Bacillus cereus is a Gram-positive rod-shaped bacterium commonly found in soil, food, and marine sponges. The specific name, cereus, meaning "waxy" in Latin, refers to the appearance of colonies grown on blood agar. Some strains are harmful to humans and cause foodborne illness due to their spore-forming nature, while other strains can be beneficial as probiotics for animals, and even exhibit mutualism with certain plants. B. cereus bacteria may be aerobes or facultative anaerobes, and like other members of the genus Bacillus, can produce protective endospores. They have a wide range of virulence factors, including phospholipase C, cereulide, sphingomyelinase, metalloproteases, and cytotoxin K, many of which are regulated via quorum sensing. B. cereus strains exhibit flagellar motility.
Ichthyophthirius multifiliis, often termed "Ich", is a parasitic ciliate described by the French parasitologist Fouquet in 1876. Only one species is found in the genus which also gave name to the family. The name literally translates as "the fish louse with many children". The parasite can infect most freshwater fish species and, in contrast to many other parasites, shows low host specificity. It penetrates gill epithelia, skin and fins of the fish host and resides as a feeding stage inside the epidermis. It is visible as a white spot on the surface of the fish but, due to its internal microhabitat, it is a true endoparasite and not an ectoparasite.
Aeromonas hydrophila is a heterotrophic, Gram-negative, rod-shaped bacterium mainly found in areas with a warm climate. This bacterium can be found in fresh or brackish water. It can survive in aerobic and anaerobic environments, and can digest materials such as gelatin and hemoglobin. A. hydrophila was isolated from humans and animals in the 1950s. It is the best known of the species of Aeromonas. It is resistant to most common antibiotics and cold temperatures and is oxidase- and indole-positive. Aeromonas hydrophila also has a symbiotic relationship as gut flora inside of certain leeches, such as Hirudo medicinalis.
Elizabethkingia meningoseptica is a Gram-negative, rod-shaped bacterium widely distributed in nature. It may be normally present in fish and frogs; it may be isolated from chronic infectious states, as in the sputum of cystic fibrosis patients. In 1959, American bacteriologist Elizabeth O. King was studying unclassified bacteria associated with pediatric meningitis at the Centers for Disease Control and Prevention in Atlanta, when she isolated an organism that she named Flavobacterium meningosepticum. In 1994, it was reclassified in the genus Chryseobacterium and renamed Chryseobacterium meningosepticum(chryseos = "golden" in Greek, so Chryseobacterium means a golden/yellow rod similar to Flavobacterium). In 2005, a 16S rRNA phylogenetic tree of Chryseobacteria showed that C. meningosepticum along with C. miricola were close to each other but outside the tree of the rest of the Chryseobacteria and were then placed in a new genus Elizabethkingia named after the original discoverer of F. meningosepticum.
Florfenicol is a fluorinated synthetic analog of thiamphenicol, mainly used as a antibiotic in veterinary medicine.
The class Flavobacteriia is composed of a single class of environmental bacteria. It contains the family Flavobacteriaceae, which is the largest family in the phylum Bacteroidota. This class is widely distributed in soil, fresh, and seawater habitats. The name is often spelt Flavobacteria, but was officially named Flavobacteriia in 2012.
Columnaris (also referred to as cottonmouth and saddle-back disease) is a disease in fish which results from an infection caused by the Gram-negative, aerobic, rod-shaped bacterium Flavobacterium columnare. It was previously known as Bacillus columnaris, Chondrococcus columnaris, Cytophaga columnaris and Flexibacter columnaris. The bacteria are ubiquitous in fresh water, and cultured fish reared in ponds or raceways are the primary concern – with disease most prevalent in air temperatures above 12–14 °C. Due to the appearance of bacterial clumps, it can be mistaken for a fungal infection. The disease is highly contagious, and the outcome is commonly fatal. It is not zoonotic.
Fibrobacter succinogenes is a cellulolytic bacterium species in the genus Fibrobacter. It is present in the rumen of cattle. F. succinogenes is a gram negative, rod-shaped, obligate anaerobe that is a major contributor to cellulose digestion. Since its discovery in the 1950s, it has been studied for its role in herbivore digestion and cellulose fermentation, which can be utilized in biofuel production.
