scholarly journals Utilizing the Food–Pathogen Metabolome to Putatively Identify Biomarkers for the Detection of Shiga Toxin-Producing E. coli (STEC) from Spinach

Metabolites ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 67
Author(s):  
Snehal R. Jadhav ◽  
Rohan M. Shah ◽  
Avinash V. Karpe ◽  
Robert S. Barlow ◽  
Kate E. McMillan ◽  
...  
Keyword(s):  
Shiga Toxin ◽  
Metabolic Profiling ◽  
Biomarker Discovery ◽  
Risk Groups ◽  
Proof Of Concept ◽  
Rapid Methods ◽  
E Coli ◽  
Leafy Greens ◽  
Food Pathogen ◽  
Genomic Similarity

Shiga toxigenic E. coli (STEC) are an important cause of foodborne disease globally with many outbreaks linked to the consumption of contaminated foods such as leafy greens. Existing methods for STEC detection and isolation are time-consuming. Rapid methods may assist in preventing contaminated products from reaching consumers. This proof-of-concept study aimed to determine if a metabolomics approach could be used to detect STEC contamination in spinach. Using untargeted metabolic profiling, the bacterial pellets and supernatants arising from bacterial and inoculated spinach enrichments were investigated for the presence of unique metabolites that enabled categorization of three E. coli risk groups. A total of 109 and 471 metabolite features were identified in bacterial and inoculated spinach enrichments, respectively. Supervised OPLS-DA analysis demonstrated clear discrimination between bacterial enrichments containing different risk groups. Further analysis of the spinach enrichments determined that pathogen risk groups 1 and 2 could be easily discriminated from the other groups, though some clustering of risk groups 1 and 2 was observed, likely representing their genomic similarity. Biomarker discovery identified metabolites that were significantly associated with risk groups and may be appropriate targets for potential biosensor development. This study has confirmed that metabolomics can be used to identify the presence of pathogenic E. coli likely to be implicated in human disease.

scholarly journals Utilizing the Food-Pathogen Metabolome to Putatively Identify Biomarkers for the Detection of Shiga Toxin-Producing E. coli (STEC) from Spinach

2021 ◽  
Author(s):  
Snehal R. Jadhav ◽  
Rohan M. Shah ◽  
Avinash V. Karpe ◽  
Robert Barlow ◽  
Kate McMillan ◽  
...  
Keyword(s):  
Shiga Toxin ◽  
Metabolic Profiling ◽  
Biomarker Discovery ◽  
Risk Groups ◽  
Proof Of Concept ◽  
Rapid Methods ◽  
E Coli ◽  
Leafy Greens ◽  
Food Pathogen ◽  
Genomic Similarity

Shiga toxigenic E. coli (STEC) are an important cause of foodborne disease globally with many outbreaks linked to the consumption of contaminated foods such as leafy greens. Existing methods for STEC detection and isolation are time-consuming. Rapid methods may assist in preventing contaminated products from reaching consumers. This proof-of-concept study aimed to determine if a metabolomics approach could be used to detect STEC contamination in spinach. Using untargeted metabolic profiling, the bacterial pellets and supernatants arising from bacterial and inoculated spinach enrichments were investigated for the presence of unique metabolites that enabled categorization of three E. coli risk groups. A total of 109 and 471 metabolite features were identified in bacterial and inoculated spinach enrichments, respectively. Supervised OPLS-DA analysis demonstrated clear dis-crimination between bacterial enrichments containing different risk groups. Further analysis of the spinach enrichments determined that pathogen risk groups 1 and 2 could be easily discriminated from the other groups, though some clustering of risk groups 1 and 2 was observed, likely representing their genomic similarity. Biomarker discovery identified metabolites that were significantly associated with risk groups and may be appropriate targets for potential biosensor development. This study has confirmed that metabolomics can be used to identify the presence of pathogenic E. coli likely to be implicated in human disease.

