scholarly journals Prevalence and Characteristics of Shiga Toxin-Producing Escherichia coli from Healthy Cattle in Japan

2001 ◽  
Vol 67 (1) ◽  
pp. 484-489 ◽  
Author(s):  
Hideki Kobayashi ◽  
Jun Shimada ◽  
Muneo Nakazawa ◽  
Tetsuo Morozumi ◽  
Tarja Pohjanvirta ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Virulence Factor ◽  
Shiga Toxin ◽  
Animal Groups ◽  
E Coli ◽  
Healthy Cattle ◽  
Stool Samples ◽  
Enterocyte Effacement ◽  
Virulence Factor Genes

ABSTRACT The prevalence of Shiga toxin-producing Escherichia coli (STEC) in Japan was examined by using stool samples from 87 calves, 88 heifers, and 183 cows on 78 farms. As determined by screening with stx-PCR, the prevalence was 46% in calves, 66% in heifers, and 69% in cows; as determined by nestedstx-PCR, the prevalence was 100% in all animal groups. Of the 962 isolates picked by colony stx hybridization, 92 isolates from 54 farms were characterized to determine their O serogroups, virulence factor genes, and antimicrobial resistance. Of these 92 isolates, 74 (80%) could be classified into O serogroups; 50% of these 74 isolates belonged to O serogroups O8, O26, O84, O113, and O116 and 1 isolate belonged to O serogroup O157. Locus of enterocyte effacement genes were detected in 24% of the isolates, and enterohemorrhagic E. coli (EHEC) hlyA genes were detected in 72% of the isolates. Neither the bundle-forming pilus gene nor the enteropathogenic E. coli adherence factor plasmid was found. STEC strains with characteristics typical of isolates from human EHEC infections, which were regarded as potential EHEC strains, were present on 11.5% of the farms.

scholarly journals Correlation Between Antimicrobial Resistance, Virulence Determinants and Biofilm Formation Ability Among Extraintestinal Pathogenic Escherichia coli Strains Isolated in Catalonia, Spain

2022 ◽  
Vol 12 ◽  
Author(s):  
Victoria Ballén ◽  
Yaiza Gabasa ◽  
Carlos Ratia ◽  
Melany Sánchez ◽  
Sara Soto
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Virulence Factor ◽  
Biofilm Formation ◽  
Clonal Diversity ◽  
Virulence Determinants ◽  
E Coli ◽  
Antimicrobial Resistance Genes ◽  
Encoding Genes ◽  
Virulence Factor Genes

Escherichia coli is a well-characterized bacterium highly prevalent in the human intestinal tract and the cause of many important infections. The aim of this study was to characterize 376 extraintestinal pathogenic E. coli strains collected from four hospitals in Catalonia (Spain) between 2016 and 2017 in terms of antimicrobial resistance, siderophore production, phylogroup classification, and the presence of selected virulence and antimicrobial resistance genes. In addition, the association between these characteristics and the ability to form biofilms was also analyzed. The strains studied were classified into four groups according to their biofilm formation ability: non-biofilm formers (15.7%), weak (23.1%), moderate (35.6%), and strong biofilm formers (25.6%). The strains were highly resistant to ciprofloxacin (48.7%), trimethoprim-sulfamethoxazole (47.9%), and ampicillin (38%), showing a correlation between higher resistance to ciprofloxacin and lower biofilm production. Seventy-three strains (19.4%) were ESBL-producers. However, no relationship between the presence of ESBL and biofilm formation was found. The virulence factor genes fimH (92%), pgaA (84.6%), and irp1 (77.1%) were the most prevalent in all the studied strains. A statistically significant correlation was found between biofilm formation and the presence of iroN, papA, fimH, sfa, cnf, hlyA, iutA, and colibactin-encoding genes clbA, clbB, clbN, and clbQ. Interestingly, a high prevalence of colibactin-encoding genes (19.9%) was observed. Colibactin is a virulence factor, which interferes with the eukaryotic cell cycle and has been associated with colorectal cancer in humans. Most colibactin-encoding E. coli isolates belonged to phylogroup B2, exhibited low antimicrobial resistance but moderate or high biofilm-forming ability, and were significantly associated with most of the virulence factor genes tested. Additionally, the analysis of their clonal relatedness by PFGE showed 48 different clusters, indicating a high clonal diversity among the colibactin-positive strains. Several studies have correlated the pathogenicity of E. coli and the presence of virulence factor genes; however, colibactin and its relationship to biofilm formation have been scarcely investigated. The increasing prevalence of colibactin in E. coli and other Enterobacteriaceae and the recently described correlation with biofilm formation, makes colibactin a promising therapeutic target to prevent biofilm formation and its associated adverse effects.

