scholarly journals Diversity of Shiga Toxin-Producing Escherichia coli (STEC) O26:H11 Strains Examined viastxSubtypes and Insertion Sites of Stx and EspK Bacteriophages

2015 ◽  
Vol 81 (11) ◽  
pp. 3712-3721 ◽  
Author(s):  
Ludivine Bonanno ◽  
Estelle Loukiadis ◽  
Patricia Mariani-Kurkdjian ◽  
Eric Oswald ◽  
Lucille Garnier ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Sequence Type ◽  
Phylogenetic Groups ◽  
Content Type ◽  
Shiga Toxins ◽  
E Coli ◽  
Food Borne ◽  
Insertion Sites ◽  
Human Infections

ABSTRACTShiga toxin-producingEscherichia coli(STEC) is a food-borne pathogen that may be responsible for severe human infections. Only a limited number of serotypes, including O26:H11, are involved in the majority of serious cases and outbreaks. The main virulence factors, Shiga toxins (Stx), are encoded by bacteriophages. Seventy-four STEC O26:H11 strains of various origins (including human, dairy, and cattle) were characterized for theirstxsubtypes and Stx phage chromosomal insertion sites. The majority of food and cattle strains possessed thestx1asubtype, while human strains carried mainlystx1aorstx2a. ThewrbAandyehVgenes were the main Stx phage insertion sites in STEC O26:H11, followed distantly byyecEandsbcB. Interestingly, the occurrence of Stx phages inserted in theyecEgene was low in dairy strains. In most of the 29stx-negativeE. coliO26:H11 strains also studied here, these bacterial insertion sites were vacant. Multilocus sequence typing of 20stx-positive orstx-negativeE. coliO26:H11 strains showed that they were distributed into two phylogenetic groups defined by sequence type 21 (ST21) and ST29. Finally, an EspK-carrying phage was found inserted in thessrAgene in the majority of the STEC O26:H11 strains but in only a minority of thestx-negativeE. coliO26:H11 strains. The differences in thestxsubtypes and Stx phage insertion sites observed in STEC O26:H11 according to their origin might reflect that strains circulating in cattle and foods are clonally distinct from those isolated from human patients.

scholarly journals Emergence of Escherichia coli encoding Shiga toxin 2f in human Shiga toxin-producing E. coli (STEC) infections in the Netherlands, January 2008 to December 2011

2014 ◽  
Vol 19 (17) ◽  
Author(s):  
I Friesema ◽  
K van der Zwaluw ◽  
T Schuurman ◽  
M Kooistra-Smid ◽  
E Franz ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
The Netherlands ◽  
Shiga Toxin ◽  
Distinct Group ◽  
Shiga Toxins ◽  
E Coli ◽  
Mild Disease ◽  
Shiga Toxin 2 ◽  
Almost All ◽  
Human Infections

The Shiga toxins of Shiga toxin-producing Escherichia coli (STEC) can be divided into Shiga toxin 1 (Stx1) and Shiga toxin 2 (Stx2) with several sub-variants. Variant Stx2f is one of the latest described, but has been rarely associated with symptomatic human infections. In the enhanced STEC surveillance in the Netherlands, 198 STEC O157 cases and 351 STEC non-O157 cases, including 87 stx2f STEC isolates, were reported between 2008 and 2011. Most stx2f strains belonged to the serogroups O63:H6 (n=47, 54%), O113:H6 (n=12, 14%) and O125:H6 (n=12, 14%). Of the 87 stx2f isolates, 84 (97%) harboured the E. coli attaching and effacing (eae) gene, but not the enterohaemorrhagic E. coli haemolysin (hly) gene. Stx2f STEC infections show milder symptoms and a less severe clinical course than STEC O157 infections. Almost all infections with stx2f (n=83, 95%) occurred between June and December, compared to 170/198 (86%) of STEC O157 and 173/264 (66%) of other STEC non-O157. Stx2f STEC infections in the Netherlands are more common than anticipated, and form a distinct group within STEC with regard to virulence genes and the relatively mild disease.

