Survival strategy of intracellular Rhodococcus equi : the role of virulence plasmid.

细胞内马红球菌的生存策略：毒力质粒的作用。

• 批准号: 12460140
• 负责人: TAKAI Shinji
• 金额: $ 9.22万
• 依托单位: Kitasato University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12460140/
• 关键词: Rhodococcu equi; virulence plasmid; DNA sequence; pathogenicity; intracellular bacteri; macrophage; horse; virulence; 病原性プラミスド; Rhodococcus equi; 食菌抵抗性

At least three virulence levels of Rhodococcus equi have been identified : virulence, intermediate virulence, and avirulence. Virulent R. equi is characterized by the presence of virulence-associated 15-to 17-kDa antigens (VapA), virulence plasmid DNA of 85 to 90 kb, and suppurative pneumonia in foals (mouse LD_<50>=10^6). R. equi strains of intermediate virulence are identified by a virulence associated 20-kDa antigen (VapB) and virulence plasmid DNA of 79 to 100 kb and are found in the submaxillary lymph nodes of pigs (mouse LD_<50>=10^7). To analyze the difference of virulence levels in R. equi, the virulence plasmid of the R. equi strain A3 of intermediate virulence (pREA3) was sequenced and compared with the DNA sequence of the virulence plasmid (p33701). pREA3 was 79,288 by and the plasmid encoded 71 open reading frames (ORFs). Of the 71 ORFs, 52 were found to be almost identical to those in the virulence plasmid (p33701). pREA3 also has a pathogenicity island containing 5 new virulence-associated protein (vap) genes [vapI, vapJ (2 copies), vapK, and vapL] located upstream of vapB. There was extensive homology in the region except the pathogenicity island between p33701 and pREA3. These results suggest that the difference in the structure and function of the pathogenicity islands between p33701 and pREA3 might be responsible for the difference in virulence levels of R. equi.

已鉴定出马红球菌至少三种毒力水平：毒力、中毒力和无毒力。强毒马罗氏菌的特征是存在毒力相关的15至17kDa抗原(VapA)、85至90kb的毒力质粒DNA以及马驹中的化脓性肺炎(小鼠LD_<50>=10^6)。中等毒力的马罗氏菌菌株通过毒力相关的 20-kDa 抗原 (VapB) 和 79 至 100 kb 的毒力质粒 DNA 进行鉴定，并在猪颌下淋巴结中发现（小鼠 LD_<50>=10^7） 。为了分析马罗氏菌毒力水平的差异，对马罗氏菌中毒力菌株A3（pREA3）的毒力质粒进行测序，并与毒力质粒（p33701）的DNA序列进行比较。 pREA3为79,288个，该质粒编码71个开放阅读框(ORF)。在 71 个 ORF 中，发现 52 个与毒力质粒 (p33701) 中的 ORF 几乎相同。 pREA3 还具有一个位于 vapB 上游的致病岛，其中包含 5 个新的毒力相关蛋白 (vap) 基因 [vapI、vapJ（2 个拷贝）、vapK 和 vapL]。 p33701 和 pREA3 之间除致病性岛外，该区域存在广泛的同源性。这些结果表明p33701和pREA3之间致病性岛的结构和功能的差异可能是马罗氏菌毒力水平差异的原因。

项目成果

Takai, S., et al.: "Rhodococcus equi pneumonia in a crossbred foal in Kumamoto: clinical isolates contained new virulence plasmids,90-kb type DI and type IV"Vet. Microbiol.. 82. 373-381 (2001)

Takai, S. 等人：“熊本杂交小马驹中的马红球菌肺炎：临床分离株含有新的毒力质粒、90-kb DI 型和 IV 型”兽医。

Yuyama, T., et al.: "Molecular epidemiology of virulent Rhodococcus epui in thoroughbred horses in Kagoshima"J. Vet. Med. Sci.. 64(8). 715-718 (2002)

Yuyama, T., et al.：“鹿儿岛纯种马中强毒力红球菌的分子流行病学”J.

Morton, AC et al.: "Epidemiology Of Rhodococcus equi Strains On Thoroughbred Horse Farms"Appl Environ Microbiol. 67. 2167-2175 (2001)

Morton, AC 等人：“纯种马场马红球菌菌株的流行病学”Appl Environ Microbiol。

Takai, S. et al.: "Identification of virulence-associated antigens and plasmids in Rhodococcus equi from AIDS patients and prevalence of virulent R. equi in soil collected from domestic animal farms in Chiang Mai."Am.J.TroMed.Hyg.. 66. 52-55 (2002)

Takai, S. 等人：“艾滋病患者马红球菌毒力相关抗原和质粒的鉴定以及从清迈家畜养殖场收集的土壤中马红球菌的毒力流行情况。”Am.J.TroMed.Hyg。

Flynn, O. et al.: "Virulence-associated protein characterisation of Rhodococcus equi isolated from bovine lymph nodes"Vet. Microbiol.. 78. 221-228 (2001)

Flynn, O. 等人：“从牛淋巴结中分离出的马红球菌的毒力相关蛋白特征”Vet。