Presence of Shiga Toxin–Producing Escherichia coli, Enteroinvasive E. coli, Enteropathogenic E. coli, and Enterotoxigenic E. coli on Tomatoes from Public Markets in Mexico

2013 ◽  
Vol 76 (9) ◽  
pp. 1621-1625 ◽  
Author(s):  
CARLOS A. GÓMEZ-ALDAPA ◽  
M. del REFUGIO TORRES-VITELA ◽  
OTILIO A. ACEVEDO-SANDOVAL ◽  
ESMERALDA RANGEL-VARGAS ◽  
ANGÉLICA VILLARRUEL-LÓPEZ ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Foodborne Pathogens ◽  
Shiga Toxin ◽  
Fecal Coliforms ◽  
Tomato Variety ◽  
Public Markets ◽  
E Coli ◽  
Diarrheagenic Escherichia Coli ◽  
Tomato Sample

Diarrheagenic Escherichia coli pathotypes (DEP) are important foodborne pathogens in various countries, including Mexico. However, no data exist on the presence of DEP on fresh tomatoes (Solanum lycopericum) from Mexico. The frequency of fecal coliforms (FC), E. coli, and DEP were determined for two tomato varieties. One hundred samples of a saladette tomato variety and 100 samples of a red round tomato variety were collected from public markets in Pachuca, Mexico. Each tomato sample consisted of four whole tomatoes. For the 100 saladette samples, coliform bacterial, FC, E. coli, and DEP were identified in 100, 70, 60, and 10% of samples, respectively. For the 100 red round samples, coliform bacterial, FC, E. coli, and DEP were identified in 100, 75, 65, and 11% of samples, respectively. Identified DEP included Shiga toxin–producing E. coli (STEC), enteroinvasive E. coli (EIEC), enteropathogenic E. coli (EPEC), and enterotoxigenic E. coli (ETEC). STEC were isolated from 6% of saladette samples and 5% of red round samples. ETEC were isolated from 3% of saladette samples and 4% of red round samples. EPEC were isolated from 2% of saladette samples and 3% of red round samples, and EIEC were isolated from 1% of saladette samples. Both STEC and ETEC were identified in two saladette samples and 1 red round sample. E. coli O157:H7 was not detected in any STEC-positive samples.

scholarly journals Seasonal prevalence and characterization of Shiga toxin-producing Escherichia coli on pork carcasses at three steps of the harvest process at two commercial processing plants in the US

2020 ◽  
Author(s):  
Ivan Nastasijevic ◽  
John W. Schmidt ◽  
Marija Boskovic ◽  
Milica Glisic ◽  
Norasak Kalchayanand ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Foodborne Pathogens ◽  
Shiga Toxin ◽  
Severe Disease ◽  
Control Point ◽  
Plate Count ◽  
Seasonal Effect ◽  
E Coli ◽  
Significant Control ◽  
Pork Products

