Viable but nonculturable (VBNC)

bacteria 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 am ...

refers as to bacteria that are in a state of very low metabolic activity and do not divide, but are alive and have the ability to become culturable once resuscitated. Bacteria in a VBNC state cannot grow on standard growth media, though

flow cytometry Flow cytometry (FC) is a technique used to detect and measure physical and chemical characteristics of a population of cells or particles. In this process, a sample containing cells or particles is suspended in a fluid and injected into the flow ...

can measure the viability of the bacteria. Bacteria can enter the VBNC state as a response to

stress Stress may refer to: Science and medicine * Stress (biology), an organism's response to a stressor such as an environmental condition * Stress (linguistics), relative emphasis or prominence given to a syllable in a word, or to a word in a phrase ...

, due to adverse

nutrient A nutrient is a substance used by an organism to survive, grow, and reproduce. The requirement for dietary nutrient intake applies to animals, plants, fungi, and protists. Nutrients can be incorporated into cells for metabolic purposes or excre ...

temperature Temperature is a physical quantity that expresses quantitatively the perceptions of hotness and coldness. Temperature is measured with a thermometer. Thermometers are calibrated in various temperature scales that historically have relied o ...

osmotic Osmosis (, ) is the spontaneous net movement or diffusion of solvent molecules through a selectively-permeable membrane from a region of high water potential (region of lower solute concentration) to a region of low water potential (region ...

oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements ...

, and

light Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 t ...

conditions. The cells that are in the VBNC state are morphologically smaller, and demonstrate reduced nutrient transport, rate of respiration, and synthesis of macromolecules. Sometimes, VBNC bacteria can remain in that state for over a year. It has been shown that numerous pathogens and non-pathogens can enter the VBNC state, and therefore it has significant implications in

pathogenesis Pathogenesis is the process by which a disease or disorder develops. It can include factors which contribute not only to the onset of the disease or disorder, but also to its progression and maintenance. The word comes from Greek πάθος ''pat ...

bioremediation Bioremediation broadly refers to any process wherein a biological system (typically bacteria, microalgae, fungi, and plants), living or dead, is employed for removing environmental pollutants from air, water, soil, flue gasses, industrial effluent ...

, and other branches of

microbiology Microbiology () is the scientific study of microorganisms, those being unicellular (single cell), multicellular (cell colony), or acellular (lacking cells). Microbiology encompasses numerous sub-disciplines including virology, bacteriology, ...

. The existence of the VBNC state is controversial. The validity and interpretation of the assays to determine the VBNC state have been questioned.

VBNC pathogens

Species known to enter a VBNC state: *'' E.M.S'' *'' Aeromonas salmonicida'' *''

Agrobacterium tumefaciens ''Agrobacterium radiobacter'' (more commonly known as ''Agrobacterium tumefaciens'') is the causal agent of crown gall disease (the formation of tumours) in over 140 species of eudicots. It is a rod-shaped, Gram-negative soil bacterium. Symptom ...

'' *''

Burkholderia cepacia ''Burkholderia cepacia'' complex (BCC), or simply ''Burkholderia cepacia'', is a group of catalase-producing, lactose-nonfermenting, Gram-negative bacteria composed of at least 20 different species, including ''B. cepacia'', '' B. m ...

'' *''

Burkholderia pseudomallei ''Burkholderia pseudomallei'' (also known as ''Pseudomonas pseudomallei'') is a Gram-negative, bipolar, aerobic, motile rod-shaped bacterium. It is a soil-dwelling bacterium endemic in tropical and subtropical regions worldwide, particularly in T ...

'' *''

Brettanomyces bruxellensis ''Brettanomyces bruxellensis'' (the anamorph of ''Dekkera bruxellensis'') is a yeast associated with the Zenne, Senne valley near Brussels, Belgium. Despite its Latin species name, ''B. bruxellensis'' is found all over the globe. In the wild, it ...

'' *''

Campylobacter coli ''Campylobacter coli'' is a Gram-negative, microaerophilic, non-endospore-forming, S-shaped bacterial species within genus ''Campylobacter''. In humans, it ''C. coli'' can cause campylobacteriosis, a diarrhoeal disease which is the most freque ...

