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Rita R. Colwell - One of the best experts on this subject based on the ideXlab platform.
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Conversion of Viable but Nonculturable enteric bacteria to culturable by co‐culture with eukaryotic cells
Microbiology and immunology, 2012Co-Authors: Mitsutoshi Senoh, Rita R. Colwell, Jayeeta Ghosh-banerjee, Thandavarayan Ramamurthy, Shin-ichi Miyoshi, G. Balakrish Nair, Yoshifumi TakedaAbstract:Viable but Nonculturable (VBNC) Vibrio cholerae non-O1/non-O139, V. parahaemolyticus, enterohemorrhagic Escherichia coli, enterotoxigenic E. coli, enteropathogenic E. coli, Shigella flexneri, and Salmonella enterica were converted to the culturable state by co-culture with selected eukaryotic cells, e.g., HT-29, Caco-2, T84, HeLa, Intestine 407, and CHO cells.
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Recovery in culture of Viable but Nonculturable Vibrio parahaemolyticus : regrowth or resuscitation?
The ISME journal, 2007Co-Authors: François Coutard, Rita R. Colwell, Monique Pommepuy, Philippe Crassous, Mickaël Droguet, Eric Gobin, Dominique Hervio-heathAbstract:The objective of this study was to explore the recovery of culturability of Viable but Nonculturable (VBNC) Vibrio parahaemolyticus after temperature upshift and to determine whether regrowth or resuscitation occurred. A clinical strain of V. parahaemolyticus Vp5 was rendered VBNC by exposure to artificial seawater (ASW) at 4°C. Aliquots of the ASW suspension of cells (0.1, 1 and 10 ml) were subjected to increased temperatures of 20°C and 37°C. Culturability of the cells in the aliquots was monitored for colony formation on a rich medium and changes in morphology were measured by scanning (SEM) and transmission (TEM) electron microscopy. Samples of VBNC cells were fixed and examined by SEM, revealing a heterogeneous population comprising small cells and larger, flattened cells. Forty-eight hours after temperature upshift to 20°C or 37°C, both elongation and division by binary fission of the cells were observed, employing SEM and TEM, but only in the 10-ml aliquots. The results suggest that a portion of VBNC cells is able to undergo cell division. It is concluded that a portion of VBNC cells of V. parahaemolyticus subjected to cold temperatures remain Viable. After temperature upshift, regrowth of those cells, rather than resuscitation of all bacteria of the initial inoculum, appears to be responsible for recovery of culturability of VBNC cells of V. parahaemolyticus. Nutrient in filtrates of VBNC cells is hypothesized to allow growth of the temperature-responsive cells, with cell division occurring via binary fission, but also including an atypical, asymmetric cell division.
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Virulence of Viable but Nonculturable S. Typhimurium LT2 after peracetic acid treatment
International journal of food microbiology, 2006Co-Authors: Anne Jolivet-gougeon, Rita R. Colwell, F. Sauvager, Martine Bonnaure-mallet, Michel CormierAbstract:S. Typhimurium LT2 cells suspended in sterilized sewage effluent water (SEW) and in distilled water microcosms were exposed to 0, 7, 15 and 20 mg/l peracetic acid, and tested for viability and virulence. After treatment for one hour, colony forming units decreased by at least 5 log units at peracetic acid concentration of 7 mg/l. In SEW, at peracetic acid concentration of 15 mg/l, the cells were Nonculturable (VNC), but retained virulence as demonstrated by invasion assays of HeLa cells. Higher concentrations (greater than or equal to 20 mg/l) resulted in bacterial death, i.e. substrate non-responsive cells. Despite morphological alterations of the bacteria after peracetic acid treatment, visualized by transmission electronic microscopy, conservation of both adhesive and invasive capacities was confirmed by scanning electron microscopy after exposure to 0-15 mg/l peracetic acid. Public health professionals need to recognize that peracetic acid-treated Salmonella is capable of modifying its physiological characteristics, including entering and recovering from the Viable but Nonculturable state, and may remain virulent after a stay in SEW followed by peracetic acid treatment.