Outbreak of Shiga Toxin–Producing Escherichia coli (STEC) O104:H4 Infection in Germany Causes a Paradigm Shift with Regard to Human Pathogenicity of STEC Strains

2012 ◽  
Vol 75 (2) ◽  
pp. 408-418 ◽  
Author(s):  
LOTHAR BEUTIN ◽  
ANNETT MARTIN
Keyword(s):  
Escherichia Coli ◽  
Hemolytic Uremic Syndrome ◽  
Shiga Toxin ◽  
Outbreak Strain ◽  
Fenugreek Seeds ◽  
E Coli ◽  
Aggregative Adherence ◽  
Uremic Syndrome ◽  
Enterocyte Effacement ◽  
The Way

An outbreak that comprised 3,842 cases of human infections with enteroaggregative hemorrhagic Escherichia coli (EAHEC) O104:H4 occurred in Germany in May 2011. The high proportion of adults affected in this outbreak and the unusually high number of patients that developed hemolytic uremic syndrome makes this outbreak the most dramatic since enterohemorrhagic E. coli (EHEC) strains were first identified as agents of human disease. The characteristics of the outbreak strain, the way it spread among humans, and the clinical signs resulting from EAHEC infections have changed the way Shiga toxin–producing E. coli strains are regarded as human pathogens in general. EAHEC O104:H4 is an emerging E. coli pathotype that is endemic in Central Africa and has spread to Europe and Asia. EAHEC strains have evolved from enteroaggregative E. coli by uptake of a Shiga toxin 2a (Stx2a)–encoding bacteriophage. Except for Stx2a, no other EHEC-specific virulence markers including the locus of enterocyte effacement are present in EAHEC strains. EAHEC O104:H4 colonizes humans through aggregative adherence fimbrial pili encoded by the enteroaggregative E. coli plasmid. The aggregative adherence fimbrial colonization mechanism substitutes for the locus of enterocyte effacement functions for bacterial adherence and delivery of Stx2a into the human intestine, resulting clinically in hemolytic uremic syndrome. Humans are the only known natural reservoir known for EAHEC. In contrast, Shiga toxin–producing E. coli and EHEC are associated with animals as natural hosts. Contaminated sprouted fenugreek seeds were suspected as the primary vehicle of transmission of the EAHEC O104:H4 outbreak strain in Germany. During the outbreak, secondary transmission (human to human and human to food) was important. Epidemiological investigations revealed fenugreek seeds as the source of entry of EAHEC O104:H4 into the food chain; however, microbiological analysis of seeds for this pathogen produced negative results. The survival of EAHEC in seeds and the frequency of human carriers of EAHEC should be investigated for a better understanding of EAHEC transmission routes.

Molecular characterization and prevalence of virulence factor genes of Shiga toxin-producing Escherichia coli (STEC) isolated from diarrheic children

Gene Reports ◽  
2021 ◽  
pp. 101379
Author(s):  
Mohammad Moeinirad ◽  
Masoumeh Douraghi ◽  
Abbas Rahimi Foroushani ◽  
Rahimeh Sanikhani ◽  
Mohammad Mehdi Soltan Dallal
Keyword(s):  
Escherichia Coli ◽  
Molecular Characterization ◽  
Virulence Factor ◽  
Shiga Toxin ◽  
Virulence Factor Genes

scholarly journals Haemolytic uraemic syndrome and Shiga toxin-producing Escherichia coli infection in children in France