ABSTRACTShiga toxin (stx) -producing Escherichia coli (STEC) are foodborne pathogens that have a significant impact on public health, with those possessing the attachment factor intimin (eae) referred to as enterohemorrhagic E. coli (EHEC) associated with life threatening illnesses. Cattle and beef are considered typical sources of STEC, but their presence in pork products is a growing concern. Therefore, carcasses (n=1536) at two U.S. pork processors were sampled once per season at three stages of harvest (post-stunning skins; post-scald carcasses; chilled carcasses) then examined using PCR for stx and eae, aerobic plate count (APC) and Enterobacteriaceae counts (EBC). Skins, post-scald, and chilled carcasses had prevalence of stx (85.3, 17.5, and 5.4%, respectively), with 82.3, 7.8, and 1.7% respectively, having stx and eae present. All stx positive samples were subjected to culture isolation that resulted in 368 STEC and 46 EHEC isolates. The most frequently identified STEC were serogroup O121, O8, and O91(63, 6.7, and 6.0% of total STEC, respectively). The most frequently isolated EHEC was serotype O157:H7 (63% of total EHEC). Results showed that scalding significantly reduced (P < 0.05) carcass APC and EBC by 3.00 and 2.50 log10 CFU/100 cm2 respectively. A seasonal effect was observed with STEC prevalence lower (P < 0.05) in winter. The data from this study shows significant (P < 0.05) reduction in the incidence of STEC (stx) from 85.3% to 5.4% and of EHEC (stx+eae) from 82.3% to 1.7% within slaughter-to-chilling continuum, respectively, and that potential EHEC can be confirmed present throughout using culture isolation.IMPORTANCESeven serogroups of Shiga toxin-producing Escherichia coli (STEC) are responsible for most (>75%) cases of severe illnesses caused by STEC and are considered adulterants of beef. However, some STEC outbreaks have been attributed to pork products although the same E. coli are not considered adulterants in pork because little is known of their prevalence along the pork chain. The significance of the work presented here is that it identifies disease causing STEC, enterohemorrhagic E. coli (EHEC), demonstrating that these same organisms are a food safety hazard in pork as well as beef. The results show that most STEC isolated from pork are not likely to cause severe disease in humans and that processes used in pork harvest, such as scalding, offer a significant control point to reduce contamination. The results will assist the pork processing industry and regulatory agencies to optimize interventions to improve the safety of pork products.

scholarly journals Prevalence and molecular characterization of Shiga toxin-producing escherichia coli isolates from human and sheep in Al-Madinah Al-Munawarah

Infectio ◽  
2017 ◽  
Vol 21 (2) ◽  
Author(s):  
Eman Fathi Sharafa ◽  
Iman I. Shabanaa
Keyword(s):  
Escherichia Coli ◽  
Foodborne Pathogens ◽  
Shiga Toxin ◽  
Genetic Relatedness ◽  
Control Measures ◽  
Health Concern ◽  
Global Public Health ◽  
E Coli ◽  
Life Threatening

Shiga toxin-producing Escherichia coli (STEC) strains have emerged as important foodborne pathogens of global public health concern, causing life-threatening diseases. Sheep and their products have been documented as important reservoirs for STECs, especially E. coli O157. The aim of this study was to investigate STECs from diarrheal human and sheep in Al-Madinah Al-Munawarah, Saudi Arabia. Fecal samples were collected between June and August, 2015 from diarrheal humans (n = 134) and sheep (n = 87). Presumptive E. coli human-and sheep-isolated strains were identified for their serotypes, the associated virulence genes (Shiga toxin [stx1 , stx2 ], haemolysin [ehxA] and intimin [eae]) by polymerase chain reaction and their susceptibility to antibiotics. Pulsed-field gel electrophoresis (PFGE) was used to demonstrate the genetic relatedness between Serotype O157:H7 human- and sheep-isolated strains. Forty eight (48/221; 21.7%) STECs were recovered from both human and sheep, their serotypes were as follows: O157:H7, O26:H11, O157:HNM, O26:HNM, O128:H2, O48:HNM, O111:HNM and OUT:HUT. Various virulence profiles and multiple antibiotic resistance were observed among the isolates. Twenty eight O157:H7 serotypes (17 human isolates and 11 sheep isolates) were identified in 13 PFGE pulsotypes, where human and sheep isolates were highly related. PFGE banding profiles together with serotypes and genotypes afford proof that human and sheep can be colonized and infected with similar E. coli O157:H7 strains. Our findings highlight the importance of epidemiological and microbiological surveillance of STECs; as well as the development of control measures to decrease risks associated with zoonotic O157:H7.

