ABORDAGEM MOLECULAR APLICADA À PARACOCCIDIOIDOMICOSE: IDENTIFICAÇÃO DAS ESPÉCIES DO GÊNERO Paracoccidioides EM MATO GROSSO DO SUL PARA O APRIMORAMENTO DO IMUNODIAGNÓSTICO

Abstract

Paracoccidioidomycosis (PCM) is a systemic mycosis caused by the species P. brasiliensis sensu stricto, P. americana, P. restrepiensis, P. venezuelensis and P. lutzii. The disease is restricted to Latin America, with approximately 80% of cases occurring in Brazil, mainly in the South, Southeast and Midwest regions. However, the distribution of the species involved in the etiology of PCM in Mato Grosso do Sul, a region in Midwest Brazil known for being an endemic area for PCM, is poorly understood. the reactivityin the serological double immunodiffusion test (DID), which is used to diagnosis and cure criterion, can be species-specific. The objective of this study is to determine the species of the genus Paracoccidioides involved in the etiology of PCM in the State and to investigate whether the circulating phylogenetic species influences the reactivity profile in DID. For this purpose, thirteen new cases of PCM residing in Mato Grosso do Sul, in the period from 2016 to 2019, were included. All of these were male, most of whom were engaged in or had previously engaged in rural activity. The age ranged was between 17 and 59 years old, with 11 (84.6%) of the cases being over 40 years old. Sixteen clinical isolates were obtained from these cases, and their genomic DNA were genotyped by tub1-PCR-RFLP. The DID test was conducted using exoantigens from the strains genotyped in this study. The findings revealed that the majority of the isolates (11/16; 68.8%) belonged to Paracoccidioides brasiliensis sensu stricto, followed by P. restrepiensis (4/16; 25.0%) and P. lutzii (1/16; 6.2%). No differences were observed in the clinical and epidemiological data, amongthe cases of PCM caused by different species of Paracoccidioides. Approximately 30% of the cases resulted in false-negative results in the DID test. Patients with PCM caused by P. brasiliensis and P. restrepiensis, both belonging to thethe P. brasiliensis complex, showed no differences in seroreactivity in the DID test against antigens produced from these species; while seroreaction against antigens produced from P. lutzii was low. Interestingly, the only patient with P. lutzii PCM was seroreactive exclusively to P. lutzii antigen, indicating a species-specific reaction. Based on these findings, it can be concluded that P. brasiliensis sensu stricto is the predominant specie in this Mato Grosso do Sul. Furthermore, using antigens from different species of Paracoccidioides spp increase the sensitivity of the DID test in patients from this region, thereby improving both the accuracy of diagnosis and the serological criterion for determing cure.