Rhodococcus equi Infections in Goats: Characterization of Virulence Plasmids

Abstract

Rhodococcus equi is an uncommon cause of systemic pyogranulomatous infections in goats with macroscopic similarities to caseous lymphadenitis caused by Corynebacterium pseudotuberculosis. Caprine cases have previously been reported to be caused by avirulent R. equi strains. Six cases of R. equi infection in goats yielding 8 R. equi isolates were identified from 2000 to 2017. Lesions varied from bronchopneumonia, vertebral and humeral osteomyelitis, and subcutaneous abscesses, to disseminated infection involving the lungs, lymph nodes, and multiple visceral organs. Isolates of R. equi from infected goats were analyzed by polymerase chain reaction for R. equi virulence-associated plasmid ( vap) genes. Seven of 8 isolates carried the VapN plasmid, originally characterized in bovine isolates, while 1 isolate lacked virulence plasmids and was classified as avirulent. The VapN plasmid has not been described in isolates cultured from goats.

Microbiological assessment of sheep lymph nodes with lymphadenitis found during post-mortem examination of slaughtered sheep: implications for veterinary-sanitary meat control

“…In Poland, to date, this species has been detected in the lymph nodes of clinically healthy cattle, red deer ( Cervus elaphus ) and roe deer ( Capreolus capreolus ) [ 16 , 46 ]. However, R. equi should still be considered a potential pathogen of sheep, because it has been isolated from domestic goats ( Capra hircus ), camels ( Camelus dromedarius ), and llamas ( Lama glama ) in other countries [ 47 ]. Moreover, R. equi has been detected in the lymph nodes of cattle and American bison ( Bison bison ) in co-infection with Mycobacterium spp.…”

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

“…Since its discovery in 2015 (Valero-Rello et al 2015), pVAPN has been detected in R. equi isolates from cattle, sheep, goats and dogs (Bryan et al 2017;Ribeiro et al 2018;Stranahan et al 2018;Nakagawa et al 2018;Saied et al 2019). In a study of lymph node samples from cattle, 41Á9% (13 of 31) of isolates carried pVAPN, whereas all isolates from faecal samples were negative (Ribeiro et al 2018).…”

“…Previously, R. equi strains have been classified as virulent strains having 15-to 17-kDa proteins designated VapA, intermediately virulent strains having a 20-kDa protein designated VapB, and avirulent (Takai et al 1991;Takai et al 1995). At present, three host-associated virulence plasmid types of R. equi have been recognized: the circular plasmids pVAPA and pVAPB associated with equine and porcine isolates respectively (Takai et al 1991;Takai et al 1995), and the recently detected linear plasmid pVAPN related to bovine and caprine isolates, which cause granulomatous lesions of the lungs, kidneys, liver and mesenteric and abomasum lymph nodes of cattle and goats (Valero-Rello et al 2015;Ribeiro et al 2018;Stranahan et al 2018;Nakagawa et al 2018;Saied et al 2019). That means that four distinct virulence levels of strains are recognized: virulent strains carrying pVAPA, pVAPB or pVAPN and avirulent strains lacking these virulence plasmids (Valero-Rello et al 2015;MacArthur et al 2017).…”

A case report on disseminated <i>Rhodococcus equi</i> infection in a Japanese black heifer

“…Recently, a novel linear virulence plasmid encoding VapN (pVapN) was characterized in cattle, goat, and human isolates [ 1 , 14 , 15 , 24 ]. In cattle, R. equi has low pathogenicity and lesions are mostly confined to a single lymph node [ 5 ].…”

“…Accordingly, it is thought that pathogenesis caused by R. equi in cattle is similar to that in the porcine host. Conversely, some cases of disseminated R. equi infection have been reported in goats [ 2 , 3 , 4 , 6 , 15 ]. The present case is similar to the previous, caprine cases.…”