2000 ◽  
Vol 124 (2) ◽  
pp. 215-220 ◽  
Author(s):  
B. DECLUDT ◽  
P. BOUVET ◽  
P. MARIANI-KURKDJIAN ◽  
F. GRIMONT ◽  
P. A. D. GRIMONT ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Prospective Study ◽  
Shiga Toxin ◽  
Haemolytic Uraemic Syndrome ◽  
Serum Samples ◽  
E Coli ◽  
Escherichia Coli Infection ◽  
Stool Samples ◽  
Polymerase Chain

We conducted a study to determine the incidence of haemolytic uraemic syndrome (HUS) in children in France and to assess the role of Shiga-toxin-producing Escherichia coli (STEC) infection in the aetiology of HUS. In collaboration with the Société de Néphrologie Pédiatrique we undertook a retrospective review of all cases of HUS hospitalized from January 1993 to March 1995 and a 1-year prospective study (April 1995–March 1996) of epidemiological and microbiological features of cases of HUS. The polymerase chain reaction (PCR) procedure was used to detect stx, eae, e-hlyA genes directly from case stool samples. Serum samples from cases were examined for antibodies to lipopolysaccharide (LPS) of 26 major STEC serogroups. Two hundred and eighty-six cases were reported. The average incidence per year was 0·7/105 children < 15 years and 1·8/105 children < 5 years. During the prospective study, 122/130 cases were examined for evidence of STEC infection using PCR and/or serological assays and 105 (86%) had evidence of STEC infection. Serum antibodies to E. coli O157 LPS were detected in 79 (67%) cases tested. In conclusion, this study showed that STEC infection is an important cause of HUS in children in France, with a high proportion related to the O157 serogroup.

scholarly journals Localization of the Insertion Site and Pathotype Determination of the Locus of Enterocyte Effacement of Shiga Toxin-Producing Escherichia coli Strains

2004 ◽  
Vol 70 (1) ◽  
pp. 61-68 ◽  
Author(s):  
Yolande Bertin ◽  
Karima Boukhors ◽  
Valerie Livrelli ◽  
Christine Martin
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Insertion Site ◽  
Pcr Amplification ◽  
Food Samples ◽  
Asymptomatic Children ◽  
Healthy Cattle ◽  
Sporadic Cases ◽  
Enterocyte Effacement ◽  
Great Genetic Diversity

ABSTRACT Of 220 Shiga toxin-producing Escherichia coli (STEC) strains collected in central France from healthy cattle, food samples, and asymptomatic children, 12 possessed the eae gene included in the locus of enterocyte effacement (LEE) pathogenicity island. Based on gene typing, we observed 7 different eae espA espB tir pathotypes among the 12 STEC strains and described the new espAβv variant. As previously observed, the O157 serogroup is associated with eaeγ, O26 is associated with eaeβ, and O103 is associated with eaeε. However, the unexpected eaeζ allele was detected in 5 of the 12 isolates. PCR amplification and pulsed-field gel electrophoresis using the I-CeuI endonuclease followed by Southern hybridization indicated that the LEE was inserted in the vicinity of the selC (three isolates), pheU (two isolates), or pheV (six isolates) tRNA gene. Six isolates harbored two or three of these tRNA loci altered by the insertion of integrase genes (CP4-int and/or int-phe), suggesting the insertion of additional foreign DNA fragments at these sites. In spite of great genetic diversity of LEE pathotypes and LEE insertion sites, bovine strains harbor alleles of LEE genes that are frequently found in clinical STEC strains isolated from outbreaks and sporadic cases around the world, underscoring the potential risk of the bovine strains on human health.

scholarly journals Antibiotic resistance and virulence genes of extraintestinal pathogenic Escherichia coli from tropical estuary, south India

2015 ◽  
Vol 9 (05) ◽  
pp. 496-504 ◽  
Author(s):  
Divya Sukumaran ◽  
Abdulla A Mohamed Hatha
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Multidrug Resistance ◽  
Virulence Factor ◽  
Virulence Genes ◽  
Antimicrobial Agents ◽  
Diffusion Method ◽  
Disk Diffusion Method ◽  
E Coli ◽  
Virulence Factor Genes

