The bacteria associated with the plague is Yersinia pestis. This pathogen is the causative agent of the bubonic plague, septicemic plague, and pneumonic plague, all of which have significant historical and epidemiological importance. Yersinia pestis primarily spreads through flea bites, direct contact with infected animals, or respiratory droplets from infected individuals.
In contrast to the other options, which are associated with different types of infections, Yersinia pestis is specifically recognized for its role in plague outbreaks, making it distinct in the context of this question. For instance, Salmonella is commonly linked to foodborne illnesses, Escherichia coli includes strains that can cause severe gastrointestinal issues, and Streptococcus is predominantly associated with conditions such as strep throat and other throat infections. Understanding the specific association of Yersinia pestis with the plague is crucial for grasping public health issues related to this historically significant disease.