scholarly journals A System Model for Understanding the Role of Animal Feces as a Route of Contamination of Leafy Greens before Harvest

2016 ◽  
Vol 83 (2) ◽  
Author(s):  
Abhinav Mishra ◽  
Hao Pang ◽  
Robert L. Buchanan ◽  
Donald W. Schaffner ◽  
Abani K. Pradhan
Keyword(s):  
The United States ◽  
System Model ◽  
Content Type ◽  
E Coli ◽  
Leafy Greens ◽  
Mathematical System ◽  
Soil Irrigation ◽  
Foodborne Outbreaks ◽  
Wild Pig

ABSTRACT The majority of foodborne outbreaks in the United States associated with the consumption of leafy greens contaminated with Escherichia coli O157:H7 have been reported during the period of July to November. A dynamic system model consisting of subsystems and inputs to the system (soil, irrigation, cattle, wild pig, and rainfall) simulating a hypothetical farm was developed. The model assumed two crops of lettuce in a year and simulated planting, irrigation, harvesting, ground preparation for the new crop, contamination of soil and plants, and survival of E. coli O157:H7. As predicted by the baseline model for crops harvested in different months from conventional fields, an estimated 13 out of 257 (5.05%) first crops harvested in July would have at least one plant with at least 1 CFU of E. coli O157:H7. Predictions indicate that no first crops would be contaminated with at least 1 CFU of E. coli O157:H7 for other months (April to June). The maximum E. coli O157:H7 concentration in a plant was higher in the second crop (27.10 CFU) than in the first crop (9.82 CFU). For the second crop, the probabilities of having at least one plant with at least 1 CFU of E. coli O157:H7 in a crop were predicted as 15/228 (6.6%), 5/333 (1.5%), 14/324 (4.3%), and 6/115 (5.2%) in August, September, October, and November, respectively. For organic fields, the probabilities of having at least one plant with ≥1 CFU of E. coli O157:H7 in a crop (3.45%) were predicted to be higher than those for the conventional fields (2.15%). IMPORTANCE This study is the first attempt toward developing a mathematical system model to understand the pathway of E. coli O157:H7 in the production of leafy greens. Results of the presented system model indicate that the seasonality of outbreaks of E. coli O157:H7-associated contamination of leafy greens was in good agreement with the prevalence of this pathogen in cattle and wild pig feces in a major leafy greens-producing region in California. On the basis of comparisons among the results of different scenarios, it can be recommended that the concentration of E. coli O157:H7 in leafy greens can be reduced considerably if contamination of soil with wild pig and cattle feces is mitigated.

scholarly journals The Growing Season, but Not the Farming System, Is a Food Safety Risk Determinant for Leafy Greens in the Mid-Atlantic Region of the United States

2015 ◽  
Vol 81 (7) ◽  
pp. 2395-2407 ◽  
Author(s):  
Sasha C. Marine ◽  
Sivaranjani Pagadala ◽  
Fei Wang ◽  
Donna M. Pahl ◽  
Meredith V. Melendez ◽  
...  
Keyword(s):  
United States ◽  
Food Safety ◽  
Growing Season ◽  
Farming System ◽  
The United States ◽  
Atlantic Region ◽  
Content Type ◽  
E Coli ◽  
Leafy Greens ◽  
Food Safety Risk

