Kivi Mårten, Rodin Sandra, Kupershmidt Ilya, Lundin Annelie, Tindberg Ylva, Granström Marta, Engstrand Lars
Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden.
BMC Microbiol. 2007 Jun 11;7:54. doi: 10.1186/1471-2180-7-54.
Helicobacter pylori infection is exceptionally prevalent and is considered to be acquired primarily early in life through person-to-person transmission within the family. H. pylori is a genetically diverse bacterial species, which may facilitate adaptation to new hosts and persistence for decades. The present study aimed to explore the genetic diversity of clonal isolates from a mother and her three children in order to shed light on H. pylori transmission and host adaptation.
Two different H. pylori strains and strain variants were identified in the family members by PCR-based molecular typing and sequencing of five loci. Genome diversity was further assessed for 15 isolates by comparative microarray hybridizations. The microarray consisted of 1,745 oligonucleotides representing the genes of two previously sequenced H. pylori strains. The microarray analysis detected a limited mean number (+/- standard error) of divergent genes between clonal isolates from the same and different individuals (1 +/- 0.4, 0.1%, and 3 +/- 0.3, 0.2%, respectively). There was considerable variability between the two different strains in the family members (147 +/- 4, 8%) and for all isolates relative to the two sequenced reference strains (314 +/- 16, 18%). The diversity between different strains was associated with gene functional classes related to DNA metabolism and the cell envelope.
The present data from clonal H. pylori isolates of family members do not support that transmission and host adaptation are associated with substantial sequence diversity in the bacterial genome. However, important phenotypic modifications may be determined by additional genetic mechanisms, such as phase-variation. Our findings can aid further exploration of H. pylori genetic diversity and adaptation.
幽门螺杆菌感染极为普遍，被认为主要在生命早期通过家庭内人际传播而获得。幽门螺杆菌是一种基因多样的细菌物种，这可能有助于其适应新宿主并持续存在数十年。本研究旨在探究一名母亲及其三个孩子的克隆分离株的基因多样性，以阐明幽门螺杆菌的传播及宿主适应性。
通过基于聚合酶链反应（PCR）的分子分型和五个位点的测序，在家庭成员中鉴定出两种不同的幽门螺杆菌菌株及菌株变体。通过比较微阵列杂交对15个分离株进一步评估基因组多样性。该微阵列由1745个寡核苷酸组成，代表了两个先前测序的幽门螺杆菌菌株的基因。微阵列分析检测到来自相同个体和不同个体的克隆分离株之间差异基因的平均数量有限（±标准误差）（分别为1±0.4，0.1%和3±0.3，0.2%）。家庭成员中两种不同菌株之间（147±4，8%）以及所有分离株相对于两个测序参考菌株之间（314±16，18%）存在相当大的变异性。不同菌株之间的多样性与DNA代谢和细胞膜相关的基因功能类别有关。
来自家庭成员幽门螺杆菌克隆分离株的当前数据不支持传播和宿主适应性与细菌基因组中大量序列多样性相关。然而，重要的表型修饰可能由其他遗传机制决定，如相变。我们的发现有助于进一步探索幽门螺杆菌的基因多样性和适应性。
