scholarly journals Role of Extracellular Structures of Escherichia coli O157:H7 in Initial Attachment to Biotic and Abiotic Surfaces

2015 ◽  
Vol 81 (14) ◽  
pp. 4720-4727 ◽  
Author(s):  
Attila Nagy ◽  
Joseph Mowery ◽  
Gary R. Bauchan ◽  
Lili Wang ◽  
Lydia Nichols-Russell ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Severe Disease ◽  
Surface Proteins ◽  
Surface Structures ◽  
Human Pathogens ◽  
Initial Attachment ◽  
Content Type ◽  
E Coli ◽  
Abiotic Surfaces ◽  
Glass Surfaces

ABSTRACTInfection by human pathogens through the consumption of fresh, minimally processed produce and solid plant-derived foods is a major concern of the U.S. and global food industries and of public health services. EnterohemorrhagicEscherichia coliO157:H7 is a frequent and potent foodborne pathogen that causes severe disease in humans. Biofilms formed byE. coliO157:H7 facilitate cross-contamination by sheltering pathogens and protecting them from cleaning and sanitation operations. The objective of this research was to determine the role that several surface structures ofE. coliO157:H7 play in adherence to biotic and abiotic surfaces. A set of isogenic deletion mutants lacking major surface structures was generated. The mutant strains were inoculated onto fresh spinach and glass surfaces, and their capability to adhere was assessed by adherence assays and fluorescence microscopy methods. Our results showed that filament-deficient mutants bound to the spinach leaves and glass surfaces less strongly than the wild-type strain did. We mimicked the switch to the external environment—during which bacteria leave the host organism and adapt to lower ambient temperatures of cultivation or food processing—by decreasing the temperature from 37°C to 25°C and 4°C. We concluded that flagella and some other cell surface proteins are important factors in the process of initial attachment and in the establishment of biofilms. A better understanding of the specific roles of these structures in early stages of biofilm formation can help to prevent cross-contaminations and foodborne disease outbreaks.

scholarly journals Potentially Human-Pathogenic Escherichia coli O26 in Norwegian Sheep Flocks

2011 ◽  
Vol 77 (14) ◽  
pp. 4949-4958 ◽  
Author(s):  
C. Sekse ◽  
M. Sunde ◽  
B.-A. Lindstedt ◽  
P. Hopp ◽  
T. Bruheim ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Variable Number Tandem Repeat ◽  
Variable Number ◽  
Human Pathogens ◽  
Content Type ◽  
Representative Sampling ◽  
E Coli ◽  
Pathogenic Escherichia Coli ◽  
Close Relationship ◽  
Large Survey

ABSTRACTA national survey ofEscherichia coliO26 in Norwegian sheep flocks was conducted, using fecal samples to determine the prevalence. In total, 491 flocks were tested, andE. coliO26 was detected in 17.9% of the flocks. One hundred forty-twoE. coliO26 isolates were examined for flagellar antigens (H typing) and four virulence genes, includingstxandeae, to identify possible Shiga toxin-producingE. coli(STEC) and enteropathogenicE. coli(EPEC). Most isolates (129 out of 142) were identified asE. coliO26:H11. They possessedeaeand may have potential as human pathogens, although only a small fraction were identified as STEC O26:H11, giving a prevalence in sheep flocks of only 0.8%. Correspondingly, the sheep flock prevalence of atypical EPEC (aEPEC) O26:H11 was surprisingly high (15.9%). The genetic relationship between theE. coliO26:H11 isolates was investigated by pulsed-field gel electrophoresis (PFGE) and multilocus variable number tandem repeat analysis (MLVA), identifying 63 distinct PFGE profiles and 22 MLVA profiles. Although the MLVA protocol was less discriminatory than PFGE and a few cases of disagreement were observed, comparison by partition mapping showed an overall good accordance between the two methods. A close relationship between a few isolates of aEPEC O26:H11 and STEC O26:H11 was identified, but all theE. coliO26:H11 isolates should be considered potentially pathogenic to humans. The present study consisted of a representative sampling of sheep flocks from all parts of Norway. This is the first large survey of sheep flocks focusing onE. coliO26 in general, including results of STEC, aEPEC, and nonpathogenic isolates.

scholarly journals Evaluation of Aerated Steam Treatment of Alfalfa and Mung Bean Seeds To Eliminate High Levels of Escherichia coli O157:H7 and O178:H12, Salmonella enterica, and Listeria monocytogenes