Internalization and Fate of Escherichia coli O157:H7 in Leafy Green Phyllosphere Tissue Using Various Spray Conditions

2014 ◽  
Vol 77 (5) ◽  
pp. 713-721 ◽  
Author(s):  
MARILYN C. ERICKSON ◽  
CATHY C. WEBB ◽  
LINDSEY E. DAVEY ◽  
ALISON S. PAYTON ◽  
IAN D. FLITCROFT ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Low Dose ◽  
High Dose ◽  
Escherichia Coli O157 ◽  
Inoculum Level ◽  
E Coli ◽  
Leafy Greens ◽  
The Past ◽  
Microbe Interactions

In the past decade, leafy greens have been implicated in several outbreaks of foodborne illness, and research has focused on contamination during preharvest operations. Concerns have been raised that internalization of pathogens into the edible tissue occurs where postharvest chemical interventions would be ineffective. This study was initiated to measure the degree and fate of Escherichia coli O157:H7 internalized in the phyllosphere tissue of leafy greens when spray conditions, inoculum level, and type of leafy green were varied. Two spraying treatments were applied: (i) spraying individual spinach or lettuce leaves on plants once with a high dose (7 to 8 log CFU/ml) of E. coli O157:H7 and (ii) spraying spinach, lettuce, or parsley plants repeatedly (once per minute) with a low dose (2.7 to 4.2 log CFU/ml) of E. coli O157:H7 over a 10- to 20-min period. With the high-dose spray protocol, no significant differences in the prevalence of internalization occurred between Shiga toxin–negative E. coli O157:H7 isolates and virulent isolates (P > 0.05), implying that the Shiga toxin virulence factors did not influence internalization or the subsequent fate of those populations under these test conditions. Significantly greater internalization of E. coli O157:H7 occurred in spinach leaves compared with lettuce leaves when leaves were sprayed once with the high-dose inoculum (P < 0.05), whereas internalization was not observed in lettuce leaves but continued to be observed in spinach and parsley leaves following repeated spraying of the low-dose inoculum. Based on these results, it is surmised that a moisture film was generated when spraying was repeated and this film assisted in the mobilization of pathogen cells to plant apertures, such as stomata. E. coli O157:H7 cells that were internalized into spinach tissue using a low-dose repeat-spray protocol were temporary residents because they were not detected 2 days later, suggesting that plant-microbe interactions may be responsible.

scholarly journals ppGpp and cytotoxicity diversity in Shiga toxin-producingEscherichia coli(STEC) isolates

2017 ◽  
Vol 145 (11) ◽  
pp. 2204-2211 ◽  
Author(s):  
A. E. STELLA ◽  
D. LUZ ◽  
R. M. F. PIAZZA ◽  
B. SPIRA
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Phenotypic Characteristics ◽  
Guanosine Tetraphosphate ◽  
E Coli ◽  
Healthy Sheep ◽  
Food Pathogen ◽  
Low Levels ◽  
High Cytotoxicity ◽  
Genotypic Characteristics

SUMMARYShiga toxin-producingEscherichia coli(STEC) is a known food pathogen, which main reservoir is the intestine of ruminants. The abundance of different STEC lineages in nature reflect a heterogeneity that is characterised by the differential expression of certain genotypic characteristics, which in turn are influenced by the environmental conditions to which the microorganism is exposed. Bacterial homeostasis and stress response are under the control of the alarmone guanosine tetraphosphate (ppGpp), which intrinsic levels varies across theE. colispecies. In the present study, 50 STEC isolates from healthy sheep were evaluated regarding their ppGpp content, cytotoxicity and other relevant genetic and phenotypic characteristics. We found that the level of ppGpp and cytotoxicity varied considerably among the examined strains. Isolates that harboured thestx2 gene were the least cytotoxic and presented the highest levels of ppGpp. Allstx2 isolates belonged to phylogroup A, while strains that carriedstx1 or bothstx1 andstx2 genes pertained to phylogroup B1. All but twostx2 isolates belonged to thestx2b subtype. Strains that belonged to phylogroup B1 displayed on average low levels of ppGpp and high cytotoxicity. Overall, there was a negative correlation between cytotoxicity and ppGpp.