ABSTRACTSmall- and medium-size farms in the mid-Atlantic region of the United States use varied agricultural practices to produce leafy greens during spring and fall, but the impact of preharvest practices on food safety risk remains unclear. To assess farm-level risk factors, bacterial indicators,Salmonella enterica, and Shiga toxin-producingEscherichia coli(STEC) from 32 organic and conventional farms were analyzed. A total of 577 leafy greens, irrigation water, compost, field soil, and pond sediment samples were collected.Salmonellawas recovered from 2.2% of leafy greens (n= 369) and 7.7% of sediment (n= 13) samples. There was an association betweenSalmonellarecovery and growing season (fall versus spring) (P= 0.006) but not farming system (organic or conventional) (P= 0.920) or region (P= 0.991). No STEC was isolated. In all, 10% of samples were positive forE. coli: 6% of leafy greens, 18% of irrigation water, 10% of soil, 38% of sediment, and 27% of compost samples. Farming system was not a significant factor for levels ofE. colior aerobic mesophiles on leafy greens but was a significant factor for total coliforms (TC) (P< 0.001), with higher counts from organic farm samples. Growing season was a factor for aerobic mesophiles on leafy greens (P= 0.004), with higher levels in fall than in spring. Water source was a factor for all indicator bacteria (P< 0.001), and end-of-line groundwater had marginally higher TC counts than source samples (P= 0.059). Overall, the data suggest that seasonal events, weather conditions, and proximity of compost piles might be important factors contributing to microbial contamination on farms growing leafy greens.

scholarly journals NOD2 Signaling Contributes to Host Defense in the Lungs against Escherichia coli Infection

2012 ◽  
Vol 80 (7) ◽  
pp. 2558-2569 ◽  
Author(s):  
Balamayooran Theivanthiran ◽  
Sanjay Batra ◽  
Gayathriy Balamayooran ◽  
Shanshan Cai ◽  
Koichi Kobayashi ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Host Defense ◽  
The United States ◽  
Bacterial Burden ◽  
Bacterial Killing ◽  
Ligand Interaction ◽  
Chemokine Production ◽  
Content Type ◽  
E Coli

ABSTRACTBacterial pneumonia remains a significant cause of mortality in the United States. The innate immune response is the first line of defense against invading bacteria. Neutrophil recruitment to the lungs is the first step in a multistep sequence leading to bacterial clearance. Ligand interaction with pattern-recognizing receptors (PRRs) leads to chemokine production, which drives neutrophils to the site of infection. Although we demonstrated that RIP2 is important for host defense in the lungs againstEscherichia coli, the individual roles of NOD1 and NOD2 in pulmonary defense have not been addressed. Here, we explored the role of NOD2 in neutrophil-mediated host defense against an extracellular pathogen,E. coli. We found enhanced bacterial burden and reduced neutrophil and cytokine/chemokine levels in the lungs of NOD2−/−mice followingE. coliinfection. Furthermore, we observed reduced activation of NF-κB and mitogen-activated protein kinases (MAPKs) in the lungs of NOD2−/−mice uponE. colichallenge. Moreover, NOD2−/−neutrophils show impaired intracellular bacterial killing. Using NOD2/RIP2−/−mice, we observed bacterial burden and neutrophil accumulation in the lungs similar to those seen with NOD2−/−mice. In addition, bone marrow-derived macrophages obtained from NOD2/RIP2−/−mice demonstrate a reduction in activation of NF-κB and MAPKs similar to that seen with NOD2−/−mice in response toE. coli. These findings unveil a previously unrecognized role of the NOD2-RIP2 axis for host defense against extracellular Gram-negative bacteria. This pathway may represent a novel target for the treatment of lung infection/inflammation.

scholarly journals Spo0A Suppresses sin Locus Expression in Clostridioides difficile

mSphere ◽  
2020 ◽  
Vol 5 (6) ◽  
Author(s):  
Babita Adhikari Dhungel ◽  
Revathi Govind
Keyword(s):  
Diarrheal Disease ◽  
Toxin Production ◽  
The United States ◽  
Upstream Region ◽  
Pcr Analysis ◽  
Bacterial Cells ◽  
Master Regulator ◽  
Content Type ◽  
Clostridioides Difficile