2013 ◽  
Vol 79 (15) ◽  
pp. 4613-4619 ◽  
Author(s):  
Patrick Studer ◽  
Werner E. Heller ◽  
Jörg Hummerjohann ◽  
David Drissner
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Salmonella Enterica ◽  
Mung Bean ◽  
Germination Rate ◽  
Steam Treatment ◽  
Heat Sensitivity ◽  
Human Pathogens ◽  
Content Type ◽  
E Coli

ABSTRACTSprouts contaminated with human pathogens are able to cause food-borne diseases due to the favorable growth conditions for bacteria during germination and because of minimal processing steps prior to consumption. We have investigated the potential of hot humid air, i.e., aerated steam, to treat alfalfa and mung bean seeds which have been artificially contaminated withEscherichia coliO157:H7,Salmonella entericasubsp.entericaserovar Weltevreden, andListeria monocytogenesScott A. In addition, a recently collectedE. coliO178:H12 isolate, characterized by a reduced heat sensitivity, was exposed to the treatment described. Populations ofE. coliO157:H7 andS. entericaon alfalfa and mung bean seeds could be completely eliminated by a 300-s treatment with steam at 70 ± 1°C as revealed by enrichment studies.L. monocytogenesandE. coliO178:H12 could not be completely eliminated from artificially inoculated seeds. However, bacterial populations were reduced by more than 5 log CFU/g on alfalfa and by more than 4 log CFU/g on mung bean seeds. The germination rate of mung beans was not affected by the 300-s treatment compared to the germination rate of untreated seeds whereas that of alfalfa seeds was significantly lower by 11.9%. This chemical-free method is an effective alternative to the 20,000-ppm hypochlorite treatment presently recommended by the U.S. Food and Drug Administration (FDA).

scholarly journals Occurrence of Potentially Human-Pathogenic Escherichia coli O103 in Norwegian Sheep

2013 ◽  
Vol 79 (23) ◽  
pp. 7502-7509 ◽  
Author(s):  
Camilla Sekse ◽  
Marianne Sunde ◽  
Petter Hopp ◽  
Torkjel Bruheim ◽  
Kofitsyo Sewornu Cudjoe ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Human Pathogens ◽  
Outbreak Strain ◽  
Banding Patterns ◽  
Sheep Population ◽  
Content Type ◽  
E Coli ◽  
Pathogenic Escherichia Coli ◽  
Uremic Syndrome ◽  
Low Prevalence

ABSTRACTThe investigation of an outbreak of hemorrhagic-uremic syndrome in Norway in 2006 indicated that the outbreak strainEscherichia coliO103:H25 could originate from sheep. A national survey of the Norwegian sheep population was performed, with the aim of identifying and describing a possible reservoir of potentially human-pathogenicE. coliO103, in particular of the H types 2 and 25. The investigation of fecal samples from 585 sheep flocks resulted in 1,222E. coliO103 isolates that were analyzed for the presence ofeaeandstxgenes, while a subset of 369 isolates was further examined for flagellar antigens (H typing),stxsubtypes,bfpA,astA, and molecular typing by pulsed-field gel electrophoresis (PFGE). The total ovineE. coliO103 serogroup was genetically diverse by numbers of H types, virulotypes, and PFGE banding patterns identified, although a tendency of clustering toward serotypes was seen. The flocks positive for potentially human-pathogenicE. coliO103 were geographically widely distributed, and no association could be found with county or geographical region. The survey showed thateae-negative,stx-negativeE. coliO103, probably nonpathogenic to humans, is very common in sheep, with 27.5% of flocks positive. Moreover, the study documented a low prevalence (0.7%) of potentially human-pathogenic Shiga toxin-producingE. coliO103:H2, while STEC O103:H25 was not detected. However, 3.1% and 5.8% of the flocks were positive for enteropathogenicE. coliO103 belonging to H types 2 and 25, respectively. These isolates are of concern as potential human pathogens by themselves but more importantly as possible precursors for human-pathogenic STEC.

scholarly journals CsgA Production by Escherichia coli O157:H7 Alters Attachment to Abiotic Surfaces in Some Growth Environments