scholarly journals Identification of Human-Pathogenic Strains of Shiga Toxin-Producing Escherichia coli from Food by a Combination of Serotyping and Molecular Typing of Shiga Toxin Genes

2007 ◽  
Vol 73 (15) ◽  
pp. 4769-4775 ◽  
Author(s):  
Lothar Beutin ◽  
Angelika Miko ◽  
Gladys Krause ◽  
Karin Pries ◽  
Sabine Haby ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Severe Illness ◽  
Shiga Toxins ◽  
E Coli ◽  
Food Borne ◽  
Length Polymorphisms ◽  
Beef Products ◽  
Pcr Products ◽  
Shiga Toxin Genes

ABSTRACT We examined 219 Shiga toxin-producing Escherichia coli (STEC) strains from meat, milk, and cheese samples collected in Germany between 2005 and 2006. All strains were investigated for their serotypes and for genetic variants of Shiga toxins 1 and 2 (Stx1 and Stx2). stx 1 or variant genes were detected in 88 (40.2%) strains and stx 2 and variants in 177 (80.8%) strains. Typing of stx genes was performed by stx-specific PCRs and by analysis of restriction fragment length polymorphisms (RFLP) of PCR products. Major genotypes of the Stx1 (stx 1, stx 1c, and stx 1d) and the Stx2 (stx 2, stx 2d, stx 2-O118, stx 2e, and stx 2g) families were detected, and multiple types of stx genes coexisted frequently in STEC strains. Only 1.8% of the STEC strains from food belonged to the classical enterohemorrhagic E. coli (EHEC) types O26:H11, O103:H2, and O157:H7, and only 5.0% of the STEC strains from food were positive for the eae gene, which is a virulence trait of classical EHEC. In contrast, 95 (43.4%) of the food-borne STEC strains carried stx 2 and/or mucus-activatable stx 2d genes, an indicator for potential high virulence of STEC for humans. Most of these strains belonged to serotypes associated with severe illness in humans, such as O22:H8, O91:H21, O113:H21, O174:H2, and O174:H21. stx 2 and stx 2d STEC strains were found frequently in milk and beef products. Other stx types were associated more frequently with pork (stx 2e), lamb, and wildlife meat (stx 1c). The combination of serotyping and stx genotyping was found useful for identification and for assignment of food-borne STEC to groups with potential lower and higher levels of virulence for humans.

scholarly journals Origin and Evolution of Hybrid Shiga Toxin-Producing and Uropathogenic Escherichia coli Strains of Sequence Type 141

2019 ◽  
Vol 58 (1) ◽  
Author(s):  
Noble Selasi Gati ◽  
Barbara Middendorf-Bauchart ◽  
Stefan Bletz ◽  
Ulrich Dobrindt ◽  
Alexander Mellmann
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
The United States ◽  
Sequence Type ◽  
Comparative Genomic ◽  
Trna Genes ◽  
Ancestral Reconstruction ◽  
Content Type ◽  
E Coli ◽  
Tract Infections

ABSTRACT Hybrid Shiga toxin-producing Escherichia coli (STEC) and uropathogenic E. coli (UPEC) strains of multilocus sequence type 141 (ST141) cause both urinary tract infections and diarrhea in humans and are phylogenetically positioned between STEC and UPEC strains. We used comparative genomic analysis of 85 temporally and spatially diverse ST141 E. coli strains, including 14 STEC/UPEC hybrids, collected in Germany (n = 13) and the United States (n = 1) to reconstruct their molecular evolution. Whole-genome sequencing data showed that 89% of the ST141 E. coli strains either were STEC/UPEC hybrids or contained a mixture of virulence genes from other pathotypes. Core genome analysis and ancestral reconstruction revealed that the ST141 E. coli strains clustered into two lineages that evolved from a common ancestor in the mid-19th century. The STEC/UPEC hybrid emerged ∼100 years ago by acquiring an stx prophage, which integrated into previously unknown insertion site between rcsB and rcsD, followed by the insertion of a pathogenicity island (PAI) similar to PAI II of UPEC strain 536 (PAI II536-like). The two variants of PAI II536-like were associated with tRNA genes leuX and pheU, respectively. Finally, microevolution within PAI II536-like and acquisition of the enterohemorrhagic E. coli plasmid were observed. Our data suggest that intestinal pathogenic E. coli (IPEC)/extraintestinal pathogenic E. coli (ExPEC) hybrids are widespread and that selection pressure within the ST141 E. coli population led to the emergence of the STEC/UPEC hybrid as a clinically important subgroup. We hypothesize that ST141 E. coli strains serve as a melting pot for pathogroup conversion between IPEC and ExPEC, contrasting the classical theory of pathogen emergence from nonpathogens and corroborating our recent phenomenon of heteropathogenicity among pathogenic E. coli strains.