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In vitro adhesion to human cells by Viable but Nonculturable Enterococcus faecalis.
Current microbiology, 2002Co-Authors: Carla Pruzzo, Maria Del Mar Lleò, Caterina Signoretto, Rita R. Colwell, Renato Tarsi, Massimiliano Zampini, Pietro CanepariAbstract:The ability of Viable but Nonculturable (VBNC) Enterococcus faecalis to adhere to Caco-2 and Girardi heart cultured cells and to urinary tract epithelial cells (ECs) was studied. Enterococci were harvested during the vegetative growth phase (early exponential and stationary), in the VBNC state, and after recovery of the ability to divide. VBNC bacteria maintained their adherence capability but the efficiency of attachment was reduced by about 50 to 70%, depending on the target cell employed. The decrease was transient, since enterococci that regained their culturability showed adherence values similar to those observed for actively growing cells. Analysis of the invasive properties of E. faecalis revealed that the VBNC state caused a decrease in the number of bacteria that entered the cultured HEK cells as a result of the reduction in the number of adhering bacteria. These results highlight the importance of studies of the VBNC phenomenon, with respect to both microbial survival in the environment and the impact on human health.
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Entry of Vibrio harveyi and Vibrio fischeri into the Viable but Nonculturable state.
Journal of applied microbiology, 2002Co-Authors: Neelam Ramaiah, Russell T. Hill, Jacques Ravel, William L. Straube, Rita R. ColwellAbstract:AIMS Physiological responses of marine luminous bacteria, Vibrio harveyi (ATCC 14216) and V. fischeri (UM1373) to nutrient-limited normal strength (35 ppt iso-osmolarity) and low (10 ppt hypo-osmolarity) salinity conditions were determined. METHODS AND RESULTS Plate counts, direct Viable counts, actively respiring cell counts, nucleoid-containing cell counts, and total counts were determined. Vibrio harveyi incubated at 22 degrees C in nutrient-limited artificial seawater (ASW) became Nonculturable after approximately 62 and 45 d in microcosms of 35 ppt and 10 ppt ASW, respectively. In contrast, V. fischeri became Nonculturable at approximately 55 and 31 d in similar microcosms. Recovery of both culturability and luminescence of cells in the Viable but Nonculturable state was achieved by addition of nutrient broth or nutrient broth supplemented with a carbon source, including luminescence-stimulating compounds. Temperature upshift from 22 degrees C to 30 degrees C or 37 degrees C did not result in recovery from nonculturability. CONCLUSIONS The study confirms entry of V. harveyi and V. fischeri into the Viable but Nonculturable state under low-nutrient conditions and demonstrates nutrient-dependent resuscitation from this state. SIGNIFICANCE AND IMPACT OF THE STUDY This study confirms loss of luminescence of V. harveyi and V. fischeri on entry into the Viable but Nonculturable state and suggests that enumeration of luminescent cells in water samples may be a rapid method to deduce the nutrient status of a water sample.
James D Oliver - One of the best experts on this subject based on the ideXlab platform.
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Relationship between the Viable but Nonculturable State and Antibiotic Persister Cells.
Journal of bacteriology, 2018Co-Authors: Mesrop Ayrapetyan, Tiffany C. Williams, James D OliverAbstract:Bacteria have evolved numerous means of survival in adverse environments with dormancy, as represented by "persistence" and the "Viable but Nonculturable" (VBNC) state, now recognized to be common modes for such survival. VBNC cells have been defined as cells which, induced by some stress, become Nonculturable on media that would normally support their growth but which can be demonstrated by various methods to be alive and capable of returning to a metabolically active and culturable state. Persister cells have been described as a population of cells which, while not being antibiotic resistant, are antibiotic tolerant. This drug-tolerant phenotype is thought to be a result of stress-induced and stochastic physiological changes as opposed to mutational events leading to true resistance. In this review, we describe these two dormancy strategies, characterize the molecular underpinnings of each state, and highlight the similarities and differences between them. We believe these survival modes represent a continuum between actively growing and dead cells, with VBNC cells being in a deeper state of dormancy than persister cells.