2011 ◽  
Vol 77 (20) ◽  
pp. 7339-7344 ◽  
Author(s):  
R. M. Goulter-Thorsen ◽  
E. Taran ◽  
I. R. Gentle ◽  
K. S. Gobius ◽  
G. A. Dykes
Keyword(s):  
Escherichia Coli ◽  
Growth Medium ◽  
Epifluorescence Microscopy ◽  
Clear Correlation ◽  
Bacterial Cells ◽  
Content Type ◽  
E Coli ◽  
Abiotic Surfaces ◽  
Significant Difference ◽  
Force Mapping

ABSTRACTThe role of curli expression in attachment ofEscherichia coliO157:H7 to glass, Teflon, and stainless steel (SS) was investigated through the creation ofcsgAknockout mutants in two isolates ofE. coliO157:H7. Attachment assays using epifluorescence microscopy and measurements of the force of adhesion of bacterial cells to the substrates using atomic force microscopy (AFM) force mapping were used to determine differences in attachment between wild-type (wt) andcsgA-negative (ΔcsgA) strains following growth in four different media. The hydrophobicity of the cells was determined using contact angle measurements (CAM) and bacterial adhesion to hydrocarbons (BATH). The attachment assay results indicated that ΔcsgAstrains attached to glass, Teflon, and SS surfaces in significantly different numbers than their wt counterparts in a growth medium-dependent fashion (P< 0.05). However, no clear correlation was seen between attachment numbers, surface type, or growth medium. No correlation was seen between BATH and CAM results (R2< 0.70). Hydrophobicity differed between the wt and ΔcsgAin some cases in a growth medium- and method-dependent fashion (P< 0.05). AFM force mapping revealed no significant difference in the forces of adhesion to glass and SS surfaces between wt and ΔcsgAstrains (P> 0.05) but a significantly greater force of adhesion to Teflon for one of the two wt strains than for its ΔcsgAcounterpart (P< 0.05). This study shows that CsgA production byE. coliO157:H7 may alter attachment behavior in some environments; however, further investigation is required in order to determine the exact relationship between CsgA production and attachment to abiotic surfaces.

scholarly journals Role of Enteroaggregative Escherichia coli Virulence Factors in Uropathogenesis

2013 ◽  
Vol 81 (4) ◽  
pp. 1164-1171 ◽  
Author(s):  
Erik J. Boll ◽  
Carsten Struve ◽  
Nadia Boisen ◽  
Bente Olesen ◽  
Steen G. Stahlhut ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Virulence Factors ◽  
Outbreak Strain ◽  
Content Type ◽  
E Coli ◽  
Abiotic Surfaces ◽  
Extraintestinal Disease ◽  
First Time ◽  
Specific Virulence

ABSTRACTA multiresistant clonalEscherichia coliO78:H10 strain qualifying molecularly as enteroaggregativeEscherichia coli(EAEC) was recently shown to be the cause of a community-acquired outbreak of urinary tract infection (UTI) in greater Copenhagen, Denmark, in 1991. This marks the first time EAEC has been associated with an extraintestinal disease outbreak. Importantly, the outbreak isolates were recovered from the urine of patients with symptomatic UTI, strongly implying urovirulence. Here, we sought to determine the uropathogenic properties of the Copenhagen outbreak strain and whether these properties are conferred by the EAEC-specific virulence factors. We demonstrated that through expression of aggregative adherence fimbriae, the principal adhesins of EAEC, the outbreak strain exhibited pronouncedly increased adherence to human bladder epithelial cells compared to prototype uropathogenic strains. Moreover, the strain was able to produce distinct biofilms on abiotic surfaces, including urethral catheters. These findings suggest that EAEC-specific virulence factors increase uropathogenicity and may have played a significant role in the ability of the strain to cause a community-acquired outbreak of UTI. Thus, inclusion of EAEC-specific virulence factors is warranted in future detection and characterization of uropathogenicE. coli.

scholarly journals Elevated Levels of an Enzyme Involved in Coenzyme B 12 Biosynthesis Kills Escherichia coli

mBio ◽  
2022 ◽  
Author(s):  
Victoria L. Jeter ◽  
Jorge C. Escalante-Semerena
Keyword(s):  
Escherichia Coli ◽  
Vitamin B ◽  
Human Pathogens ◽  
Content Type ◽  
E Coli ◽  
Coenzyme B

E. coli is the best-studied prokaryote, and some strains of this bacterium are human pathogens. We show that when the level of the enzyme that catalyzes the penultimate step of vitamin B 12 biosynthesis is elevated, the viability of E. coli decreases.