scholarly journals Virulence Genes in Expanded-Spectrum-Cephalosporin-Resistant and -Susceptible Escherichia coli Isolates from Treated and Untreated Chickens

2015 ◽  
Vol 60 (3) ◽  
pp. 1874-1877 ◽  
Author(s):  
S. Baron ◽  
S. Delannoy ◽  
S. Bougeard ◽  
E. Larvor ◽  
E. Jouy ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Virulence Factors ◽  
Shiga Toxin ◽  
Virulence Genes ◽  
Phylogenetic Groups ◽  
Content Type ◽  
E Coli ◽  
Heat Stable ◽  
Intestinal Infections

This study investigated antimicrobial resistance, screened for the presence of virulence genes involved in intestinal infections, and determined phylogenetic groups ofEscherichia coliisolates from untreated poultry and poultry treated with ceftiofur, an expanded-spectrum cephalosporin. Results show that none of the 76 isolates appeared to be Shiga toxin-producingE. colior enteropathogenicE. coli. All isolates were negative for the major virulence factors/toxins tested (ehxA,cdt, heat-stable enterotoxin [ST], and heat-labile enterotoxin [LT]). The few virulence genes harbored in isolates generally did not correlate with isolate antimicrobial resistance or treatment status. However, some of the virulence genes were significantly associated with certain phylogenetic groups.

scholarly journals Day-to-Day Dynamics of Commensal Escherichia coli in Zimbabwean Cows Evidence Temporal Fluctuations within a Host-Specific Population Structure

2017 ◽  
Vol 83 (13) ◽  
Author(s):  
Méril Massot ◽  
Camille Couffignal ◽  
Olivier Clermont ◽  
Camille D'Humières ◽  
Jérémie Chatel ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Treatment ◽  
Shiga Toxin ◽  
Sampling Period ◽  
Time Frame ◽  
Phylogenetic Groups ◽  
Antibiotic Resistant ◽  
Content Type ◽  
E Coli ◽  
Short Time

ABSTRACT To get insights into the temporal pattern of commensal Escherichia coli populations, we sampled the feces of four healthy cows from the same herd in the Hwange District of Zimbabwe daily over 25 days. The cows had not received antibiotic treatment during the previous 3 months. We performed viable E. coli counts and characterized the 326 isolates originating from the 98 stool samples at a clonal level, screened them for stx and eae genes, and tested them for their antibiotic susceptibilities. We observed that E. coli counts and dominant clones were different among cows, and very few clones were shared. No clone was shared by three or four cows. Clone richness and evenness were not different between cows. Within each host, the variability in the E. coli count was evidenced between days, and no clone was found to be dominant during the entire sampling period, suggesting the existence of clonal interference. Dominant clones tended to persist longer than subdominant ones and were mainly from phylogenetic groups A and B1. Five E. coli clones were found to contain both the stx 1 and stx 2 genes, representing 6.3% of the studied isolates. All cows harbored at least one Shiga toxin-producing E. coli (STEC) strain. Resistance to tetracycline, penicillins, trimethoprim, and sulfonamides was rare and observed in three clones that were shed at low levels in two cows. This study highlights the fact that the commensal E. coli population, including the STEC population, is host specific, is highly dynamic over a short time frame, and rarely carries antibiotic resistance determinants in the absence of antibiotic treatment. IMPORTANCE The literature about the dynamics of commensal Escherichia coli populations is very scarce. Over 25 days, we followed the total E. coli counts daily and characterized the sampled clones in the feces of four cows from the same herd living in the Hwange District of Zimbabwe. This study deals with the day-to-day dynamics of both quantitative and qualitative aspects of E. coli commensal populations, with a focus on both Shiga toxin-producing E. coli and antibiotic-resistant E. coli strains. We show that the structure of these commensal populations was highly specific to the host, even though the cows ate and roamed together, and was highly dynamic between days. Such data are of importance to understand the ecological forces that drive the dynamics of the emergence of E. coli clones of particular interest within the gastrointestinal tract and their transmission between hosts.

