scholarly journals Diverse Virulence Gene Content of Shiga Toxin-Producing Escherichia coli from Finishing Swine

2014 ◽  
Vol 80 (20) ◽  
pp. 6395-6402 ◽  
Author(s):  
Marion Tseng ◽  
Pina M. Fratamico ◽  
Lori Bagi ◽  
Sabine Delannoy ◽  
Patrick Fach ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Virulence Genes ◽  
Genetic Relatedness ◽  
Virulence Gene ◽  
Health Concern ◽  
Limited Information ◽  
Content Type ◽  
Genes Encoding ◽  
Critical Public Health

ABSTRACTShiga toxin-producingEscherichia coli(STEC) infections are a critical public health concern because they can cause severe clinical outcomes, such as hemolytic uremic syndrome, in humans. Determining the presence or absence of virulence genes is essential in assessing the potential pathogenicity of STEC strains. Currently, there is limited information about the virulence genes carried by swine STEC strains; therefore, this study was conducted to examine the presence and absence of 69 virulence genes in STEC strains recovered previously from finishing swine in a longitudinal study. A subset of STEC strains was analyzed by pulsed-field gel electrophoresis (PFGE) to examine their genetic relatedness. Swine STEC strains (n= 150) were analyzed by the use of a high-throughput real-time PCR array system, which included 69 virulence gene targets. Three major pathotypes consisted of 16 different combinations of virulence gene profiles, and serotypes were determined in the swine STEC strains. The majority of the swine STEC strains (n= 120) belonged to serotype O59:H21 and carried the same virulence gene profile, which consisted of 9 virulence genes:stx2e,iha,ecs1763,lpfAO113,estIa(STa),ehaA,paa,terE, andureD. Theeae,nleF, andnleH1-2genes were detected in one swine STEC strain (O49:H21). Other genes encoding adhesins, includingiha, were identified (n= 149). The PFGE results demonstrated that swine STEC strains from pigs raised in the same finishing barn were closely related. Our results revealed diverse virulence gene contents among the members of the swine STEC population and enhance understanding of the dynamics of transmission of STEC strains among pigs housed in the same barn.

scholarly journals Association of Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR) Elements with Specific Serotypes and Virulence Potential of Shiga Toxin-Producing Escherichia coli

2013 ◽  
Vol 80 (4) ◽  
pp. 1411-1420 ◽  
Author(s):  
Magaly Toro ◽  
Guojie Cao ◽  
Wenting Ju ◽  
Marc Allard ◽  
Rodolphe Barrangou ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Virulence Genes ◽  
Genetic Relatedness ◽  
Average Length ◽  
Content Type ◽  
Virulence Potential ◽  
Short Palindromic Repeat ◽  
K 12 ◽  
Potential Pathogenicity

ABSTRACTShiga toxin-producingEscherichia coli(STEC) strains (n= 194) representing 43 serotypes andE. coliK-12 were examined for clustered regularly interspaced short palindromic repeat (CRISPR) arrays to study genetic relatedness among STEC serotypes. A subset of the strains (n= 81) was further analyzed for subtype I-Ecasand virulence genes to determine a possible association of CRISPR elements with potential virulence. Four types of CRISPR arrays were identified. CRISPR1 and CRISPR2 were present in all strains tested; 1 strain also had both CRISPR3 and CRISPR4, whereas 193 strains displayed a short, combined array, CRISPR3-4. A total of 3,353 spacers were identified, representing 528 distinct spacers. The average length of a spacer was 32 bp. Approximately one-half of the spacers (54%) were unique and found mostly in strains of less common serotypes. Overall, CRISPR spacer contents correlated well with STEC serotypes, and identical arrays were shared between strains with the same H type (O26:H11, O103:H11, and O111:H11). There was no association identified between the presence of subtype I-Ecasand virulence genes, but the total number of spacers had a negative correlation with potential pathogenicity (P< 0.05). Fewer spacers were found in strains that had a greater probability of causing outbreaks and disease than in those with lower virulence potential (P< 0.05). The relationship between the CRISPR-cassystem and potential virulence needs to be determined on a broader scale, and the biological link will need to be established.