ABSTRACT Clostridioides difficile is the leading cause of nosocomial infection and is the causative agent of antibiotic-associated diarrhea. The severity of the disease is directly associated with toxin production, and spores are responsible for the transmission and persistence of the organism. Previously, we characterized sin locus regulators SinR and SinR′ (we renamed it SinI), where SinR is the regulator of toxin production and sporulation. The SinI regulator acts as its antagonist. In Bacillus subtilis, Spo0A, the master regulator of sporulation, controls SinR by regulating the expression of its antagonist, sinI. However, the role of Spo0A in the expression of sinR and sinI in C. difficile had not yet been reported. In this study, we tested spo0A mutants in three different C. difficile strains, R20291, UK1, and JIR8094, to understand the role of Spo0A in sin locus expression. Western blot analysis revealed that spo0A mutants had increased SinR levels. Quantitative reverse transcription-PCR (qRT-PCR) analysis of its expression further supported these data. By carrying out genetic and biochemical assays, we show that Spo0A can bind to the upstream region of this locus to regulates its expression. This study provides vital information that Spo0A regulates the sin locus, which controls critical pathogenic traits such as sporulation, toxin production, and motility in C. difficile. IMPORTANCE Clostridioides difficile is the leading cause of antibiotic-associated diarrheal disease in the United States. During infection, C. difficile spores germinate, and the vegetative bacterial cells produce toxins that damage host tissue. In C. difficile, the sin locus is known to regulate both sporulation and toxin production. In this study, we show that Spo0A, the master regulator of sporulation, controls sin locus expression. Results from our study suggest that Spo0A directly regulates the expression of this locus by binding to its upstream DNA region. This observation adds new detail to the gene regulatory network that connects sporulation and toxin production in this pathogen.

scholarly journals Key Role of Capsular Polysaccharide in the Induction of Systemic Infection and Abortion by Hypervirulent Campylobacter jejuni

2017 ◽  
Vol 85 (6) ◽  
Author(s):  
Orhan Sahin ◽  
Samantha A. Terhorst ◽  
Eric R. Burrough ◽  
Zhangqi Shen ◽  
Zuowei Wu ◽  
...  
Keyword(s):  
Guinea Pig ◽  
Campylobacter Jejuni ◽  
Capsular Polysaccharide ◽  
Systemic Infection ◽  
The United States ◽  
Content Type ◽  
Model Following ◽  
Capsule Production ◽  
Guinea Pig Model

ABSTRACT Campylobacter jejuni is a zoonotic pathogen, and a hypervirulent clone, named clone SA, has recently emerged as the predominant cause of ovine abortion in the United States. To induce abortion, orally ingested Campylobacter must translocate across the intestinal epithelium, spread systemically in the circulation, and reach the fetoplacental tissue. Bacterial factors involved in these steps are not well understood. C. jejuni is known to produce capsular polysaccharide (CPS), but the specific role that CPS plays in systemic infection and particularly abortion in animals remains to be determined. In this study, we evaluated the role of CPS in bacteremia using a mouse model and in abortion using a pregnant guinea pig model following oral challenge. Compared with C. jejuni NCTC 11168 and 81-176, a clone SA isolate (IA3902) resulted in significantly higher bacterial counts and a significantly longer duration of bacteremia in mice. The loss of capsule production via gene-specific mutagenesis in IA3902 led to the complete abolishment of bacteremia in mice and abortion in pregnant guinea pigs, while complementation of capsule expression almost fully restored these phenotypes. The capsule mutant strain was also impaired for survival in guinea pig sera and sheep blood. Sequence-based analyses revealed that clone SA possesses a unique CPS locus with a mosaic structure, which has been stably maintained in all clone SA isolates derived from various hosts and times. These findings establish CPS as a key virulence factor for the induction of systemic infection and abortion in pregnant animals and provide a viable candidate for the development of vaccines against hypervirulent C. jejuni.

scholarly journals Molecular Characterization of Commensal Escherichia coli Adapted to Different Compartments of the Porcine Gastrointestinal Tract

2012 ◽  
Vol 78 (19) ◽  
pp. 6799-6803 ◽  
Author(s):  
Sam Abraham ◽  
David M. Gordon ◽  
James Chin ◽  
Huub J. M. Brouwers ◽  
Peter Njuguna ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Gastrointestinal Tract ◽  
Random Amplified Polymorphic Dna ◽  
Content Type ◽  
E Coli ◽  
Plasmid Replicon ◽  
Different Strains ◽  
Different Characteristics