Introduction: Escherichia coli strains can cause a variety of intestinal and extraintestinal diseases. Extraintestinal pathogenic E. coli (ExPEC) strains have the ability to cause severe extraintestinal infections. Multidrug resistance among ExPEC could complicate human infections. Methodology: Escherichia coli strains were isolated during the period of January 2010 to December 2012 from five different stations set at Cochin estuary. Susceptibility testing was determined by the disk-diffusion method using nine different antimicrobial agents. A total of 155 strains of Escherichia coli were screened for the presence of virulence factor genes including papAH, papC, sfa/focDE, iutA,and kpsMT II associated with ExPEC. Results: Among the 155 E. coli isolates, 26 (16.77%), carried two or more virulence genes typical of ExPEC. Furthermore, 19.23% of the ExPEC isolates with multidrug resistance were identified to belong to phylogenetic groups B2 and D. Statistically significant association of iutA gene in ExPEC was found with papC (p < 0.001) and kpsMT II (p < 0.001) genes. ExPEC isolates were mainly resistant to ampicillin (23.07%), tetracycline (19.23%), co-trimoxazole (15.38%), and cefotaxime (15.38%). The adhesion genes papAH and sfa/focDE were positively associated with resistance to gentamicin, chloramphenicol, and cefotaxime (p < 0.05). Conclusions: Co-occurrence of virulence factor genes with antibiotic resistance among ExPEC poses considerable threat to those who use this aquatic system for a living and for recreation.

scholarly journals Virulence Properties of Shiga Toxin-Producing Escherichia coli (STEC) Strains of Serogroup O118, a Major Group of STEC Pathogens in Calves

1998 ◽  
Vol 36 (6) ◽  
pp. 1604-1607 ◽  
Author(s):  
L. H. Wieler ◽  
Anja Schwanitz ◽  
Elke Vieler ◽  
Barbara Busse ◽  
H. Steinrück ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Diagnostic Value ◽  
Adhesive Properties ◽  
E Coli ◽  
Virulence Potential ◽  
High Prevalence ◽  
Enterocyte Effacement ◽  
Diarrheic Calves ◽  
Virulence Properties

Shiga toxin-producing Escherichia coli (STEC) strains of serogroup O118 are the most prevalent group among STEC strains in diarrheic calves in Germany (L. H. Wieler, Ph.D. thesis, University of Giessen, 1997). To define their virulence properties, 42 O118 (O118:H16 [n = 38] and O118:H− [n = 4]) strains were characterized. The strains displayed three different Stx combinations (Stx1 [36 of 42], Stx1 and Stx2 [2 of 42], and Stx2 [4 of 42]). A total of 41 strains (97.6%) harbored a large virulence-associated plasmid containinghly EHEC (hly from enterohemorrhagicE. coli). The strains’ adhesive properties varied in relation to the eukaryotic cells tested. Only 28 of 42 strains (66.7%) showed localized adhesion (LA) in the human HEp-2 cell line. In contrast, in bovine fetal calf lung (FCL) cells, the number of LA-positive strains was much higher (37 of 42 [88.1%]). The locus of enterocyte effacement (LEE) was detected in 41 strains (97.6%). However, not all LEE-positive strains reacted positively in the fluorescence actin-staining (FAS) test, which indicated the attaching and effacing (AE) lesion. In HEp-2 cells, only 22 strains (52.4%) were FAS positive, while in FCL cells, the number of FAS-positive strains was significantly higher (38 of 42 [90.5%; P < 0.001]). In conclusion, the vast majority of the O118 STEC strains from calves (41 of 42 [97.6%]) have a high virulence potential (stx, hly EHEC, and LEE). This virulence potential and the high prevalence of STEC O118 strains in calves suggest that these strains could be a major health threat for humans in the future. In addition, the poor association between results of the geno- and phenotypical tests to screen for the AE ability of STEC strains calls the diagnostic value of the FAS test into question.

scholarly journals Is Shiga Toxin-Producing Escherichia coli O45 No Longer a Food Safety Threat? The Danger is Still Out There

