Ulcerative, granulomatous glossitis and enteritis caused by Rhodococcus equi in a heifer

Rhodococcus equi-Occurrence in Goats and Clinical Case Report

Background: Rhodococcus equi infection is commonly known in equine medicine to cause frequently fatal rhodococcosis. Infections in other species and people are also reported. Clinical manifestation in goats is relatively similar to horses and humans, but data regarding bacterium prevalence are scarce. Thus, the study aimed to estimate the occurrence of R. equi in goats. Methods: During post mortem examination, submandibular, mediastinal, and mesenteric lymph nodes were collected. Standard methods were used for bacteria isolation and identification. Results: A total of 134 goats were examined, and 272 lymph node samples were collected. R. equi was isolated from four animals. All four isolates carried the choE gene, and one also had traA and pVAPN plasmid genes. Conclusions: To the authors’ best knowledge, this is the first report of R. equi occurrence and genetic diversity in goats. The results may help create a model for treating rhodococcosis in other animal species and assessing the role of meat contamination as a potential source of human infection. This research should be considered a pilot study for further application of the goat as a model of R. equi infection in horses and humans.

Reinvestigation of the virulence of Rhodococcus equi isolates from patients with and without AIDS

Rhodococcus equi emerged as a zoonotic pathogen of human immunodeficiency virus-infected patients over the last three decades. Two virulence plasmid types of R. equi, pVAPA and pVAPB associated with equine and porcine isolates, have been recognized, and more recently, pVAPN, a novel host-associated virulence plasmid in R. equi, was found in bovine and caprine isolates. We reinvestigated 39 previously reported isolates of R. equi from patients with and without acquired immunodeficiency syndrome (AIDS) by detecting vapA, vapB and vapN using PCR and plasmid profiling. After excluding one isolate that could not be cultured from frozen storage, eight isolates carried a virulence plasmid encoding vapA (pVAPA), 10 carried a virulence plasmid encoding vapB (pVAPB), seven carried a virulence plasmid encoding vapN (pVAPN) and 13 were negative for those genes. Of the 29 isolates from patients with AIDS, 7, 10 and 5 harboured pVAPA, pVAPB and pVAPN respectively. Among nine isolates from patients without AIDS, one and two harboured pVAPA and pVAPN respectively. This study demonstrated that pVAPN-positive R. equi existed in human isolates before 1994 and reaffirmed that equine-associated pVAPA-positive, porcine-associated pVAPB-positive and bovine- or caprine-associated pVAPN-positive R. equi are widely spread globally. Because domestic animals might be major sources of human infection, further research is needed to reveal the prevalence of pVAPN-positive R. equi infection in cattle and goats.