scholarly journals Viable but Nonculturable Bacteria: Food Safety and Public Health Perspective

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Md. Fakruddin ◽  
Khanjada Shahnewaj Bin Mannan ◽  
Stewart Andrews
Keyword(s):  
Public Health ◽  
Food Safety ◽  
Pathogenic Bacteria ◽  
Disease Outbreaks ◽  
Human Pathogens ◽  
Vbnc State ◽  
Public Health Perspective ◽  
Viable But Nonculturable ◽  
Vbnc Bacteria ◽  
Adverse Environmental Conditions

The viable but nonculturable (VBNC) state is a unique survival strategy of many bacteria in the environment in response to adverse environmental conditions. VBNC bacteria cannot be cultured on routine microbiological media, but they remain viable and retain virulence. The VBNC bacteria can be resuscitated when provided with appropriate conditions. A good number of bacteria including many human pathogens have been reported to enter the VBNC state. Though there have been disputes on the existence of VBNC in the past, extensive molecular studies have resolved most of them, and VBNC has been accepted as a distinct survival state. VBNC pathogenic bacteria are considered a threat to public health and food safety due to their nondetectability through conventional food and water testing methods. A number of disease outbreaks have been reported where VBNC bacteria have been implicated as the causative agent. Further molecular and combinatorial research is needed to tackle the threat posed by VBNC bacteria with regard to public health and food safety.

scholarly journals The Viable But Nonculturable State ofRalstonia solanacearum May Be Involved in Long-Term Survival and Plant Infection

2001 ◽  
Vol 67 (9) ◽  
pp. 3866-3872 ◽  
Author(s):  
Brian E. Grey ◽  
Todd R. Steck
Keyword(s):  
Pathogenic Bacteria ◽  
Physiological Status ◽  
Cupric Sulfate ◽  
Vbnc State ◽  
In Planta ◽  
Term Survival ◽  
Viable But Nonculturable ◽  
Plant Infection ◽  
Nonculturable State ◽  
Vbnc Bacteria

ABSTRACT The role of the dormant-like viable but nonculturable (VBNC) condition in the etiology of bacterial infection was examined using a plant system. The plant-pathogenic bacterium Ralstonia solanacearum was first shown to enter into the VBNC state both in response to cupric sulfate when in a saline solution and when placed in autoclaved soil. To determine if the VBNC condition is related to pathogenesis, the physiological status of bacteria recovered from different regions of inoculated tomato plants was determined at different stages of infection. The fraction of in planta bacteria that were VBNC increased during infection and became greater than 99% by the late stage of disease. The possibility that soil-dwelling VBNC bacteria may resuscitate and infect plants was also examined. When tomato seeds were germinated in sterile soil that contained VBNC but no detectable culturable forms of R. solanacearumcells, resuscitation was observed to occur in soil adjacent to plant roots; these resuscitated bacteria were able to infect plants. This is the first report of R. solanacearum entering the VBNC state and of resuscitation of any VBNC plant-pathogenic bacteria and provides evidence that the VBNC state may be involved in explaining the persistent nature of some infections.

scholarly journals Induction and Resuscitation of Viable but Nonculturable Corynebacterium diphtheriae

2021 ◽  
Vol 9 (5) ◽  
pp. 927
Author(s):  
Takashi Hamabata ◽  
Mitsutoshi Senoh ◽  
Masaaki Iwaki ◽  
Ayae Nishiyama ◽  
Akihiko Yamamoto ◽  
...  
Keyword(s):  
Low Temperatures ◽  
Diphtheria Toxin ◽  
Pathogenic Bacteria ◽  
Corynebacterium Diphtheriae ◽  
Human Pathogen ◽  
Vbnc State ◽  
Viable But Nonculturable ◽  
Environmental Survival ◽  
Reverse Transcription Quantitative Pcr ◽  
Morphological Differences

Many pathogenic bacteria, including Escherichia coli and Vibrio cholerae, can become viable but nonculturable (VBNC) following exposure to specific stress conditions. Corynebacterium diphtheriae, a known human pathogen causing diphtheria, has not previously been shown to enter the VBNC state. Here, we report that C. diphtheriae can become VBNC when exposed to low temperatures. Morphological differences in culturable and VBNC C. diphtheriae were examined using scanning electron microscopy. Culturable cells presented with a typical rod-shape, whereas VBNC cells showed a distorted shape with an expanded center. Cells could be transitioned from VBNC to culturable following treatment with catalase. This was further evaluated via RNA sequence-based transcriptomic analysis and reverse-transcription quantitative PCR of culturable, VBNC, and resuscitated VBNC cells following catalase treatment. As expected, many genes showed different behavior by resuscitation. The expression of both the diphtheria toxin and the repressor of diphtheria toxin genes remained largely unchanged under all four conditions (culturable, VBNC, VBNC after the addition of catalase, and resuscitated cells). This is the first study to demonstrate that C. diphtheriae can enter a VBNC state and that it can be rescued from this state via the addition of catalase. This study helps to expand our general understanding of VBNC, the pathogenicity of VBNC C. diphtheriae, and its environmental survival strategy.

