Editorial Commentary: Fecal Shedding of Shiga Toxin-Producing Escherichia coli: What Should Be Done to Prevent Secondary Cases?

Cattle are the main reservoirs for Shiga toxin–producing Escherichia coli (STEC) strains. E. coli O26, O45, O103, O111, O121, O145, and O157 are among the STEC serogroups that cause severe foodborne illness and have been declared as adulterants by the U.S. Department of Agriculture, Food Safety and Inspection Service. The objectives of this study were (i) to estimate the prevalence of non-O157 STEC and E. coli O157 in naturally infected beef cows and in steer calves at postweaning, during finishing, and at slaughter and (ii) to test non-O157 STEC isolates for the presence of virulence genes stx1, stx2, eaeA, and ehlyA. Samples were collected from study animals during multiple sampling periods and included fecal grabs, rectal swabs, and midline sponge samples. Laboratory culture, PCR, and multiplex PCR were performed to recover and identify E. coli and the virulence genes. The prevalence of non-O157 STEC (serogroups O26, O45, O103, O111, O121, O113, and O145) fecal shedding ranged from 8% (4 of 48 samples) to 39% (15 of 38 samples) in cows and 2% (1 of 47 samples) to 38% (9 of 24 samples) in steer calves. The prevalence of E. coli O157 fecal shedding ranged from 0% (0 of 38 samples) to 52% (25 of 48 samples) in cows and 2% (1 of 47 samples) to 31% (15 of 48 samples) in steer calves. In steer calves, the prevalence of non-O157 STEC and E. coli O157 was highest at postweaning, at 16% (15 of 96 samples) and 23% (22 of 96 samples), respectively. Among the 208 non-O157 STEC isolates, 79% (164 isolates) had stx1, 79% (165 isolates) had stx2, and 58% (121 isolates) had both stx1 and stx2 genes. The percentage of non-O157 STEC isolates encoding the eaeA gene was low; of the 165 isolates tested, 8 (5%) were positive for eaeA and 135 (82%) were positive for ehlyA. Findings from this study provide further evidence of non-O157 STEC shedding in beef cows and steer calves particularly at the stage of postweaning and before entry into the feedlot.

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Agritourism and Kidding Season: A Large Outbreak of Human Shiga Toxin-Producing Escherichia coli O157 (STEC O157) Infections Linked to a Goat Dairy Farm—Connecticut, 2016

Frontiers in Veterinary Science ◽

10.3389/fvets.2021.744055 ◽

2021 ◽

Vol 8 ◽

Author(s):

Megin C. Nichols ◽

Paul Gacek ◽

Quyen Phan ◽

Kelly J. Gambino-Shirley ◽

Lauren M. Gollarza ◽

...

Keyword(s):

Escherichia Coli ◽

Shiga Toxin ◽

Disease Transmission ◽

Dairy Farm ◽

Running Water ◽

Fecal Shedding ◽

Time Period ◽

Laboratory Confirmation ◽

Large Outbreak ◽

Uremic Syndrome

The objective of this study was to determine sources of Shiga toxin-producing Escherichia coli O157 (STEC O157) infection among visitors to Farm X and develop public health recommendations. A case-control study was conducted. Case-patients were defined as the first ill child (aged <18 years) in the household with laboratory-confirmed STEC O157, or physician-diagnosed hemolytic uremic syndrome with laboratory confirmation by serology, who visited Farm X in the 10 days prior to illness. Controls were selected from Farm X visitors aged <18 years, without symptoms during the same time period as case-patients. Environment and animal fecal samples collected from Farm X were cultured; isolates from Farm X were compared with patient isolates using whole genome sequencing (WGS). Case-patients were more likely than controls to have sat on hay bales at the doe barn (adjusted odds ratio: 4.55; 95% confidence interval: 1.41–16.13). No handwashing stations were available; limited hand sanitizer was provided. Overall, 37% (29 of 78) of animal and environmental samples collected were positive for STEC; of these, 62% (18 of 29) yielded STEC O157 highly related by WGS to patient isolates. STEC O157 environmental contamination and fecal shedding by goats at Farm X was extensive. Farms should provide handwashing stations with soap, running water, and disposable towels. Access to animal areas, including animal pens and enclosures, should be limited for young children who are at risk for severe outcomes from STEC O157 infection. National recommendations should be adopted to reduce disease transmission.

