Escherichia

Overview
Escherichia is a genus of Gram-negative, non-spore forming, facultatively anaerobic, rod-shaped bacteria from the family Enterobacteriaceae. Inhabitants of the gastrointestinal tracts of warm-blooded animals, Escherichia species provide a portion of the microbially-derived vitamin K for their host. Escherichia coli are the most numerous aerobic commensal inhabitants of the large intestine in humans.

Pathogenesis
While many Escherichia are harmless commensals, particular strains of some species are human pathogens, and are known as the most common cause of urinary tract infections, significant sources of gastrointestinal disease, ranging from simple diarrhea to dysentery-like conditions, as well as a wide-range of other pathogenic states. While E. coli is responsible for the vast majority of Escherichia-related pathogenesis, other members of the genus have also been implicated in human disease. ,