Factors Affecting Compost Tea as a Potential Source of Escherichia coli and Salmonella on Fresh Produce†

2007 ◽  
Vol 70 (4) ◽  
pp. 828-834 ◽  
Author(s):  
D. T. INGRAM ◽  
P. D. MILLNER
Keyword(s):  
Escherichia Coli ◽  
Foodborne Pathogens ◽  
Salmonella Enteritidis ◽  
Fresh Produce ◽  
Fecal Coliforms ◽  
Compost Tea ◽  
Human Pathogens ◽  
Growth And Survival ◽  
E Coli ◽  
Nutrient Supplements

Compost tea (CT) is an unheated on-farm infusion of compost used as a spray or soil drench to promote plant growth and control foliar and root diseases. Because food safety involves all aspects from farm to fork, CT should meet basic microbiological criteria for water quality. This report describes the effects of two CT production processes, aerated and nonaerated, on growth and survival of foodborne pathogens and fecal coliforms. Seven commercially available nutrients used to supplement CT were tested individually and in combination for their effects on the growth of Escherichia coli and Salmonella. Compost containing 101 to 103 CFU/g initial concentrations of E. coli O157:H7 and Salmonella Enteritidis were used to assess growth and survival responses to aerated CT (36-h preparations) and nonaerated CT (8.5-day preparations). Pathogen and fecal coliform populations were undetectable by 8.5 days in nonaerated CT without nutrient supplements. E. coli O157:H7 decreased to below detection levels in aerated CT at 36 h without the use of supplements. In contrast, the addition of commercially formulated mixtures or combinations of nutrient supplements resulted in growth of E. coli O157: H7, Salmonella, and fecal coliforms by 1 to 4 log CFU/g in both aerated and nonaerated CT. When nutrient supplements were added, aerated CT sustained higher concentrations of E. coli O157:H7, Salmonella, and fecal coliforms than did nonaerated CT. Thus, addition of supplements supports growth of human pathogens from very low initial concentrations in both aerated and nonaerated CT and should be avoided when CT is used on fresh produce.

scholarly journals Fallow Deer (Dama dama) as a Reservoir of Shiga Toxin-Producing Escherichia coli (STEC)

Animals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 881
Author(s):  
Anna Szczerba-Turek ◽  
Bernard Kordas
Keyword(s):  
Escherichia Coli ◽  
Polymerase Chain Reaction ◽  
Foodborne Pathogens ◽  
Shiga Toxin ◽  
Fallow Deer ◽  
Dama Dama ◽  
Chain Reaction ◽  
E Coli ◽  
Deer Population ◽  
Polymerase Chain

Shiga toxin-producing Escherichia (E.) coli (STEC) are responsible for the outbreaks of serious diseases in humans. Only a few reports on fallow deer as a reservoir of foodborne pathogens have been published to date. The purpose of this study was to determine the occurrence of STEC strains in the fallow deer population in Poland. In all, 94 fallow deer swabs were tested. Polymerase chain reaction (PCR) was performed to detect the virulence profile of stx1, stx2 and eae or aggR genes, to identify the subtypes of stx1 and stx2 genes and to perform O and H serotyping. STEC and attaching and effacing (AE)-STEC were identified in 13 isolates (13.83%). The most hazardous virulence profile was detected in three strains, namely stx2d serotype O103:HNM, eae/stx1a serotype O26:HNM and eae/stx1a serotype O157:H7. The predominant stx gene was stx2, which was identified in 76.92% of isolates. E. coli O157 was detected in 4/94 (4.26%). Other E. coli serogroups, O26, O103, O111 and O145, were identified in 14/94 fallow deer (14.89%). The present findings suggest that fallow deer are carriers of STEC/AE-STEC that are potentially pathogenic to humans.

scholarly journals Mixed Biofilm Formation by Shiga Toxin–Producing Escherichia coli and Salmonella enterica Serovar Typhimurium Enhanced Bacterial Resistance to Sanitization due to Extracellular Polymeric Substances†

2013 ◽  
Vol 76 (9) ◽  
pp. 1513-1522 ◽  
Author(s):  
RONG WANG ◽  
NORASAK KALCHAYANAND ◽  
JOHN W. SCHMIDT ◽  
DAYNA M. HARHAY
Keyword(s):  
Escherichia Coli ◽  
Food Safety ◽  
Foodborne Pathogens ◽  
Shiga Toxin ◽  
Biofilm Formation ◽  
Extracellular Polymeric Substances ◽  
Bacterial Resistance ◽  
Salmonella Enterica Serovar Typhimurium ◽  
E Coli ◽  
Serovar Typhimurium

