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Two specific strains of Histoplasma capsulatum causing mucocutaneous manifestations of histoplasmosis: a frequent manifestation of histoplasmosis in Latin America

Abstract number: P1582

Goldani L., Cunha V., Aquino V., Lunardi L.

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 alter 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 to 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 the H. capsulatum isolates from the 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. The H. capsulatum clinical strains Hc1 was isolated in 6 patients and Hc2 in 2 patients 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. 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 America species of H. capsulatum might explain its increased dermatotropism.

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Subject:
Location: Barcelona, Spain
Presentation type:
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