scholarly journals Induction of Escherichia coli and Salmonella typhimurium into the viable but nonculturable state following chlorination of wastewater

2005 ◽  
Vol 3 (3) ◽  
pp. 249-257 ◽  
Author(s):  
James D. Oliver ◽  
Maya Dagher ◽  
Karl Linden
Keyword(s):  
Escherichia Coli ◽  
Salmonella Typhimurium ◽  
Stationary Phases ◽  
Health Hazard ◽  
Physiological State ◽  
Treated Wastewater ◽  
Vbnc State ◽  
Viable But Nonculturable ◽  
Nonculturable Cells ◽  
Nonculturable State

We examined the effects of chlorine disinfection on Escherichia coli and Salmonella typhimurium in secondary-treated wastewater to determine whether such treatment might induce these bacteria into the viable but nonculturable (VBNC) state. In this state, cells lose culturability but retain viability and the potential to revert to the metabolically active and infectious state. To examine the effects of chlorination on cells in different physiological states, cells from the logarithmic and stationary phases, or nutrient starved, or grown in natural wastewater, were studied. Isogenic cells with and without plasmids were also examined. Whereas a mixture of free and combined chlorine, as occurs under typical wastewater disinfection, was found to be rapidly lethal to most cells, regardless of their physiological state or plasmid content, c. 104 of the original 106 cells ml−1 did survive in the VBNC state. While we were not successful in resuscitating these cells to the culturable state, the presence of such nonculturable cells in treated wastewater offers a potential public health hazard.

scholarly journals Induction of Viable but Nonculturable Escherichia coli O157:H7 in the Phyllosphere of Lettuce: a Food Safety Risk Factor

2011 ◽  
Vol 77 (23) ◽  
pp. 8295-8302 ◽  
Author(s):  
Laura-Dorina Dinu ◽  
Susan Bach
Keyword(s):  
Escherichia Coli ◽  
Food Safety ◽  
Low Temperature ◽  
Cell Density ◽  
Prolonged Storage ◽  
Potential Hazard ◽  
Vbnc State ◽  
Viable But Nonculturable ◽  
Content Type ◽  
E Coli

ABSTRACTEscherichia coliO157:H7 continues to be an important human pathogen and has been increasingly linked to food-borne illness associated with fresh produce, particularly leafy greens. The aim of this work was to investigate the fate ofE. coliO157:H7 on the phyllosphere of lettuce under low temperature and to evaluate the potential hazard of viable but nonculturable (VBNC) cells induced under such stressful conditions. First, we studied the survival of six bacterial strains following prolonged storage in water at low temperature (4°C) and selected two strains with different nonculturable responses for the construction ofE. coliO157:H7 Tn7gfptransformants in order to quantitatively assess the occurrence of human pathogens on the plant surface. Under a suboptimal growth temperature (16°C), bothE. coliO157:H7 strains maintained culturability on lettuce leaves, but under more stressful conditions (8°C), the bacterial populations evolved toward the VBNC state. The strain-dependent nonculturable response was more evident in the experiments with different inoculum doses (109and 106E. coliO157:H7 bacteria per g of leaf) when strain BRMSID 188 lost culturability after 15 days and strain ATCC 43895 lost culturability within 7 days, regardless of the inoculum dose. However, the number of cells entering the VBNC state in high-cell-density inoculum (approximately 55%) was lower than in low-cell-density inoculum (approximately 70%). We recorded the presence of verotoxin for 3 days in samples that contained a VBNC population of 4 to 5 log10cells but did not detect culturable cells. These findings indicate thatE. coliO157:H7 VBNC cells are induced on lettuce plants, and this may have implications regarding food safety.

scholarly journals New Insights into the Formation of Viable but Nonculturable Escherichia coli O157:H7 Induced by High-Pressure CO 2

mBio ◽  
2016 ◽  
Vol 7 (4) ◽  
Author(s):  
Feng Zhao ◽  
Yongtao Wang ◽  
Haoran An ◽  
Yanling Hao ◽  
Xiaosong Hu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
High Pressure ◽  
Cell Division ◽  
State Formation ◽  
Metabolic Activity ◽  
Rna Seq ◽  
Vbnc State ◽  
Viable But Nonculturable ◽  
E Coli ◽  
State Entry

