A family of gram-negative bacteria usually found in soil or water and including many plant pathogens and a few animal pathogens.

A family of gram-negative, aerobic bacteria in the order Pseudomonadales. Some strains are parasites of the mucosal membranes of animals and humans; others are found in association with food products or in the environment.

A species of gram-negative bacteria in the genus PASTEURELLA, found in the NASOPHARYNX of normal GUINEA PIGS; RATS; HAMSTERS; MICE; DOGS; and CATS. When associated with disease, it is usually a secondary invader. Occasional infections have been reported in humans.

A family of gram-negative, facultatively anaerobic, rod-shaped bacteria that do not form endospores. Its organisms are distributed worldwide with some being saprophytes and others being plant and animal parasites. Many species are of considerable economic importance due to their pathogenic effects on agriculture and livestock.