Prevalence of Virulence Plasmids in Environmental Isolates of Rhodococcus equi from Horse-Breeding Farms in Hokkaido.

Takaı̈, Shinji; Anzai, Tohru; Yamaguchi, Katsushi; Kakizaki, Seiko; Takahagi, J.; Sato, Yoshito; Takehara, F.; Tamada, Yoshihiro; Matsukura, Susumu; Tani, A.; Kato, Masakatsu; Seno, Noboru; Sasaki, Yukako; Tsubaki, Shiro; Kamada, Masanobu

doi:10.1294/jes.5.21

Cited by 40 publications

(44 citation statements)

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“…8,12,17 In this study, similar concentrations of R. equi were isolated from soil of all 5 R. equi endemic farms, but virulent R. equi were only detected on 3 of the 5 farms. There was some variation in the number of soil samples and isolates tested between farms (Table 1), with the smallest numbers coming from those farms with no virulent R. equi.…”

Section: Discussionmentioning

confidence: 46%

Prevalence of Virulent Rhodococcus Equi in Soil from Five R. Equi-Endemic Horse-Breeding Farms and Restriction Fragment Length Polymorphisms of Virulence Plasmids in Isolates from Soil and Infected Foals in Texas

et al. 2001

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Abstract. Rhodococcus equi isolates (462) obtained from 64 soil samples collected on 5 R. equi-endemic horse-breeding farms and isolates from 100 infected foals in Texas were examined to determine the prevalence and genotypic diversity of virulence-associated plasmids. Isolates were tested for the presence of 15-17-kDa virulence-associated protein antigens (VapA) by immunoblotting and virulence-associated plasmids by PCR. Plasmid DNAs were isolated and analyzed by digestion with restriction endonucleases for estimation of size and comparison of polymorphisims. Rhodococcus equi were isolated from soil of all 5 farms; however, virulent R. equi were only isolated from 3 of the 5 farms and represented 18.8% (87 of 462) of total isolates. Of the 87 virulent soil isolates, 56 (64.5%) contained an 85-kb type I plasmid, 23 (26.4%) an 87-kb type I plasmid, 7 (8%) a newly defined 85-kb type III plasmid (Tx 43), and 1 (1.1%) a newly defined 85-kb type IV plasmid (Tx 47). Of the 100 isolates from infected foals, 96 were virulent. Of the 96 virulent isolates, 51 (53.1%) contained an 85-kb type I plasmid, 39 (40.6%) an 87-kb type I plasmid, 4 (4.2%) an 85-kb type III plasmid (Tx 43), and 2 (2.1%) an 85-kb type IV plasmid (Tx 47). There are at least 4 different R. equi virulenceassociated plasmids in Texas, 2 of which have not previously been described. Based upon virulence plasmid typing, there is geographic diversity among isolates of R. equi from clinical and environmental samples on horse-breeding farms in Texas. There is not a strong correlation between the presence of virulent R. equi in farm soils and the R. equi disease status of those farms.Rhodococcus equi is one of the most important bacterial pathogens of young foals. Infections caused by this organism are characterized by chronic, suppurative bronchopneumonia and enteritis associated with a high mortality rate. 1,7,18 It was previously reported that the 15-17-kDa virulence-associated protein antigens (VapA) of R. equi are associated with virulence in mice 15,19 and that the presence of an 85-or a 90-kb plasmid is essential for virulence and the expression of VapA. 10,14,[22][23][24] These virulence-associated antigens and virulence plasmids have been used as epidemiologic markers to identify virulent R. equi isolates from horses and their environment by Western blot (immunoblot) assay using a monoclonal antibody and plasmid profiles. 4,11,12,16,17,21 More recently, restriction enzyme digestion patterns of virulence plasmids in human and foal isolates from several countries were examined. 6,20 The digestion patterns divided the plasmids of virulent isolates into 5 closely related types. Three of the 5 types had already been reported in Canadian and Japanese isolates, 6 and 2 new types were identified in French and Japanese isolates. 9,20 These 5 types of plasmids were designated as 85-kb type I (p-REAT701), 85-kb type II (a new type), 87-kb type I (EcoRI and BamHI type 2), 6 87-kb type II (a new type), and 90-kb (pREL1). The 85-kb type I plasmid was found in isolat...

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Section: Discussionmentioning

confidence: 46%

Prevalence of Virulent Rhodococcus Equi in Soil from Five R. Equi-Endemic Horse-Breeding Farms and Restriction Fragment Length Polymorphisms of Virulence Plasmids in Isolates from Soil and Infected Foals in Texas

et al. 2001

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“…Virulent R. equi, which are characterized by a virulence-associated 15-17-kDa protein antigen (VapA) and a virulence plasmid of 85-90 kb, have been isolated from the lesions of infected foals and the disease has been reproduced experimentally [22,23]. However, avirulent R. equi, which have no virulence-associated antigens or plasmids and do not cause disease in foals, are distributed widely in horses and their environments [10,23]. Epidemiological studies have revealed that horse-breeding farms with endemic infections are heavily contaminated with virulent R. equi [9,17].…”

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Molecular Typing of VapA-Positive Rhodococcus equi Isolates from Jeju Native Horses, Korea

