Chryseobacterium

''Chryseobacterium'' is a genus of Gram-negative bacteria. ''Chryseobacterium'' species are chemoorganotrophic, rod shape gram-negative bacteria. ''Chryseobacterium'' form typical yellow-orange color colonies due to flexirubin-type pigment. The genus contains more than 100 described species from diverse habitats, including freshwater sources, soil, marine fish, and human hosts.

History

The genus ''Chryseobacterium'' was originally created in 1994 by Vandamme ''et al''. for six bacterial taxa that, at that time, were classified as members of the genus '' Flavobacterium'': ''F. balustinum'', ''F. indologenes'', ''F. gleum'', ''F. meningosepticum'', ''F. indoltheticum'', and ''F. scophthalmum''. In 2005 an additional genus, ''Elizabethkingia'', was created for two species within the genus ''Chryseobacterium''; namely, ''C. meningosepticum'' and ''C. miricola.'' In 2002 standards and guidelines for description of novel taxa in the family of ''Flavobacteriaceae'' were published by Bernardet ''et al.'' By 2006, the genus ''Chryseobacterium'' had expanded to 10 species, by 2014 more than 60 species and currently more than 100.

Ecology

''Chryseobacterium'' spp. were recovered from soils, plant roots, flowers, decaying plant material and maple sap. Some plant-associated ''Chryseobacterium'' strains are able to inhibit plant pathogenic fungi. ''Chryseobacterium'' spp. were also recovered from freshwater creeks, lakes, their sediments, water cooling systems, drinking water, lactic acid beverages, beer bottling plants, bioreactor sludge, polluted soil, marine sediment and permafrost. ''Chryseobacterium'' spp. are associated with a multitude of animals - they have been detected in the midgut of mosquitos, within cockroach guts, millipede feces, and penguin guano, gut homogenates of freshwater copepods, bird feathers, cow's milk, raw meats and chicken. ''Chryseobacterium'' spp. were recovered from the mucus of apparently healthy fish, however sometimes they are considered as a spoilage organism. Three novel cold-tolerant species of ''Chryseobacterium'', ''C. oranimense'' ''C. haifense'', and ''C. bovis'', have been detected in raw milk in Israel.
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Pathogenesis

The most pathogenic Flavobacterium spp., ''Chryseobacterium meningosepticum'', which caused numerous infections, was reclassified to the genus ''Elizabethkingia.'' ''Chryseobacterium indologenes'' although ubiquitous in nature, mainly found in soil and water, is an uncommon human pathogen. However, in rare cases it can cause serious infections, particularly among the immunocompromised. Most of the time infections are hospital acquired, often associated with immunosuppression or indwelling catheters. It has been reported as the causative agent in bacteremia, peritonitis, pneumonia, empyema, pyelonephritis, cystitis, meningitis and central venous catheter-associated infections. The numbers of reported ''C. indologenes'' infections are increasing. The majority of reported infections have been from Taiwan and only about 10% have been outside of Asia. A few reports have come from Australia, India, Europe and the USA. ''C. indologenes'' is also pathogenic to the soft tick, whereas other ''Chryseobacterium'' spp. were recovered from diseased turtles, frogs and fish, in particularly ''C. scophthalmum, C. joostei, C. piscicola, C. chaponense, C. viscerum and C. oncorhynchi, C. aahli, C. hominis, C. shigense'' as well as ''C. indologenes'' which is associated with human diseases.

Certain ''Chryseobacterium'' species were reported as having unusual matrix digesting properties, being able to degrade most difficult collagenous matrices, such as feathers or exoskeletons. These properties are likely mediated through the action of specific chitinases and collagenase-like metalloproteases. Some of the species, such as ''Chryseobacterium nematophagum'' were shown to be able to infect, kill and ultimately consume all nematode tissues, including the normally highly insoluble cuticular exoskeleton. Chitinase, geleatinase and collagenase metalloprotease activities have been linked to ''Chryseobacterium'' gliding motility exerted through type IX secretion systems. Indeed, some of these enzymes possess C-terminal type IX secretion signals. ''Chryseobacterium'' themselves have neither collagen nor chitin proteins or structures. ''Chryseobacterium'' species belong to the ''Bacteriodetes'' phylum, members of which are being increasingly describes as having unusually linked motility and secretory system.

Botulinum neurotoxin-like (BoNT-like) toxins were detected in the genome of ''Chryseobacterium piperi'' str. CTM and they present a highly divergent group of BoNT-like toxins. One of the predicted ''C. piperi'' BoNT-like toxins induced necrotic cell death in human kidney cells, but was not found to cleave common SNARE substrates of BoNTs.

Antibiotic resistance

''Chryseobacterium spp.'' are inherently resistant to a wide spectrum of antibiotics, including tetracyclines, erythromycin, linezolid, polymyxins, aminoglycosides, chloramphenicol, and many beta-lactams, while also being intermediately sensitive to vancomycin and clindamycin and vary in their sensitivity to trimethoprim-sulfamethoxazole''.''

Species

Species include:

See also

*Bacteroidota
*Flavobacteriaceae

References

{{Taxonbar, from=Q5114574

Flavobacteria
Bacteria genera