scholarly journals Role of orf73 in the development of lambdoid bacteriophages during infection of the Escherichia coli host

2019 ◽  
Author(s):  
Karolina Zdrojewska ◽  
Aleksandra Dydecka ◽  
Bożena Nejman-Faleńczyk ◽  
Gracja Topka ◽  
Agnieszka Necel ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Burst Size ◽  
Survival Rates ◽  
Lytic Cycle ◽  
Host Cells ◽  
Shiga Toxins ◽  
E Coli ◽  
Human Infections

Shiga toxin-producing Escherichia coli (STEC) is a group of pathogenic strains responsible for human infections that result in bloody diarrhea and hemorrhagic colitis, often with severe complications. The main virulence factors of STEC are Shiga toxins encoded by stx genes located in genomes of Shiga toxin-converting bacteriophages (Stx phages). These bacterial viruses are clustered in the lambdoid bacteriophages family represented by phage λ. Here, we report that expression of orf73 from the exo-xis region of the phage genome promotes the lysogenic pathway of development of λ and Φ24B phages. We demonstrated that the mutant phages with deletions of orf73 revealed higher burst size during the lytic cycle. Moreover, survival rates of E. coli infected with mutant bacteriophages were lower relative to wild-type viruses. Additionally, orf73 deletion negatively influenced the lysogenization process of E. coli host cells. We conclude that orf73 plays an important biological role in the development of lambdoid viruses, and probably it is involved in the network of molecular mechanism of the lysis-vs.-lysogenization decision.

scholarly journals Phylogenetic and Molecular Analysis of Food-Borne Shiga Toxin-Producing Escherichia coli

2013 ◽  
Vol 79 (8) ◽  
pp. 2731-2740 ◽  
Author(s):  
Elisabeth Hauser ◽  
Alexander Mellmann ◽  
Torsten Semmler ◽  
Helen Stoeber ◽  
Lothar H. Wieler ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Virulence Gene ◽  
Human Infection ◽  
Pathogenic Potential ◽  
Content Type ◽  
E Coli ◽  
Food Borne ◽  
Strain Collection ◽  
Integration Sites

ABSTRACTSeventy-five food-associated Shiga toxin-producingEscherichia coli(STEC) strains were analyzed by molecular and phylogenetic methods to describe their pathogenic potential. The presence of the locus of proteolysis activity (LPA), the chromosomal pathogenicity island (PAI) PAI ICL3, and the autotransporter-encoding genesabAwas examined by PCR. Furthermore, the occupation of the chromosomal integration sites of the locus of enterocyte effacement (LEE),selC,pheU, andpheV, as well as the Stx phage integration sitesyehV,yecE,wrbA,z2577, andssrA, was analyzed. Moreover, the antibiotic resistance phenotypes of all STEC strains were determined. Multilocus sequence typing (MLST) was performed, and sequence types (STs) and sequence type complexes (STCs) were compared with those of 42 hemolytic-uremic syndrome (HUS)-associated enterohemorrhagicE. coli(HUSEC) strains. Besides 59 STs and 4 STCs, three larger clusters were defined in this strain collection. Clusters A and C consist mostly of highly pathogeniceae-positive HUSEC strains and some related food-borne STEC strains. A member of a new O26 HUS-associated clone and the 2011 outbreak strainE. coliO104:H4 were found in cluster A. Cluster B comprises onlyeae-negative food-borne STEC strains as well as mainlyeae-negative HUSEC strains. Although food-borne strains of cluster B were not clearly associated with disease, serotypes of important pathogens, such as O91:H21 and O113:H21, were in this cluster and closely related to the food-borne strains. Clonal analysis demonstrated eight closely related genetic groups of food-borne STEC and HUSEC strains that shared the same ST and were similar in their virulence gene composition. These groups should be considered with respect to their potential for human infection.

