Virulence plasmids of rhodococcus equi isolates from Cuban patients with AIDS

Rhodococcus equi is an animal pathogen and zoonotic human opportunistic pathogen associated with immunosuppressive conditions. The pathogenicity of R. equi is linked to three animal host-associated virulence plasmids encoding a family of "Virulence Associated Proteins" (VAPs). Here, the PCR-based TRAVAP molecular typing system for the R. equi virulence plasmids was applied to 26 R. equi strains isolated between 2010 and 2016 at the Institute of Tropical Medicine "Pedro Kourí," Cuba, from individuals living with HIV/AIDS. TRAVAP detects 4 gene markers, traA common to the three virulence plasmids, and vapA, vapB, and vapN specific to each of the host-associated plasmid types (equine pVAPA, porcine pVAPB, and ruminant pVAPN). Of the 26 isolates, six were positive to the vapB (porcine-type) marker, 4 (15.4%) to the vapA (equine- type) marker, and 1 (3.8%) to the vapN (ruminant-type) marker. Most of the isolates 14 (53.8%) were negative to all TRAVAP markers, suggesting they lacked a virulence plasmid. To our knowledge, this work is the first to report the molecular characterization of R. equi isolates from Cuba. Our findings provide insight into the zoonotic origin of R. equi infections in people and the potential dispensability of the virulence plasmid in immunosuppressed patients.