The mycological and molecular study of Hortaea werneckii isolated from blood and splenic abscess

Abstract

Hortaea werneckii is an environmental dematiaceous fungus found in the halophilic environment. It causes tinea nigra. We report the isolation of H. werneckii from blood and splenic abscess of two patients with acute myelomonocytic leukaemia. H. werneckii grew at room temperature but not at 37 degrees C, it was identified by biochemical tests, growth characteristics and the presence of conspicuous collarette intercalary on dividing yeast cells. The use of specific oligonucleotide primer Hor-F (5'-TGGACACCTTCA TAACTCTTG-3') and Hor-R (5'-TCACAACGCTTAGAGACGG-3') confirmed the two isolates were H. werneckii. The sequence for 281 nucleotide of HW299 and HW403 were 99% identical but differed only in one nucleotide. In vitro anti-fungal susceptibility testing showed that the isolates were resistant to amphotericin B and flucytosine.

Enzymatic Activity and Susceptibility to Antifungal Agents of Brazilian Environmental Isolates of Hortaea werneckii

“…The isolates were sensitive to itraconazole [12,14], ketoconazole [12,45] and voriconazole [12], as we found for our isolates. Gupta et al [14] found resistance to fluconazole, and Ng et al [12] reported that two isolates from patients with acute myeloid leukemia were sensitive to fluconazole and resistant to amphotericin B. In our study, the isolates were resistant to fluconazole and presented low sensitivity to amphotericin B, showing that resistance to these antifungal agents can be found in environmental isolates of H. werneckii; therefore, clinical administration of these agents should be viewed with care.…”

“…There are no such reports for environmental isolates of this fungus; however, studies concerning the in vitro antifungal activity of clinical isolates were found [12,14,45]. The isolates were sensitive to itraconazole [12,14], ketoconazole [12,45] and voriconazole [12], as we found for our isolates. Gupta et al [14] found resistance to fluconazole, and Ng et al [12] reported that two isolates from patients with acute myeloid leukemia were sensitive to fluconazole and resistant to amphotericin B.…”

“…Although Tinea nigra is the main disease associated with H. werneckii, and most cases resolve with keratinolytic agents [6,7] or with topical antifungal agents [13,15,18,46,47], there are reports of immunocompromised patients with more severe infections [12,48]. Therefore, in vitro antifungal susceptibility assays are important to find the ideal treatment for these severe infection conditions in view of the resistance profiles reported in the literature and in the present study.…”

“…This mycosis was originally observed in 1891 [1] and has since being reported from several places in South America [2][3][4][5][6][7][8] and other countries [9,10], including cases from infants [7,11]. The clinical presentation is generally a single hyperchromic macule, not symptomatic, in palms and soles, but there is a report of isolation of H. werneckii from blood and splenic abscess [12]. Treatment is usually done by topic or oral administration of antifungal agents [7,[13][14][15][16][17][18].…”

“…Although there are few reports of antifungal resistance, in vitro antifungal susceptibility testing showed that some isolates were resistant to amphotericin B and flucytosine [12], and one case of Tinea nigra failed to respond to treatment with systemic terbinafine [18].…”