scholarly journals Phylogenetic Grouping and Virulence Potential of Extended-Spectrum-β-Lactamase-Producing Escherichia coli Strains in Cattle

2012 ◽  
Vol 78 (13) ◽  
pp. 4677-4682 ◽  
Author(s):  
Charlotte Valat ◽  
Frédéric Auvray ◽  
Karine Forest ◽  
Véronique Métayer ◽  
Emilie Gay ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Virulence Determinants ◽  
Phylogenetic Groups ◽  
Content Type ◽  
E Coli ◽  
Extended Spectrum ◽  
Specific Distribution ◽  
Extended Spectrum Beta Lactamases ◽  
Phylogenetic Grouping ◽  
Almost All

ABSTRACTIn line with recent reports of extended-spectrum beta-lactamases (ESBLs) inEscherichia coliisolates of highly virulent serotypes, such as O104:H4, we investigated the distribution of phylogroups (A, B1, B2, D) and virulence factor (VF)-encoding genes in 204 ESBL-producingE. coliisolates from diarrheic cattle. ESBL genes, VFs, and phylogroups were identified by PCR and a commercial DNA array (Alere, France). ESBL genes belonged mostly to the CTX-M-1 (65.7%) and CTX-M-9 (27.0%) groups, whereas those of the CTX-M-2 and TEM groups were much less represented (3.9% and 3.4%, respectively). One ESBL isolate wasstx1andeaepositive and belonged to a major enterohemorrhagicE. coli(EHEC) serotype (O111:H8). Two other isolates wereeaepositive butstxnegative; one of these had serotype O26:H11. ESBL isolates belonged mainly to phylogroup A (55.4%) and, to lesser extents, to phylogroups D (25.5%) and B1 (15.6%), whereas B2 strains were quasi-absent (1/204). The number of VFs was significantly higher in phylogroup B1 than in phylogroups A (P= 0.04) and D (P= 0.02). Almost all of the VFs detected were found in CTX-M-1 isolates, whereas only 64.3% and 33.3% of them were found in CTX-M-9 and CTX-M-2 isolates, respectively. These results indicated that the widespread dissemination of theblaCTX-Mgenes within theE. colipopulation from cattle still spared the subpopulation of EHEC/Shiga-toxigenicE. coli(STEC) isolates. In contrast to other reports on non-ESBL-producing isolates from domestic animals, B1 was not the main phylogroup identified. However, B1 was found to be the most virulent phylogroup, suggesting host-specific distribution of virulence determinants among phylogenetic groups.

scholarly journals A New Clone Sweeps Clean: the Enigmatic Emergence of Escherichia coli Sequence Type 131

2014 ◽  
Vol 58 (9) ◽  
pp. 4997-5004 ◽  
Author(s):  
Ritu Banerjee ◽  
James R. Johnson
Keyword(s):  
Escherichia Coli ◽  
Sequence Type ◽  
Rapid Expansion ◽  
Future Research ◽  
Content Type ◽  
Extended Spectrum Beta Lactamase ◽  
E Coli ◽  
Phylogenetic Studies ◽  
Ecological Success

ABSTRACTEscherichia colisequence type 131 (ST131) is an extensively antimicrobial-resistantE. coliclonal group that has spread explosively throughout the world. Recent molecular epidemiologic and whole-genome phylogenetic studies have elucidated the fine clonal structure of ST131, which comprises multiple ST131 subclones with distinctive resistance profiles, including the (nested) H30, H30-R, and H30-Rx subclones. The most prevalent ST131 subclone, H30, arose from a single common fluoroquinolone (FQ)-susceptible ancestor containing allele 30 offimH(type 1 fimbrial adhesin gene). An early H30 subclone member acquired FQ resistance and launched the rapid expansion of the resulting FQ-resistant subclone, H30-R. Subsequently, a member of H30-R acquired the CTX-M-15 extended-spectrum beta-lactamase and launched the rapid expansion of the CTX-M-15-containing subclone within H30-R, H30-Rx. Clonal expansion clearly is now the dominant mechanism for the rising prevalence of both FQ resistance and CTX-M-15 production in ST131 and inE. coligenerally. Reasons for the successful dissemination and expansion of the key ST131 subclones remain undefined but may include increased transmissibility, greater ability to colonize and/or persist in the intestine or urinary tract, enhanced virulence, and more-extensive antimicrobial resistance compared to otherE. coli. Here we discuss the epidemiology and molecular phylogeny of ST131 and its key subclones, possible mechanisms for their ecological success, implications of their widespread dissemination, and future research needs.

