Abdelbary Mohamed M H, Hatting Maximilian, Dahlhausen Andrea, Bott Alexandra, Conrads Georg
Division of Nosocomial Pathogens and Antibiotic Resistances, Department of Infectious Diseases, Robert Koch Institute, Wernigerode Branch, 38855 Wernigerode, Germany.
Division of Oral Microbiology and Immunology, Department of Operative Dentistry, Periodontology and Preventive Dentistry, Rheinisch-Westfälische Technische Hochschule (RWTH) University Hospital, 52074 Aachen, Germany.
Int J Mol Sci. 2024 Dec 17;25(24):13507. doi: 10.3390/ijms252413507.
The oral-gut axis is a complex system linking the oral cavity and gastrointestinal tract, impacting host health and microbial composition. This study investigates genetic changes and adaptive mechanisms employed by streptococci-one of the few genera capable of colonizing oral and intestinal niches-within the same individual. We conducted whole-genome sequencing (WGS) on 218 streptococcal isolates from saliva and fecal samples of 14 inflammatory bowel disease (IBD) patients and 12 healthy controls. Our analysis identified 16 streptococcal species, with , , , , and being the most prevalent. dominated the oral niche in both IBD patients (33%) and healthy controls (26%). It was also the primary species in fecal samples from IBD patients and the second most prevalent in those from healthy controls. was more prevalent in the gut than in the oral cavity in both groups. Comparative genomics demonstrated a within-host microevolution of streptococci, showing adaptations via recombination and acquisition of mobile genetic elements (MGEs). Intestinal streptococcal genomes exhibited a higher proportion of intact phages and a significantly greater acquisition of the gene, which confers tetracycline resistance compared to oral genomes. Core-genome single-nucleotide polymorphisms (SNPs) analysis showed significant genetic divergence between oral and intestinal streptococcal genomes within the same individual. Our findings also unveil distinct niche-specific mutation signatures within intestinal genomes, indicating the emergence of distinct clonal lineages within each niche and suggesting that within-host streptococcal evolution is individual-dependent, initiated in the oral cavity.
口腔 - 肠道轴是一个连接口腔和胃肠道的复杂系统，影响宿主健康和微生物组成。本研究调查了链球菌（能够定殖于同一个体口腔和肠道生态位的少数菌属之一）所采用的遗传变化和适应性机制。我们对来自14名炎症性肠病（IBD）患者和12名健康对照的唾液和粪便样本中的218株链球菌分离株进行了全基因组测序（WGS）。我们的分析确定了16种链球菌，其中 、 、 、 和 最为常见。 在IBD患者（33%）和健康对照（26%）的口腔生态位中均占主导地位。它也是IBD患者粪便样本中的主要菌种，在健康对照的粪便样本中是第二常见的菌种。在两组中， 在肠道中比在口腔中更为普遍。比较基因组学表明链球菌在宿主体内发生了微进化，显示出通过重组和获得移动遗传元件（MGEs）实现的适应性。与口腔基因组相比，肠道链球菌基因组中完整噬菌体的比例更高，并且 基因的获得显著更多，该基因赋予四环素抗性。核心基因组单核苷酸多态性（SNP）分析表明，同一个体内口腔和肠道链球菌基因组之间存在显著的遗传差异。我们的研究结果还揭示了肠道基因组内不同的生态位特异性突变特征，表明每个生态位内出现了不同的克隆谱系，并表明宿主体内链球菌的进化是个体依赖的，始于口腔。
