scholarly journals Genomic Investigation of Virulence Potential in Shiga Toxin Escherichia coli (STEC) Strains From a Semi-Hard Raw Milk Cheese

2021 ◽  
Vol 11 ◽  
Author(s):  
Claudia Cortimiglia ◽  
Maria Francesca Borney ◽  
Daniela Bassi ◽  
Pier Sandro Cocconcelli
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Public Awareness ◽  
Virulence Gene ◽  
Raw Milk ◽  
Virulence Determinants ◽  
Pathogenic Potential ◽  
Virulence Potential ◽  
Genetic Features ◽  
Raw Milk Cheese

Shiga-toxin-producing Escherichia coli (STEC) represents a significant cause of foodborne disease. In the last years, an increasing number of STEC infections associated with the consumption of raw and pasteurized milk cheese have been reported, contributing to raise the public awareness. The aim of this study is to evaluate the main genomic features of STEC strains isolated from a semi-hard raw milk cheese, focusing on their pathogenic potential. The analysis of 75 cheese samples collected during the period between April 2019 and January 2020 led to the isolation of seven strains from four stx-positive enrichment. The genome investigation evidenced the persistence of two serotypes, O174:H2 and O116:H48. All strains carried at least one stx gene and were negative for eae gene. The virulence gene pattern was homogeneous among the serogroup/ST and included adherence factors (lpfA, iha, ompT, papC, saa, sab, hra, and hes), enterohemolysin (ehxA), serum resistance (iss, tra), cytotoxin-encoding genes like epeA and espP, and the Locus of Adhesion and Autoaggregation Pathogenicity Islands (LAA PAIs) typically found in Locus of Enterocyte Effacement (LEE)-negative STEC. Genome plasticity indicators, namely, prophagic sequences carrying stx genes and plasmid replicons, were detected, leading to the possibility to share virulence determinants with other strains. Overall, our work adds new knowledge on STEC monitoring in raw milk dairy products, underlining the fundamental role of whole genome sequencing (WGS) for typing these unknown isolates. Since, up to now, some details about STEC pathogenesis mechanism is lacking, the continuous monitoring in order to protect human health and increase knowledge about STEC genetic features becomes essential.

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.

Prevalence and pathogenic potential of Escherichia coli isolates from raw milk and raw milk cheese in Egypt

2016 ◽  
Vol 221 ◽  
pp. 69-76 ◽  
Author(s):  
Rabee A. Ombarak ◽  
Atsushi Hinenoya ◽  
Sharda Prasad Awasthi ◽  
Atsushi Iguchi ◽  
Ayaka Shima ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Raw Milk ◽  
Pathogenic Potential ◽  
Raw Milk Cheese

scholarly journals Molecular Characterization of Shiga Toxin-Producing Escherichia coli Strains Isolated in Poland

2016 ◽  
Vol 65 (3) ◽  
pp. 261-269 ◽  
Author(s):  
Aleksandra Januszkiewicz ◽  
Waldemar Rastawicki
Keyword(s):  
Escherichia Coli ◽  
Virulence Factors ◽  
Shiga Toxin ◽  
Virulence Gene ◽  
Virulence Determinants ◽  
E Coli ◽  
Heat Stable ◽  
Food Borne ◽  
Wide Range ◽  
Uremic Syndrome

Shiga toxin-producing Escherichia coli (STEC) strains also called verotoxin-producing E. coli (VTEC) represent one of the most important groups of food-borne pathogens that can cause several human diseases such as hemorrhagic colitis (HC) and hemolytic – uremic syndrome (HUS) worldwide. The ability of STEC strains to cause disease is associated with the presence of wide range of identified and putative virulence factors including those encoding Shiga toxin. In this study, we examined the distribution of various virulence determinants among STEC strains isolated in Poland from different sources. A total of 71 Shiga toxin-producing E. coli strains isolated from human, cattle and food over the years 1996 – 2010 were characterized by microarray and PCR detection of virulence genes. As stx1a subtype was present in all of the tested Shiga toxin 1 producing E. coli strains, a greater diversity of subtypes was found in the gene stx2, which occurred in five subtypes: stx2a, stx2b, stx2c, stx2d, stx2g. Among STEC O157 strains we observed conserved core set of 14 virulence factors, stable in bacteria genome at long intervals of time. There was one cattle STEC isolate which possessed verotoxin gene as well as sta1 gene encoded heat-stable enterotoxin STIa characteristic for enterotoxigenic E. coli. To the best of our knowledge, this is the first comprehensive analysis of virulence gene profiles identified in STEC strains isolated from human, cattle and food in Poland. The results obtained using microarrays technology confirmed high effectiveness of this method in determining STEC virulotypes which provides data suitable for molecular risk assessment of the potential virulence of this bacteria.