ABSTRACT The formation of viable but nonculturable (VBNC) Escherichia coli O157:H7 induced by high-pressure CO 2 (HPCD) was investigated using RNA sequencing (RNA-Seq) transcriptomics and isobaric tag for relative and absolute quantitation (iTRAQ) proteomic methods. The analyses revealed that 97 genes and 56 proteins were significantly changed upon VBNC state entry. Genes and proteins related to membrane transport, central metabolisms, DNA replication, and cell division were mainly downregulated in the VBNC cells. This caused low metabolic activity concurrently with a division arrest in cells, which may be related to VBNC state formation. Cell division repression and outer membrane overexpression were confirmed to be involved in VBNC state formation by homologous expression of z2046 coding for transcriptional repressor and ompF encoding outer membrane protein F. Upon VBNC state entry, pyruvate catabolism in the cells shifted from the tricarboxylic acid (TCA) cycle toward the fermentative route; this led to a low level of ATP. Combating the low energy supply, ATP production in the VBNC cells was compensated by the degradation of l -serine and l -threonine, the increased AMP generation, and the enhanced electron transfer. Furthermore, tolerance of the cells with respect to HPCD-induced acid, oxidation, and high CO 2 stresses was enhanced by promoting the production of ammonia and NADPH and by reducing CO 2 production during VBNC state formation. Most genes and proteins related to pathogenicity were downregulated in the VBNC cells. This would decrease the cell pathogenicity, which was confirmed by adhesion assays. In conclusion, the decreased metabolic activity, repressed cell division, and enhanced survival ability in E. coli O157:H7 might cause HPCD-induced VBNC state formation. IMPORTANCE Escherichia coli O157:H7 has been implicated in large foodborne outbreaks worldwide. It has been reported that the presence of as few as 10 cells in food could cause illness. However, the presence of only 0.73 to 1.5 culturable E. coli O157:H7 cells in salted salmon roe caused infection in Japan. Investigators found that E. coli O157:H7 in the viable but nonculturable (VBNC) state was the source of the outbreak. So far, formation mechanisms of VBNC state are not well known. In a previous study, we demonstrated that high-pressure CO 2 (HPCD) could induce the transition of E. coli O157:H7 into the VBNC state. In this study, we used RNA-Seq transcriptomic analysis combined with the iTRAQ proteomic method to investigate the formation of VBNC E. coli O157:H7 induced by HPCD treatment. Finally, we proposed a putative formation mechanism of the VBNC cells induced by HPCD, which may provide a theoretical foundation for controlling the VBNC state entry induced by HPCD treatment.

scholarly journals Vancomycin Resistance Is Maintained in Enterococci in the Viable but Nonculturable State and after Division Is Resumed

2003 ◽  
Vol 47 (3) ◽  
pp. 1154-1156 ◽  
Author(s):  
Maria del Mar Lleò ◽  
Barbara Bonato ◽  
Caterina Signoretto ◽  
Pietro Canepari
Keyword(s):  
Vancomycin Resistance ◽  
Survival Strategy ◽  
Vbnc State ◽  
Additional Risk ◽  
Viable But Nonculturable ◽  
Vancomycin Resistant Enterococci ◽  
Nonculturable State ◽  
Resistance Trait ◽  
Vancomycin Resistant ◽  
Viable But Nonculturable State

ABSTRACT Stressed vancomycin-resistant enterococci (VRE) can activate a survival strategy known as the viable but nonculturable (VBNC) state and are able to maintain vancomycin resistance. During restoration of division they continue to express the vancomycin resistance trait. We suggest that VBNC enterococci may constitute further reservoirs of VRE and therefore represent an additional risk for human health.

scholarly journals The Dynamic Transition of Persistence toward the Viable but Nonculturable State during Stationary Phase Is Driven by Protein Aggregation

mBio ◽  
2021 ◽  
Author(s):  
Liselot Dewachter ◽  
Celien Bollen ◽  
Dorien Wilmaerts ◽  
Elen Louwagie ◽  
Pauline Herpels ◽  
...  
Keyword(s):  
Stationary Phase ◽  
Protein Aggregation ◽  
Conceptual Framework ◽  
Vbnc State ◽  
Viable But Nonculturable ◽  
Dynamic Transition ◽  
Nonculturable State ◽  
First Time ◽  
Further Development ◽  
Viable But Nonculturable State

While persistence and the viable but nonculturable (VBNC) state are currently investigated in isolation, our results strongly indicate that these phenotypes represent different stages of the same dormancy program and that they should therefore be studied within the same conceptual framework. Moreover, we show here for the first time that the dynamics of protein aggregation perfectly match the onset and further development of bacterial dormancy and that different dormant phenotypes are linked to different stages of protein aggregation.

scholarly journals Induction of a Viable but Nonculturable State, Thermal and Sanitizer Tolerance, and Gene Expression Correlation with the Desiccation Adapted Biofilm and Planktonic Salmonella in Powdered Infant Formula