scholarly journals Shiga Toxin-Producing Escherichia coli (STEC) and STEC-Associated Virulence Genes in Raw Ground Pork in Canada

2021 ◽  
Author(s):  
Helen Zhang ◽  
Etsuko Yamamoto ◽  
Johanna Murphy ◽  
Catherine Carrillo ◽  
Annie Locas
Keyword(s):  
Escherichia Coli ◽  
Foodborne Pathogens ◽  
Shiga Toxin ◽  
Virulence Genes ◽  
Virulence Gene ◽  
Toxin Gene ◽  
Gene Profiles ◽  
Ground Pork ◽  
Genes Encoding ◽  
Human Illness

Shiga toxin-producing Escherichia coli (STEC) O157:H7/NM and some non-O157 STEC are foodborne pathogens. In response to pork-associated O157 STEC outbreaks in Canada, we investigated the occurrence of STEC in Canadian retail raw ground pork during the period of November 1, 2014 and March 31, 2016. Isolated STEC were characterized to determine the Shiga-toxin gene ( stx ) subtype and the presence of virulence genes encoding intimin ( eae ), and enterohemorrhagic E. coli hemolysin (hlyA) . O157 STEC and non-O157 STEC were isolated from 0.11% (1/879) and 2.24% (13/580) of the pork samples. STEC virulence gene profiles containing both eae and hlyA were found only in the O157 STEC ( stx 2a , eae , hlyA ) isolate. The eae gene was absent from all non-O157 STEC isolates. Of the 13 non-O157 STEC isolates, two virulence genes of stx 1a and hlyA were found in four (30.8%) O91:H14 STEC isolates, while one virulence gene of stx 2e, stx 1a , and stx 2a was identified in five (38.5%), two (15.4%) and one (7.7%) STEC isolates respectively of various serotypes. The remaining non-O157 STEC isolate carried stx 2 , but the subtype is unknown as this isolate could not be recovered for sequencing. O91:H14 STEC ( stx 1a, hlyA ) was previously reported in association with diarrhea illnesses, while the other non-O157 STEC isolates identified in this study are not known to be associated with severe human illnesses. Virulence gene profiles identified in this study indicate that the occurrence of non-O157 STEC capable of causing severe human illness is rare in Canadian retail pork. However, O157 STEC in ground pork can occasionally occur, therefore education regarding the potential risks associated with STEC contamination of pork would be beneficial for the public and those in the food industry in order to help reduce foodborne illnesses.

scholarly journals Molecular Profiling of Shiga Toxin-Producing Escherichia coli and Enteropathogenic E. coli Strains Isolated from French Coastal Environments

2016 ◽  
Vol 82 (13) ◽  
pp. 3913-3927 ◽  
Author(s):  
C. Balière ◽  
A. Rincé ◽  
S. Delannoy ◽  
P. Fach ◽  
M. Gourmelon
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Virulence Gene ◽  
Coastal Environment ◽  
Pathogenicity Islands ◽  
Content Type ◽  
E Coli ◽  
Gene Profiles ◽  
Genes Encoding ◽  
High Level