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Interspecific Quorum Sensing Mediates the Resuscitation of Viable but Nonculturable Vibrios
Applied and environmental microbiology, 2014Co-Authors: Mesrop Ayrapetyan, Tiffany C. Williams, James D OliverAbstract:Entry and exit from dormancy are essential survival mechanisms utilized by microorganisms to cope with harsh environments. Many bacteria, including the opportunistic human pathogen Vibrio vulnificus, enter a form of dormancy known as the Viable but Nonculturable (VBNC) state. VBNC cells can resuscitate when suitable conditions arise, yet the molecular mechanisms facilitating resuscitation in most bacteria are not well understood. We discovered that bacterial cell-free supernatants (CFS) can awaken preexisting dormant vibrio populations within oysters and seawater, while CFS from a quorum sensing mutant was unable to produce the same resuscitative effect. Furthermore, the quorum sensing autoinducer AI-2 could induce resuscitation of VBNC V. vulnificus in vitro, and VBNC cells of a mutant unable to produce AI-2 were unable to resuscitate unless the cultures were supplemented with exogenous AI-2. The quorum sensing inhibitor cinnamaldehyde delayed the resuscitation of wild-type VBNC cells, confirming the importance of quorum sensing in resuscitation. By monitoring AI-2 production by VBNC cultures over time, we found quorum sensing signaling to be critical for the natural resuscitation process. This study provides new insights into the molecular mechanisms stimulating VBNC cell exit from dormancy, which has significant implications for microbial ecology and public health.
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resistance to environmental stresses by vibrio vulnificus in the Viable but Nonculturable state
FEMS Microbiology Ecology, 2013Co-Authors: Joanna Nowakowska, James D OliverAbstract:Vibrio vulnificus is responsible for 95% of all seafood-associated fatalities in the United States. When water temperatures drop below c . 13 °C, the cells enter into the Viable but Nonculturable (VBNC) state wherein they are unable to grow on routine media but retain viability and the ability to return to the culturable state. The aim of this study was to determine whether V. vulnificus cells in the VBNC state are protected against a variety of potentially lethal challenges (heat, oxidative, osmotic, pH, ethanol, antibiotic and heavy metal) and to examine genetic regulators that might underlie such protection. The data presented here indicate that VBNC cells of this pathogen are protected against a wide variety of stresses and retain the ability to return to the culturable state. Surprisingly, we found no significant difference in the expression of relA and spoT between VBNC and logarithmic cells, nor any significant difference in the expression of rpoS in the case of the clinical (C) genotype of this pathogen. However, expression of relA was significantly different in VBNC cells of the environmental (E) genotype compared with logarithmic cells. This might account for findings indicating an enhanced ability for E-genotype cells to withstand environmental changes better than C-genotype cells.
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Survival of spinach-associated Helicobacter pylori in the Viable but Nonculturable state
Food Control, 2010Co-Authors: Alan Buck, James D OliverAbstract:The environmental reservoir and mode of transmission of Helicobacter pylori is currently unknown due to difficulties in isolating H. pylori from non-human sources. The purpose of this study was to determine the ability of H. pylori to survive in a Viable but Nonculturable (VBNC) state when in association with spinach. H. pylori cells rapidly became non-detectable by plating, however mRNA transcripts were detected 6 days after the cells were introduced to the spinach. It was found that exposure to white light rapidly induced the VBNC state in H. pylori, suggesting sunlight may be a factor in loss of culturability of this pathogen. Our study indicates that spinach-associated H. pylori cells can remain Viable and virulent despite their lack of culturability, which may help explain the lack of culturability from environmental sources.
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Recent findings on the Viable but Nonculturable state in pathogenic bacteria.
