Dept. Veterinary Medicine, Madingley Road, University of Cambridge, Cambridge, CB3 0ES, UK.
Dept. Genetics, Evolution and Environment, University College London, Darwin Building, Gower Street, London, WC1E 6BT, UK.
Microbiology (Reading). 2024 Sep;170(9). doi: 10.1099/mic.0.001500.
The sit-and-wait hypothesis predicts that bacteria can become more virulent when they survive and transmit outside of their hosts due to circumventing the costs of host mortality. While this hypothesis is largely supported theoretically and through comparative analysis, experimental validation is limited. Here we test this hypothesis in , an opportunistic zoonotic pig pathogen, where a pathogenic ecotype proliferated during the change to intensive pig farming that amplifies opportunities for fomite transmission. We show in an environmental survival experiment that pathogenic ecotypes survive for longer than commensal ecotypes, despite similar rates of decline. The presence of a polysaccharide capsule has no consistent effect on survival. Our findings suggest that extended survival in the food chain may augment the zoonotic capability of . Moreover, eliminating the long-term environmental survival of bacteria could be a strategy that will both enhance infection control and curtail the evolution of virulence.
坐以待毙假说预测，当细菌在宿主外存活和传播时，由于避免了宿主死亡的成本，它们可能变得更具毒力。虽然这一假说在理论上和通过比较分析得到了广泛支持，但实验验证是有限的。在这里，我们在 ，一种机会性人畜共患病猪病原体中检验了这一假说，在向集约化养猪的转变过程中，一种病原生态型大量繁殖，增加了媒介传播的机会。我们在一个环境生存实验中表明，尽管致病性生态型的下降速度相似，但它们的存活时间却长于共生性生态型。多糖荚膜的存在对生存没有一致的影响。我们的研究结果表明，在食物链中延长存活时间可能会增强 的人畜共患能力。此外，消除细菌的长期环境生存可能是一种既能增强感染控制又能遏制毒力进化的策略。
