Corynebacterium pseudotuberculosis biovar ovis strains isolated from small ruminants herds from the Brazilian Amazon present clonal genomic profile

This study tested the hypothesis that Corynebacterium pseudotuberulosis strains isolated from small herds of ruminants in the state of Pará have a clonal genomic profile. Serum samples were collected from 169 animals and used in an indirect ELISA that detected specific antibodies against C. pseudotuberculsis in 24% of the animals monitored in the field. Among sheep and goats, 20 animals had a confirmed symptomatic diagnosis of Caseous Lymphadenitis Disease (CL) and caseous material from the abscesses was sampled. From these samples, seven bacterial strains were isolated and identified as C. pseudotuberculosis biovar ovis. Bacterial genomic DNA was extracted and subjected to fingerprint analysis (BOX-PCR and ERIC-PCR). The fingerprint analysis revealed the existence of two main groups of isolated strains, with one of these groups necessarily formed by strains A27 and A31 (at least 62% similarity), and the other group formed by the remaining isolated strains. The genome outline of the A27 and A31 strains was sequenced using Illumina NovaSeq 6000 technology. The preliminary genomes A27 and A31 grouped with other genomes of C. pseudotuberculosis biovar ovis when compared to 46 genomes of C. pseudotuberculosis belonging to both biovars (ovis and equi) isolated worldwide. More than 99% of similarity was observed when comparing the draft genomes A27 and A31 with other genomes of C. pseudotuberculosis biovar ovis strains isolated from the Brazilian Amazon. The mapping readouts generated with preliminary A27 and A31 genomes using the reference genome of C. pseudotuberculosis 42/02-A showed more than 99% coverage. The central genome consisted of 78% of the orthogroups in the pangenome analysis. The specific genes that encode unique proteins in the A27 and A31 genomes yield molecular information about how each species adapts to its ecological niches. This study shows that strains of C. pseudotuberculosis biovar ovis isolated from small ruminant herds in the Brazilian Amazon showed a clonal genomic profile.