''Renibacterium salmoninarum'' is a member of the

Micrococcaceae The family ''Micrococcaceae'' includes bacterial genera of Gram positive cocci that inhabit the air and skin, such as ''Micrococcus luteus''. Genera The family ''Micrococcaceae'' comprises the following genera: * '' Acaricomes'' Pukall ''et al ...

family. It is a

Gram-positive In bacteriology, gram-positive bacteria are bacteria that give a positive result in the Gram stain test, which is traditionally used to quickly classify bacteria into two broad categories according to their type of cell wall. Gram-positive bacte ...

, intracellular

bacterium Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...

that causes disease in young

salmonid Salmonidae is a family of ray-finned fish that constitutes the only currently extant family in the order Salmoniformes . It includes salmon (both Atlantic and Pacific species), trout (both ocean-going and landlocked), chars, freshwater whitefis ...

fish. The infection is most commonly known as "

bacterial kidney disease Bacterial kidney disease (BKD, also known as white boil disease) is a systemic infection caused by the bacterium ''Renibacterium salmoninarum''. The disease affects populations of wild salmonid Salmonidae is a family of ray-finned fish that cons ...

" but may also be referred to as BKD, White Boil Disease, Dee Disease, Salmonid Kidney Disease and Corynebacterial Kidney Disease. It is of significant ecologic importance due to its effect on both farmed and wild

salmonids Salmonidae is a family of ray-finned fish that constitutes the only currently extant family in the order Salmoniformes . It includes salmon (both Atlantic and Pacific species), trout (both ocean-going and landlocked), chars, freshwater whitefi ...

. The disease is found in

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...

and

Scandinavia Scandinavia; Sámi languages: /. ( ) is a subregion#Europe, subregion in Northern Europe, with strong historical, cultural, and linguistic ties between its constituent peoples. In English usage, ''Scandinavia'' most commonly refers to Denmark, ...

, and is spread both vertically and horizontally.

Pacific salmon ''Oncorhynchus'' is a genus of fish in the family Salmonidae; it contains the Pacific salmon and Pacific trout. The name of the genus is derived from the Greek ὄγκος (ónkos, “lump, bend”) + ῥύγχος (rhúnkhos, “snout”), in r ...

appear to be the most susceptible to the disease.

Clinical signs

The severity of clinical signs is very variable. There may be no outward clinical signs, or fish may show signs of lethargy and

anaemia Anemia or anaemia (British English) is a blood disorder in which the blood has a reduced ability to carry oxygen due to a lower than normal number of red blood cells, or a reduction in the amount of hemoglobin. When anemia comes on slowly, th ...

. Haemorrhagic skin lesions and

exophthalmos Exophthalmos (also called exophthalmus, exophthalmia, proptosis, or exorbitism) is a bulging of the eye anteriorly out of the orbit. Exophthalmos can be either bilateral (as is often seen in Graves' disease) or unilateral (as is often seen in ...

may develop.''Renibacterium salmoninarum'', reviewed and published by Wikivet a
''Renibacterium salmoninarum''
accessed 19/09/2011. On

postmortem examination An autopsy (post-mortem examination, obduction, necropsy, or autopsia cadaverum) is a surgical procedure that consists of a thorough examination of a corpse by dissection to determine the cause, mode, and manner of death or to evaluate any di ...

there are normally signs of

necrosis Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. Necrosis is caused by factors external to the cell or tissue, such as infection, or trauma which result in the unregulated dige ...

and

granulomatous inflammation A granuloma is an aggregation of macrophages that forms in response to chronic inflammation. This occurs when the immune system attempts to isolate foreign substances that it is otherwise unable to eliminate. Such substances include infectious o ...

on the internal organs, especially the

kidney The kidneys are two reddish-brown bean-shaped organs found in vertebrates. They are located on the left and right in the retroperitoneal space, and in adult humans are about in length. They receive blood from the paired renal arteries; blood ...

. A diagnosis cannot be made based on clinical signs, instead laboratory tests such as specialised

bacterial culture A microbiological culture, or microbial culture, is a method of multiplying microbial organisms by letting them reproduce in predetermined culture medium under controlled laboratory conditions. Microbial cultures are foundational and basic diagn ...

ELISA The enzyme-linked immunosorbent assay (ELISA) (, ) is a commonly used analytical biochemistry assay, first described by Eva Engvall and Peter Perlmann in 1971. The assay uses a solid-phase type of enzyme immunoassay (EIA) to detect the presence ...

, PCR and fluorescent antibody testing are necessary to identify the bacteria. Ideally more than one test should be used to confirm diagnosis.

Treatment & control

Oral or injectable

antibiotics An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention o ...

should be used to treat the infection. Intraperitoneal vaccination can also be used to treat fish in an outbreak. Prevention is very important, and husbandry measures such as segregation, culling and decontamination should be used to ensure infection is not introduced.

References

External links

Type strain of ''Renibacterium salmoninarum'' at Bac''Dive'' - the Bacterial Diversity Metadatabase
{{Taxonbar, from=Q16989049 Bacterial diseases of fish Bacteria described in 1980 Micrococcaceae