Research Publications (Food Safety)

Escherichia coli strains carrying Shiga toxins 1 and 2 (stx1 and stx2), intimin (eae), and hemolysin (ehxA) production genes were found in grass shoot, rhizosphere soil, and stable manure samples from a small-scale cattle farm located at the center of Netherlands, using cultivation-dependent and -independent microbiological detection techniques.

ABSTRACT The objective of this study was to determine the prevalence of Shiga toxin-producing E. coli (STEC) O157:H7 in colon content and on carcasses from pigs slaughtered at provincially licensed abattoirs (PLAs) in Alberta. In 2017, carcass sponge samples and colon content samples were collected from 504 healthy market hogs at thirty-nine PLAs and analyzed for E. coli O157:H7. Carcass samples were also analyzed for generic E. coli and aerobic colony count (ACC).

Cattle harbor Shiga toxin-producing Escherichia coli (STEC) in their intestinal tract, thereby providing these microorganisms with an ecological niche, but without this colonization leading to any clinical signs. In a preceding study, genotypic characterization of bovine STEC isolates unveiled that their ability to colonize cattle persistently (STECper) or only sporadically (STECspo) is more closely associated with the overall composition of the accessory rather than the core genome.

In August 2018, Public Health England (PHE) was made aware of five probable cases of Shiga toxin‐producing Escherichia coli (STEC) O157:H7 among individuals reporting participation in a mud‐based obstacle race. An additional four cases, identified via routine whole‐genome sequencing, were subsequently linked to the same event. Two of the nine cases were due to secondary household transmission.

Author(s): Changbao Wang, Hua Hang, Shoubiao Zhou, Yan D. Niu, Hechao Du, Kim Stanford, Tim A. McAllister

Calf diarrhea is one of the considerable infectious diseases in calves, which results in tremendous economic losses globally. To determine the prevalence of Shiga-toxigenic E. coli (STEC) and Enterotoxigenic E.

Author(s): Luca Grispoldi, Musafiri Karama, Chrystalleni Hadjicharalambous, Fabrizio de Stefani, Giulia Ventura, Margherita Ceccarelli, Marco Revoltella, Paola Sechi, Carlo Crotti, Antonio D'Innocenzo, Gerardo Couto Contreras, Beniamino Cenci-Goga

There is increasing evidence that diversity changes in bacterial communities of beef cattle correlates to the presence of Shiga toxin-producing Escherichia coli (STEC). However, studies that found an association between STEC and bacterial diversity have been focused on pre-slaughter stages in the beef supply chain.

Shiga toxin (Stx)-producing Escherichia coli (STEC) O157:H7 is an enteric pathogen that causes life-threatening disease in humans, with cattle being major natural reservoirs. A group of STEC O157:H7 with a dramatic combination of high virulence potentials and super-shedder bovine origin have been isolated. Here, an STEC O157:H7 isolate, JEONG-1266, was analyzed by comparative genomics, stx genotyping, and phenotypic analyses.

Following infection with certain strains of Shiga toxin-producing Escherichia coli (STEC), particularly enterohemorrhagic ones, patients are at elevated risk for developing life-threatening extraintestinal complications, such as acute renal failure. Hence, these bacteria represent a public health concern in both developed and developing countries.

Shiga toxin (STx) produced by Shigella and closely related Shiga toxin 1 and 2 (STx1 and STx2) synthesized by Shiga toxin-producing Escherichia coli (STEC) are bacterial AB5 toxins. All three toxins target kidney cells and may cause life-threatening renal disease. While Shigella infections can be treated with antibiotics, resistance is increasing. Moreover, antibiotic therapy is contraindicated for STEC, and there are no definitive treatments for STEC-induced disease.

Shiga toxins (Stxs), syn. Vero(cyto)toxins, are potent bacterial exotoxins and the principal virulence factor of enterohemorrhagic Escherichia coli (EHEC), a subset of Shiga toxin-producing E. coli (STEC). EHEC strains, e.g., strains of serovars O157:H7 and O104:H4, may cause individual cases as well as large outbreaks of life-threatening diseases in humans.