scholarly journals Genotypic and Phenotypic Profiles of Escherichia coli Isolates Belonging to Clinical Sequence Type 131 (ST131), Clinical Non-ST131, and Fecal Non-ST131 Lineages from India

2014 ◽  
Vol 58 (12) ◽  
pp. 7240-7249 ◽  
Author(s):  
Arif Hussain ◽  
Amit Ranjan ◽  
Nishant Nandanwar ◽  
Anshu Babbar ◽  
Savita Jadhav ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Sequence Type ◽  
Care Hospital ◽  
Zebra Fish ◽  
Esbl Production ◽  
Sensitivity Testing ◽  
Metabolic Potential ◽  
Content Type ◽  
E Coli ◽  
Antimicrobial Resistance Gene

ABSTRACTIn view of the epidemiological success of CTX-M-15-producing lineages ofEscherichia coliand particularly of sequence type 131 (ST131), it is of significant interest to explore its prevalence in countries such as India and to determine if antibiotic resistance, virulence, metabolic potential, and/or the genetic architecture of the ST131 isolates differ from those of non-ST131 isolates. A collection of 126E. coliisolates comprising 43 ST131E. coli, 40 non-ST131E. coli, and 43 fecalE. coliisolates collected from a tertiary care hospital in India was analyzed. These isolates were subjected to enterobacterial repetitive intergenic consensus (ERIC)-based fingerprinting, O typing, phylogenetic grouping, antibiotic sensitivity testing, and virulence and antimicrobial resistance gene (VAG) detection. Representative isolates from this collection were also analyzed by multilocus sequence typing (MLST), conjugation, metabolic profiling, biofilm production assay, and zebra fish lethality assay. All of the 43 ST131E. coliisolates were exclusively associated with phylogenetic group B2 (100%), while most of the clinical non-ST131 and stool non-ST131E. coliisolates were affiliated with the B2 (38%) and A (58%) phylogenetic groups, respectively. Significantly greater proportions of ST131 isolates (58%) than non-ST131 isolates (clinical and stoolE. coliisolates, 5% each) were technically identified to be extraintestinal pathogenicE. coli(ExPEC). The clinical ST131, clinical non-ST131, and stool non-ST131E. coliisolates exhibited high rates of multidrug resistance (95%, 91%, and 91%, respectively), extended-spectrum-β-lactamase (ESBL) production (86%, 83%, and 91%, respectively), and metallo-β-lactamase (MBL) production (28%, 33%, and 0%, respectively). CTX-M-15 was strongly linked with ESBL production in ST131 isolates (93%), whereas CTX-M-15 plus TEM were present in clinical and stool non-ST131E. coliisolates. Using MLST, we confirmed the presence of two NDM-1-positive ST131E. coliisolates. The aggregate bioscores (metabolite utilization) for ST131, clinical non-ST131, and stool non-ST131E. coliisolates were 53%, 52%, and 49%, respectively. The ST131 isolates were moderate biofilm producers and were more highly virulent in zebra fish than non-ST131 isolates. According to ERIC-based fingerprinting, the ST131 strains were more genetically similar, and this was subsequently followed by the genetic similarity of clinical non-ST131 and stool non-ST131E. colistrains. In conclusion, our data provide novel insights into aspects of the fitness advantage ofE. colilineage ST131 and suggest that a number of factors are likely involved in the worldwide dissemination of and infections due to ST131E. coliisolates.

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