FEMS microbiology reviews, 2009Co-Authors: James D OliverAbstract:Many bacteria, including a variety of important human pathogens, are known to respond to various environmental stresses by entry into a novel physiological state, where the cells remain Viable, but are no longer culturable on standard laboratory media. On resuscitation from this ‘Viable but Nonculturable’ (VBNC) state, the cells regain culturability and the renewed ability to cause infection. It is likely that the VBNC state is a survival strategy, although several interesting alternative explanations have been suggested. This review describes the VBNC state, the various chemical and physical factors known to induce cells into this state, the cellular traits and gene expression exhibited by VBNC cells, their antibiotic resistance, retention of virulence and ability to attach and persist in the environment, and factors that have been found to allow resuscitation of VBNC cells. Along with simple reversal of the inducing stresses, a variety of interesting chemical and biological factors have been shown to allow resuscitation, including extracellular resuscitation-promoting proteins, a novel quorum-sensing system (AI-3) and interactions with amoeba. Finally, the central role of catalase in the VBNC response of some bacteria, including its genetic regulation, is described.
Ishrat Rahman - One of the best experts on this subject based on the ideXlab platform.
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potential virulence of Viable but Nonculturable shigella dysenteriae type 1
Applied and Environmental Microbiology, 1996Co-Authors: Ishrat Rahman, Manoucher Shahamat, M A R Chowdhury, Rita R. ColwellAbstract:We examined a virulent strain of Shigella dysenteriae type 1 after induction into the Viable but Nonculturable (VBNC) state for its ability to (i) maintain the Shiga toxin (stx) gene; (ii) maintain biologically active Shiga toxin (ShT); and (iii) adhere to intestinal epithelial cells (Henle 407 cell line). PCR was used to amplify the stx gene from VBNC cells of S. dysenteriae type 1, thereby establishing its presence even when cells are in the VBNC state. VBNC S. dysenteriae type 1 ShT was monitored by the enzyme-linked immunosorbent assay with mouse monoclonal antibodies against the B subunit of ShT and affinity-purified rabbit polyclonal antibodies against ShT. We used the Henle 407 cell line to study the adhesive property of VBNC S. dysenteriae type 1 cells in a series of tissue culture experiments. Results showed that VBNC S. dysenteriae type 1 not only maintained the stx gene and biologically active ShT but also remained capable of adhering to Henle 407 cells. However, S. dysenteriae type 1 cells lost the ability to invade Henle 407 cells after entering the VBNC state. From results of the study, we conclude that VBNC cells of S. dysenteriae type 1 retain several virulence factors and remain potentially virulent, posing a public health problem.
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methionine uptake and cytopathogenicity of Viable but Nonculturable shigella dysenteriae type 1
Applied and Environmental Microbiology, 1994Co-Authors: Ishrat Rahman, Manoucher Shahamat, P A Kirchman, E Russekcohen, Rita R. ColwellAbstract:A pathogenic strain of Shigella dysenteriae type 1 was selected for study to elucidate the physiology and potential pathogenicity of organisms in the Viable but Nonculturable (VBNC) state in the environment. Studies in our laboratory have shown that S. dysenteriae type 1 survives in laboratory microcosms in the VBNC state for long periods of time, i.e., more than 6 months. VBNC cells of S. dysenteriae type 1 were found to retain cytopathogenicity for cultured HeLa cells. To determine whether VBNC S. dysenteriae type 1 expressed protein after loss of culturability, 35S-labelled methionine was added to suspensions of VBNC cells. Total cellular proteins were extracted and examined by autoradiography. Results indicate that VBNC S. dysenteriae type 1 is capable of both active uptake of methionine and incorporation of methionine into protein. Amino acid uptake and protein synthesis substantiate the viability of cells of S. dysenteriae type 1 in the VBNC state, i.e., although the cells are unable to be cultured on laboratory media by standard bacteriological methods, the cells remain metabolically active. Furthermore, VBNC cells of S. dysenteriae type 1 may pose a potential public health hazard that has not yet been recognized. Images
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Methionine uptake and cytopathogenicity of Viable but Nonculturable Shigella dysenteriae type 1.