Biotic and Abiotic Variables Affecting Internalization and Fate of Escherichia coli O157:H7 Isolates in Leafy Green Roots

2014 ◽  
Vol 77 (6) ◽  
pp. 872-879 ◽  
Author(s):  
MARILYN C. ERICKSON ◽  
CATHY C. WEBB ◽  
LINDSEY E. DAVEY ◽  
ALISON S. PAYTON ◽  
IAN D. FLITCROFT ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Field Trials ◽  
Green Plant ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Leafy Greens ◽  
Indigenous Microbial Community ◽  
Shiga Toxin Genes ◽  
Food Safety Risk

Preharvest internalization of Escherichia coli O157:H7 into the roots of leafy greens is a food safety risk because the pathogen may be systemically transported to edible portions of the plant. In this study, both abiotic (degree of soil moisture) and biotic (E. coli O157:H7 exposure, presence of Shiga toxin genes, and type of leafy green) factors were examined to determine their potential effects on pathogen internalization into roots of leafy greens. Using field soil that should have an active indigenous microbial community, internalized populations in lettuce roots were 0.8 to 1.6 log CFU/g after exposure to soil containing E. coli O157:H7 at 5.6 to 6.1 log CFU/g. Internalization of E. coli O157:H7 into leafy green plant roots was higher when E. coli O157:H7 populations in soil were increased to 7 or 8 log CFU/g or when the soil was saturated with water. No differences were noted in the extent to which internalization of E. coli O157:H7 occurred in spinach, lettuce, or parsley roots; however, in saturated soil, maximum levels in parsley occurred later than did those in spinach or lettuce. Translocation of E. coli O157:H7 from roots to leaves was rare; therefore, decreases observed in root populations over time were likely the result of inactivation within the plant tissue. Shiga toxin–negative (nontoxigenic) E. coli O157:H7 isolates were more stable than were virulent isolates in soil, but the degree of internalization of E. coli O157:H7 into roots did not differ between isolate type. Therefore, these nontoxigenic isolates could be used as surrogates for virulent isolates in field trials involving internalization.

W1780 Ciprofloxacin in Rabbits Infected with a Shiga-Toxin (Stx)-Producing E. coli (Stec) Srain Leads to Worse Clinical Outcome and Increased Toxin Release

2008 ◽  
Vol 134 (4) ◽  
pp. A-714
Author(s):  
Antonio Serna ◽  
Chengru Zhu ◽  
Amelia J. Nugent ◽  
Erin K. Okeefe ◽  
Edgar Boedeker
Keyword(s):  
Clinical Outcome ◽  
Shiga Toxin ◽  
E Coli

scholarly journals Hemoconcentration and predictors in Shiga toxin-producing E. coli-hemolytic uremic syndrome (STEC-HUS)

2021 ◽  
Author(s):  
Sebastian Loos ◽  
Jun Oh ◽  
Laura van de Loo ◽  
Markus J. Kemper ◽  
Martin Blohm ◽  
...  
Keyword(s):  
Risk Factor ◽  
Serum Creatinine ◽  
Hemolytic Uremic Syndrome ◽  
Shiga Toxin ◽  
Neurological Symptoms ◽  
Fluid Loss ◽  
Good Prediction ◽  
E Coli ◽  
Complicated Course ◽  
Uremic Syndrome