2020 ◽  
Vol 8 (5) ◽  
pp. 782 ◽  
Author(s):  
Yujie Zhang ◽  
Yen-Te Liao ◽  
Xiaohong Sun ◽  
Vivian C.H. Wu
Keyword(s):  
Escherichia Coli ◽  
Virulence Factors ◽  
Shiga Toxin ◽  
Evolutionary Relationship ◽  
Severe Illness ◽  
Next Generation Sequencing Technology ◽  
E Coli ◽  
Related Information ◽  
Foodborne Outbreaks ◽  
Enterocyte Effacement

Many Shiga toxin-producing Escherichia coli (STEC) strains, including the serogroups of O157 and most of the top six non-O157 serotypes, are frequently associated with foodborne outbreaks. Therefore, they have been extensively studied using next-generation sequencing technology. However, related information regarding STEC O45 strains is scarce. In this study, three environmental E. coli O45:H16 strains (RM11911, RM13745, and RM13752) and one clinical E. coli O45:H2 strain (SJ7) were sequenced and used to characterize virulence factors using two reference E. coli O45:H2 strains of clinical origin. Subsequently, whole-genome-based phylogenetic analysis was conducted for the six STEC O45 strains and nine other reference STEC genomes, in order to evaluate their evolutionary relationship. The results show that one locus of enterocyte effacement pathogenicity island was found in all three STEC O45:H2 strains, but not in the STEC O45:H16 strains. Additionally, E. coli O45:H2 strains were evolutionarily close to E. coli O103:H2 strains, sharing high homology in terms of virulence factors, such as Stx prophages, but were distinct from E. coli O45:H16 strains. The findings show that E. coli O45:H2 may be as virulent as E. coli O103:H2, which is frequently associated with severe illness and can provide genomic evidence to facilitate STEC surveillance.

scholarly journals Prevalences of Shiga Toxin Subtypes and Selected Other Virulence Factors among Shiga-Toxigenic Escherichia coli Strains Isolated from Fresh Produce

2013 ◽  
Vol 79 (22) ◽  
pp. 6917-6923 ◽  
Author(s):  
Peter C. H. Feng ◽  
Shanker Reddy
Keyword(s):  
Escherichia Coli ◽  
Virulence Factors ◽  
Virulence Factor ◽  
Shiga Toxin ◽  
Fresh Produce ◽  
Putative Virulence Factor ◽  
Content Type ◽  
Human Illness ◽  
Subtilase Cytotoxin ◽  
Virulence Factor Genes

ABSTRACTShiga-toxigenicEscherichia coli(STEC) strains were isolated from a variety of fresh produce, but mostly from spinach, with an estimated prevalence rate of 0.5%. A panel of 132 produce STEC strains were characterized for the presence of virulence and putative virulence factor genes and for Shiga toxin subtypes. About 9% of the isolates were found to have theeaegene, which encodes the intimin binding protein, and most of these belonged to known pathogenic STEC serotypes, such as O157:H7 and O26:H11, or to serotypes that reportedly have caused human illness. Among theeae-negative strains, there were three O113:H21 strains and one O91:H21 strain, which historically have been implicated in illness and therefore may be of concern as well. TheehxAgene, which encodes enterohemolysin, was found in ∼60% of the isolates, and thesaaandsubABgenes, which encode STEC agglutinating adhesin and subtilase cytotoxin, respectively, were found in ∼30% of the isolates. However, the precise roles of these three putative virulence factors in STEC pathogenesis have not yet been fully established. Thestx1aandstx2asubtypes were present in 22% and 56%, respectively, of the strains overall and were the most common subtypes among produce STEC strains. Thestx2dsubtype was the second most common subtype (28% overall), followed bystx2c(7.5%), and only 2 to 3% of the produce STEC strains had thestx2eandstx2gsubtypes. Almost half of the produce STEC strains had only partial serotypes or were untyped, and most of those that were identified belonged to unremarkable serotypes. Considering the uncertainties of some of these Stx subtypes and putative virulence factors in causing human illness, it is difficult to determine the health risk of many of these produce STEC strains.

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