An Overview of Molecular Stress Response Mechanisms in Escherichia coli Contributing to Survival of Shiga Toxin–Producing Escherichia coli during Raw Milk Cheese Production

2011 ◽  
Vol 74 (5) ◽  
pp. 849-864 ◽  
Author(s):  
SILVIO PENG ◽  
TAURAI TASARA ◽  
JÖRG HUMMERJOHANN ◽  
ROGER STEPHAN
Keyword(s):  
Escherichia Coli ◽  
Stress Response ◽  
Foodborne Pathogens ◽  
Stress Responses ◽  
Shiga Toxin ◽  
Pathogenic Bacteria ◽  
Raw Milk ◽  
Heat Shock Stress ◽  
Raw Milk Cheese ◽  
Cheese Production

The ability of foodborne pathogens to survive in certain foods mainly depends on stress response mechanisms. Insight into molecular properties enabling pathogenic bacteria to survive in food is valuable for improvement of the control of pathogens during food processing. Raw milk cheeses are a potential source for human infections with Shiga toxin–producing Escherichia coli (STEC). In this review, we focused on the stress response mechanisms important for allowing STEC to survive raw milk cheese production processes. The major components and regulation pathways for general, acid, osmotic, and heat shock stress responses in E. coli and the implications of these responses for the survival of STEC in raw milk cheeses are discussed.

scholarly journals An Environmental Shiga Toxin-Producing Escherichia coli O145 Clonal Population Exhibits High-Level Phenotypic Variation That Includes Virulence Traits

2015 ◽  
Vol 82 (4) ◽  
pp. 1090-1101 ◽  
Author(s):  
Michelle Qiu Carter ◽  
Beatriz Quinones ◽  
Xiaohua He ◽  
Wayne Zhong ◽  
Jacqueline W. Louie ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Virulence Determinants ◽  
Content Type ◽  
Clinical Strains ◽  
Production Region ◽  
E Coli ◽  
Virulence Traits ◽  
Virulence Potential ◽  
High Level

ABSTRACTShiga toxin-producingEscherichia coli(STEC) serotype O145 is one of the major non-O157 serotypes associated with severe human disease. Here we examined the genetic diversity, population structure, virulence potential, and antimicrobial resistance profiles of environmental O145 strains recovered from a major produce production region in California. Multilocus sequence typing analyses revealed that sequence type 78 (ST-78), a common ST in clinical strains, was the predominant genotype among the environmental strains. Similarly, all California environmental strains belonged to H28, a common H serotype in clinical strains. Although most environmental strains carried an intactfliCgene, only one strain retained swimming motility. Diversestxsubtypes were identified, includingstx1a,stx2a,stx2c, andstx2e. Although no correlation was detected between thestxgenotype and Stx1 production, high Stx2 production was detected mainly in strains carryingstx2aonly and was correlated positively with the cytotoxicity of Shiga toxin. All environmental strains were capable of producing enterohemolysin, whereas only 10 strains were positive for anaerobic hemolytic activity. Multidrug resistance appeared to be common, as nearly half of the tested O145 strains displayed resistance to at least two different classes of antibiotics. The core virulence determinants of enterohemorrhagicE. coliwere conserved in the environmental STEC O145 strains; however, there was large variation in the expression of virulence traits among the strains that were highly related genotypically, implying a trend of clonal divergence. Several cattle isolates exhibited key virulence traits comparable to those of the STEC O145 outbreak strains, emphasizing the emergence of hypervirulent strains in agricultural environments.

scholarly journals Paediatric haemolytic uraemic syndrome related to Shiga toxin-producing Escherichia coli, an overview of 10 years of surveillance in France, 2007 to 2016

2019 ◽  
Vol 24 (8) ◽  
Author(s):  
Mathias Bruyand ◽  
Patricia Mariani-Kurkdjian ◽  
Simon Le Hello ◽  
Lisa-A King ◽  
Dieter Van Cauteren ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Renal Failure ◽  
Shiga Toxin ◽  
Haemolytic Uraemic Syndrome ◽  
Raw Milk ◽  
National Reference ◽  
Food Borne ◽  
Raw Milk Cheese ◽  
Over Time ◽  
Microbiological Surveillance

