The Pathogenic Actinobacterium Rhodococcus Equi: What's in a Name?

Overview

Journal Mol Microbiol

Specialties Microbiology
Molecular Biology

Date 2019 May 18

PMID 31099908

Citations 24

Authors

Jose A Vazquez-Boland

Wim G Meijer

Affiliations

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Abstract

Rhodococcus equi is the only recognized animal pathogenic species within an extended genus of metabolically versatile Actinobacteria of considerable biotechnological interest. Best known as a horse pathogen, R. equi is commonly isolated from other animal species, particularly pigs and ruminants, and causes severe opportunistic infections in people. As typical in the rhodococci, R. equi niche specialization is extrachromosomally determined, via a conjugative virulence plasmid that promotes intramacrophage survival. Progress in the molecular understanding of R. equi and its recent rise as a novel paradigm of multihost adaptation has been accompanied by an unusual nomenclatural instability, with a confusing succession of names: "Prescottia equi", "Prescotella equi", Corynebacterium hoagii and Rhodococcus hoagii. This article reviews current advances in the genomics, biology and virulence of this pathogenic actinobacterium with a unique mechanism of plasmid-transferable animal host tropism. It also discusses the taxonomic and nomenclatural issues around R. equi in the light of recent phylogenomic evidence that confirms its membership as a bona fide Rhodococcus.

Citing Articles

sp. nov., a new species isolated from equine farm soil closely related to the pathogen .

Vazquez-Boland J, Val-Calvo J, Duquesne F, Decorosi F, Viti C, Petry S Int J Syst Evol Microbiol. 2025; 75(3).

PMID: 40063668 PMC: 11893733. DOI: 10.1099/ijsem.0.006679.

In vitro susceptibility pattern of Rhodococcus equi isolated from patients to antimicrobials recommended exclusively to humans, to domestic animals and to both.

Ribeiro N, Silva P, de Lima Paz P, Arabe Filho M, Listoni F, Listoni E Rev Inst Med Trop Sao Paulo. 2025; 67:e3.

PMID: 39907395 PMC: 11790073. DOI: 10.1590/S1678-9946202567003.

Clade-1 Vap virulence proteins of Rhodococcus equi are associated with the cell surface and support intracellular growth in macrophages.

Yerlikaya Z, Miranda-CasoLuengo R, Yin Y, Cheng C, Meijer W PLoS One. 2025; 20(1):e0316541.

PMID: 39761314 PMC: 11703076. DOI: 10.1371/journal.pone.0316541.

Complete genome sequence of the saprophytic actinomycete DSD51W, closely related to the multi-host pathogen .

Yerlikaya Z, Miranda-CasoLuengo R, O Gaora P, Meijer W Microbiol Resour Announc. 2024; 13(12):e0059724.

PMID: 39470233 PMC: 11636088. DOI: 10.1128/mra.00597-24.

Whole-genome sequencing and pathogenicity analysis of Rhodococcus equi isolated in horses.

Hu B, Gao S, Zhang H, Li Q, Li G, Zhang S BMC Vet Res. 2024; 20(1):362.

PMID: 39129003 PMC: 11318318. DOI: 10.1186/s12917-024-04167-9.

References

Vazquez-Boland J, Giguere S, Hapeshi A, MacArthur I, Anastasi E, Valero-Rello A . Rhodococcus equi: the many facets of a pathogenic actinomycete. Vet Microbiol. 2013; 167(1-2):9-33. DOI: 10.1016/j.vetmic.2013.06.016. View

Zhu Y, Xu M, Shen M, Chen Z, Qin Z . [Cloning, sequencing and identification of replication origin of Rhodococcus linear plasmid pNSL1]. Wei Sheng Wu Xue Bao. 2010; 50(8):1098-103. View

Barabote R, Saier Jr M . Comparative genomic analyses of the bacterial phosphotransferase system. Microbiol Mol Biol Rev. 2005; 69(4):608-34. PMC: 1306802. DOI: 10.1128/MMBR.69.4.608-634.2005. View

Kampfer P, Dott W, Martin K, Glaeser S . Rhodococcus defluvii sp. nov., isolated from wastewater of a bioreactor and formal proposal to reclassify [Corynebacterium hoagii] and Rhodococcus equi as Rhodococcus hoagii comb. nov. Int J Syst Evol Microbiol. 2013; 64(Pt 3):755-761. DOI: 10.1099/ijs.0.053322-0. View

MacArthur I, Anastasi E, Alvarez S, Scortti M, Vazquez-Boland J . Comparative Genomics of Rhodococcus equi Virulence Plasmids Indicates Host-Driven Evolution of the vap Pathogenicity Island. Genome Biol Evol. 2017; 9(5):1241-1247. PMC: 5434932. DOI: 10.1093/gbe/evx057. View

