Characterization of strains of Mycoplasma mycoides subsp mycoides small colony type isolated from recent outbreaks of contagious bovine pleuropneumonia in Botswana and Tanzania:: Evidence for a new biotype
Characterization of strains of Mycoplasma mycoides subsp mycoides small colony type isolated from recent outbreaks of contagious bovine pleuropneumonia in Botswana and Tanzania:: Evidence for a new biotype
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DOI：
10.1128/jcm.38.4.1419-1425.2000
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发表时间：
2000-04-01
影响因子：
9.4
通讯作者：
Brodlie, M
中科院分区：
文献类型：
--
作者：
March, JB;Clark, J;Brodlie, M
从非洲最近暴发的传染性牛胸膜肺炎(CBPP)中分离到4株支原体支原体亚种，支原体小集落类型(MMMSC)。一种名为M375的博茨瓦纳毒株表现出与当代野毒株以及更老的野毒株和疫苗株(可追溯到1936年的非洲、澳大利亚和欧洲毒株)的许多显著表型差异。不同之处包括形态改变，被膜多糖产生减少，体外对MMMSC兔高免疫抗血清高度敏感，以及免疫印迹后独特的多态。虽然使用IS1634的插入序列分析清楚地表明了与西非毒株的密切进化关系，但与IS1296的杂交显示，在所研究的所有其他MMMSC毒株中都没有出现一条带。这些数据表明，M375菌株发生了缺失，这可能解释了其表型改变的原因，包括体外生长不良和相对不能引起小鼠败血症。猪肺炎支原体亚种(传染性山羊胸膜肺炎[CCPP]的病原体)也表现出这些特征，M375抗血清在体外表现出一定的活性(在所测试的各种MMMSC抗血清中是独一无二的)。这些发现可能具有进化意义，因为CCPP被认为是肺特有的，没有败血症阶段(不同于CBPP)。由于M375是从一例CBPP临床病例中分离出来的，这种新的生物型可能相当广泛，但由于培养困难和/或潜在的疾病综合征改变，通常不会被分离出来。从博茨瓦纳同期自然感染的牛获得的恢复期抗血清，在体外生长抑制试验中对M375菌株具有活性，但对所测试的任何其他MMMSC菌株均不起作用。因此，M375株可能具有一套不同于其他MMMSC株(包括疫苗株)的保护性抗原，这些发现对控制当前非洲的CBPP疫情具有重要意义。
Four strains of Mycoplasma mycoides subsp, mycoides small colony type (MmmSC) isolated from recent outbreaks of contagious bovine pleuropneumonia (CBPP) in Africa have been investigated. One Botswanan strain, M375, displayed numerous and significant phenotypic differences from both contemporary field isolates and older field and vaccine strains (African, Australian, and European strains dating back to 1936). Differences include altered morphology, reduced capsular polysaccharide production, high sensitivity to MmmSC rabbit hyperimmune antisera in vitro, and unique polymorphisms following immunoblotting. While insertion sequence analysis using IS1634 clearly indicates a close evolutionary relationship to west African strains, hybridization with IS1296 shows the absence of a band present in all other strains of MmmSC examined. The data suggest that a deletion has occurred in strain M375, which may explain its altered phenotype, including poor growth in vitro and a relative inability to cause septicemia in mice. These characteristics are also exhibited by Il Mycoplasma capricolum subsp, capripneumoniae (causal agent of contagious caprine pleuropneumonia [CCPP]), against which M375 antiserum exhibited some activity in vitro (unique among the various MmmSC antisera tested). These findings may have evolutionary implications, since CCPP is believed to be lung specific and without a septicemic phase (unlike CBPP). Since M375 was isolated from a clinical case of CBPP, this novel biotype may be fairly widespread but not normally isolated due to difficulty of culture and/or a potentially altered disease syndrome. Bovine convalescent antisera (obtained from contemporary naturally infected cattle in Botswana) were active against strain M375 in an in vitro growth inhibition test but not against any other strains of MmmSC tested. There exists the possibility therefore, that strain M375 may possess a set of protective antigens different from those of other strains of MmmSC (including vaccine strains), These findings have implications for the control of the current CBPP epidemic in Africa.