Rhodococcus equi Infections in Dogs

Abstract

Five cases of Rhodococcus equi infection in dogs were identified from 2003 to 2014. Three of the dogs had severe, internal lesions attributable to R. equi that have not been previously described: endophthalmitis, endocarditis, and suppurative pleuropneumonia. Isolates from 4 of the dogs were analyzed by polymerase chain reaction for Rhodococcus virulence-associated plasmid (vap) genes. One isolate was vapA-positive, 2 lacked a virulence plasmid, and 1 carried the novel vapN-associated plasmid (pVAPN) recently characterized in bovine isolates. The pVAPN plasmid has not been described in isolates cultured from companion animals. Four of the dogs either were receiving immunosuppressive drugs or had endocrinopathies. R. equi has the potential to cause significant infections in dogs, and immunocompromised animals should be considered at risk for infection.

Detection of vapN in Rhodococcus equi isolates cultured from humans

“…Multiple bands were observed for the previously published vapB primers [ 12 ] in isolates that did not carry the vapB plasmid. The vapB control strain 99–213 and the majority of the vapB -positive human isolates amplified a non-specific band of approximately 700 bp with the previously published vapN primer set [ 20 ]. Sequencing of the aberrant band in 99–213 revealed that it was a region of the vapB gene (99% identity to KX443407.1) and was not similar to the intended vapN gene.…”

“…Primers amplifying internal regions of the vap genes or PAI-type conserved flanking regions were selected to minimize non-specific products. The PCR results for the new primer set were compared with the results from previously published primer sets for detection of vap genes [ 12 , 20 ]. A PCR using the R .…”

“…equi -specific cholesterol oxidase gene choE was used to ensure correct speciation and adequate DNA extraction for each isolate [ 21 ]. The following control strains were used for each PCR assay: ATCC ® 33701 ™ ( vapA -positive), clinical porcine isolate EIDL 99–213 ( vapB -positive), clinical canine isolate TAMU 49–33 ( vapN -positive) [ 20 ], and ATCC ® 6939 ™ (avirulent genotype). PCR reagent concentrations were calculated according to the manufacturer’s recommendations (AmpliTaq ® DNA polymerase; ThermoFisher Scientific, USA).…”

Characterisation and outcome of idiopathic pyogranulomatous lymphadenitis in 64 English springer spaniel dogs

“…Multiple agents have been identified to cause pyogranulomatous inflammation, including bacteria [Actinomyces, Bartonella (Pappalardo et al 2000, Pappalardo et al 2001, Saunders & Monroe 2006, Morales et al 2007, Tucker et al 2014, Drut et al 2014, Mycobacterium, Nocardia and Staphylococcus], fungi (Aspergillus, Blastomyces, Coccidioides, Cryptococcus, Histoplasma), oomycetes (Pythium) and protozoa (Neospora, Toxoplasma, Leishmania) (Mylonakis et al 2005, Greene 2012). Other infectious agents associated with granulomatous and pyogranulomatous lymphadenitis have also been recently reported, such as Rhodococcus equi (Bryan et al 2017), Sporotrichum pruinosum (Magstadt et al 2018), Cladosporium cladosporioides-complex (Spano et al 2018), Talaromyces helicus (Tomlinson et al 2011), Chrysosporium species (Cook et al 2016), Scytalidium (Dunlap et al 2015), Paracoccidioides brasiliensis (Headley et al 2017) and circovirus (Li et al 2013).…”

“…Other infectious agents associated with granulomatous and pyogranulomatous lymphadenitis have also been recently reported, such as Rhodococcus equi (Bryan et al . ), Sporotrichum pruinosum (Magstadt et al . ), Cladosporium cladosporioides‐complex (Spano et al .…”