ABSTRACTThe role ofEscherichia colias a pathogen has been the focus of considerable study, while much less is known about it as a commensal and how it adapts to and colonizes different environmental niches within the mammalian gut. In this study, we characterizeEscherichia coliorganisms (n= 146) isolated from different regions of the intestinal tracts of eight pigs (dueodenum, ileum, colon, and feces). The isolates were typed using the method of random amplified polymorphic DNA (RAPD) and screened for the presence of bacteriocin genes and plasmid replicon types. Molecular analysis of variance using the RAPD data showed thatE. coliisolates are nonrandomly distributed among different gut regions, and that gut region accounted for 25% (P< 0.001) of the observed variation among strains. Bacteriocin screening revealed that a bacteriocin gene was detected in 45% of the isolates, with 43% carrying colicin genes and 3% carrying microcin genes. Of the bacteriocins observed (H47, E3, E1, E2, E7, Ia/Ib, and B/M), the frequency with which they were detected varied with respect to gut region for the colicins E2, E7, Ia/Ib, and B/M. The plasmid replicon typing gave rise to 25 profiles from the 13 Inc types detected. Inc F types were detected most frequently, followed by Inc HI1 and N types. Of the Inc types detected, 7 were nonrandomly distributed among isolates from the different regions of the gut. The results of this study indicate that not only may the different regions of the gastrointestinal tract harbor different strains ofE. colibut also that strains from different regions have different characteristics.

The future of maternity wear: Generation Z's expectations of dressing for pregnancy

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Elizabeth Anne Weigle ◽  
Laura McAndrews
Keyword(s):  
United States ◽  
Online Survey ◽  
The United States ◽  
The Body ◽  
Content Type ◽  
Longitudinal Approach ◽  
Shopping Experience ◽  
Physical Changes ◽  
Practical Implications

PurposeThe purpose of this paper is to investigate Generation Z's physical expectations of being pregnant and their outlook for maternity wear shopping.Design/methodology/approachFemales in this cohort (n = 207) participated in an online survey that included questions about perceptions of pregnancy, physical self-concept and forecasted shopping behaviors.FindingsResults indicated that this group is concerned with physical changes of pregnancy and expect to treat each area of the body in a different way. Women's expected physical concerns of pregnancy predict how much they anticipate accentuating their pregnant body. Gen Z anticipates wearing loose maternity garments and they envision a thoughtful, in-store shopping experience for styles that are equally fashionable and comfortable, such as dresses.Research limitations/implicationsThis study should be extended to future generational cohorts like Generation Alpha, along with Gen Z outside of the United States and women in the United States who are non-white. Further studies should take a longitudinal approach to gauge changes in this cohort's expectations as they progress through pregnancy.Practical implicationsThis paper provides maternity wear retail brands and designers a foundation for product development and marketing geared toward this large cohort.Originality/valueThe study is the first to inquire about Gen Z's outlook on pregnancy, specifically their envisioned changes to each body area and the role of maternity garments to fulfill needs and concerns.

The effect of intellectual property treaties on international innovation collaboration: a study based on USPTO patents during 1976–2017

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
JianQin Xiang ◽  
Feicheng Ma ◽  
Haiyan Wang
Keyword(s):  
Intellectual Property ◽  
The United States ◽  
Content Type ◽  
Global Innovation ◽  
Collaboration Environment ◽  
International Patent ◽  
Record Data ◽  
Innovation Cooperation ◽  
States Patent