Son

Lee

Yamatoda

et al. 2006

The Journal of Veterinary Medical Science

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ABSTRACT. We recently demonstrated the presence of virulence-associated protein antigen (VapA)-positive Rhodococcus equi in Jeju Island, Korea. These bacteria contained one of two distinct plasmid types, a 90-kb type II plasmid, which has been found in isolates from the native Kiso horses of Japan, and a new variant, a 90-kb type V plasmid. However, the genotypic characters of the VapA-positive R. equi from Jeju native horses and their environments are poorly understood. Ninety-eight isolates from soil samples and 89 isolates from fecal samples were collected from five farms that breed or have bred Jeju native horses, and were tested for the presence of VapA by immunoblotting and PCR. Of the 98 soil isolates and 89 fecal isolates, seven and 13 were VapA-positive R. equi, respectively. In 2003, two Jeju foals died suddenly and were brought to the Faculty of Veterinary Medicine, Cheju National University, for postmortem examination. Pure cultures of R. equi were isolated from the lung lesions of both foals. Rhodococcus equi is one of the most important bacterial pathogens in one-to three-month-old foals. Infections caused by this organism are characterized by chronic, suppurative bronchopneumonia, which is often accompanied by ulcerative enteritis and mesenteric lymphadenitis [1,6,9]. Since the first isolation of Rhodococcus equi from the lung abscesses of Swedish foals by Magnusson in 1923 [4], the disease has been described in many areas of the world [1,6]. The discovery of virulence-associated antigens and virulence plasmids has clarified some aspects of the virulence of R. equi [14,18]. Virulent R. equi, which are characterized by a virulence-associated 15-17-kDa protein antigen (VapA) and a virulence plasmid of 85-90 kb, have been isolated from the lesions of infected foals and the disease has been reproduced experimentally [22,23]. However, avirulent R. equi, which have no virulence-associated antigens or plasmids and do not cause disease in foals, are distributed widely in horses and their environments [10,23]. Epidemiological studies have revealed that horse-breeding farms with endemic infections are heavily contaminated with virulent R. equi [9,17].The restriction-enzyme digestion patterns of virulent virulence plasmids from foals have allowed the plasmids of virulent isolates to be categorized into 12 closely related types and have revealed geographic differences in the distributions of these virulence plasmids, not only throughout the world, but also within Japan [7,11,15,16,19,20,22]. In a recent study, we isolated virulent R. equi containing the 90-kb type II plasmid that has been found in isolates from the native Kiso horses of Japan, from fecal and environmental samples of the native Jeju horse and thoroughbred horse farms on Jeju Island, Korea, and a new variant, the 90-kb type V plasmid [20]. However, only one virulent R. equi was isolated from soil samples collected from a Jeju native horse farm [20].The purposes of this study were to investigate the prevalence of virulent R. equi in Jeju native ...

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“…With a worldwide distribution, the disease generally occurs sporadically, becoming endemic on some farms [11,14,25]. Recent studies of its epidemiology and experimental infections in foals have shown that only virulent strains of R. equi, which express a 15-17-kDa virulence-associated protein antigen (VapA) and harbor a virulence plasmid of 85-90-kb, can cause the disease in foals, and that farms with endemic disease are more contaminated with virulent R. equi than those without the disease [15,20,24,26,29].…”

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Rhodococcus equi Virulence Plasmids Recovered from Horses and Their Environment in Jeju, Korea: 90-kb Type II and a New Variant, 90-kb Type V

Takaı̈

Son

Lee

et al. 2003

The Journal of Veterinary Medical Science

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ABSTRACT. Rhodococcus equi was isolated from fecal and soil samples from four native Jeju horse farms and six Thoroughbred farms in Jeju, Korea. The isolates were examined for the presence of virulence-associated 15-17-kDa antigens (VapA) by colony blotting, using the monoclonal antibody 10G5, and for the gene encoding VapA by PCR. R. equi was isolated from all 36 soil samples collected from the 10 farms with between 5.0 × 10 2 and 7.5 × 10 4 colony-forming units (cfu) per gram of soil, and from 37 of 40 fecal samples with between 5.0 × 10 1 and 1.1 × 10 5 cfu per gram of feces. Virulent R. equi was isolated from seven farms and appeared in 2.0% of isolates (10 of 508). Of the 10 virulent isolates, four contained a 90-kb type II plasmid, which has been found in isolates from the Kiso native horses of Japan, and the other six contained a new variant, which did not display the EcoRI and EcoT22I digestion patterns of the 10 representative plasmids already reported (85-kb types I, II, III, and IV; 87-kb types I and II; 90-kb types I, II, III, and IV). We designated the new variant as the "90-kb type V" plasmid, because its EcoRI digestion pattern is similar to that of the 90-kb type II plasmid. This is the first report of the prevalence of virulent R. equi in Jeju, Korea. The same virulence plasmid type is found in both Korean and Japanese isolates, providing insight into the origin, ancestry, and dispersal of native horses in Korea and Japan.

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Prevalence of Virulence Plasmids in Environmental Isolates of Rhodococcus equi from Horse-Breeding Farms in Hokkaido.

Cited by 40 publications

References 16 publications

Prevalence of Virulent Rhodococcus Equi in Soil from Five R. Equi-Endemic Horse-Breeding Farms and Restriction Fragment Length Polymorphisms of Virulence Plasmids in Isolates from Soil and Infected Foals in Texas

Prevalence of Virulent Rhodococcus Equi in Soil from Five R. Equi-Endemic Horse-Breeding Farms and Restriction Fragment Length Polymorphisms of Virulence Plasmids in Isolates from Soil and Infected Foals in Texas

Molecular Typing of VapA-Positive Rhodococcus equi Isolates from Jeju Native Horses, Korea

Rhodococcus equi Virulence Plasmids Recovered from Horses and Their Environment in Jeju, Korea: 90-kb Type II and a New Variant, 90-kb Type V

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