ABSTRACTShiga toxin-producingEscherichia coli(STEC) and enteropathogenicE. coli(EPEC) strains may be responsible for food-borne infections in humans. Twenty-eight STEC and 75 EPEC strains previously isolated from French shellfish-harvesting areas and their watersheds and belonging to 68 distinguishable serotypes were characterized in this study. High-throughput real-time PCR was used to search for the presence of 75E. colivirulence-associated gene targets, and genes encoding Shiga toxin (stx) and intimin (eae) were subtyped using PCR tests and DNA sequencing, respectively. The results showed a high level of diversity between strains, with 17 unique virulence gene profiles for STEC and 56 for EPEC. Seven STEC and 15 EPEC strains were found to display a large number or a particular combination of genetic markers of virulence and the presence ofstxand/oreaevariants, suggesting their potential pathogenicity for humans. Among these, an O26:H11stx1aeae-β1 strain was associated with a large number of virulence-associated genes (n= 47), including genes carried on the locus of enterocyte effacement (LEE) or other pathogenicity islands, such as OI-122, OI-71, OI-43/48, OI-50, OI-57, and the high-pathogenicity island (HPI). One O91:H21 STEC strain containing 4stxvariants (stx1a,stx2a,stx2c, andstx2d) was found to possess genes associated with pathogenicity islands OI-122, OI-43/48, and OI-15. Among EPEC strains harboring a large number of virulence genes (n, 34 to 50), eight belonged to serotype O26:H11, O103:H2, O103:H25, O145:H28, O157:H7, or O153:H2.IMPORTANCEThe speciesE. coliincludes a wide variety of strains, some of which may be responsible for severe infections. This study, a molecular risk assessment study ofE. colistrains isolated from the coastal environment, was conducted to evaluate the potential risk for shellfish consumers. This report describes the characterization of virulence gene profiles andstx/eaepolymorphisms ofE. coliisolates and clearly highlights the finding that the majority of strains isolated from coastal environment are potentially weakly pathogenic, while some are likely to be more pathogenic.

scholarly journals Molecular Epidemiology of NDM-1-Producing Enterobacteriaceae and Acinetobacter baumannii Isolates from Pakistan

2014 ◽  
Vol 58 (9) ◽  
pp. 5589-5593 ◽  
Author(s):  
Anna L. Sartor ◽  
Muhammad W. Raza ◽  
Shahid A. Abbasi ◽  
Kathryn M. Day ◽  
John D. Perry ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Molecular Epidemiology ◽  
Genetic Relatedness ◽  
Antibiotic Resistance Genes ◽  
Enterobacter Cloacae ◽  
Content Type ◽  
Plasmid Replicon ◽  
Genes Encoding ◽  
Clonal Spread ◽  
Encoding Genes

ABSTRACTThe molecular epidemiology of 66 NDM-producing isolates from 2 Pakistani hospitals was investigated, with their genetic relatedness determined using repetitive sequence-based PCR (Rep-PCR). PCR-based replicon typing and screening for antibiotic resistance genes encoding carbapenemases, other β-lactamases, and 16S methylases were also performed. Rep-PCR suggested a clonal spread ofEnterobacter cloacaeandEscherichia coli. A number of plasmid replicon types were identified, with the incompatibility A/C group (IncA/C) being the most common (78%). 16S methylase-encoding genes were coharbored in 81% of NDM-producingEnterobacteriaceae.

scholarly journals Isolation and Characterization of Potentially Pathogenic Antimicrobial-Resistant Escherichia coli Strains from Chicken and Pig Farms in Spain

2010 ◽  
Vol 76 (9) ◽  
pp. 2799-2805 ◽  
Author(s):  
Pilar Cortés ◽  
Vanessa Blanc ◽  
Azucena Mora ◽  
Ghizlane Dahbi ◽  
Jesús E. Blanco ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Virulence Genes ◽  
Phylogenetic Analyses ◽  
Virulence Gene ◽  
E Coli ◽  
Isolation And Characterization ◽  
Zoonotic Risk ◽  
Poultry Farms ◽  
Pig Farms ◽  
Genes Encoding