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Characterization of 4 T1-like lytic bacteriophages that lyse Shiga-toxin Escherichia coli O157:H7

Canadian Journal of Microbiology ◽

10.1139/w2012-063 ◽

2012 ◽

Vol 58 (7) ◽

pp. 923-927 ◽

Cited By ~ 14

Author(s):

Yan D. Niu ◽

Kim Stanford ◽

Hans-W. Ackermann ◽

Tim A. McAllister

Keyword(s):

Escherichia Coli ◽

Shiga Toxin ◽

Enzyme Digestion ◽

Average Multiplicity ◽

Restriction Enzyme Digestion ◽

Escherichia Coli O157 ◽

Fecal Shedding ◽

E Coli ◽

Phage Types

Bacteriophages are associated with reduced fecal shedding of Shiga-toxin-producing Escherichia coli O157:H7 (STEC O157:H7) in cattle. Four phages exhibiting activity against 12 of 14 STEC O157:H7 strains, representing 11 common phage types, were isolated. Phages did not lyse non-O157 E. coli, with 11 of the 12 STEC strains exhibiting extreme susceptibility (average multiplicity of infection (MOI) = 0.0003−0.0007). All phages had icosahedral heads with tapered, noncontractile tails, a morphology indicative of T1-like Siphoviridae. Genome size of all phages was ∼44 kb, but EcoRІ or HindIII digestion profiles differed among phages. Based on restriction enzyme digestion profiles, phages AHP24, AHS24, and AHP42 were more related (66.7%−82.4%) to each other than to AKS96, while AHP24 and AHS24, isolated from the same feedlot pen, exhibited the highest identity (88.9%−92.3%). Phages AHP24 and AHS24 exhibited the broadest host range and strongest lytic activity against STEC O157:H7, making them strong candidates for biocontrol of this bacterium in cattle.

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Detection and Quantification of Seven Major Serogroups of Shiga Toxin–Producing Escherichia coli on Hides of Cull Dairy, Cull Beef, and Fed Beef Cattle at Slaughter†

Journal of Food Protection ◽

10.4315/0362-028x.jfp-17-497 ◽

2018 ◽

Vol 81 (8) ◽

pp. 1236-1244 ◽

Cited By ~ 5

Author(s):

LANCE W. NOLL ◽

PRAGATHI B. SHRIDHAR ◽

SAMUEL E. IVES ◽

ELVA CHA ◽

T. G. NAGARAJA ◽

...

Keyword(s):

Escherichia Coli ◽

Beef Cattle ◽

Shiga Toxin ◽

Mixed Models ◽

Culture Method ◽

Immunomagnetic Separation ◽

Processing Plant ◽

Fecal Shedding ◽

Study Population ◽

Spiral Plate

ABSTRACT Dehiding during beef cattle processing can introduce fecal contaminants, including Shiga toxin–producing Escherichia coli (STEC), from hides onto carcass surfaces, creating the potential for contaminated beef. Fecal shedding of major STEC serogroups (O26, O45, O103, O111, O121, O145, and O157; STEC-7) may differ among cattle populations, yet no study has been conducted to isolate STEC-7 on hides of multiple cattle types on the same production days at the same processing plant. Our objective was to estimate and compare prevalence and concentrations of STEC-7 on hides of cull dairy, cull beef, and fed beef cattle from the same date and processing plant. Overall, 1,500 cattle hides were sponge sampled from cull dairy (n = 500), cull beef (n = 500) and fed beef cattle (n = 500) over 10 processing days. To determine prevalence, samples were subjected to an immunomagnetic separation culture method, and presumptive STEC isolates were tested by PCR for serogroup and major virulence genes. A spiral plate method was used to enumerate STEC-7 from hide samples. Data were analyzed with linear mixed models. All STEC-7 serogroups except O121 were detected and quantified on cattle hides in this study population. Slightly more fed beef hides (77 of 500; 15.4%) and cull beef hides (76 of 500; 15.2%) were positive for at least one STEC-7 strain compared with cull dairy hides (57 of 500; 11.4%), but cattle type was not significantly associated (P = 0.19) with STEC-7 prevalence. Fed beef hides had a significantly higher prevalence (P < 0.05) of STEC O103, O145, and O157 serogroups than did either of the other cattle types. The highest proportions of quantifiable samples were for STEC O145 (32 of 1,500 samples; 2.1%) and O157 (31 of 1,500 samples; 2.1%) serogroups, with the majority of concentrations at 3 to 5 and 2 to 4 log CFU/100 cm2 of hide, respectively. Results indicate that hide contamination with some major STEC serogroups differs significantly among cattle types at harvest, even within the same day and location.

