Ocampo-Sosa Alain A, Lewis Deborah A, Navas Jesus, Quigley Frances, Callejo Raquel, Scortti Mariela, Leadon Desmond P, Fogarty Ursula, Vazquez-Boland Jose A
Bacterial Molecular Pathogenesis Group, Faculty of Medical and Veterinary Sciences, University of Bristol, Bristol, UK.
J Infect Dis. 2007 Sep 1;196(5):763-9. doi: 10.1086/519688. Epub 2007 Jul 13.
Molecular typing of the actinomycete Rhodococcus equi is insufficiently developed, and little is known about the epidemiology and transmission of this multihost pathogen. We report a simple, reliable polymerase chain reaction typing system for R. equi based on 3 plasmid gene markers: traA from the conserved conjugal transfer machinery and vapA and vapB, found in 2 different plasmid subpopulations. This "TRAVAP" typing scheme classifies R. equi into 4 categories: traA(+)/vapA(+)B(-), traA(+)/vapA(-)B(+), traA(+)/vapAB(-), and traA(-)/vapAB(-) (plasmidless). A TRAVAP survey of 215 R. equi strains confirmed the strong link between vapA (traA(+)/vapA(+)B(-) plasmids) and horse isolates and revealed other host-related plasmid associations: between traA(+)/vapA(-)B(+) and pigs and between traA(+)/vapAB(-)--a new type of R. equi plasmid--and cattle. Plasmidless strains were more frequent among isolates from nonpathological specimens. All plasmid categories were common in human isolates, which possibly reflects the predominantly opportunistic nature of R. equi infection in this host and a zoonotic origin.
马红球菌的分子分型研究尚不完善，对于这种多宿主病原体的流行病学和传播情况知之甚少。我们报道了一种基于3个质粒基因标记的简单、可靠的马红球菌聚合酶链反应分型系统：来自保守接合转移机制的traA以及在2个不同质粒亚群中发现的vapA和vapB。这种“TRAVAP”分型方案将马红球菌分为4类：traA(+)/vapA(+)B(-)、traA(+)/vapA(-)B(+)、traA(+)/vapAB(-)和traA(-)/vapAB(-)（无质粒）。对215株马红球菌菌株的TRAVAP调查证实了vapA（traA(+)/vapA(+)B(-)质粒）与马匹分离株之间的紧密联系，并揭示了其他与宿主相关的质粒关联：traA(+)/vapA(-)B(+)与猪之间，以及traA(+)/vapAB(-)（一种新型马红球菌质粒）与牛之间。无质粒菌株在非病理标本分离株中更为常见。所有质粒类别在人类分离株中都很常见，这可能反映了该宿主中马红球菌感染主要为机会性感染的性质以及人畜共患病起源。