Aeromonas salmonicida is a pathogenic bacterium that severely impacts salmonid populations and other species. It was first discovered in a Bavarian brown trout hatchery by Emmerich and Weibel in 1894. Aeromonas salmonicida's ability to infect a variety of hosts, multiply, and adapt, make it a prime virulent bacterium. A. salmonicida is an etiological agent for furunculosis, a disease that causes sepsis, haemorrhages, muscle lesions, inflammation of the lower intestine, spleen enlargement, and death in freshwater fish populations. It is found worldwide with the exception of South America. The major route of contamination is poor water quality; however, it can also be associated stress factors such as overcrowding, high temperatures, and trauma. Spawning and smolting fish are prime victims of furunculosis due to their immunocompromised state of being.
Streptococcus iniae is a species of Gram-positive, sphere-shaped bacterium belonging to the genus Streptococcus. Since its isolation from an Amazon freshwater dolphin in the 1970s, S. iniae has emerged as a leading fish pathogen in aquaculture operations worldwide, resulting in over US$100M in annual losses. Since its discovery, S. iniae infections have been reported in at least 27 species of cultured or wild fish from around the world. Freshwater and saltwater fish including tilapia, red drum, hybrid striped bass, and rainbow trout are among those susceptible to infection by S. iniae. Infections in fish manifest as meningoencephalitis, skin lesions, and septicemia.
Cytophaga is a genus of Gram-negative, gliding, rod-shaped bacteria. This bacterium is commonly found in soil, rapidly digests crystalline cellulose C. hutchinsonii is able to use its gliding motility to move quickly over surfaces. Although the mechanism for this is not known, there is a belief that the flagellum is not used
Halomonas titanicae is a gram-negative, halophilic species of bacteria which was isolated in 2010 from rusticles recovered from the wreck of the RMS Titanic. It has been estimated by Henrietta Mann, one of the researchers that first isolated it, that the action of microbes like H. titanicae may bring about the total deterioration of the Titanic by 2030. While the bacteria have been identified as a potential danger to oil rigs and other man-made objects in the deep sea, they also have the potential to be used in bioremediation to accelerate the decomposition of shipwrecks littering the ocean floor.
Bacterial cold water disease (BCWD) is a bacterial disease of freshwater fish, specifically salmonid fish. It is caused by the bacterium Flavobacterium psychrophilum, a psychrophilic, gram-negative rod-shaped bacterium of the family Flavobacteriaceae. This bacterium is found in fresh waters with the optimal growth temperature below 13 °C, and it can be seen in any area with water temperatures consistently below 15 °C. Salmon are the most commonly affected species. This disease is not zoonotic.
Vibrio anguillarum is a species of prokaryote that belongs to the family Vibrionaceae, genus Vibrio. V. anguillarum is typically 0.5 - 1 μm in diameter and 1 - 3 μm in length. It is a gram-negative, comma-shaped rod bacterium that is commonly found in seawater and brackish waters. It is polarly flagellated, non-spore-forming, halophilic, and facultatively anaerobic. V. anguillarum has the ability to form biofilms. V. anguillarum is pathogenic to various fish species, crustaceans, and mollusks.
Flavobacterium psychrophilum is a psychrophilic, gram-negative bacterial rod, belonging to the Bacteroidota. It is the causative agent of bacterial coldwater disease (BCWD) and was first isolated in 1948 during a die-off in the salmonid Oncorhynchus kisutch.
Tenacibaculum is a gram-negative and motile bacterial genus from the family of Flavobacteriaceae.
Flavobacterium branchiarum is a bacterium from the genus of Flavobacterium which can cause bacterial gill disease in rainbow trouts.
Flavobacterium branchiicola is a bacterium from the genus of Flavobacterium.
Flavobacterium collinsii is a bacterium from the genus of Flavobacterium.
Cetobacterium somerae is a microaerotolerant, Gram-negative, and rod-shaped anaerobic bacteria found in the gastrointestinal tract of fish living in freshwater ecosystems. The bacteria is also immobile and non-spore forming. C. somerae was first isolated from the feces of children with Autism spectrum disorder. Members of bacteria within the Cetobacterium genus tend to dominate the microbiota of fish in freshwater ecosystems. Cetobacterium somerae also produces vitamin B-12 within the gastrointestinal tract of fish in order to provide nutritional support for growth.
