Levantamento da diversidade genotípica de IGS1 rDNA de cinco espécies de trichosporon e sua relação com a emergência de resistência à antifúngicos, sítio de isolamento e dispersão geográfica mundial

Abstract

Trichosporon spp. are fungi belonging to the phylum Basidiomycota, class Tremellomycetes and order Trichosporonales. They are pleomorphic, growing as blastoconidia, pseudohyphae, true hyphae and arthroconidia. Trichosporon spp. encompass 20 species, of which at least nine are of clinical importance, with the most relevant being: T. asahii, T. asteroides, T. faecale, T. inkin and T. ovoides. The species of the genus are identified by sequencing the IGS1 intergenic spacer region (Intergenic Spacer region) of the rDNA, which has genotypic diversity identified in T.asahii and T. faecale. The objective of this work was to carry out a systematic survey of IGS1 sequences of five Trichosporon species and of epidemiological data to relate the emergence of antifungal resistance to the genotypes of these species. For this purpose, IGS1 sequences from T. asahii, T. asteroides, T. faecale, T. inkin and T. ovoides deposited at the NCBI-GenBank until 12/31/2019 were searched. Also being carried out, dating analysis of radiation events of genotypes to understand the dispersion and microevolution of each species. In the searches, 496 sequences were found for T. asahii. For the other species, 39 sequences from T. asteroides, 29 from T. faecale, 39 from T. inkin and four sequences from T. ovoides were found. The haplotype analysis showed the existence of 32 genotypes for T. asahii, 15 already described in the literature and 17 new. For the species T. asteroides and T. ovoides, four genotypes each were found, identified in an unprecedented way in this work. T. faecale and T. inkin presented six genotypes each, and T. faecale confirmed two genotypes already described in the literature and four identified in the present work. The geographic distribution revealed the presence of T. asahii isolates in 11 countries, namely: Argentina, Brazil, China, United States of America (USA), France, Greece, India, Japan, Mexico, Tunisia and Turkey, as well as the others species were prevalent in seven countries: Argentina, Brazil, China, India, Portugal, Switzerland and Turkey, highlighting the predominance of all species in Brazil, with the exception of T. ovoides. As for the distribution of T. asahii genotypes, G1 is prevalent in the world, with 207 sequences, followed by G3, both present in nine of the 11 countries, mainly in Brazil and China. G4, with 89 sequences, was prevalent in China, G7, with 31 sequences, was prevalent in Brazil. Of the 17 new genotypes, 13 were isolated in Brazil, 1 in China, 1 in Greece and 2 in India. The main isolation sites were: blood (153), urine (123), superficial mycoses (63), respiratory tract (45), other sites of human origin or without identified sites (110). G1 was dominant in all sites, except in the airway, with most G4. In blood samples, in addition to G1, G3, G4, G5 and G7 were found; in urine, G1 and G3, G4, G5 and G7 and in superficial mycoses, G1, G3, G4 and G7. The main isolation sites were: blood (12) and airways (11) for T. asteroides; superficial mycoses (19) for T. faecale; superficial mycoses (18) for T. inkin. G1 was prevalent in the world for the species: T. asteroides,T. faecale and T. inkin, predominant in Brazil.T. ovoides, but there was a prevalence in India. The results of minimal inhibitory concentration of different antifungal agentes for T.asahii were: FLZ: G3 > G5 > G4 ≈ G7 > G1 > G16 > G6, AMB: G3 > G1 > G1 >G4 ≈ G5 > G6 > G7, to VRZ: G3 > G5 > G4 > G7 > G1 = G6 > G16, to ITZ: G3>G5>G4>G7>G1>G16, CAS: G5≈G3>G7>G1>G6>G4 and 5-FC: G16>G5>G1>G3> G4>G7 For T. faecale, AMB: G1>G3>G5>G2, FLZ: G2>G1>G3>G5, ITZ: G2>G1>G3>G5, VRZ: G1>G3=G5>G2. For T. asteoides, AMB: G1>G2>G3, FLZ: G1>G3>G2, ITZ: G3>G2 >G1, and VRZ: G3>G2>G1. For T. inkin, AMB: G4>G1>G3, FLZ: G4>G3>G1, ITZ: G4>G1 >G3 e VRZ: G4>G3>G1. T. ovoides did not present antifungal susceptibility data in the literature. In conclusion, it was possible to detect new IGS1 rDNA genotypes in the five species of Trichosporon spp., Brazil being one of the countries with the highest number of isolates, both from blood and urine for T. asahii, and from respiratory samples and superficial mycoses for non-T asahii species, confirming that voriconazole has the lowest MICs and should be the drug of choice for treating trichosporonoses, regardless of genotype.