ABSTRACT To ascertain whether on animal farms there reside extended-spectrum β-lactamase (ESBL) and plasmidic class C β-lactamase-producing Escherichia coli isolates potentially pathogenic for humans, phylogenetic analyses, pulsed-field gel electrophoresis (PFGE) typing, serotyping, and virulence genotyping were performed for 86 isolates from poultry (57 isolates) and pig (29 isolates) farms. E. coli isolates from poultry farms carried genes encoding enzymes of the CTX-M-9 group as well as CMY-2, whereas those from pig farms mainly carried genes encoding CTX-M-1 enzymes. Poultry and pig isolates differed significantly in their phylogenetic group assignments, with phylogroup A predominating in pig isolates and phylogroup D predominating in avian isolates. Among the 86 farm isolates, 23 (26.7%) carried two or more virulence genes typical of extraintestinal pathogenic E. coli (ExPEC). Of these, 20 were isolated from poultry farms and only 3 from pig farms. Ten of the 23 isolates belonged to the classic human ExPEC serotypes O2:H6, O2:HNM, O2:H7, O15:H1, and O25:H4. Despite the high diversity of serotypes and pulsotypes detected among the 86 farm isolates, 13 PFGE clusters were identified. Four of these clusters contained isolates with two or more virulence genes, and two clusters exhibited the classic human ExPEC serotypes O2:HNM (ST10) and O2:H6 (ST115). Although O2:HNM and O2:H6 isolates of human and animal origins differed with respect to their virulence genes and PFGE pulsotypes, the O2:HNM isolates from pigs showed the same sequence type (ST10) as those from humans. The single avian O15:H1 isolate was compared with human clinical isolates of this serotype. Although all were found to belong to phylogroup D and shared the same virulence gene profile, they differed in their sequence types (ST362-avian and ST393-human) and PFGE pulsotypes. Noteworthy was the detection, for the first time, in poultry farms of the clonal groups O25b:H4-ST131-B2, producing CTX-M-9, and O25a-ST648-D, producing CTX-M-32. The virulence genes and PFGE profiles of these two groups were very similar to those of clinical human isolates. While further studies are required to determine the true zoonotic potential of these clonal groups, our results emphasize the zoonotic risk posed especially by poultry farms, but also by pig farms, as reservoirs of ESBL- and CMY-2-encoding E. coli.

scholarly journals Molecular Profiling of Escherichia coli O157:H7 and Non-O157 Strains Isolated from Humans and Cattle in Alberta, Canada

2014 ◽  
Vol 53 (3) ◽  
pp. 986-990 ◽  
Author(s):  
Linda Chui ◽  
Vincent Li ◽  
Patrick Fach ◽  
Sabine Delannoy ◽  
Katarzyna Malejczyk ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Virulence Genes ◽  
Molecular Profiling ◽  
Surveillance Program ◽  
Escherichia Coli O157 ◽  
Significant Determinant ◽  
Content Type ◽  
Virulence Markers ◽  
Almost All

Virulence markers in Shiga toxin-producingEscherichia coli(STEC) and their association with diseases remain largely unknown. This study determines the importance of 44 genetic markers for STEC (O157 and non-O157) from human clinical cases and their correlation to disease outcome. STEC isolated from a cattle surveillance program were also included. The virulence genes tested were present in almost all O157:H7 isolates but highly variable in non-O157 STEC isolates. Patient age was a significant determinant of clinical outcome.

scholarly journals Prevalence and molecular characterization of Shiga toxin-producing escherichia coli isolates from human and sheep in Al-Madinah Al-Munawarah

Infectio ◽  
2017 ◽  
Vol 21 (2) ◽  
Author(s):  
Eman Fathi Sharafa ◽  
Iman I. Shabanaa
Keyword(s):  
Escherichia Coli ◽  
Foodborne Pathogens ◽  
Shiga Toxin ◽  
Genetic Relatedness ◽  
Control Measures ◽  
Health Concern ◽  
Global Public Health ◽  
E Coli ◽  
Life Threatening

