This family consists of several virulence-associated proteins from Rhodococcus equi. Rhodococcus equi is an important pulmonary pathogen of foals and is increasingly isolated from pneumonic infections and other infections in human immunodeficiency virus (HIV)-infected patients. Isolates from foals possess a large virulence plasmid, varying in size from 80 to 90 kb. Isolates lacking the plasmid are avirulent to foals. Little is known about the function of the plasmid apart from its encoding a virulence associated surface proteins [1].

1: DNA sequence and comparison of virulence plasmids from Rhodococcus equi ATCC 33701 and 103. Takai S, Hines SA, Sekizaki T, Nicholson VM, Alperin DA, Osaki M, Takamatsu D, Nakamura M, Suzuki K, Ogino N, Kakuda T, Dan H, Prescott JF; Infect Immun 2000;68:6840-6847. PMID:11083803