'' *'' Campylobacter jejuni'' *'' Campylobacter lari'' *'' Cytophaga allerginae'' *'' Enterobacter aerogenes'' *''

Enterobacter cloacae ''Enterobacter cloacae'' is a clinically significant Gram-negative, facultatively-anaerobic, rod-shaped bacterium. Microbiology In microbiology labs, ''E. cloacae'' is frequently grown at 30 °C on nutrient agar or at 35 °C in tr ...

'' *'' Enterococcus faecalis'' *'' Enterococcus hirae'' *''

Enterococcus faecium ''Enterococcus faecium'' is a Gram-positive, gamma-hemolytic or non- hemolytic bacterium in the genus '' Enterococcus''. It can be commensal (innocuous, coexisting organism) in the gastrointestinal tract of humans and animals, but it may also ...

'' *'' Erwinia amylovora'' *''

Escherichia coli ''Escherichia coli'' (),Wells, J. C. (2000) Longman Pronunciation Dictionary. Harlow ngland Pearson Education Ltd. also known as ''E. coli'' (), is a Gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus '' Esc ...

'' (including EHEC) *''

Francisella tularensis ''Francisella tularensis'' is a pathogenic species of Gram-negative coccobacillus, an aerobic bacterium. It is nonspore-forming, nonmotile, and the causative agent of tularemia, the pneumonic form of which is often lethal without treatment. It ...

'' *''

Helicobacter pylori ''Helicobacter pylori'', previously known as ''Campylobacter pylori'', is a gram-negative, microaerophilic, spiral (helical) bacterium usually found in the stomach. Its helical shape (from which the genus name, helicobacter, derives) is thoug ...

'' *''

Klebsiella aerogenes ''Klebsiella aerogenes'', previously known as ''Enterobacter aerogenes,'' is a Gram-negative, oxidase negative, catalase positive, citrate positive, indole negative, rod-shaped bacterium. The bacterium is approximately 1-3 microns in length, a ...

'' *''

Klebsiella pneumoniae ''Klebsiella pneumoniae'' is a Gram-negative, non-motile, encapsulated, lactose- fermenting, facultative anaerobic, rod-shaped bacterium. It appears as a mucoid lactose fermenter on MacConkey agar. Although found in the normal flora of the mo ...

'' *'' Klebsiella planticola'' *''

Legionella pneumophila ''Legionella pneumophila'' is a thin, aerobic, pleomorphic, flagellated, non-spore-forming, Gram-negative bacterium of the genus '' Legionella''. ''L. pneumophila'' is the primary human pathogenic bacterium in this group and is the causative ...

'' *''

Listeria monocytogenes ''Listeria monocytogenes'' is the species of pathogenic bacteria that causes the infection listeriosis. It is a facultative anaerobic bacterium, capable of surviving in the presence or absence of oxygen. It can grow and reproduce inside the host ...

'' *'' Micrococcus luteus'' *''

Mycobacterium tuberculosis ''Mycobacterium tuberculosis'' (M. tb) is a species of pathogenic bacteria in the family Mycobacteriaceae and the causative agent of tuberculosis. First discovered in 1882 by Robert Koch, ''M. tuberculosis'' has an unusual, waxy coating on it ...

'' *'' Mycobacterium smegmatis'' *'' Pasteurella piscicida'' *''

Pseudomonas aeruginosa ''Pseudomonas aeruginosa'' is a common encapsulated, gram-negative, aerobic– facultatively anaerobic, rod-shaped bacterium that can cause disease in plants and animals, including humans. A species of considerable medical importance, ''P. a ...

'' *''

Pseudomonas syringae ''Pseudomonas syringae'' is a rod-shaped, Gram-negative bacterium with polar flagella. As a plant pathogen, it can infect a wide range of species, and exists as over 50 different pathovars, all of which are available to researchers from inte ...

