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 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 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 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 Choice of library preparation and its effects on sequence quality, genome assembly, and precise in silico prediction of virulence genes in shiga toxin producing Escherichia coli

2020 ◽  
Author(s):  
Julie Haendiges ◽  
Karen Jinneman ◽  
Narjol Gonzalez-Escalona
Keyword(s):  
Escherichia Coli ◽  
Illumina Sequencing ◽  
Foodborne Pathogens ◽  
Shiga Toxin ◽  
Virulence Genes ◽  
Sequence Data ◽  
Virulence Gene ◽  
Illumina Miseq ◽  
Source Tracking ◽  
Library Preparation

AbstractWhole genome sequencing (WGS) provides essential public health information and is used worldwide for pathogen surveillance, epidemiology, and source tracking. The sequencing of foodborne pathogens is commonly performed with Illumina sequencing chemistry to obtain data with high accuracy. The choice of library preparation method for highly complex organisms is very critical and can affect the final data output. The majority of Illumina sequencing platforms use rapid library preparation such as Nextera XT (transposon-based technology) (Illumina San Diego, CA), but this preparation has the potential to miss randomly distributed segments of genomes that might be important for downstream analyses. The Illumina Nextera DNA Prep library preparation kit, the successor of Nextera XT, shows better overall coverage of the complete genome. This study compared the quality of sequence data generated using Nextera XT and Nextera DNA Prep kits for DNA library preparation on an Illumina MiSeq, using a set of 30 O121:H19 shiga-toxin positive Escherichia coli strains isolated from flour during a 2016 outbreak. The performance of the two kits were evaluated using several metrics including sequencing quality, assembly quality, uniformity of genome coverage, and virulence gene identification. Overall, the results showed that in all of the analysed metrics, the Nextera DNA Prep kit performed outstanding in comparison to Nextera XT. The Nextera DNA Prep kit allowed for comprehensive detection of all virulence genes, which is of extremely high importance for making an educated assessment of the virulence potential of Escherichia coli. This comprehensive side-by-side comparison will be of significance for those interested in improving their sequencing workflow for STECs and the determination of health risks using WGS data.

Detection of virulence genes of APEC (avian pathogenic Escherichia coli) isolated from poultry in Noakhali, Bangladesh

2021 ◽  
Vol 7 (1) ◽  
pp. 967-972
Author(s):  
Farzana Ehetasum Hossain ◽  
Saiful Islam ◽  
Md Aminul Islam ◽  
Shariful Islam ◽  
Firoz Ahmed
Keyword(s):  
Escherichia Coli ◽  
Virulence Genes ◽  
Virulence Gene ◽  
Economic Loss ◽  
Point Of View ◽  
Pcr Analysis ◽  
Avian Pathogenic Escherichia Coli ◽  
Gene Profiles ◽  
Pathogenic Escherichia Coli ◽  
Wide Range

Avian colibacillosis, caused by avian pathogenic Escherichia coli (APEC), is one of the major infectious diseases of poultry that bring about great economic loss for the Bangladesh poultry industry. The present study aimed to determine the virulence genes of avian pathogenic Escherichia coli (APEC) from cases of colibacillosis in poultry at the Noakhali district of Bangladesh. Currently, virulence-associated gene profiles of APEC isolates were investigated by polymerase chain reaction (PCR). A total of 24 (twenty-four) Escherichia coli isolates were collected and presumptively identified from 8 (eight) colibacillosis cases from 4 commercial broiler poultry farms (2 broilers per farm) in Noakhali, Bangladesh. The pathogenesis of Escherichia coli involves a wide range of different virulence genes. At this point, four virulence genes, iutA, hlyF, iroN, and iss were detected by PCR analysis. It has been observed that iutA, iss, hlyF, and iroN genes were found in 7(29.16%), 20(83.33%), 22(91.66%), and 24(100%) APEC isolates respectively. Furthermore, out of the twenty-four APEC isolates, six (25%) isolates had four virulence genes, fourteen (58.33%) isolates carried at least three virulence genes, three (12.5%) isolates carried two genes and one (4.16%) isolates had one virulence gene. Most importantly. six types of virulence gene profiles existed within the APEC isolates from which profile number 3 (hlyF, iroN, iss) having 13 (54.16%) isolates were predominant. The occurrence of APEC isolates of this region which is responsible for avian colibacillosis cases can be a matter of concern from the public health point of view. Future investigations will be able to utilize these virulence genes to identify APEC in Bangladesh helping in the diagnosis and prevention of colibacillosis in poultry. Bioresearch Commu. 7(1): 967-972, 2021 (January)