Applied and environmental microbiology, 1994Co-Authors: Ishrat Rahman, Manoucher Shahamat, P A Kirchman, E. Russek-cohen, Rita R. ColwellAbstract:Abstract A pathogenic strain of Shigella dysenteriae type 1 was selected for study to elucidate the physiology and potential pathogenicity of organisms in the Viable but Nonculturable (VBNC) state in the environment. Studies in our laboratory have shown that S. dysenteriae type 1 survives in laboratory microcosms in the VBNC state for long periods of time, i.e., more than 6 months. VBNC cells of S. dysenteriae type 1 were found to retain cytopathogenicity for cultured HeLa cells. To determine whether VBNC S. dysenteriae type 1 expressed protein after loss of culturability, 35S-labelled methionine was added to suspensions of VBNC cells. Total cellular proteins were extracted and examined by autoradiography. Results indicate that VBNC S. dysenteriae type 1 is capable of both active uptake of methionine and incorporation of methionine into protein. Amino acid uptake and protein synthesis substantiate the viability of cells of S. dysenteriae type 1 in the VBNC state, i.e., although the cells are unable to be cultured on laboratory media by standard bacteriological methods, the cells remain metabolically active. Furthermore, VBNC cells of S. dysenteriae type 1 may pose a potential public health hazard that has not yet been recognized.
Jixiang Chen - One of the best experts on this subject based on the ideXlab platform.
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Entry of Vibrio cincinnatiensis into Viable but Nonculturable state and its resuscitation.
Letters in applied microbiology, 2009Co-Authors: L. Zhong, Jixiang Chen, Xiao-hua Zhang, Y.-a. JiangAbstract:Aims: The aim was to characterize the Viable but Nonculturable (VBNC) state of Vibrio cincinnatiensis and its resuscitation. Methods and Results: Vibrio cincinnatiensis VIB287 was cultured in sterilized seawater microcosms at 4°C. Plate counts, direct Viable counts and total counts were used. A large population of the V. cincinnatiensis became Nonculturable after approx. 50 day at 4°C. Electron microscopy revealed that the VBNC cells changed from rod to coccoid and decreased in size. Resuscitation of VBNC cells was achieved by temperature upshift in nutrition of yeast extract and peptone by addition of catalase or compound vitamin B. The VBNC and resuscitative cells were intraperitoneally injected into zebra fish separately. No death was observed in the group inoculated with the VBNC cells. Conclusions: Vibrio cincinnatiensis VIB287 could enter VBNC state in adverse environments. Resuscitation of VBNC cells occurred by addition of compound vitamin B or catalase to VBNC cells containing nutrient. The resuscitative cells might retain their pathogenicity. Significance and Impact of the Study: The study confirmed that V. cincinnatiensis could enter into VBNC state in seawater at low temperature and resuscitated. The resuscitative cells retained their pathogenicity, which may be important in future studies of ecology of V. cincinnatiensis.
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characterization and virulence retention of Viable but Nonculturable vibrio harveyi
FEMS Microbiology Ecology, 2008Co-Authors: Fengrong Sun, Jixiang Chen, Linhong Zhong, Xiao-hua Zhang, Rong Wang, Qianru Guo, Yi DongAbstract:Vibrio harveyi has been reported to enter into a Viable but Nonculturable (VBNC) state. Two clinical V. harveyi strains, SF1 and CW2, and the type strain, VIB295T, were incubated in sterilized seawater at 4 °C. Plate counts in these strains declined to undetectable levels (<0.1 CFU mL−1) within 69, 67 and 65 days, respectively. The direct Viable count (DVC) declined from 106 to 104 active cells mL−1 and remained constant at this level by a DVC. VBNC cell numbers could be restored via a temperature upshift when grown in yeast extract with the addition of Tween 20 or compound vitamin B. Reverse transcriptase-PCR was used to monitor virulence gene expression within VBNC cells. No expression of the hemolysin gene was detected in VBNC cells. VBNC and resuscitative cells were intraperitoneally injected into zebra fish separately. No death was observed in the groups inoculated with VBNC cells. The fish inoculated with the resuscitative cells died within 7 days, the lethal dose 50% (LD50) being 2.85 × 104 CFU mL−1, a value similar to that for groups inoculated with normal cells (2.28 × 104 CFU mL−1). This suggested that VBNC V. harveyi might retain pathogenic potential.
