Gammaproteobacteria

Gammaproteobacteria is a class of several medically, ecologically and scientifically important groups of bacteria, such as the Enterobacteriaceae (Escherichia coli), Vibrionaceae and Pseudomonadaceae. An exceeding number of important pathogens belongs to this class, e.g. Salmonella (enteritis and typhoid fever), Yersinia (plague), Vibrio (cholera), Pseudomonas aeruginosa (lung infections in hospitalised or cystic fibrosis patients), and Klebsiella pneumoniae responsible for causing pneumonia. Like all Proteobacteria, the Gammaproteobacteria are Gram-negative.