耶尔辛氏菌属（Yersinia）系细菌界的一个属。耶尔辛氏菌属内的细菌均为革兰氏阴性菌。这些细菌属于杆状菌，按异化类型分则属于兼性厌氧菌。该属内的细菌长达几微米，直径则不到一微米。耶尔辛氏菌属内的细菌有些是致病菌，比如具高死亡率的鼠疫的元凶鼠疫杆菌（ Y. pestis）。啮齿目是耶尔辛氏菌属的主要宿主，不过这其他的哺乳动物（比如兔子、家畜）以及鸟类也可成为这类细菌的宿主。耶尔辛氏菌属内的细菌可通过血液传播（比如鼠疫杆菌就是如此），也可通过消化道传播，比如有时耶尔辛氏菌属就能通过食物产品（尤其是蔬菜、牛奶衍生产品、肉类）传播。另外，沾有耶尔辛氏菌属的粪便或尿液也能传播这种细菌。

Yersinia is a genus of bacteria in the family Enterobacteriaceae. Yersinia species are Gram-negative, rod-shaped bacteria, a few micrometers long and fractions of a micrometer in diameter, and are facultative anaerobes. Some members of Yersinia are pathogenic in humans; in particular, Y. pestis is the causative agent of the plague. Rodents are the natural reservoirs of Yersinia; less frequently, other mammals serve as the host. Infection may occur either through blood (in the case of Y. pestis) or in an alimentary fashion, occasionally via consumption of food products (especially vegetables, milk-derived products, and meat) contaminated with infected urine or feces.