Shiga toxin–producing Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium are important foodborne pathogens capable of forming single-species biofilms or coexisting in multispecies biofilm communities. Bacterial biofilm cells are usually more resistant to sanitization than their planktonic counterparts, so these foodborne pathogens in biofilms pose a serious food safety concern. We investigated how the coexistence of E. coli O157:H7 and Salmonella Typhimurium strains would affect bacterial planktonic growth competition and mixed biofilm composition. Furthermore, we also investigated how mixed biofilm formation would affect bacterial resistance to common sanitizers. Salmonella Typhimurium strains were able to outcompete E. coli strains in the planktonic growth phase; however, mixed biofilm development was highly dependent upon companion strain properties in terms of the expression of bacterial extracellular polymeric substances (EPS), including curli fimbriae and exopolysaccharide cellulose. The EPS-producing strains with higher biofilm-forming abilities were able to establish themselves in mixed biofilms more efficiently. In comparison to single-strain biofilms, Salmonella or E. coli strains with negative EPS expression obtained significantly enhanced resistance to sanitization by forming mixed biofilms with an EPS-producing companion strain of the other species. These observations indicate that the bacterial EPS components not only enhance the sanitizer resistance of the EPS-producing strains but also render protections to their companion strains, regardless of species, in mixed biofilms. Our study highlights the potential risk of cross-contamination by multispecies biofilms in food safety and the need for increased attention to proper sanitization practices in food processing facilities.

Limitations of Immunomagnetic Separation for Detection of the Top Seven Serogroups of Shiga Toxin–Producing Escherichia coli

2017 ◽  
Vol 80 (4) ◽  
pp. 598-603 ◽  
Author(s):  
J. Hallewell ◽  
T. Alexander ◽  
T. Reuter ◽  
K. Stanford
Keyword(s):  
Escherichia Coli ◽  
Quantitative Pcr ◽  
Foodborne Pathogens ◽  
Shiga Toxin ◽  
Immunomagnetic Separation ◽  
Detection Methods ◽  
Conventional Pcr ◽  
E Coli ◽  
Pure Cultures

ABSTRACT Shiga toxin–producing Escherichia coli (STEC) strains are foodborne pathogens that negatively impact human health and compromise food safety. Serogroup O157 is the most frequently isolated and studied STEC serogroup, but six others (O26, O45, O103, O111, O121, and O145) have also been identified as significant sources of human disease and collectively have been referred to as the “top six” pathogenic serogroups. Because detection methods for non-O157 serogroups are not yet refined, the objective of this study was to compare the effectiveness of immunomagnetic separation (IMS) for recovery of serogroup O157 isolates with that for each of the top six E. coli serogroups in pure and mixed cultures of STEC at 103 to 107 CFU/mL. After serogroup-specific IMS, DNA was extracted from cultured isolates to analyze the specificity of each IMS assay using conventional and quantitative PCR. In pure cultures, DNA copy number obtained after IMS was lower for O111 and O157 (P &lt; 0.01) than for other serogroups. Based on quantitative PCR (qPCR) analyses, specificity was reduced for all IMS assays when STEC isolates were mixed at 7 log CFU/mL, although the O157 IMS assays recovered only O157 over a wider range of concentrations than did assays for non-O157 serogroups. At the lowest dilution tested, conventional PCR was specific for all serogroups except O121 and O145. For these two serogroups, no dilution tested recovered only O121 or O145 when evaluated with conventional PCR. Refinements to IMS assays, development of selective media, and determination of optimal enrichment times to reduce background microflora or competition among serogroups would be especially beneficial for recovery of O111, O121, and O145 serogroups to improve STEC detection and isolation.

