论文标题
肺炎球菌和应力征收假设：权衡链接$ r_0 $和在国家之间共同殖民化的敏感性
Pneumococcus and the stress-gradient hypothesis: a trade-off links $R_0$ and susceptibility to co-colonization across countries
论文作者
论文摘要
现代分子技术已经彻底改变了我们对细菌流行病学的理解，但在常见的理论框架中，跨不同环境的数据仍然不足。近年来，由多态细菌链球菌链球菌引起的肺炎球菌共殖民化已越来越多地研究。虽然肺炎链球菌的全球基因组多样性和血清型分布已经很好地表征，但关于共殖化模式如何变化的信息有限，这对于理解细菌进化和动力学至关重要。在文献中收集了丰富的横断面肺炎球菌定殖研究数据集，我们量化了17个地理位置的儿童人群中传播强度和共殖化率的模式。在相互作用菌株之间假设相似性的假设下，将这些数据拟合到SIS模型中，我们的分析揭示了传输强度（$ r_0 $）和对共殖化的敏感性（$ k $）之间的负相变的强大模式。为了支持生态学（SGH）中的应力梯度假设，肺炎血清型似乎在高转移环境中竞争更多，而在低转移环境中的竞争更少，这是一种权衡，这最终导致单人与共同殖民化的比率$ = 1/（r_0-1）k $。在我们的数学模型中，这种保护表明在多晶体共存中保存“稳定多样性复杂性”制度。我们发现血清型组成的研究差异没有主要研究差异，这表明跨环境的同一血清型的基本适应。我们的工作强调，从全球流行病学数据中了解肺炎球菌的传播模式可以受益于简单的分析方法，这些分析方法解释了菌株之间的准中性，共殖化以及可变的环境适应。
Modern molecular technologies have revolutionized our understanding of bacterial epidemiology, but reported data across different settings remain under-integrated in common theoretical frameworks. Pneumococcus serotype co-colonization, caused by the polymorphic bacteria Streptococcus pneumoniae, has been increasingly investigated in recent years. While the global genomic diversity and serotype distribution of S. pneumoniae are well-characterized, there is limited information on how co-colonization patterns vary globally, critical for understanding bacterial evolution and dynamics. Gathering a rich dataset of cross-sectional pneumococcal colonization studies in the literature, we quantified patterns of transmission intensity and co-colonization prevalence in children populations across 17 geographic locations. Fitting these data to an SIS model with co-colonization under the assumption of similarity among interacting strains, our analysis reveals strong patterns of negative co-variation between transmission intensity ($R_0$) and susceptibility to co-colonization ($k$). In support of the stress-gradient hypothesis in ecology (SGH), pneumococcus serotypes appear to compete more in high-transmission settings and less in low-transmission settings, a trade-off which ultimately leads to a conserved ratio of single to co-colonization $μ=1/(R_0-1)k$. Within our mathematical model, such conservation suggests preservation of 'stability-diversity-complexity' regimes in multi-strain coexistence. We find no major study differences in serotype composition, pointing to underlying adaptation of the same set of serotypes across environments. Our work highlights that understanding pneumococcus transmission patterns from global epidemiological data can benefit from simple analytical approaches that account for quasi-neutrality among strains, co-colonization, as well as variable environmental adaptation.
