Comprehensive Molecular Dissection of Dermatophilus congolensis Genome and First Observation of tet(Z) Tetracycline Resistance.

Dermatophilus congolensis is a bacterial pathogen mostly of ruminant livestock in the tropics/subtropics and certain temperate climate areas. It causes dermatophilosis, a skin disease that threatens food security by lowering animal productivity and compromising animal health and welfare. Since it is a prevalent infection in ruminants, dermatophilosis warrants more research. There is limited understanding of its pathogenicity, and as such, there is no registered vaccine against D. congolensis. To better understanding the genomics of D. congolensis, the primary aim of this work was to investigate this bacterium using whole-genome sequencing and bioinformatic analysis. D. congolensis is a high GC member of the Actinobacteria and encodes approximately 2527 genes. It has an open pan-genome, contains many potential virulence factors, secondary metabolites and encodes at least 23 housekeeping genes associated with antimicrobial susceptibility mechanisms and some isolates have an acquired antimicrobial resistance gene. Our isolates contain a single CRISPR array Cas type IE with classical 8 Cas genes. Although the isolates originate from the same geographical location there is some genomic diversity among them. In conclusion, we present the first detailed genomic study on D. congolensis, including the first observation of tet(Z), a tetracycline resistance-conferring gene.

Dermatophilus congolensis associated bronchopneumonia in an alpaca.

A severe, chronic, locally extensive granulomatous bronchopneumonia was diagnosed on post-mortem and histopathological examination of an adult alpaca. Dermatophilus congolensis organisms were isolated from the lungs and genotypic identification of aerobic culture was confirmed by sequence analysis of the entire 16S rDNA gene. This is the first report of D. congolensis-associated bronchopneumonia in any species.