scholarly journals Detection and Potential Virulence of Viable but Non-Culturable (VBNC) Listeria monocytogenes: A Review

2021 ◽  
Vol 9 (1) ◽  
pp. 194
Author(s):  
Nathan E. Wideman ◽  
James D. Oliver ◽  
Philip Glen Crandall ◽  
Nathan A. Jarvis
Keyword(s):  
Public Health ◽  
Listeria Monocytogenes ◽  
Viable Count ◽  
Vbnc State ◽  
Testing Methods ◽  
Tetrazolium Chloride ◽  
Definitive Evidence ◽  
Virulence Potential ◽  
Vbnc Bacteria ◽  
The Impact

The detection, enumeration, and virulence potential of viable but non-culturable (VBNC) pathogens continues to be a topic of discussion. While there is a lack of definitive evidence that VBNC Listeria monocytogenes (Lm) pose a public health risk, recent studies suggest that Lm in its VBNC state remains virulent. VBNC bacteria cannot be enumerated by traditional plating methods, so the results from routine Lm testing may not demonstrate a sample’s true hazard to public health. We suggest that supplementing routine Lm testing methods with methods designed to enumerate VBNC cells may more accurately represent the true level of risk. This review summarizes five methods for enumerating VNBC Lm: Live/Dead BacLightTM staining, ethidium monoazide and propidium monoazide-stained real-time polymerase chain reaction (EMA- and PMA-PCR), direct viable count (DVC), 5-cyano-2,3-ditolyl tetrazolium chloride-4′,6-diamidino-2-phenylindole (CTC-DAPI) double staining, and carboxy-fluorescein diacetate (CDFA) staining. Of these five supplementary methods, the Live/Dead BacLightTM staining and CFDA-DVC staining currently appear to be the most accurate for VBNC Lm enumeration. In addition, the impact of the VBNC state on the virulence of Lm is reviewed. Widespread use of these supplemental methods would provide supporting data to identify the conditions under which Lm can revert from its VBNC state into an actively multiplying state and help identify the environmental triggers that can cause Lm to become virulent. Highlights: Rationale for testing for all viable Listeria (Lm) is presented. Routine environmental sampling and plating methods may miss viable Lm cells. An overview and comparison of available VBNC testing methods is given. There is a need for resuscitation techniques to recover Lm from VBNC. A review of testing results for post VBNC virulence is compared

Insects as vectors of foodborne pathogenic bacteria

2011 ◽  
Vol 4 (1) ◽  
pp. 5-16 ◽  
Author(s):  
Jeffrey Blazar ◽  
Marc Allard ◽  
E. Kurt Lienau
Keyword(s):  
Food Safety ◽  
Foodborne Pathogens ◽  
Pathogenic Bacteria ◽  
Current Knowledge ◽  
Disease Outbreaks ◽  
House Fly ◽  
American Cockroach ◽  
Health Concern ◽  
Foodborne Disease ◽  
Salmonella Spp

AbstractFood safety is an important consideration worldwide. To maintain and improve our current knowledge of foodborne disease outbreaks, we must understand some of the more imminent issues related to food safety. A variety of agents are responsible for transmitting the estimated 76 million cases of illnesses caused by foodborne pathogens every year. This review explores why insects pose a serious health concern, in terms of worldwide food safety initiatives, by looking at evidence in published <abs>Food safety is an important consideration worldwide. To maintain and improve our current knowledge of foodborne disease outbreaks, we must understand some of the more imminent issues related to food safety. A variety of agents are responsible for transmitting the estimated 76 million cases of illnesses caused by foodborne pathogens every year. This review explores why insects pose a serious health concern, in terms of worldwide food safety initiatives, by looking at evidence in published literature. We highlight at least eleven different species of insects, including the lesser mealworm, Alphitobius diaperinus (Panzer); secondary screwworm, Cochliomyia macellaria (Fabricius); synanthropic flies [flesh fly, Sarcophaga carnaria (L.); house fly, Musca domestica (L.); fruit fly, Drosophila melanogaster (Meigen); and stable fly, Stomoxys calcitrans (L.)], American cockroach, Periplaneta americana (L.); German cockroach, Blatella germanica (L.); Oriental cockroach, Blatta orientalis (L.); Pacific beetle cockroach, Diploptera punctata (Eschscholtz); and Speckled feeder cockroach, Nauphoeta cinerea (Olivier), which act as vectors for Salmonella spp. or Escherichia coli and illustrate how these insects are successful vectors of foodborne disease outbreaks. We propose that insects be considered as one of the latest issues in food safety initiatives. Not only are some insects extremely important contributors to diseases, but now we suggest that more research into insects as potential carriers of E. coli and Salmonella spp., and therefore as contributing to foodborne disease outbreaks, is granted.