'' *'' Pseudomonas putida KT2440'' *''

Ralstonia solanacearum ''Ralstonia solanacearum'' is an aerobic non-spore-forming, Gram-negative, plant pathogenic bacterium. ''R. solanacearum'' is soil-borne and motile with a polar flagellar tuft. It colonises the xylem, causing bacterial wilt in a very wide range ...

'' *'' Rhizobium leguminosarum'' *''

Rhizobium meliloti ''Ensifer meliloti'' (formerly ''Rhizobium meliloti'' and ''Sinorhizobium meliloti'') are an aerobic, Gram-negative, and diazotrophic species of bacteria. ''S. meliloti'' are motile and possess a cluster of peritrichous flagella. ''S. meliloti'' ...

'' *''

Salmonella enterica ''Salmonella enterica'' (formerly ''Salmonella choleraesuis'') is a rod-headed, flagellate, facultative anaerobic, Gram-negative bacterium and a species of the genus ''Salmonella''. A number of its serovars are serious human pathogens. Epidemi ...

'' *''

Salmonella Typhi ''Salmonella enterica'' subsp. ''enterica'' is a subspecies of '' Salmonella enterica'', the rod-shaped, flagellated, aerobic, Gram-negative bacterium. Many of the pathogenic serovars of the ''S. enterica'' species are in this subspecies, includi ...

'' *''

Salmonella Typhimurium ''Salmonella enterica'' subsp. ''enterica'' is a subspecies of ''Salmonella enterica'', the rod-shaped, flagellated, aerobic, Gram-negative bacterium. Many of the pathogenic serovars of the ''S. enterica'' species are in this subspecies, includin ...

'' *''

Serratia marcescens ''Serratia marcescens'' () is a species of rod-shaped, Gram-negative bacteria in the family Yersiniaceae. It is a facultative anaerobe and an opportunistic pathogen in humans. It was discovered in 1819 by Bartolomeo Bizio in Padua, Italy.Serr ...

'' *''

Shigella dysenteriae ''Shigella dysenteriae'' is a species of the rod-shaped bacterial genus ''Shigella''. ''Shigella'' species can cause shigellosis ( bacillary dysentery). Shigellae are Gram-negative, non-spore-forming, facultatively anaerobic, nonmotile bacte ...

'' *''

Shigella flexneri ''Shigella flexneri'' is a species of Gram-negative bacteria in the genus ''Shigella'' that can cause diarrhea in humans. Several different serogroups of ''Shigella'' are described; ''S. flexneri'' belongs to group ''B''. ''S. flexneri'' infec ...

'' *'' Shigella sonnei'' *''

Streptococcus faecalis ''Enterococcus faecalis'' – formerly classified as part of the group D '' Streptococcus'' system – is a Gram-positive, commensal bacterium inhabiting the gastrointestinal tracts of humans. Like other species in the genus '' Enterococcus'' ...

'' *'' Vibrio anguillarum'' *'' Vibrio campbellii'' *''

Vibrio cholerae ''Vibrio cholerae'' is a species of Gram-negative, facultative anaerobe and comma-shaped bacteria. The bacteria naturally live in brackish or saltwater where they attach themselves easily to the chitin-containing shells of crabs, shrimps, and oth ...

'' *'' Vibrio harveyi'' *'' Vibrio mimicus'' *'' Vibrio parahaemolyticus'' *'' Vibrio shiloi'' *'' Vibrio vulnificus'' (types 1 and 2) *'' Xanthomonas campestris'' *''

Xanthomonas axonopodis ''Xanthomonas'' (from greek: ''xanthos'' – “yellow”; ''monas'' – “entity”) is a genus of bacteria, many of which cause plant diseases. There are at least 27 plant associated ''Xanthomonas spp.'', that all together infect at least 400 ...

'' pv. citri *''

Yersinia pestis ''Yersinia pestis'' (''Y. pestis''; formerly '' Pasteurella pestis'') is a gram-negative, non-motile, coccobacillus bacterium without spores that is related to both ''Yersinia pseudotuberculosis'' and ''Yersinia enterocolitica''. It is a facult ...

References

Bacteria Bacteriology {{Molecular-cell-biology-stub