PurposeStudies have indicated that international innovation collaboration has promoted technology transfer and knowledge spillover between countries. The conclusion of various international intellectual property (IP) treaties has played an essential role in optimizing the international innovation and collaboration environment. This study investigates the effect of IP treaties on international innovation collaboration and whether international IP treaties can promote collaboration between a country and other economies in the world.Design/methodology/approachAfter collecting and extracting the patent record data from the United States Patent and Trademark Office (USPTO), a final dataset of 3,213,626 cooperative patents and 465,236 pairs of collaborations between two countries or regions is established. Based on the international patent collaboration data of 192 countries during 1976–2017, the changes in patent collaboration indicators after these countries joined 23 IP treaties are analyzed.FindingsInternational IP treaties have significantly increased the number of patent cooperation countries of a country and its importance in international cooperation networks. The role of IP treaties is more manifested by the increased opportunities for a country's international innovation cooperation than its influence on global innovation; this is of extreme significance for developing countries to introduce advanced technologies.Originality/valueGinarte and Park (1997) have confirmed that IP treaties have helped to raise the level of IP protection. In this study, the increase in the degree centrality of the international innovation network is evidence of IP treaties to promote innovation cooperation. For a developing country, joining an intellectual property treaty may strengthen intellectual property protection and optimize its own international innovation cooperation methods.

The role of agency costs in the voluntary adoption of XBRL-based financial reporting

2020 ◽  
Vol 16 (5) ◽  
pp. 599-622
Author(s):  
Mehdi Khedmati ◽  
Farshid Navissi ◽  
Mohammed Aminu Sualihu ◽  
Zakiya Tofik-Abu
Keyword(s):  
United States ◽  
Financial Reporting ◽  
Agency Costs ◽  
The United States ◽  
Matched Pair ◽  
Alternative Measure ◽  
Content Type ◽  
Using Data ◽  
Voluntary Adoption

PurposeThe purpose of this paper is to examine whether and how firm's agency costs played a role in the voluntary adoption of the eXtensible Business Reporting Language (XBRL) under the SEC's voluntary filing program (VFP) that encouraged the voluntary adoption of the XBRL.Design/methodology/approachThis study employs a logistics regression and a sample of 140 firms that voluntarily participated in the VFP during its entire existence in the United States, and 140 matched-pair counterparts that did not voluntarily adopt the XBRL to investigate the role of agency costs in the voluntary adoption of XBRL-based financial reporting.FindingsWe find evidence consistent with the conjecture that a firm's low magnitude of agency costs plays a significant motivating role in the voluntary adoption of XBRL-based financial reporting. Our results continue to hold after using an alternative measure of agency costs and conducting two-stage least squares regressions. Supplementing these results, the study also shows that the level of agency costs of voluntary XBRL adopters remains statistically unchanged after the adoption while the level of agency costs associated with the firms that did not participate in SEC's VFP significantly decline after the adoption during the XBRL mandate.Practical implicationsThe findings of this study suggest that based on a firm's level of agency costs, regulators and policymakers, especially those in countries that are yet to mandate XBRL reporting, can, in advance, identify firms that are more likely to comply with their new financial reporting initiatives.Originality/valueThis paper provides first evidence on the role of agency costs in the voluntary adoption of XBRL using data from the United States.

scholarly journals Population Structure and Antimicrobial Resistance of Canine UropathogenicEscherichia coli

2018 ◽  
Vol 56 (9) ◽  
Author(s):  
Tessa E. LeCuyer ◽  
Barbara A. Byrne ◽  
Joshua B. Daniels ◽  
Dubraska V. Diaz-Campos ◽  
G. Kenitra Hammac ◽  
...  
Keyword(s):  
Population Structure ◽  
Antimicrobial Resistance ◽  
Companion Animals ◽  
Sequence Type ◽  
Content Type ◽  
E Coli ◽  
Extraintestinal Disease ◽  
Human Infections ◽  
Sequence Types