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Spiral Plating Method To Quantify the Six Major Non-O157 Escherichia coli Serogroups in Cattle Feces

Journal of Food Protection ◽

10.4315/0362-028x.jfp-16-360 ◽

2017 ◽

Vol 80 (5) ◽

pp. 848-856 ◽

Cited By ~ 5

Author(s):

Pragathi B. Shridhar ◽

Lance W. Noll ◽

Charley A. Cull ◽

Xiaorong Shi ◽

Natalia Cernicchiaro ◽

...

Keyword(s):

Escherichia Coli ◽

Shiga Toxin ◽

Foodborne Illnesses ◽

Fecal Samples ◽

Fecal Shedding ◽

E Coli ◽

Cattle Feces ◽

Plating Method ◽

Pure Cultures ◽

High Concentrations

ABSTRACT Cattle are a major reservoir of the six major Shiga toxin–producing non-O157 Escherichia coli (STEC) serogroups (O26, O45, O103, O111, O121, and O145) responsible for foodborne illnesses in humans. Besides prevalence in feces, the concentrations of STEC in cattle feces play a major role in their transmission dynamics. A subset of cattle, referred to as super shedders, shed E. coli O157 at high concentrations (≥4 log CFU/g of feces). It is not known whether a similar pattern of fecal shedding exists for non-O157. Our objectives were to initially validate the spiral plating method to quantify the six non-O157 E. coli serogroups with pure cultures and culture-spiked fecal samples and then determine the applicability of the method and compare it with multiplex quantitative PCR (mqPCR) assays for the quantification of the six non-O157 E. coli serogroups in cattle fecal samples collected from commercial feedlots. Quantification limits of the spiral plating method were 3 log, 3 to 4 log, and 3 to 5 log CFU/mL or CFU/g for individual cultures, pooled pure cultures, and cattle fecal samples spiked with pooled pure cultures, respectively. Of the 1,152 cattle fecal samples tested from eight commercial feedlots, 122 (10.6%) and 320 (27.8%) harbored concentrations ≥4 log CFU/g of one or more of the six serogroups of non-O157 by spiral plating and mqPCR methods, respectively. A majority of quantifiable samples, detected by either spiral plating (135 of 137, 98.5%) or mqPCR (239 of 320, 74.7%), were shedding only one serogroup. Only one of the quantifiable samples was positive for a serogroup carrying Shiga toxin (stx1) and intimin (eae) genes; 38 samples were positive for serogroups carrying the intimin gene. In conclusion, the spiral plating method can be used to quantify non-O157 serogroups in cattle feces, and our study identified a subset of cattle that was super shedders of non-O157 E. coli. The method has the advantage of quantifying non-O157 STEC, unlike mqPCR that quantifies serogroups only.

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Duration of Fecal Shedding of Shiga Toxin–Producing Escherichia coli O104:H4 in Patients Infected During the 2011 Outbreak in Germany: A Multicenter Study

Clinical Infectious Diseases ◽

10.1093/cid/cis1218 ◽

2013 ◽

Vol 56 (8) ◽

pp. 1132-1140 ◽

Cited By ~ 32

Author(s):

Ralf P. Vonberg ◽

Michael Höhle ◽

Martin Aepfelbacher ◽

Franz C. Bange ◽

Cristina Belmar Campos ◽

...

Keyword(s):

Escherichia Coli ◽

Multicenter Study ◽

Shiga Toxin ◽

Fecal Shedding

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Duration of fecal shedding of Shiga toxin- producing Escherichia coli among children with hemolytic uremic syndrome

Archivos Argentinos de Pediatria ◽

10.5546/aap.2021.eng.39 ◽

2021 ◽

Vol 119 (1) ◽

Keyword(s):

Escherichia Coli ◽

Hemolytic Uremic Syndrome ◽

Shiga Toxin ◽

Fecal Shedding ◽

Uremic Syndrome

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Fecal Shedding of Non-O157 Serogroups of Shiga Toxin–Producing Escherichia coli in Feedlot Cattle Vaccinated with an Escherichia coli O157:H7 SRP Vaccine or Fed a Lactobacillus-Based Direct-Fed Microbial†

Journal of Food Protection ◽

10.4315/0362-028x.jfp-13-358 ◽

2014 ◽

Vol 77 (5) ◽

pp. 732-737 ◽

Cited By ~ 11

Author(s):

N. CERNICCHIARO ◽

D. G. RENTER ◽

C. A. CULL ◽

Z. D. PADDOCK ◽

X. SHI ◽

...