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Characterization and virulence retention of Viable but Nonculturable Vibrio harveyi.
FEMS microbiology ecology, 2008Co-Authors: Fengrong Sun, Jixiang Chen, Linhong Zhong, Xiao-hua Zhang, Rong Wang, Qianru Guo, Yi DongAbstract:Vibrio harveyi has been reported to enter into a Viable but Nonculturable (VBNC) state. Two clinical V. harveyi strains, SF1 and CW2, and the type strain, VIB295T, were incubated in sterilized seawater at 4 °C. Plate counts in these strains declined to undetectable levels (
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Characterization and resuscitation of Viable but Nonculturable Vibrio alginolyticus VIB283.
Archives of microbiology, 2007Co-Authors: Jixiang Chen, Xiao-hua ZhangAbstract:The aim of this study was to investigate the Viable but Nonculturable (VBNC) state of the bacterium. Vibrio alginolyticus VIB283 was cultured in sterilized seawater microcosm at 4°C. Culturability of the cells in the microcosm was monitored by spread plate count (PC) on 2216E agar, PCs declined to undetectable levels (
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characterization and resuscitation of Viable but Nonculturable vibrio alginolyticus vib283
Archives of Microbiology, 2007Co-Authors: Jixiang Chen, Xiao-hua ZhangAbstract:The aim of this study was to investigate the Viable but Nonculturable (VBNC) state of the bacterium. Vibrio alginolyticus VIB283 was cultured in sterilized seawater microcosm at 4°C. Culturability of the cells in the microcosm was monitored by spread plate count (PC) on 2216E agar, PCs declined to undetectable levels (<0.1 CFU/ml) within 90 days. Total cell counts remained constant throughout the period as determined by acridine orange direct count (AODC). The direct Viable counts, on the other hand, declined from 1010 to 109 CFU/ml active cells and remained fairly constant at this level by direct Viable count (DVC), which indicated that a large population of cells entered into the VBNC state. The VBNC cells could be resuscitated by temperature upshift with and without the presence of nutrition. The resuscitated time were 16 h and 8 days respectively. The resuscitation was not achieved in chick embryos. The morphology of the VBNC, normal and resuscitated cells was studied with scanning electron microscope and flow cytometry. The cells changed from rod or arc to coccoid and decreased in size when entered into the VBNC state. The resuscitated and the normal cells had almost no morphological differences.
Xiao-hua Zhang - One of the best experts on this subject based on the ideXlab platform.
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Entry of Vibrio cincinnatiensis into Viable but Nonculturable state and its resuscitation.
Letters in applied microbiology, 2009Co-Authors: L. Zhong, Jixiang Chen, Xiao-hua Zhang, Y.-a. JiangAbstract:Aims: The aim was to characterize the Viable but Nonculturable (VBNC) state of Vibrio cincinnatiensis and its resuscitation. Methods and Results: Vibrio cincinnatiensis VIB287 was cultured in sterilized seawater microcosms at 4°C. Plate counts, direct Viable counts and total counts were used. A large population of the V. cincinnatiensis became Nonculturable after approx. 50 day at 4°C. Electron microscopy revealed that the VBNC cells changed from rod to coccoid and decreased in size. Resuscitation of VBNC cells was achieved by temperature upshift in nutrition of yeast extract and peptone by addition of catalase or compound vitamin B. The VBNC and resuscitative cells were intraperitoneally injected into zebra fish separately. No death was observed in the group inoculated with the VBNC cells. Conclusions: Vibrio cincinnatiensis VIB287 could enter VBNC state in adverse environments. Resuscitation of VBNC cells occurred by addition of compound vitamin B or catalase to VBNC cells containing nutrient. The resuscitative cells might retain their pathogenicity. Significance and Impact of the Study: The study confirmed that V. cincinnatiensis could enter into VBNC state in seawater at low temperature and resuscitated. The resuscitative cells retained their pathogenicity, which may be important in future studies of ecology of V. cincinnatiensis.