scholarly journals Survival Strategy of Erwinia amylovora against Copper: Induction of the Viable-but-Nonculturable State

2006 ◽  
Vol 72 (5) ◽  
pp. 3482-3488 ◽  
Author(s):  
M�nica Ordax ◽  
Ester Marco-Noales ◽  
Mar�a M. L�pez ◽  
Elena G. Biosca
Keyword(s):  
Pathogenic Bacteria ◽  
Erwinia Amylovora ◽  
Control Plant ◽  
Viable Cell ◽  
Epifluorescence Microscopy ◽  
Survival Strategy ◽  
Vbnc State ◽  
Tetrazolium Chloride ◽  
Viable But Nonculturable ◽  
Cell Counts

ABSTRACT Copper compounds, widely used to control plant-pathogenic bacteria, have traditionally been employed against fire blight, caused by Erwinia amylovora. However, recent studies have shown that some phytopathogenic bacteria enter into the viable-but-nonculturable (VBNC) state in the presence of copper. To determine whether copper kills E. amylovora or induces the VBNC state, a mineral medium without copper or supplemented with 0.005, 0.01, or 0.05 mM Cu2+ was inoculated with 107 CFU/ml of this bacterium and monitored over 9 months. Total and viable cell counts were determined by epifluorescence microscopy using the LIVE/DEAD kit and by flow cytometry with 5-cyano-2,3-ditolyl tetrazolium chloride and SYTO 13. Culturable cells were counted on King's B nonselective solid medium. Changes in the bacterial morphology in the presence of copper were observed by scanning electron microscopy. E. amylovora entered into the VBNC state at all three copper concentrations assayed, much faster when the copper concentration increased. The addition of different agents which complex copper allowed the resuscitation (restoration of culturability) of copper-induced VBNC cells. Finally, copper-induced VBNC cells were virulent only for the first 5 days, while resuscitated cells always regained their pathogenicity on immature fruits over 9 months. These results have shown, for the first time, the induction of the VBNC state in E. amylovora as a survival strategy against copper.

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 Public health and food safety in the WHO African region

2012 ◽  
Vol 12 (52) ◽  
pp. 6317-6335
Author(s):  
P Mensah ◽  
◽  
L Mwamakamba ◽  
D Nsue-Milang ◽  
C Mohamed ◽  
...  
Keyword(s):  
Public Health ◽  
Food Safety ◽  
Pathogenic Bacteria ◽  
Food Control ◽  
African Region ◽  
Short Supply ◽  
Regional Food ◽  
Safety And Health ◽  
Safety Systems ◽  
Safety Strategy

Contaminated food continues to cause numerous devastating outbreaks in the African Region. In Africa, a large proportion of ready-to-eat foods are sold by the informal sector, especially as street foods. The hygienic aspects of vending operations and the safety of these foods are problematic for food safety regulators. The global food crisis has worsened an already precarious food situation because when food is in short supply people are more concerned about satisfying hunger than the safety of the food. The aetiological agents include various pathogenic bacteria, parasites and viruses. Chemical contaminants are becoming increasingly important. Human factors including: unhygienic practices and deliberate contamination, environmental factors, such as unsafe water, unsafe waste disposal and exposure of food to insects and dust, undercooked food, and prolonged storage of cooked food without refrigeration are the main predisposing factors. WHO’s position is that food safety must be recognised as a public health function and access to safe food as a basic human right. The work of WHO in food safety is in line with its core functions and various global and regional commitments, especially the document entitled “Food Safety and Health: A Strategy for the WHO African Region (AFR/RC57/4) adopted in 2007. WHO has been supporting countries to strengthen food safety systems and partnerships and advocacy; to develop evidence-based food safety policies; strengthen laboratory capacity for foodborne disease surveillance; enhance participation of countries in the standard-setting activities of the Codex Alimentarius Commission; and strengthen food safety education using the WHO Five Keys to Safer Food . The implementation of the Regional Food Safety Strategy adopts a holistic farm-to-fork approach which addresses the entire food control system. Much has been achieved since the adoption of the document Food Safety and health: A Strategy for the WHO African Region, but commitment to food safety still remains low due to competing priorities. In particular, countries are now shifting away from fragmented food control implementation towards multi-agency and coordinated as well as single agency systems. The Codex Trust Fund has facilitated participation and capacity building for Codex work. Although funding for the Food Safety Programme has increased as compared to the levels in 2002, this remains inadequate. WHO will continue to support countries to strengthen food safety systems in line with its core functions and as enshrined in the regional food safety strategy.

