosis caused by C. gattii especially in patients living and coming from endemic areas.