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characterization and virulence retention of Viable but Nonculturable vibrio harveyi
FEMS Microbiology Ecology, 2008Co-Authors: Fengrong Sun, Jixiang Chen, Linhong Zhong, Xiao-hua Zhang, Rong Wang, Qianru Guo, Yi DongAbstract:Vibrio harveyi has been reported to enter into a Viable but Nonculturable (VBNC) state. Two clinical V. harveyi strains, SF1 and CW2, and the type strain, VIB295T, were incubated in sterilized seawater at 4 °C. Plate counts in these strains declined to undetectable levels (<0.1 CFU mL−1) within 69, 67 and 65 days, respectively. The direct Viable count (DVC) declined from 106 to 104 active cells mL−1 and remained constant at this level by a DVC. VBNC cell numbers could be restored via a temperature upshift when grown in yeast extract with the addition of Tween 20 or compound vitamin B. Reverse transcriptase-PCR was used to monitor virulence gene expression within VBNC cells. No expression of the hemolysin gene was detected in VBNC cells. VBNC and resuscitative cells were intraperitoneally injected into zebra fish separately. No death was observed in the groups inoculated with VBNC cells. The fish inoculated with the resuscitative cells died within 7 days, the lethal dose 50% (LD50) being 2.85 × 104 CFU mL−1, a value similar to that for groups inoculated with normal cells (2.28 × 104 CFU mL−1). This suggested that VBNC V. harveyi might retain pathogenic potential.
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Characterization and virulence retention of Viable but Nonculturable Vibrio harveyi.
FEMS microbiology ecology, 2008Co-Authors: Fengrong Sun, Jixiang Chen, Linhong Zhong, Xiao-hua Zhang, Rong Wang, Qianru Guo, Yi DongAbstract:Vibrio harveyi has been reported to enter into a Viable but Nonculturable (VBNC) state. Two clinical V. harveyi strains, SF1 and CW2, and the type strain, VIB295T, were incubated in sterilized seawater at 4 °C. Plate counts in these strains declined to undetectable levels (
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Characterization and resuscitation of Viable but Nonculturable Vibrio alginolyticus VIB283.
Archives of microbiology, 2007Co-Authors: Jixiang Chen, Xiao-hua ZhangAbstract:The aim of this study was to investigate the Viable but Nonculturable (VBNC) state of the bacterium. Vibrio alginolyticus VIB283 was cultured in sterilized seawater microcosm at 4°C. Culturability of the cells in the microcosm was monitored by spread plate count (PC) on 2216E agar, PCs declined to undetectable levels (
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characterization and resuscitation of Viable but Nonculturable vibrio alginolyticus vib283
Archives of Microbiology, 2007Co-Authors: Jixiang Chen, Xiao-hua ZhangAbstract:The aim of this study was to investigate the Viable but Nonculturable (VBNC) state of the bacterium. Vibrio alginolyticus VIB283 was cultured in sterilized seawater microcosm at 4°C. Culturability of the cells in the microcosm was monitored by spread plate count (PC) on 2216E agar, PCs declined to undetectable levels (<0.1 CFU/ml) within 90 days. Total cell counts remained constant throughout the period as determined by acridine orange direct count (AODC). The direct Viable counts, on the other hand, declined from 1010 to 109 CFU/ml active cells and remained fairly constant at this level by direct Viable count (DVC), which indicated that a large population of cells entered into the VBNC state. The VBNC cells could be resuscitated by temperature upshift with and without the presence of nutrition. The resuscitated time were 16 h and 8 days respectively. The resuscitation was not achieved in chick embryos. The morphology of the VBNC, normal and resuscitated cells was studied with scanning electron microscope and flow cytometry. The cells changed from rod or arc to coccoid and decreased in size when entered into the VBNC state. The resuscitated and the normal cells had almost no morphological differences.
