Analyses of the Genetic Diversity and Population Structures of Sporothrix spp. Clinical Isolates from Paraíba, Brazil

Sporotrichosis is a subcutaneous mycosis of global distribution, capable of affecting both humans and animals, and caused by species of the genus Sporothrix spp. This study aimed to evaluate the genetic diversity and mating type distribution of clinical isolates of human sporotrichosis in Paraíba, Brazil, to better understand the population structure, epidemiology, and diversification of this pathogen, as well as to explore possible transmission routes.

Methods: A total of 36 clinical isolates were morphologically identified, and clinical and demographic data were collected. Fungal DNA extraction was then performed, followed by species-specific PCR using markers targeting the calmodulin gene. The mating type idiomorph of the species was identified by PCR using primers targeting the MAT1-1 and MAT1-2 loci. Amplified Fragment Length Polymorphism (AFLP) was used to evaluate the genetic variability of Sporothrix spp.

Results: The distribution of the disease identified that all cases occurred in João Pessoa and adjacent cities. From the 36 isolates, the majority (75%) being affected females, a prevalent occurrence of the lymphocutaneous form, and 98% zoonotic transmission were confirmed. Micro- and macromorphological structures were similar to each other, confirming Sporothrix spp. All isolates were confirmed as S. brasiliensis and the presence of a single sexual idiomorph, MAT1-2, was detected. The AFLP results indicate the possibility of the circulation of one or two genetic groups in João Pessoa and the metropolitan region.

Conclusions: To our knowledge, this is the first time isolates in the Paraíba state are genetically characterised, all identified as Sporothrix brasiliensis. It is likely that this species in Paraiba originated from Rio de Janeiro, as all they possess the MAT1-2 idiomorph, indicating low intergenotypic variation.