ABSTRACTEscherichia coliis the most common cause of human and canine urinary tract infection (UTI). Clonal groups, often with high levels of antimicrobial resistance, are a major component of theE. colipopulation that causes human UTI. While little is known about the population structure ofE. colithat causes UTI in dogs, there is evidence that dogs and humans can share fecal strains ofE. coliand that human-associated strains can cause disease in dogs. In order to better characterize theE. colistrains that cause canine UTI, we analyzed 295E. coliisolates obtained from canine urine samples from five veterinary diagnostic laboratories and analyzed their multilocus sequence types, phenotypic and genotypic antimicrobial resistance profiles, and virulence-associated gene repertoires. Sequence type 372 (ST372), an infrequent human pathogen, was the predominant sequence type in dogs at all locations. Extended-spectrum β-lactamase-producing isolates withblaCTX-Mgenes were uncommon in canine isolates but when present were often associated with sequence types that have been described in human infections. This provides support for occasional cross-host-species sharing of strains that cause extraintestinal disease and highlights the importance of understanding the role of companion animals in the overall transmission patterns of extraintestinal pathogenicE. coli.

scholarly journals Extraintestinal Pathogenic and Antimicrobial-Resistant Escherichia coli, Including Sequence Type 131 (ST131), from Retail Chicken Breasts in the United States in 2013

2017 ◽  
Vol 83 (6) ◽  
Author(s):  
James R. Johnson ◽  
Stephen B. Porter ◽  
Brian Johnston ◽  
Paul Thuras ◽  
Sarah Clock ◽  
...  
Keyword(s):  
United States ◽  
Escherichia Coli ◽  
Virulence Genes ◽  
Meat Products ◽  
The United States ◽  
Sequence Type ◽  
The Other ◽  
Antibiotic Resistant ◽  
Content Type ◽  
E Coli

ABSTRACT Chicken meat products are hypothesized to be vehicles for transmitting antimicrobial-resistant and extraintestinal pathogenic Escherichia coli (ExPEC) to consumers. To reassess this hypothesis in the current era of heightened concerns about antimicrobial use in food animals, we analyzed 175 chicken-source E. coli isolates from a 2013 Consumer Reports national survey. Isolates were screened by PCR for ExPEC-defining virulence genes. The 25 ExPEC isolates (12% of 175) and a 2:1 randomly selected set of 50 non-ExPEC isolates were assessed for their phylogenetic/clonal backgrounds and virulence genotypes for comparison with their resistance profiles and the claims on the retail packaging label (“organic,” “no antibiotics,” and “natural”). Compared with the findings for non-ExPEC isolates, the group of ExPEC isolates had a higher prevalence of phylogroup B2 isolates (44% versus 4%; P < 0.001) and a lower prevalence of phylogroup A isolates (4% versus 30%; P = 0.001), a higher prevalence of multiple individual virulence genes, higher virulence scores (median, 11 [range, 4 to 16] versus 8 [range, 1 to 14]; P = 0.001), and higher resistance scores (median, 4 [range, 0 to 8] versus 3 [range, 0 to 10]; P < 0.001). All five isolates of sequence type 131 (ST131) were ExPEC (P = 0.003), were as extensively resistant as the other isolates tested, and had higher virulence scores than the other isolates tested (median, 12 [range, 11 to 13] versus 8 [range, 1 to 16]; P = 0.005). Organic labeling predicted lower resistance scores (median, 2 [range, 0 to 3] versus 4 [range, 0 to 10]; P = 0.008) but no difference in ExPEC status or virulence scores. These findings document a persisting reservoir of extensively antimicrobial-resistant ExPEC isolates, including isolates from ST131, in retail chicken products in the United States, suggesting a potential public health threat. IMPORTANCE We found that among Escherichia coli isolates from retail chicken meat products purchased across the United States in 2013 (many of these isolates being extensively antibiotic resistant), a minority had genetic profiles suggesting an ability to cause extraintestinal infections in humans, such as urinary tract infection, implying a risk of foodborne disease. Although isolates from products labeled “organic” were less extensively antibiotic resistant than other isolates, they did not appear to be less virulent. These findings suggest that retail chicken products in the United States, even if they are labeled “organic,” pose a potential health threat to consumers because they are contaminated with extensively antibiotic-resistant and, presumably, virulent E. coli isolates.

Sign in / Sign up

Export Citation Format

Share Document