Keyword(s):

Escherichia Coli ◽

Shiga Toxin ◽

Feedlot Cattle ◽

Fecal Samples ◽

Fecal Shedding ◽

E Coli ◽

Multiplex Pcr Assay ◽

Porin Proteins ◽

To Receive ◽

Cumulative Prevalence

The objectives of this study were to determine whether fecal shedding of non-O157 Shiga toxin–producing Escherichia coli (STEC) in feedlot cattle was affected by the use of an E. coli O157:H7 vaccine or a direct-fed microbial (DFM) and whether the shedding of a particular non-O157 STEC serogroup within feces was associated with shedding of O157 or other non-O157 STEC serogroups. A total of 17,148 cattle in 40 pens were randomized to receive one, both, or neither (control) of the two interventions: a vaccine based on the siderophore receptor and porin proteins (E. coli SRP vaccine, two doses) and a DFM product (low-dose Bovamine). Fresh fecal samples (30 samples per pen) were collected weekly from pen floors for four consecutive weeks beginning approximately 56 days after study allocation. DNA extracted from enriched samples was tested for STEC O157 and non-O157 serogroups O26, O45, O103, O111, O121, and O145 and for four major virulence genes (stx1, stx2, eae, and ehxA) using an 11-gene multiplex PCR assay. Generalized linear mixed models were used to analyze the effects of treatments and make within-sample comparisons of the presence of O-serogroup–specific genes. Results of cumulative prevalence measures indicated that O157 (14.6%), O26 (10.5%), and O103 (10.3%) were the most prevalent STEC O serogroups. However, the vaccine, DFM, or both had no significant effect (P > 0.05) on fecal prevalence of the six non-O157 STEC serogroups in feedlot cattle. Within-sample comparisons of the presence of STEC serogroup–specific genes indicated that fecal shedding of E. coli O157 in cattle was associated with an increased probability (P < 0.05) of fecal shedding of STEC O26, O45, O103, and O121. Our study revealed that neither the E. coli O157:H7 vaccine, which reduced STEC O157 fecal shedding, nor the DFM significantly affected fecal shedding of non-O157 STEC serogroups, despite the fact that the most prevalent non-O157 STEC serogroups tended to occur concurrently with O157 STEC strains within fecal samples.

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Characterizing the Cattle Gut Microbiome in Farms with a High and Low Prevalence of Shiga Toxin-Producing Escherichia coli

Microorganisms ◽

10.3390/microorganisms9081737 ◽

2021 ◽

Vol 9 (8) ◽

pp. 1737

Author(s):

Karla Vasco ◽

Brian Nohomovich ◽

Pallavi Singh ◽

Cristina Venegas-Vargas ◽

Rebekah E. Mosci ◽

...

Keyword(s):

Escherichia Coli ◽

Shiga Toxin ◽

Foodborne Pathogen ◽

16S Rrna Gene Sequencing ◽

Rrna Gene ◽

Fecal Shedding ◽

Microbiome Composition ◽

Uremic Syndrome ◽

Rrna Gene Sequencing ◽

Low Prevalence

Cattle are the main reservoirs of Shiga toxin-producing Escherichia coli (STEC), a major foodborne pathogen associated with acute enteric disease and hemolytic–uremic syndrome in humans. A total of 397 beef and dairy cattle from 5 farms were included in this study, of which 660 samples were collected for 16S rRNA gene sequencing. The microbiota of farms with a high-STEC prevalence (HSP) had greater richness compared to those of farms with a low-STEC prevalence (LSP). Longitudinal analyses showed STEC-shedders from LSP farms had higher microbiome diversity; meanwhile, changes in the microbiome composition in HSP farms were independent of the STEC shedding status. Most of the bacterial genera associated with STEC shedding in dairy farms were also correlated with differences in the percentage of forage in diet and risk factors of STEC carriage such as days in milk, number of lactations, and warm temperatures. Identifying factors that alter the gut microbiota and enable STEC colonization in livestock could lead to novel strategies to prevent fecal shedding and the subsequent transmission to humans.

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