Shiga toxin-producing Escherichia coli (STEC) strains have emerged as important foodborne pathogens of global public health concern, causing life-threatening diseases. Sheep and their products have been documented as important reservoirs for STECs, especially E. coli O157. The aim of this study was to investigate STECs from diarrheal human and sheep in Al-Madinah Al-Munawarah, Saudi Arabia. Fecal samples were collected between June and August, 2015 from diarrheal humans (n = 134) and sheep (n = 87). Presumptive E. coli human-and sheep-isolated strains were identified for their serotypes, the associated virulence genes (Shiga toxin [stx1 , stx2 ], haemolysin [ehxA] and intimin [eae]) by polymerase chain reaction and their susceptibility to antibiotics. Pulsed-field gel electrophoresis (PFGE) was used to demonstrate the genetic relatedness between Serotype O157:H7 human- and sheep-isolated strains. Forty eight (48/221; 21.7%) STECs were recovered from both human and sheep, their serotypes were as follows: O157:H7, O26:H11, O157:HNM, O26:HNM, O128:H2, O48:HNM, O111:HNM and OUT:HUT. Various virulence profiles and multiple antibiotic resistance were observed among the isolates. Twenty eight O157:H7 serotypes (17 human isolates and 11 sheep isolates) were identified in 13 PFGE pulsotypes, where human and sheep isolates were highly related. PFGE banding profiles together with serotypes and genotypes afford proof that human and sheep can be colonized and infected with similar E. coli O157:H7 strains. Our findings highlight the importance of epidemiological and microbiological surveillance of STECs; as well as the development of control measures to decrease risks associated with zoonotic O157:H7.

scholarly journals Serotypes and Virulence Gene Profiles of Shiga Toxin-Producing Escherichia coli Strains Isolated from Feces of Pasture-Fed and Lot-Fed Sheep

2004 ◽  
Vol 70 (7) ◽  
pp. 3910-3917 ◽  
Author(s):  
Steven P. Djordjevic ◽  
Vidiya Ramachandran ◽  
Karl A. Bettelheim ◽  
Barbara A. Vanselow ◽  
Peter Holst ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Virulence Genes ◽  
Virulence Gene ◽  
Human Consumption ◽  
Gene Profiles ◽  
Healthy Sheep ◽  
Uremic Syndrome ◽  
Australian Sheep ◽  
Cattle And Sheep

ABSTRACT Shiga toxin-producing Escherichia coli (STEC) strains possessing genes for enterohemolysin (ehxA) and/or intimin (eae), referred to here as complex STEC (cSTEC), are more commonly recovered from the feces of humans with hemolytic uremic syndrome and hemorrhagic colitis than STEC strains that do not possess these accessory virulence genes. Ruminants, particularly cattle and sheep, are recognized reservoirs of STEC populations that may contaminate foods destined for human consumption. We isolated cSTEC strains from the feces of longitudinally sampled pasture-fed sheep, lot-fed sheep maintained on diets comprising various combinations of silage and grain, and sheep simultaneously grazing pastures with cattle to explore the diversity of cSTEC serotypes capable of colonizing healthy sheep. A total of 67 cSTEC serotypes were isolated, of which 21 (31.3%), mainly isolated from lambs, have not been reported. Of the total isolations, 58 (86.6%) were different from cSTEC serotypes isolated from a recent study of longitudinally sampled healthy Australian cattle (M. Hornitzky, B. A. Vanselow, K. Walker, K. A. Bettelheim, B. Corney, P. Gill, G. Bailey, and S. P. Djordjevic, Appl. Environ. Microbiol. 68:6439-6445, 2002). Our data suggest that cSTEC serotypes O5:H−, O75:H8, O91:H−, O123:H−, and O128:H2 are well adapted to colonizing the ovine gastrointestinal tract, since they were the most prevalent serotypes isolated from both pasture-fed and lot-fed sheep. Collectively, our data show that Australian sheep are colonized by diverse cSTEC serotypes that are rarely isolated from healthy Australian cattle.

scholarly journals Ethanolamine Controls Expression of Genes Encoding Components Involved in Interkingdom Signaling and Virulence in Enterohemorrhagic Escherichia coli O157:H7

mBio ◽  
2012 ◽  
Vol 3 (3) ◽  
Author(s):  
Melissa M. Kendall ◽  
Charley C. Gruber ◽  
Christopher T. Parker ◽  
Vanessa Sperandio
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Cell Signaling ◽  
Nitrogen Source ◽  
Virulence Genes ◽  
Virulence Gene ◽  
Human Pathogen ◽  
Signaling Molecule ◽  
Content Type ◽  
Virulence Gene Expression

