Columnaris disease in fish: a review with emphasis on bacterium-host interactions

Abstract

Flavobacterium columnare (F. columnare) is the causative agent of columnaris disease. This bacterium affects both cultured and wild freshwater fish including many susceptible commercially important fish species. F. columnare infections may result in skin lesions, fin erosion and gill necrosis, with a high degree of mortality, leading to severe economic losses. Especially in the last decade, various research groups have performed studies aimed at elucidating the pathogenesis of columnaris disease, leading to significant progress in defining the complex interactions between the organism and its host. Despite these efforts, the pathogenesis of columnaris disease hitherto largely remains unclear, compromising the further development of efficient curative and preventive measures to combat this disease. Besides elaborating on the agent and the disease it causes, this review aims to summarize these pathogenesis data emphasizing the areas meriting further investigation.

Physiology and immunology of mucosal barriers in catfish (Ictalurus spp.)

“…143 Another area in need of study is to better understand how pathogenic bacteria of catfish, such as F. columnare, can persist on mucosal surfaces of healthy fish. 145,146 Interestingly, F. columnare has been shown to be easily outcompeted by other species of bacteria. 147 However, when fish develop columnaris disease, the mucosal surfaces become burdened with high loads of F. columnare which often leads to death.…”

Complete genome sequence analysis of the fish pathogen Flavobacterium columnare provides insights into antibiotic resistance and pathogenicity related genes

“…However, the genes involved in sugar kinase and phosphotransferase systems were not existed, which are usually used by bacteria for specific carbohydrate uptake. Actually, F. columnare is unable to use cellulose [32] or starch [3] directly as sources of carbon and energy, but instead by other pathways to acquire nutrients from their host for survival. The 6-phosphofructokinase 1 (Pf1_00390) and pyruvate kinase (Pf1_01219) are two important enzymes which can regulate the rate of reaction in glycolysis.…”

Broad thermal tolerance is negatively correlated with virulence in an opportunistic bacterial pathogen

“…Specifically, this bacterium can cause infections both in cold‐ and in warm‐water fish species such as carp, channel catfish, goldfish, eel, perch, tilapia, pike perch, rainbow trout, brown trout, salmon, tiger muskellunge and walleye (Anderson & Conroy, 1969; Schneck & Caslake, 2006; Shoemaker, Klesius, Lim, & Yildirim, 2003). F. columnare causes epidermal infections affecting gills, skin and fins of the fish, producing either acute or chronic infections, depending on the virulence and genetic group of the strain, as well as on environmental and host‐related factors (Declercq et al., 2013). The temperature range in which it can grow actively is approximately 15 to 35°C (Declercq et al., 2013).…”

“…F. columnare causes epidermal infections affecting gills, skin and fins of the fish, producing either acute or chronic infections, depending on the virulence and genetic group of the strain, as well as on environmental and host‐related factors (Declercq et al., 2013). The temperature range in which it can grow actively is approximately 15 to 35°C (Declercq et al., 2013). Previous work on this bacterium and a number of other virulent pathogens in the context of global warming has focused mainly on long‐term empirical data examining the relationship between mean ambient temperature and disease prevalence (Karvonen, Rintamäki, Jokela, & Valtonen, 2010; Pulkkinen et al., 2010).…”