Abstract：
Bacteroides fragilis is a Gram-negative commensal bacterium commonly found in the human colon, which differentiates into two genomospecies termed divisions I and II. Through a comprehensive collection of 694 B. fragilis whole genome sequences, we identify novel features distinguishing these divisions. Our study reveals a distinct geographic distribution with division I strains predominantly found in North America and division II strains in Asia. Additionally, division II strains are more frequently associated with bloodstream infections, suggesting a distinct pathogenic potential. We report differences between the two divisions in gene abundance related to metabolism, virulence, stress response, and colonization strategies. Notably, division II strains harbor more antimicrobial resistance (AMR) genes than division I strains. These findings offer new insights into the functional roles of division I and II strains, indicating specialized niches within the intestine and potential pathogenic roles in extraintestinal sites.
OBJECTIVE: Understanding the distinct functions of microbial species in the gut microbiome is crucial for deciphering their impact on human health. Classifying division II strains as Bacteroides fragilis can lead to erroneous associations, as researchers may mistakenly attribute characteristics observed in division II strains to the more extensively studied division I B. fragilis. Our findings underscore the necessity of recognizing these divisions as separate species with distinct functions. We unveil new findings of differential gene prevalence between division I and II strains in genes associated with intestinal colonization and survival strategies, potentially influencing their role as gut commensals and their pathogenicity in extraintestinal sites. Despite the significant niche overlap and colonization patterns between these groups, our study highlights the complex dynamics that govern strain distribution and behavior, emphasizing the need for a nuanced understanding of these microorganisms.
OBJECTIVE: Understanding the distinct functions of microbial species in the gut microbiome is crucial for deciphering their impact on human health. Classifying division II strains as Bacteroides fragilis can lead to erroneous associations, as researchers may mistakenly attribute characteristics observed in division II strains to the more extensively studied division I B. fragilis. Our findings underscore the necessity of recognizing these divisions as separate species with distinct functions. We unveil new findings of differential gene prevalence between division I and II strains in genes associated with intestinal colonization and survival strategies, potentially influencing their role as gut commensals and their pathogenicity in extraintestinal sites. Despite the significant niche overlap and colonization patterns between these groups, our study highlights the complex dynamics that govern strain distribution and behavior, emphasizing the need for a nuanced understanding of these microorganisms.
摘要：
脆弱拟杆菌是人类结肠中常见的革兰氏阴性共生细菌，分为两个基因组，称为I和II。通过全面收集694个脆弱芽孢杆菌全基因组序列，我们确定了区分这些划分的新颖特征。我们的研究揭示了一个独特的地理分布，主要在北美发现I种菌株，在亚洲发现II种菌株。此外,II类菌株更经常与血流感染相关，表明有明显的致病潜力。我们报告了与代谢相关的基因丰度的两种划分之间的差异，毒力,应激反应，和殖民战略。值得注意的是,II级菌株比I级菌株具有更多的抗菌素耐药性（AMR）基因。这些发现为I区和II区菌株的功能作用提供了新的见解，指示肠道内的特殊生态位和肠外部位的潜在致病作用。
目的：了解肠道微生物群中微生物种类的独特功能对于破译它们对人类健康的影响至关重要。将II类菌株分类为脆弱拟杆菌可能导致错误的关联，因为研究人员可能错误地将II类菌株中观察到的特征归因于更广泛研究的IB.fragilis。我们的发现强调了将这些分裂视为具有不同功能的独立物种的必要性。我们揭示了在与肠道定植和生存策略相关的基因中，I区和II区菌株之间的差异基因患病率的新发现。潜在影响它们作为肠道共生的作用及其在肠外部位的致病性。尽管这些群体之间存在显著的生态位重叠和定殖模式，我们的研究强调了控制应变分布和行为的复杂动力学，强调需要对这些微生物有细微的了解。
目的：了解肠道微生物群中微生物种类的独特功能对于破译它们对人类健康的影响至关重要。将II类菌株分类为脆弱拟杆菌可能导致错误的关联，因为研究人员可能错误地将II类菌株中观察到的特征归因于更广泛研究的IB.fragilis。我们的发现强调了将这些分裂视为具有不同功能的独立物种的必要性。我们揭示了在与肠道定植和生存策略相关的基因中，I区和II区菌株之间的差异基因患病率的新发现。潜在影响它们作为肠道共生的作用及其在肠外部位的致病性。尽管这些群体之间存在显著的生态位重叠和定殖模式，我们的研究强调了控制应变分布和行为的复杂动力学，强调需要对这些微生物有细微的了解。
