Aeromonas: A genus of gram-negative, facultatively anaerobic, rod-shaped bacteria that occurs singly, in pairs, or in short chains. Its organisms are found in fresh water and sewage and are pathogenic to humans, frogs, and fish.Aeromonas hydrophila: A species of gram-negative, facultatively anaerobic, rod-shaped bacteria that may be pathogenic for frogs, fish, and mammals, including man. In humans, cellulitis and diarrhea can result from infection with this organism.Aeromonas salmonicida: A species of gram-negative bacteria, in the family Aeromonadaceae. It is strictly parasitic and often pathogenic causing FURUNCULOSIS in SALMONIDS and ulcer disease in GOLDFISH.Gram-Negative Bacterial Infections: Infections caused by bacteria that show up as pink (negative) when treated by the gram-staining method.Aeromonas caviae: A species of gram-negative, facultatively anaerobic bacteria that is found in domestic and wild animals including birds, and fish. In humans it causes GASTROENTERITIS in young children and some adults.Water Microbiology: The presence of bacteria, viruses, and fungi in water. This term is not restricted to pathogenic organisms.Furunculosis: A persistent skin infection marked by the presence of furuncles, often chronic and recurrent. In humans, the causative agent is various species of STAPHYLOCOCCUS. In salmonid fish (SALMONIDS), the pathogen is AEROMONAS SALMONICIDA.Fish Diseases: Diseases of freshwater, marine, hatchery or aquarium fish. This term includes diseases of both teleosts (true fish) and elasmobranchs (sharks, rays and skates).Vibrionaceae: A family of gram-negative bacteria whose members predominate in the bacterial flora of PLANKTON; FISHES; and SEAWATER. Some members are important pathogens for humans and animals.Cytotoxins: Substances that are toxic to cells; they may be involved in immunity or may be contained in venoms. These are distinguished from CYTOSTATIC AGENTS in degree of effect. Some of them are used as CYTOTOXIC ANTIBIOTICS. The mechanism of action of many of these are as ALKYLATING AGENTS or MITOSIS MODULATORS.Hemolysin Proteins: Proteins from BACTERIA and FUNGI that are soluble enough to be secreted to target ERYTHROCYTES and insert into the membrane to form beta-barrel pores. Biosynthesis may be regulated by HEMOLYSIN FACTORS.Diarrhea: An increased liquidity or decreased consistency of FECES, such as running stool. Fecal consistency is related to the ratio of water-holding capacity of insoluble solids to total water, rather than the amount of water present. Diarrhea is not hyperdefecation or increased fecal weight.DNA, Bacterial: Deoxyribonucleic acid that makes up the genetic material of bacteria.Feces: Excrement from the INTESTINES, containing unabsorbed solids, waste products, secretions, and BACTERIA of the DIGESTIVE SYSTEM.Fishes: A group of cold-blooded, aquatic vertebrates having gills, fins, a cartilaginous or bony endoskeleton, and elongated bodies covered with scales.Trout: Various fish of the family SALMONIDAE, usually smaller than salmon. They are mostly restricted to cool clear freshwater. Some are anadromous. They are highly regarded for their handsome colors, rich well-flavored flesh, and gameness as an angling fish. The genera Salvelinus, Salmo, and ONCORHYNCHUS have been introduced virtually throughout the world.Bacterial Proteins: Proteins found in any species of bacterium.Virulence: The degree of pathogenicity within a group or species of microorganisms or viruses as indicated by case fatality rates and/or the ability of the organism to invade the tissues of the host. The pathogenic capacity of an organism is determined by its VIRULENCE FACTORS.Bacterial Infections: Infections by bacteria, general or unspecified.Enterotoxins: Substances that are toxic to the intestinal tract causing vomiting, diarrhea, etc.; most common enterotoxins are produced by bacteria.Salmonidae: A family of anadromous fish comprising SALMON; TROUT; whitefish; and graylings. They are the most important food and game fishes. Their habitat is the northern Atlantic and Pacific, both marine and inland, and the Great Lakes. (Nelson: Fishes of the World, 1976, p97)Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Aquaculture: Cultivation of natural faunal resources of water. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Drainage, Sanitary: A system of artificial or natural drains, generally used for the disposal of liquid wastes.