Background and Purpose. Chromoblastomycosis is a neglected tropical disease endemic to tropical and subtropical zones worldwide, affecting individuals living in low-income re-gions of Asia, Africa, and Latin America. The main clinical etiological agents belong to a well-supported clade within the order Chaetothyriales, family Herpotrichiellaceae, and gen-era Fonsecaea, Cladophialophora, Phialophora, Rhinocladiella, and Exophiala. These spe-cies share similar physiological and morphological features, making them difficult to distin-guish by conventional mycological methods. This study aimed to perform an ITS-based phylogenetic analysis of the major causative agents of chromoblastomycosis from Mexico and Venezuela, in the context of a global reference dataset.

Materials and Methods. This study aimed to perform a phylogenetic analysis based on ITS (ITS1-5.8S-ITS2) sequences from 75 strains associated with chromoblastomycosis. This da-taset included 37 strains from Mexico and Venezuela previously identified phenotypically and molecularly by our group, comprising one new clinical isolate of Fonsecaea monophora from northern Mexico characterized in the present study, together with 36 strains of Clado-phialophora carrionii, Fonsecaea pedrosoi, and Rhinocladiella aquaspersa (outgroup) re-ported in our previous studies. The remaining 38 reference sequences were retrieved from GenBank, representing strains from other geographic regions. Sequence alignments were used to build a phylogenetic tree using the Neighbor-Joining (NJ) method with bootstrap analysis of 1,000 replicates, implemented in MEGA 6.06 software.

Results. Cladophialophora carrionii clustered in a geographically-related manner, whereas Fonsecaea pedrosoi and F. monophora clustered in a species-specific manner, regardless of geographic origin, when compared against the global reference dataset.

Conclusion. This is the first molecular report of chromoblastomycosis caused by F. monophora in northern Mexico, and the first ITS-based phylogenetic analysis placing the major causative agents of chromoblastomycosis from Mexico and Venezuela within a global reference context.