A severe outbreak of highly virulent and multi-resistant dermatophytosis by species in the Trichophyton mentagrophytes/T. interdigitale complex is ongoing in India. The correct identity of the etiologic agent is a much-debated issue. In order to define species limits, a taxonomic study was undertaken combining molecular, morphological, and physiological characteristics as evidence of classification. Molecular characteristics show that T. mentagrophytes s. str. and T. interdigitale s. str. can be distinguished with difficulty from each other, but are unambiguously different from the Indian genotype, T. indotineae by sequences of the HMG gene. The entities were confirmed by multilocus analysis using tanglegrams. Phenotypic characters of morphology and physiology are not diagnostic, but statistically significant differences are observed between the molecular siblings. These properties may be drivers of separate evolutionary trends. Trichophyton mentagrophytes represents the ancestral, homothallic cloud of genotypes with a probable geophilic lifestyle, while T. indotineae and T. interdigitale behave as anthropophilic, clonal offshoots. The origin of T. indotineae, which currently causes a significant public health problem, is zoonotic, and its emergence is likely due to widespread misuse of antifungals.
Background: During the past decade, a prolonged and serious outbreak of dermatophytosis due to a terbinafine-resistant novel species in the Trichophyton mentagrophytes/T. interdigitale complex is ongoing in India, and it spreads to several European countries.
Objective: To investigate the molecular background of the squalene epoxidase (SQLE) gene in order to understand the risk of emergence and spread of multi-resistance in dermatophytes.
Methods: Antifungal susceptibility for fluconazole, griseofulvin, itraconazole, ketoconazole, miconazole, naftifine, sertaconazole, and terbinafine was tested in 135 isolates from India, China, Australia, Germany and The Netherlands. Based on the latest taxonomic insights, strains were identified as three species: T. mentagrophytes s. str. (n=35), T. indotineae (n=64 representing the Indian clone) and T. interdigitale s. str. (n=36).
Results: High minimum inhibitory concentrations (MICs) of terbinafine (>16 mg/L) were found in 34 (53%) T. indotineae isolates. These isolates showed an amino acid substitution in the 397th position of the SQLE gene. Elevated MICs of terbinafine (0.5 mg/L) were noted in 2 (3%) T. indotineae isolates; these isolates lead to Phe415Val and Leu393Ser of the SQLE gene. Stability of the effect of the mutations was proven by serial transfer on drug-free medium. Substitutions of Lys276Asn and Leu419Phe were found in susceptible T. mentagrophytes strains. The double mutant Phe377Leu/Ala448Thr showed higher MIC values for triazoles.
Conclusions: High MICs of terbinafine are as yet limited to T. indotineae, and are unlikely to be distributed through the T. mentagrophytes species complex by genetic exchange.
In malignant melanoma, tumor-associated macrophages play multiple roles in promoting tumor growth, such as inducing the transformation of melanocytes under ultraviolet irradiation, increasing angiogenesis in melanomas, and suppressing antitumor immunity. Because granzyme B-and perforin-expressing Tr1 cells could specifically eliminate antigen-presenting cells of myeloid origin, we examined whether Tr1 cells in melanoma could eliminate tumor-promoting macrophages and how the interaction between Tr1 cells and macrophages could affect the growth of melanoma cells. Tr1 cells were characterized by high interleukin 10 secretion and low Foxp3 expression and were enriched in the CD4 + CD49b + LAG-3 + T-cell fraction. Macrophages derived from peripheral blood monocytes in the presence of modified melanoma-conditioned media demonstrated tumor-promoting capacity, exemplified by improving the proliferation of cocultured A375 malignant melanoma cells. But when primary Tr1 cells were present in the macrophage-A375 coculture, the growth of A375 cells was abrogated. The conventional CD25 + Treg cells, however, were unable to inhibit macrophage-mediated increase in tumor cell growth. Further analyses showed that Tr1 cells did not directly eliminate A375 cells, but mediated the killing of tumor-promoting macrophages through the secretion of granzyme B and perforin. The tumor-infiltrating interleukin 10 + Foxp3 − CD4 + T cells expressed very low levels of granzyme B and perforin, possibly suggested the downregulation of Tr1 cytotoxic capacity in melanoma tumors. Together, these data demonstrated an antitumor function of Tr1 cells through the elimination of tumor-promoting macrophages, which was not shared by conventional Tregs.
We report a case of imported pulmonary coccidioidomycosis caused by Coccidioides posadasii in a patient who was misdiagnosed as tuberculosis and mistreated with antituberculosis medications for 18 months. The symptoms were not relieved until antifungal treatment was started. An extensive review of the coccidioidomycosis cases occurring in China reveals 38 cases, 16 of which had no associated history of travel to any traditional endemic areas. We speculate that some factors may drive Coccidioides spp. transference to China, which then causes those domestic infections. Moreover, we indicate the first, to the best of our knowledge, possible endemic areas in China.
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