Advances in Animal and Veterinary Sciences

Research Article
Adv. Anim. Vet. Sci. 3 (1S): 28 -32. Special Issue-1 (Biotechnological and molecular approaches for diagnosis, prevention and control of infectious diseases of animals)
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Sourabh Chhabra1, Sandip Kumar Khurana2*, Pradeep Kumar Kapoor1, Harisankar Singha2, Yarvendra Singh1, Richa Khirbat3

1Department of Veterinary Public Health and Epidemiology, LUVAS, Hisar; 2National Research Centre on Equines, Hisar; 3Department of Animal Biotechnology, LUVAS, Hisar, India.

*Correspondence | Sandip Kumar Khurana, National Research Centre on Equines, Hisar, India; Email:

Rhodococcus equi is widely associated with subacute or chronic suppurative bronchopneumonia, ulcerative lymphangitis, lymphadenitis and enteritis in foals aged 1-4 months. Identification of the virulence plasmids associated with R. equi is of great importance in ascertaining pathogenicity in equines. Virulence factor is associated with presence of 85-90kb plasmid which encodes various virulence associated proteins (VAP -A,-B,-C,-D,-E,-F,-G,-H). VAP A is essential for virulence in foals. This study was aimed at the evaluation of molecular characteristics of R. equi isolates from foals with respiratory problems by multiplex PCR assay that amplifies the vap gene family (vap-A,-B,- C,-D,-E,-F,-G,-H). Twenty-eight isolates of R. equi from foals with respiratory problems were used in this study. The PCR amplification reaction was performed using specific primers for vap gene family viz. vap-A,-B,-C,-D,-E,-F,- G,-H which yielded the bands of 350, 400, 450, 500, 600, 650 and 700 bp, respectively. All the 28 isolates were positive for vap A,C,D,E,F,G and H and negative for vap B gene which was characteristic of virulent R. equi isolates of equine origin. The multiplex PCR assay for the vap gene family allowed identification and characterization of virulent isolates in a simple one-step reaction. This is a significant advantage in comparison with the conventional diagnostic methodologies of R. equi strains and simultaneously evaluated the presence of the vap A gene which is responsible for virulence in foals.

Keywords | Rhodococcus equi, Equine, vap gene, Virulence- associated protein