scholarly journals Molecular Characterization of Escherichia coli Strains Isolated from Retail Meat That HarborblaCTX-MandfosA3Genes

2016 ◽  
Vol 60 (4) ◽  
pp. 2450-2455 ◽  
Author(s):  
Miaomiao Xie ◽  
Dachuan Lin ◽  
Kaichao Chen ◽  
Edward Wai Chi Chan ◽  
Wen Yao ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Meat Products ◽  
Clonal Diversity ◽  
Conjugative Plasmid ◽  
Human Pathogens ◽  
Content Type ◽  
E Coli ◽  
Retail Meats ◽  
Retail Meat

ABSTRACTA total of 55 cefotaxime-resistantEscherichia coliisolates were obtained from retail meat products purchased in Shenzhen, China, during the period November 2012 to May 2013. Thirty-seven of these 55 isolates were found to harbor ablaCTX-Mgene, with theblaCTX-M-1group being the most common type.blaCMY-2was detected in 16 isolates, alone or in combination with other extended-spectrum β-lactamase (ESBL) determinants. Importantly, thefosA3gene, which encodes fosfomycin resistance, was detected in 12 isolates, with several being found to reside in the conjugative plasmid that harbored theblaCTX-Mgene. The insertion sequence IS26was observed upstream of some of theblaCTX-M-55andfosA3genes. Conjugation experiments showed thatblaCTX-Mgenes from 15 isolates were transferrable, with Inc I1 and Inc FII being the most prevalent replicons. High clonal diversity was observed among theblaCTX-Mproducers, suggesting that horizontal transfer of theblaCTX-Mgenes amongE. colistrains in retail meats is a common event and that such strains may constitute an important reservoir ofblaCTX-Mgenes, which may be readily disseminated to other potential human pathogens.

scholarly journals Seasonal Prevalence of Shiga Toxin-Producing Escherichia coli on Pork Carcasses for Three Steps of the Harvest Process at Two Commercial Processing Plants in the United States

2020 ◽  
Vol 87 (1) ◽  
Author(s):  
Ivan Nastasijevic ◽  
John W. Schmidt ◽  
Marija Boskovic ◽  
Milica Glisic ◽  
Norasak Kalchayanand ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Severe Disease ◽  
Control Point ◽  
The United States ◽  
Plate Count ◽  
Seasonal Effect ◽  
Content Type ◽  
E Coli ◽  
Pork Products

ABSTRACT Shiga toxin-producing Escherichia coli (STEC) is a foodborne pathogen that has a significant impact on public health, with strains possessing the attachment factor intimin referred to as enterohemorrhagic E. coli (EHEC) and associated with life-threatening illnesses. Cattle and beef are considered typical sources of STEC, but their presence in pork products is a growing concern. Therefore, carcasses (n = 1,536) at two U.S. pork processors were sampled once per season at three stages of harvest (poststunning skins, postscald carcasses, and chilled carcasses) and then examined using PCR for Shiga toxin genes (stx), intimin genes (eae), aerobic plate count (APC), and Enterobacteriaceae counts (EBC). The prevalence of stx on skins, postscald, and chilled carcasses was 85.3, 17.5, and 5.4%, respectively, with 82.3, 7.8, and 1.7% of swabs, respectively, having stx and eae present. All stx-positive samples were subjected to culture isolation that resulted in 368 STEC and 46 EHEC isolates. The most frequently identified STEC were serogroups O121, O8, and O91 (63, 6.7, and 6.0% of total STEC, respectively). The most frequently isolated EHEC was serotype O157:H7 (63% of total EHEC). Results showed that scalding significantly reduced (P < 0.05) carcass APC and EBC by 3.00- and 2.50-log10 CFU/100 cm2, respectively. A seasonal effect was observed, with STEC prevalence lower (P < 0.05) in winter. The data from this study show significant (P < 0.05) reduction in the incidence of STEC (stx) from 85.3% to 5.4% and of EHEC (stx plus eae) from 82.3% to 1.7% within the slaughter-to-chilling continuum, respectively, and that potential EHEC can be confirmed present throughout using culture isolation. IMPORTANCE Seven serogroups of STEC are responsible for most (>75%) cases of severe illnesses caused by STEC and are considered adulterants of beef. However, some STEC outbreaks have been attributed to pork products, although the same E. coli are not considered adulterants in pork because little is known of their prevalence along the pork chain. The significance of the work presented here is that it identifies disease-causing STEC, EHEC, demonstrating that these same organisms are a food safety hazard in pork as well as beef. The results show that most STEC isolated from pork are not likely to cause severe disease in humans and that processes used in pork harvest, such as scalding, offer a significant control point to reduce contamination. The results will assist the pork processing industry and regulatory agencies to optimize interventions to improve the safety of pork products.

