DIETZIA SP. B32 INFECTION IN A HORSE: FIRST GENETIC CHARACTERIZATION

Mycobacteriales, class Actinobacteria. In the absence of accurate techniques, Dietzia spp. could be misidentified as Rhodococcus hoagii, formerly Rhodococcus equi. Objectives: In order to study the complete genome sequence of Dietzia strain isolated from diffuse subcutaneous nodules of a mare in Reggio Calabria (Italy), comparative and phylogenetic analyses, searches for antibiotic resistance genes, virulence factors, and genomic islands were performed. Methods: Analyses were performed for 49 genomes of Dietzia species (NCBI), and one genome was sequenced using Hiseq (Illumina), Dietzia sp. isolate. All genomes were omogenized by Prokka software. Phylogenomic trees, presence of antibiotic resistance and virulence genes were predicted by MEGAX software, CARD and VFDB databases, respectively. Images were created using iTOL. Islands of pathogenicity (PAIs), resistance (RIs), metabolic (MIs) and symbiotic islands (SIs) were predicted using GIPSy software.below 90.1% and 41 unique genes involved in “cellular component” and “molecular function. Four genes (rpoB, mtrA, rbpA, and APH(3’)-Iia) related to the antibiotic resistance, and six genes associated with virulence factors (phoP, phoR, icl, tufA, relA, and cap8E) were described. The mutation in the rpoB gene confers resistance to rifampicin. Five pathogenicity (PAIs), five resistance (RIs), two metabolic (MIs), and one symbiotic island (SI), were found. Conclusions: As the true pathogenic potential of Dietzia species is not known, the comparative analysis of Dietzia B32 contributes to better understand this increasingly emerging genus.