Giguere S, Cohen N, Keith Chaffin M, Hines S, Hondalus M, Prescott J . Rhodococcus equi: clinical manifestations, virulence, and immunity. J Vet Intern Med. 2011; 25(6):1221-30. DOI: 10.1111/j.1939-1676.2011.00804.x. View

Whittingham J, Blagova E, Finn C, Luo H, Miranda-CasoLuengo R, Turkenburg J . Structure of the virulence-associated protein VapD from the intracellular pathogen Rhodococcus equi. Acta Crystallogr D Biol Crystallogr. 2014; 70(Pt 8):2139-51. PMC: 4118825. DOI: 10.1107/S1399004714012632. View

Ekiert D, Bhabha G, Isom G, Greenan G, Ovchinnikov S, Henderson I . Architectures of Lipid Transport Systems for the Bacterial Outer Membrane. Cell. 2017; 169(2):273-285.e17. PMC: 5467742. DOI: 10.1016/j.cell.2017.03.019. View

Munoz-Elias E, McKinney J . Mycobacterium tuberculosis isocitrate lyases 1 and 2 are jointly required for in vivo growth and virulence. Nat Med. 2005; 11(6):638-44. PMC: 1464426. DOI: 10.1038/nm1252. View

10.

Byrne G, Russell D, Chen X, Meijer W . Transcriptional regulation of the virR operon of the intracellular pathogen Rhodococcus equi. J Bacteriol. 2007; 189(14):5082-9. PMC: 1951877. DOI: 10.1128/JB.00431-07. View

11.

Ocampo-Sosa A, Lewis D, Navas J, Quigley F, Callejo R, Scortti M . Molecular epidemiology of Rhodococcus equi based on traA, vapA, and vapB virulence plasmid markers. J Infect Dis. 2007; 196(5):763-9. DOI: 10.1086/519688. View

12.

Jones A, Sutcliffe I, Goodfellow M . Proposal to replace the illegitimate genus name Prescottia Jones et al. 2013 with the genus name Prescottella gen. nov. and to replace the illegitimate combination Prescottia equi Jones et al. 2013 with Prescottella equi comb. nov. Antonie Van Leeuwenhoek. 2013; 103(6):1405-7. DOI: 10.1007/s10482-013-9924-2. View

13.

Gurtler V, Mayall B, Seviour R . Can whole genome analysis refine the taxonomy of the genus Rhodococcus?. FEMS Microbiol Rev. 2004; 28(3):377-403. DOI: 10.1016/j.femsre.2004.01.001. View

14.

Oren A, Garrity G . Notification that new names of prokaryotes, new combinations, and new taxonomic opinions have appeared in volume 64, part 11, of the IJSEM. Int J Syst Evol Microbiol. 2015; 65(Pt 2):323-324. DOI: 10.1099/ijs.0.000017. View

15.

Sekine M, Tanikawa S, Omata S, Saito M, Fujisawa T, Tsukatani N . Sequence analysis of three plasmids harboured in Rhodococcus erythropolis strain PR4. Environ Microbiol. 2006; 8(2):334-46. DOI: 10.1111/j.1462-2920.2005.00899.x. View

16.

Stes E, Francis I, Pertry I, Dolzblasz A, Depuydt S, Vereecke D . The leafy gall syndrome induced by Rhodococcus fascians. FEMS Microbiol Lett. 2013; 342(2):187-94. DOI: 10.1111/1574-6968.12119. View

17.

Soriano F, Fernandez-Roblas R, Calvo R, Garcia-Calvo G . In vitro susceptibilities of aerobic and facultative non-spore-forming gram-positive bacilli to HMR 3647 (RU 66647) and 14 other antimicrobials. Antimicrob Agents Chemother. 1998; 42(5):1028-33. PMC: 105739. DOI: 10.1128/AAC.42.5.1028. View

18.

Sydor T, von Bargen K, Hsu F, Huth G, Holst O, Wohlmann J . Diversion of phagosome trafficking by pathogenic Rhodococcus equi depends on mycolic acid chain length. Cell Microbiol. 2012; 15(3):458-73. PMC: 3864644. DOI: 10.1111/cmi.12050. View

19.

van der Geize R, Dijkhuizen L . Harnessing the catabolic diversity of rhodococci for environmental and biotechnological applications. Curr Opin Microbiol. 2004; 7(3):255-61. DOI: 10.1016/j.mib.2004.04.001. View

20.

Giguere S, Hondalus M, Yager J, Darrah P, Mosser D, Prescott J . Role of the 85-kilobase plasmid and plasmid-encoded virulence-associated protein A in intracellular survival and virulence of Rhodococcus equi. Infect Immun. 1999; 67(7):3548-57. PMC: 116543. DOI: 10.1128/IAI.67.7.3548-3557.1999. View