scholarly journals Genomic Comparison Reveals Natural Occurrence of Clinically Relevant Multidrug-Resistant Extended-Spectrum-β-Lactamase-ProducingEscherichia coliStrains

2019 ◽  
Vol 85 (13) ◽  
Author(s):  
Lin Teng ◽  
Shinyoung Lee ◽  
Amber Ginn ◽  
Sarah M. Markland ◽  
Raies A. Mir ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Negative Impact ◽  
Severe Disease ◽  
Functional Characterization ◽  
Multidrug Resistant ◽  
Natural Occurrence ◽  
Genomic Comparison ◽  
Content Type ◽  
E Coli ◽  
Extended Spectrum

ABSTRACTThe effectiveness of antibiotics has been challenged by the increasing frequency of antimicrobial resistance (AMR), which has emerged as a major threat to global health. Despite its negative impact on the development of AMR, there are few effective strategies for reducing AMR in food-producing animals. Using whole-genome sequencing and comparative genomics of 36 multidrug-resistant (MDR)Escherichia colistrains isolated from beef cattle with no previous exposure to antibiotics, we obtained results suggesting that the occurrence of MDRE. colialso arises in animals with no antibiotic selective pressure. Extended-spectrum-β-lactamase-producingE. colistrains with enhanced virulence capacities for toxin production and adherence have evolved, which implies important ramifications for animal and human health. Gene exchanges by conjugative plasmids and insertion elements have driven widespread antibiotic resistance in clinically relevant pathogens. Phylogenetic relatedness ofE. colistrains from various geographic locations and hosts, such as animals, environmental sources, and humans, suggests that transmission of MDRE. colistrains occurs intercontinentally without host barriers.IMPORTANCEMultidrug-resistant (MDR)Escherichia coliisolates pose global threats to public health due to the decreasing availability of treatment options. To better understand the characteristics of MDRE. coliisolated from food-producing animals with no antibiotic exposure, we employed genomic comparison, high-resolution phylogenetics, and functional characterization. Our findings highlight the potential capacity of MDRE. colito cause severe disease and suggest that these strains are widespread intercontinentally. This study underlines the occurrence of MDRE. coliin food-producing animals raised without antibiotic use, which has alarming, critical ramifications within animal and human medical practice.

scholarly journals Recent Emergence of Escherichia coli with Cephalosporin Resistance Conferred byblaCTX-Mon Washington State Dairy Farms

2015 ◽  
Vol 81 (13) ◽  
pp. 4403-4410 ◽  
Author(s):  
Margaret A. Davis ◽  
William M. Sischo ◽  
Lisa P. Jones ◽  
Dale A. Moore ◽  
Sara Ahmed ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Dairy Farms ◽  
Washington State ◽  
Human Populations ◽  
Human Pathogens ◽  
Content Type ◽  
E Coli ◽  
The Past ◽  
Recent Emergence ◽  
Cephalosporin Resistance

ABSTRACTEnterobacteriaceae-associatedblaCTX-Mgenes have become globally widespread within the past 30 years. Among isolates from Washington State cattle,Escherichia colistrains carryingblaCTX-M(CTX-ME. colistrains) were absent from a set of 2008 isolates but present in a set of isolates from 2011. On 30 Washington State dairy farms sampled in 2012, CTX-ME. coliprevalence was significantly higher on eastern than on northwestern Washington farms, on farms with more than 3,000 adult cows, and on farms that recently received new animals. The addition of fresh bedding to calf hutches at least weekly and use of residual fly sprays were associated with lower prevalence of CTX-ME. coli. In Washington State, the occurrence of human pathogens carryingblaCTX-Mgenes preceded the emergence ofblaCTX-M-associatedE. coliin cattle, indicating that these resistance determinants and/or their bacterial hosts may have emerged in human populations prior to their dissemination to cattle populations.

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