scholarly journals Universal microbial diagnostics using random DNA probes

2016 ◽  
Vol 2 (9) ◽  
pp. e1600025 ◽  
Author(s):  
Amirali Aghazadeh ◽  
Adam Y. Lin ◽  
Mona A. Sheikh ◽  
Allen L. Chen ◽  
Lisa M. Atkins ◽  
...  
Keyword(s):  
Dna Sequences ◽  
Pathogenic Bacteria ◽  
Disease Outbreaks ◽  
Dna Probes ◽  
Signal Recovery ◽  
Human Pathogens ◽  
Infectious Disease Outbreaks ◽  
Target Dna ◽  
Detection Schemes

Early identification of pathogens is essential for limiting development of therapy-resistant pathogens and mitigating infectious disease outbreaks. Most bacterial detection schemes use target-specific probes to differentiate pathogen species, creating time and cost inefficiencies in identifying newly discovered organisms. We present a novel universal microbial diagnostics (UMD) platform to screen for microbial organisms in an infectious sample, using a small number of random DNA probes that are agnostic to the target DNA sequences. Our platform leverages the theory of sparse signal recovery (compressive sensing) to identify the composition of a microbial sample that potentially contains novel or mutant species. We validated the UMD platform in vitro using five random probes to recover 11 pathogenic bacteria. We further demonstrated in silico that UMD can be generalized to screen for common human pathogens in different taxonomy levels. UMD’s unorthodox sensing approach opens the door to more efficient and universal molecular diagnostics.

scholarly journals Biocontrol Effect of Lytic Bacteriophages Against Various Food borne Diseases

2021 ◽  
Vol 14 (02) ◽  
pp. 709-723
Author(s):  
S Rehan Ahmad ◽  
Abul Kalam ◽  
Pritha Ghosh
Keyword(s):  
Food Safety ◽  
Bacterial Cell ◽  
Pathogenic Bacteria ◽  
Nutritive Value ◽  
Disease Outbreaks ◽  
High Pressure Processing ◽  
Foodborne Diseases ◽  
Food Borne ◽  
Pathogen Control ◽  
Safe Technique

Food borne disease is one of the major causes of hospitalization and death around the world. Many advance antimicrobial techniques, food sanitation techniques are present nowadays but still Food borne diseases are become more serious day by day. Some traditional well known antimicrobial methods including chemical treatment, pasteurization, high pressure processing, and irradiation are some popular techniques to control bacteria causing Foodborne diseases but they have several drawbacks like high cost, machine and processing equipment damage, damage nutritive value and organoleptic properties of foods and more importantly adverse effect on health. In this situation most promising and safe technique is biocontrol method. The interest for natural antimicrobial agent has exhibited due to consumer awareness towards the use of chemical based pathogen control methods or preservatives in food processing sectors. Use of bacteriophage is one of the most useful and promising natural biocontrol methods that targets specific strains of bacteria and kill the specific bacterial cell (or inhibit bacterial cell count). Bacteriophages can control foodborne disease outbreaks and ensure food safety by four different stages including therapy, biocontrol, biosanitation, and preservation. Bacteriophages are easily available in the environment and can be used safely in various foods ranging from fresh fruits, perishable animal product, and vegetables to ready-to-eat food products for bacterial decontamination. Approved commercial bacteriophages are also available to ensure food safety. bacteriophage biocontrol is recently recognized as an alternative method to reducing pathogenic bacteria from foods naturally and secure food safety. This review work is a brief overview of current bacteriophage related work in the field of foodborne diseases and food safety.

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