Classification of Brucella spp. isolated from marine mammals by DNA polymorphism at the omp2 locus
Classification of Brucella spp. isolated from marine mammals by DNA polymorphism at the omp2 locus
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DOI：
10.1016/s1286-4579(01)01427-7
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发表时间：
2001-07-01
影响因子：
5.8
通讯作者：
Godfroid, J
中科院分区：
文献类型：
--
作者：
Cloeckaert, A;Verger, JM;Godfroid, J
最近的一些报告描述了从各种海洋哺乳动物如海豹、鼠海豚、海豚和小须鲸中分离和鉴定布鲁氏菌菌株的情况。这些菌株经常规分型试验鉴定为布鲁氏菌。然而，它们的总体特征与目前公认的六种布鲁氏菌中的任何一种都不可同化，有人建议它们包括一个新的命名种，称为“布鲁氏菌”。在本研究中，我们分析了DNA多态性的omp 2位点的33个海洋哺乳动物布鲁氏菌菌株分离海豹，海豚，鼠海豚和水獭。omp 2基因座含有编码孔蛋白的两个基因拷贝（命名为omp 2a和omp 2b），并且已发现其特别适用于布鲁氏菌在种、生物型或菌株水平上的分子分型和鉴定。PCR-限制性片段长度多态性（RFLP）和DNA测序表明，从海豚和江豚分离的菌株携带两个omp 2b基因拷贝，而不是一个omp 2a和一个omp 2b基因拷贝或两个类似的omp 2a基因拷贝在目前公认的物种。最近还对小须鲸布鲁氏菌分离株进行了这一观察。水獭和所有的密封分离，除了一个被证明携带一个omp 2a和一个omp 2b基因拷贝遇到的分离，从陆地哺乳动物。通过对omp 2b基因的PCR-RFLP分析，发现海洋哺乳动物布鲁氏菌分离株有一个特异性标记。虽然海洋哺乳动物布鲁氏菌分离株可能代表一个独立的组，从陆地哺乳动物分离株的基础上omp 2b序列构建的系统发育树，他们的omp 2b之间的分歧，也发现他们的omp 2a核苷酸序列之间表明，他们形成一个更异质性的组比陆地哺乳动物的分离株。因此，将海洋哺乳动物布鲁氏菌分离株归为一个种“海洋布鲁氏菌”似乎是不合适的，除非将目前公认的布鲁氏菌种进行分组。关于目前根据优先宿主对布鲁氏菌进行的分类，从海豹和海豚等多种海洋哺乳动物物种中分离出的布鲁氏菌实际上可能包括一个以上的物种，以及至少两个新种B。pinnipediae和B.鲸蜡科（cetaceae）的DNA多态性与寄主选择性和omp 2基因座DNA多态性的经典标准一致。(C)2001年，Elsevier SAS科学与医学版。
A number of recent reports have described the isolation and characterization of Brucella strains from a wide variety of marine mammals such as seals, porpoises, dolphins and a minke whale. These strains were identified as brucellae by conventional typing tests. However, their overall characteristics were not assimilable to those of any of the six currently recognized Brucella species and it was suggested that they comprise a new nomen species to be called 'Brucella maris'. In the present study we analysed DNA polymorphism at the omp2 locus of 33 marine mammal Brucella strains isolated from seals, dolphins, porpoises and an otter. The omp2 locus contains two gene copies (named omp2a and omp2b) coding for porin proteins and has been found particularly useful for molecular typing and identification of Brucella at the species, biovar, or strain level. PCR-restriction fragment length polymorphism (RFLP) and DNA sequencing showed that strains isolated from dolphins and porpoises carry two omp2b gene copies instead of one omp2a and one omp2b gene copy or two similar omp2a gene copies reported in the currently recognized species. This observation was also recently made for a minke whale Brucella isolate. The otter and all seal isolates except one were shown to carry one omp2a and one omp2b gene copy as encountered in isolates from terrestrial mammals. By PCR-RFLP of the omp2b gene, a specific marker was detected grouping the marine mammal Brucella isolates. Although marine mammal Brucella isolates may represent a separate group from terrestrial mammal isolates based on omp2b sequence constructed phylogenetic trees, the divergence found between their omp2b and also between their omp2a nucleotide sequences indicates that they form a more heterogeneous group than isolates from terrestrial mammals. Therefore, grouping the marine mammal Brucella isolates into one species 'Brucella maris' seems inappropriate unless the currently recognized Brucella species are grouped. With respect to the current classification of brucellae according to the preferential host, brucellae isolated from such diverse marine mammal species as seals and dolphins could actually comprise more than one species, and at least two new species, B. pinnipediae and B. cetaceae, could be compatible with the classical criteria of host preferentialism and DNA polymorphism at their omp2 locus. (C) 2001 Editions scientifiques et medicales Elsevier SAS.