Abstract Background Hemoconcentration has been identified as a risk factor for a complicated course in Shiga toxin-producing E. coli-hemolytic uremic syndrome (STEC-HUS). This single-center study assesses hemoconcentration and predictors at presentation in STEC-HUS treated from 2009–2017. Methods Data of 107 pediatric patients with STEC-HUS were analyzed retrospectively. Patients with mild HUS (mHUS, definition: max. serum creatinine < 1.5 mg/dL and no major neurological symptoms) were compared to patients with severe HUS (sHUS, definition: max. serum creatinine ≥ 1.5 mg/dL ± major neurological symptoms). Additionally, predictors of complicated HUS (dialysis ± major neurological symptoms) were analyzed. Results Sixteen of one hundred seven (15%) patients had mHUS. Admission of patients with sHUS occurred median 2 days earlier after the onset of symptoms than in patients with mHUS. On admission, patients with subsequent sHUS had significantly higher median hemoglobin (9.5 g/dL (3.6–15.7) vs. 8.5 g/dL (4.2–11.5), p = 0.016) than patients with mHUS. The product of hemoglobin (g/dL) and LDH (U/L) (cutoff value 13,302, sensitivity 78.0%, specificity of 87.5%) was a predictor of severe vs. mild HUS. Creatinine (AUC 0.86, 95% CI 0.79–0.93) and the previously published score hemoglobin (g/dL) + 2 × creatinine (mg/dL) showed a good prediction for development of complicated HUS (AUC 0.87, 95% CI 0.80–0.93). Conclusions At presentation, patients with subsequent severe STEC-HUS had a higher degree of hemoconcentration. This underlines that fluid loss or reduced fluid intake/administration may be a risk factor for severe HUS. The good predictive value of the score hemoglobin (g/dL) + 2 × creatinine (mg/dL) for complicated HUS could be validated in our cohort. Graphical abstract

Tracking an Escherichia coli O157:H7–Contaminated Batch of Leafy Greens through a Pilot-Scale Fresh-Cut Processing Line

2014 ◽  
Vol 77 (9) ◽  
pp. 1487-1494 ◽  
Author(s):  
ANNEMARIE L. BUCHHOLZ ◽  
GORDON R. DAVIDSON ◽  
BRADLEY P. MARKS ◽  
EWEN C. D. TODD ◽  
ELLIOT T. RYSER
Keyword(s):  
Escherichia Coli ◽  
Membrane Filtration ◽  
Fluorescent Protein ◽  
Pilot Scale ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Leafy Greens ◽  
Iceberg Lettuce ◽  
Processing Line ◽  
Fresh Cut

Cross-contamination of fresh-cut leafy greens with residual Escherichia coli O157:H7–contaminated product during commercial processing was likely a contributing factor in several recent multistate outbreaks. Consequently, radicchio was used as a visual marker to track the spread of the contaminated product to iceberg lettuce in a pilot-scale processing line that included a commercial shredder, step conveyor, flume tank, shaker table, and centrifugal dryer. Uninoculated iceberg lettuce (45 kg) was processed, followed by 9.1 kg of radicchio (dip inoculated to contain a four-strain, green fluorescent protein–labeled nontoxigenic E. coli O157:H7 cocktail at 106 CFU/g) and 907 kg (2,000 lb) of uninoculated iceberg lettuce. After collecting the lettuce and radicchio in about 40 bags (~22.7 kg per bag) along with water and equipment surface samples, all visible shreds of radicchio were retrieved from the bags of shredded product, the equipment, and the floor. E. coli O157:H7 populations were quantified in the lettuce, water, and equipment samples by direct plating with or without prior membrane filtration on Trypticase soy agar containing 0.6% yeast extract and 100 ppm of ampicillin. Based on triplicate experiments, the weight of radicchio in the shredded lettuce averaged 614.9 g (93.6%), 6.9 g (1.3%), 5.0 g (0.8%), and 2.8 g (0.5%) for bags 1 to 10, 11 to 20, 21 to 30, and 31 to 40, respectively, with mean E. coli O157:H7 populations of 1.7, 1.2, 1.1, and 1.1 log CFU/g in radicchio-free lettuce. After processing, more radicchio remained on the conveyor (9.8 g; P &lt; 0.05), compared with the shredder (8.3 g), flume tank (3.5 g), and shaker table (0.1 g), with similar E. coli O157:H7 populations (P &gt; 0.05) recovered from all equipment surfaces after processing. These findings clearly demonstrate both the potential for the continuous spread of contaminated lettuce to multiple batches of product during processing and the need for improved equipment designs that minimize the buildup of residual product during processing.

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