scholarly journals Hemolysin-Producing Strains among Diarrheagenic Escherichia coli Isolated from Children under 2 Years Old with Diarrheal Disease

Pathogens ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1022
Author(s):  
Anca Mare ◽  
Adrian Man ◽  
Felicia Toma ◽  
Cristina Nicoleta Ciurea ◽  
Răzvan Lucian Coșeriu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Diarrheal Disease ◽  
Multidrug Resistant ◽  
Enteropathogenic Escherichia Coli ◽  
E Coli ◽  
Diarrheagenic Escherichia Coli ◽  
O Antigens ◽  
Hlya Gene ◽  
High Diversity

Even if serotyping based on O antigens is still routinely used by most laboratories for the detection of diarrheagenic Escherichia coli, this method can provide false-positive reactions, due to the high diversity of O antigens. Molecular methods represent a valuable tool that clarifies these situations. In the Bacteriology Laboratory of Mureș County Hospital, between May 2016 and July 2019, 160 diarrheagenic E. coli strains were isolated from children under 2 years old with diarrheic disease. The strains were identified as Shiga toxin-producing E. coli (STEC)/enteropathogenic Escherichia coli (EPEC) via agglutination with polyvalent sera. STEC strains were serotyped using monovalent sera for serogroup O157. Simplex PCR was performed on the strains to determine the presence of the hlyA gene, and, for the positive ones, the hemolytic activity was tested. Antibiotic susceptibility of the identified diarrheagenic E. coli strains was also investigated. STEC strains were the most frequently identified (49.1%), followed by EPEC (40.2%). The hlyA gene was identified in 12 cases, representing 18.2% of the STEC strains. Even if the extended-spectrum β-lactamase (ESBL)-producing strains represented only 10%, a relevant percentage of multidrug-resistant (MDR) strains (24%) was identified.

scholarly journals Prevalence of Diarrheagenic Escherichia coli in Finns with or without Diarrhea during a Round-the-World Trip

2000 ◽  
Vol 38 (12) ◽  
pp. 4425-4429 ◽  
Author(s):  
Markku Keskimäki ◽  
Leena Mattila ◽  
Heikki Peltola ◽  
Anja Siitonen
Keyword(s):  
Escherichia Coli ◽  
Primary Culture ◽  
Shiga Toxin ◽  
Clinical Picture ◽  
Salmonella Enterica ◽  
Bacterial Pathogens ◽  
E Coli ◽  
Diarrheagenic Escherichia Coli ◽  
Enteropathogenic Bacteria ◽  
The World

The incidence of diarrhea and the prevalence of bacterial enteropathogens, viruses, and parasites in feces of subjects with and without diarrhea were evaluated in 204 Finns traveling round the world (from Finland to China, Malaysia, Australia, Fiji, Chile, and Brazil and back to Finland). Special emphasis was placed on the finding of diarrheagenic Escherichia coli (enterotoxigenic, enteropathogenic, Shiga toxin-producing, and enteroaggregative strains) by PCR from growth on primary culture plates. From the PCR-positive samples, corresponding strains were isolated, confirmed as E. coli, and O serotyped. Of all the subjects, 37% experienced a total of 90 episodes of diarrhea. No adenoviruses or rotaviruses were detected, and findings of parasites were insignificant. In contrast, enteropathogenic bacteria were present in 62% of the 65 diarrheal and in 33% of the 127 nondiarrheal samples (P < 0.001); diarrheagenic E. coli strains were found in 35 and 26% of these, respectively (not statistically significant). As a single pathogen, E. coli was found in 20 and 24% of samples (not significant). Of all diarrheagenic E. coli strains, enteropathogenic strains were the most commonly found independently of the clinical picture of the subjects, whereas Salmonella enterica as a single pathogen was the most common non-E. coli organism found in diarrheal samples. Multiple bacterial pathogens were found 10 times more commonly in diarrheal than in nondiarrheal samples (20 versus 2%; P < 0.001).

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