Characteristics of Shiga Toxin–Producing Escherichia coli Isolated from Swiss Raw Milk Cheese within a 3-Year Monitoring Program

2010 ◽  
Vol 73 (1) ◽  
pp. 88-91 ◽  
Author(s):  
C. ZWEIFEL ◽  
N. GIEZENDANNER ◽  
S. CORTI ◽  
G. KRAUSE ◽  
L. BEUTIN ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Monitoring Program ◽  
Raw Milk ◽  
Health Impact ◽  
Toxin Gene ◽  
Genes Encoding ◽  
Raw Milk Cheese ◽  
Human Infections ◽  
Hard Cheese

Food is an important vehicle for transmission of Shiga toxin–producing Escherichia coli (STEC). To assess the potential public health impact of STEC in Swiss raw milk cheese produced from cow's, goat's, and ewe's milk, 1,422 samples from semihard or hard cheese and 80 samples from soft cheese were examined for STEC, and isolated strains were further characterized. By PCR, STEC was detected after enrichment in 5.7% of the 1,502 raw milk cheese samples collected at the producer level. STEC-positive samples comprised 76 semihard, 8 soft, and 1 hard cheese. By colony hybridization, 29 STEC strains were isolated from 24 semihard and 5 soft cheeses. Thirteen of the 24 strains typeable with O antisera belonged to the serogroups O2, O22, and O91. More than half (58.6%) of the 29 strains belonged to O:H serotypes previously isolated from humans, and STEC O22:H8, O91:H10, O91:H21, and O174:H21 have also been identified as agents of hemolytic uremic syndrome. Typing of Shiga toxin genes showed that stx1 was only found in 2 strains, whereas 27 strains carried genes encoding for the Stx2 group, mainly stx2 and stx2vh-a/b. Production of Stx2 and Stx2vh-a/b subtypes might be an indicator for a severe outcome in patients. Nine strains harbored hlyA (enterohemorrhagic E. coli hemolysin), whereas none tested positive for eae (intimin). Consequently, semihard and hard raw milk cheese may be a potential source of STEC, and a notable proportion of the isolated non-O157 STEC strains belonged to serotypes or harbored Shiga toxin gene variants associated with human infections.

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 Virulence gene profiles of avian pathogenic Escherichia coli isolated from chickens with colibacillosis in Bulawayo, Zimbabwe

2015 ◽  
Vol 82 (1) ◽  
Author(s):  
Joshua Mbanga ◽  
Yvonne O. Nyararai
Keyword(s):  
Escherichia Coli ◽  
Virulence Genes ◽  
Virulence Gene ◽  
Economic Losses ◽  
Avian Pathogenic Escherichia Coli ◽  
Pcr Assay ◽  
E Coli ◽  
Gene Profiles ◽  
Pathogenic Escherichia Coli ◽  
Polymerase Chain

Colibacillosis, a disease caused by avian pathogenic Escherichia coli (APEC), is one of the main causes of economic losses in the poultry industry worldwide. This study was carried out in order to determine the APEC-associated virulence genes contained by E. coli isolates causing colibacillosis in chickens. A total of 45 E. coli isolates were obtained from the diagnostics and research branch of the Central Veterinary Laboratories, Bulawayo, Zimbabwe. These isolates were obtained from chickens with confirmed cases of colibacillosis after postmortem examination. The presence of the iutA, hlyF, ompT, frz, sitD, fimH, kpsM, sitA, sopB, uvrY, pstB and vat genes were investigated by multiplex polymerase chain reaction (PCR) assay. Of the 45 isolates, 93% were positive for the presence of at least one virulence gene. The three most prevalent virulence genes were iutA (80%), fimH (33.3%) and hlyF (24.4%). The kpsM, pstB and ompT genes had the lowest prevalence, having been detected in only 2.2% of the isolates. All 12 virulence genes studied were detected in the 45 APEC isolates. Virulence gene profiles were constructed for each APEC isolate from the multiplex data. The APEC isolates were profiled as 62.2% fitting profile A, 31.1% profile B and 6.7% profile C. None of the isolates had more than seven virulence genes. Virulence profiles of Zimbabwean APEC isolates are different from those previously reported. Zimbabwean APEC isolates appear to be less pathogenic and may rely on environmental factors and stress in hosts to establish infection.

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