Author(s): Pengcheng Dong, Tongtong Xiao, George-John E. Nychas, Yimin Zhang, Lixian Zhu, Xin Luo

Bacteriophages, natural killers of bacteria, and plant secondary metabolites, such as condensed tannins, are potential agents for the control of foodborne pathogens. The first objective of this study evaluated the efficacy of a bacteriophage SA21RB in reducing pre-formed biofilms on stainless-steel produced by two Shiga toxin-producing Escherichia coli (STEC) strains, one from South Africa and the other from Canada.

by Nader M. Sobhy, Sarah G. A. Yousef, Hamada A. Aboubakr, Muhammad Nisar, Kakambi V. Nagaraja, Sunil K. Mor, Robert J. Valeris-Chacin, Sagar M. Goyal

Shiga-toxin-producing Escherichia coli (STEC) has become an important pathogen that can cause diarrhea, hemorrhagic colitis and hemolytic uremic syndrome (HUS) in humans. Recent reports show that the type VI secretion system (T6SS) from EHEC is required to produce infection in a murine model and its expression has been related to a higher prevalence of HUS.

This research study was based on ultraviolet (UVC) light and a combination of UVC-ozone treatments that have recently received attention from the beef processing industry as antimicrobial interventions that leave no chemical residues on products. The objectives were to evaluate effectiveness of UVC and UVC in combination with gaseous ozone treatments for inactivation of pathogenic bacteria on fresh beef and the impact on fresh beef quality.

Shiga toxin-producing Escherichia coli (STEC) strains are important zoonotic foodborne pathogens, causing diarrhea, hemorrhagic colitis, and life-threatening hemolytic uremic syndrome (HUS) in humans. However, antibiotic treatment of STEC infection is associated with an increased risk of HUS. Therefore, there is an urgent need for early and effective therapeutic strategies.

Author(s): Eduardo de Freitas Costa, Marisa Ribeiro de Itapema Cardoso, Jalusa Deon Kich, Luis Gustavo Corbellini

Domestic and wild animal intrusions are identified as a food safety risk during fresh produce production. The purpose of this study was to evaluate the survival of Shiga toxin-producing Escherichia coli (STEC) in cattle, feral pig, waterfowl, deer, and raccoon feces from sources in California, Delaware, Florida, and Ohio. Fecal samples were inoculated with a cocktail of rifampicin resistant STEC (O103, O104, O111, O145, and O157 (104 to 106 CFU/g feces).

Typical hemolytic uremic syndrome (STEC‐HUS), caused by Shiga toxin (Stx)‐producing Escherichia coli (STEC), is a serious, life‐threating disease that mainly affects children. Bacteriological and genetic tests are commonly used in the routine laboratory diagnosis of STEC‐HUS; however, serological methods have emerged as useful and reliable diagnostic tools, especially when bacterial isolation fails.

Forty-eight Escherichia coli strains were chosen due to variable detection of stx or serogroup by PCR. Although all strains were initially determined to be Shiga toxin-producing Escherichia coli (STEC), their genomes revealed 11 isolates carrying stx1a, stx1b, stx2a, and/or stx2b. Assembled genome sizes varied between 4,667,418 and 5,556,121 bp, with N50 values between 79,648 and 294,166 bp and G+C contents between 50.3% and 51.4%.

Author(s): Marie Frétin, Christophe Chassard, Céline Delbès, René Lavigne, Etienne Rifa, Sébastien Theil, Benoit Fernandez, Patrice Laforce, Cécile Callon

Shiga toxin-producing Escherichia coli (STEC) are important foodborne pathogens and non-O157 serotypes have been gradually increasing in frequency. The non-O157 STEC population is diverse and is often characterized using serotyping and/or multilocus sequence typing (MLST). Although spacers within clustered regularly interspaced repeat (CRISPR) regions were shown to comprise horizontally acquired DNA elements, this region does not actively acquire spacers in STEC.

by Mariana Cap, Celeste Cingolani, Carla Lires, Marina Mozgovoj, Trinidad Soteras, Adriana Sucari, Jimena Gentiluomo, Adriana Descalzo, Gabriela Grigioni, Marcelo Signorini, Celina Horak, Sergio Vaudagna, Gerardo Leotta