ABSTRACTBacterial pathogens must be able to both recognize suitable niches within the host for colonization and successfully compete with commensal flora for nutrients in order to establish infection. Ethanolamine (EA) is a major component of mammalian and bacterial membranes and is used by pathogens as a carbon and/or nitrogen source in the gastrointestinal tract. The deadly human pathogen enterohemorrhagicEscherichia coliO157:H7 (EHEC) uses EA in the intestine as a nitrogen source as a competitive advantage for colonization over the microbial flora. Here we show that EA is not only important for nitrogen metabolism but that it is also used as a signaling molecule in cell-to-cell signaling to activate virulence gene expression in EHEC. EA in concentrations that cannot promote growth as a nitrogen source can activate expression of EHEC’s repertoire of virulence genes. The EutR transcription factor, known to be the receptor of EA, is only partially responsible for this regulation, suggesting that yet another EA receptor exists. This important link of EA with metabolism, cell-to-cell signaling, and pathogenesis, highlights the fact that a fundamental means of communication within microbial communities relies on energy production and processing of metabolites. Here we show for the first time that bacterial pathogens not only exploit EA as a metabolite but also coopt EA as a signaling molecule to recognize the gastrointestinal environment and promote virulence expression.IMPORTANCEIn order to successfully cause disease, a pathogen must be able to sense a host environment and modulate expression of its virulence genes as well as compete with the indigenous microbiota for nutrients. Ethanolamine (EA) is present in the large intestine due to the turnover of intestinal cells. Here, we show that the human pathogenEscherichia coliO157:H7, which causes bloody diarrhea and hemolytic-uremic syndrome, regulates virulence gene expression through EA metabolism and by responding to EA as a signal. These findings provide the first information directly linking EA with bacterial pathogenesis.

scholarly journals Serotypes and Virulence Profiles of Non-O157 Shiga Toxin-Producing Escherichia coli Isolates from Bovine Farms

2011 ◽  
Vol 77 (24) ◽  
pp. 8662-8668 ◽  
Author(s):  
Áine Monaghan ◽  
Brian Byrne ◽  
Séamus Fanning ◽  
Torres Sweeney ◽  
David McDowell ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Virulence Gene ◽  
Late Summer ◽  
Distribution Data ◽  
Monitoring And Control ◽  
Emerging Pathogens ◽  
Content Type ◽  
Virulence Markers ◽  
Clinically Significant

ABSTRACTNon-O157 Shiga toxin-producingEscherichia coli(STEC) strains are clinically significant food-borne pathogens. However, there is a dearth of information on serotype prevalence and virulence gene distribution, data essential for the development of public health protection monitoring and control activities for the meat and dairy industries. Thus, the objective of this study was to examine the prevalence of non-O157 STEC on beef and dairy farms and to characterize the isolates in terms of serotype and virulence markers. Bovine fecal samples (n= 1,200) and farm soil samples (n= 600) were collected from 20 farms throughout Ireland over a 12-month period. Shiga toxin-positive samples were cultured and colonies examined for the presence ofstx1and/orstx2genes by PCR. Positive isolates were serotyped and examined for a range of virulence factors, includingeaeA,hlyA,tir,espA,espB,katP,espP,etpD,saa,sab,toxB,iha,lpfAO157/OI-141,lpfAO113, andlpfAO157/OI-154. Shiga toxin and intimin genes were further examined for known variants. Significant numbers of fecal (40%) and soil (27%) samples werestxpositive, with a surge observed in late summer-early autumn. One hundred seven STEC isolates were recovered, representing 17 serotypes. O26:H11 and O145:H28 were the most clinically significant, with O113:H4 being the most frequently isolated. However, O2:H27, O13/O15:H2, and ONT:H27 also carriedstx1and/orstx2andeaeAand may be emerging pathogens.

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