Two Specific Strains of <Emphasis Type="Italic">Histoplasma capsulatum</Emphasis> causing Mucocutaneous Manifestations of Histoplasmosis: Preliminary Analysis of a Frequent Manifestation of Histoplasmosis in Southern Brazil |
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Authors: | Luciano Z Goldani Valério R Aquino Luciano W Lunardi Vanessa S Cunha Rodrigo P Santos |
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Institution: | (1) Section of Infectious Diseases and Microbiology, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil;(2) Infectious Diseases Unit, Hospital de Clínicas de Porto Alegre, Ramiro Barcelos 2350, Porto Alegre, RS, 90035-002, Brazil |
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Abstract: | 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. |
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Keywords: | Histoplasma capsulatum Histoplasmosis Strains Clinical manifestations Skin Mucocutaneous Genetic diversity Typing ITS Dermatotropism Brazil Latin America |
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