Introduction Haemolytic uraemic syndrome (HUS) related to Shiga toxin-producing Escherichia coli (STEC) is the leading cause of acute renal failure in young children. In France, HUS surveillance in children aged < 15 years was implemented starting from 1996. Aim We present the results of this surveillance between 2007 and 2016. Methods A voluntary nationwide network of 32 paediatric departments notifies cases. Two national reference centres perform microbiological STEC confirmation. Results Over the study period, the paediatric HUS incidence rate (IR) was 1.0 per 100,000 children-years, with a median of 116 cases/year. In 2011, IR peaked at 1.3 per 100,000 children-years, and decreased to 1.0 per 100,000 children-years in 2016. STEC O157 associated HUS peaked at 37 cases in 2011 and decreased to seven cases in 2016. Cases of STEC O26-associated HUS have increased since 2010 and STEC O80 associated HUS has emerged since 2012, with 28 and 18 cases respectively reported in 2016. Four STEC-HUS food-borne outbreaks were detected (three STEC O157 linked to ground beef and raw-milk cheese and one STEC O104 linked to fenugreek sprouts). In addition, two outbreaks related to person-to-person transmission occurred in distinct kindergartens (STEC O111 and O26). Conclusions No major changes in HUS IRs were observed over the study period of 10 years. However, changes in the STEC serogroups over time and the outbreaks detected argue for continuing epidemiological and microbiological surveillance.

scholarly journals Fate of Shiga toxin-producing and generic Escherichia coli during production and ripening of semihard raw milk cheese

2013 ◽  
Vol 96 (2) ◽  
pp. 815-823 ◽  
Author(s):  
S. Peng ◽  
W. Hoffmann ◽  
W. Bockelmann ◽  
J. Hummerjohann ◽  
R. Stephan ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Raw Milk ◽  
Raw Milk Cheese

scholarly journals Molecular Analysis of Shiga Toxin-Producing Escherichia coli Strains Isolated from Hemolytic-Uremic Syndrome Patients and Dairy Samples in France

2008 ◽  
Vol 74 (7) ◽  
pp. 2118-2128 ◽  
Author(s):  
Nathalie Pradel ◽  
Yolande Bertin ◽  
Christine Martin ◽  
Valérie Livrelli
Keyword(s):  
Escherichia Coli ◽  
Hemolytic Uremic Syndrome ◽  
Shiga Toxin ◽  
Severe Disease ◽  
Virulence Gene ◽  
Raw Milk ◽  
Genes Encoding ◽  
Catalase Peroxidase ◽  
Uremic Syndrome ◽  
Plasmid Profiling

ABSTRACT Shiga toxin-producing Escherichia coli (STEC) has been associated with food-borne diseases ranging from uncomplicated diarrhea to hemolytic-uremic syndrome (HUS). While most outbreaks are associated with E. coli O157:H7, about half of the sporadic cases may be due to non-O157:H7 serotypes. To assess the pathogenicity of STEC isolated from dairy foods in France, 40 strains isolated from 1,130 raw-milk and cheese samples were compared with 15 STEC strains isolated from patients suffering from severe disease. The presence of genes encoding Shiga toxins (stx 1, stx 2, and variants), intimin (eae and variants), adhesins (bfp, efa1), enterohemolysin (ehxA), serine protease (espP), and catalase-peroxidase (katP) was determined by PCR and/or hybridization. Plasmid profiling, ribotyping, and pulsed-field gel electrophoresis (PFGE) were used to further compare the strains at the molecular level. A new stx 2 variant, stx 2-CH013, associated with an O91:H10 clinical isolate was identified. The presence of the stx 2, eae, and katP genes, together with a combination of several stx 2 variants, was clearly associated with human-pathogenic strains. In contrast, dairy food STEC strains were characterized by a predominance of stx 1, with a minority of isolates harboring eae, espP, and/or katP. These associations may help to differentiate less virulent STEC strains from those more likely to cause disease in humans. Only one dairy O5 isolate had a virulence gene panel identical to that of an HUS-associated strain. However, the ribotype and PFGE profiles were not identical. In conclusion, most STEC strains isolated from dairy products in France showed characteristics different from those of strains isolated from patients.

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.

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