2021 ◽  
Author(s):  
Guiliu Chen ◽  
Mengzhe Lin ◽  
Yingqi Chen ◽  
Weiying Xu ◽  
Hongmei Zhang
Keyword(s):  
Gene Expression ◽  
Infant Formula ◽  
Physiological State ◽  
Cross Protection ◽  
Plate Count ◽  
Powdered Infant Formula ◽  
Vbnc State ◽  
Viable But Nonculturable ◽  
And Storage ◽  
Planktonic State

This study investigated the effects of the physiological state, desiccation-adaptation, and storage of powdered infant formula (PIF) on Salmonella survival and their desiccation stress-related gene expression. PIF was inoculated with S . Typhimurium in the biofilm state on beads and in the planktonic state on nitrocellulose filters and stored at 25°C for up to 270 days. 5-cyano-2,3-ditoyl tetrazolium chloride flow cytometry (CTC-FCM) and Xylose Lysine Deoxycholate (XLD) plate count experiments demonstrated that biofilm-forming Salmonella tends to enter the Viable but Nonculturable (VBNC) state (p< 0.05). The population reduction of all desiccation-adapted S. Typhimurium decreased significantly in both physiological states after exposure to mild heat (60℃) compared with non-adapted control cells (p< 0.05). Salmonella showed heat cross-protection in both physiological states, but only the planktonic state Salmonella induced cross-protection against hydrogen peroxide. As indicated by quantitative reverse transcription polymerase chain reaction (RT-qPCR), rpoS of biofilm Salmonella for all days desiccation adatption examined and plantonic Salmonella on the 7th day of dry storage were significantly upregulated (p< 0.05).The rpoE , grpE , and invA genes in S almonella of both physiological states were significantly downregulated (p< 0.05). Physiological state and storage time might affect expression levels of these genes. In conclusion, prior exposure to these conditions, including low a w , and the physiological state posed an impact on Salmonella in the VBNC state and their gene expression.

scholarly journals Differential Effects of Temperature and Starvation on Induction of the Viable-but-Nonculturable State in the Coral Pathogens Vibrio shiloi and Vibrio tasmaniensis

2006 ◽  
Vol 72 (10) ◽  
pp. 6508-6513 ◽  
Author(s):  
Thomas Vattakaven ◽  
Peter Bond ◽  
Graham Bradley ◽  
Colin B. Munn
Keyword(s):  
Vbnc State ◽  
Temperate Water ◽  
Seasonal Incidence ◽  
Viable But Nonculturable ◽  
Nonculturable State ◽  
Temperature Induction ◽  
Effects Of Temperature ◽  
Vibrio Shiloi ◽  
Membrane Roughness ◽  
Viable But Nonculturable State

ABSTRACT We compared induction of the viable-but-nonculturable (VBNC) state in two Vibrio spp. isolated from diseased corals by starving the cells and maintaining them in artificial seawater at 4 and 20°C. In Vibrio tasmaniensis, isolated from a gorgonian octocoral growing in cool temperate water (7 to 17°C), the VBNC state was not induced by incubation at 4°C after 157 days. By contrast, Vibrio shiloi, isolated from a coral in warmer water (16 to 30°C), was induced into the VBNC state by incubation at 4°C after 126 days. This result is consistent with reports of low-temperature induction in several Vibrio spp. A large proportion of the V. tasmaniensis population became VBNC after incubation for 157 days at 20°C, and V. shiloi became VBNC after incubation for 126 days at 20°C. Resuscitation of V. shiloi cells from cultures at both temperatures was achieved by nutrient addition, suggesting that starvation plays a major role in inducing the VBNC state. Our results suggest that viable V. shiloi could successfully persist in the VBNC state in seawater for significant periods at the lower temperatures that may be experienced in winter conditions, which may have an effect on the seasonal incidence of coral bleaching. For both species, electron microscopy revealed that prolonged starvation resulted in transformation of the cells from rods to cocci, together with profuse blebbing, production of a polymer-like substance, and increased membrane roughness. V. shiloi cells developed an increased periplasmic space and membrane curling; these features were absent in V. tasmaniensis.

scholarly journals Inability of Escherichia coli to resuscitate from the viable but nonculturable state

2007 ◽  
Vol 62 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Inés Arana ◽  
Maite Orruño ◽  
David Pérez-Pascual ◽  
Carolina Seco ◽  
Alicia Muela ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Viable But Nonculturable ◽  
Nonculturable State ◽  
Viable But Nonculturable State
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