scholarly journals ‘Super' or just ‘above average'? Supershedders and the transmission of Escherichia coli O157:H7 among feedlot cattle

2015 ◽  
Vol 12 (110) ◽  
pp. 20150446 ◽  
Author(s):  
Simon E. F. Spencer ◽  
Thomas E. Besser ◽  
Rowland N. Cobbold ◽  
Nigel P. French
Keyword(s):  
Escherichia Coli ◽  
Stocking Density ◽  
Preliminary Evidence ◽  
Feedlot Cattle ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Key Characteristics ◽  
Data Driven Approach ◽  
Definition Of

Supershedders have been suggested to be major drivers of transmission of Escherichia coli O157:H7 ( E. coli O157:H7) among cattle in feedlot environments, despite our relatively limited knowledge of the processes that govern periods of high shedding within an individual animal. In this study, we attempt a data-driven approach, estimating the key characteristics of high shedding behaviour, including effects on transmission to other animals, directly from a study of natural E. coli O157:H7 infection of cattle in a research feedlot, in order to develop an evidence-based definition of supershedding. In contrast to the hypothesized role of supershedders, we found that high shedding individuals only modestly increased the risk of transmission: individuals shedding over 10 3 cfu g −1 faeces were estimated to pose a risk of transmission only 2.45 times greater than those shedding below that level. The data suggested that shedding above 10 3 cfu g −1 faeces was the most appropriate definition of supershedding behaviour and under this definition supershedding was surprisingly common, with an estimated prevalence of 31.3% in colonized individuals. We found no evidence that environmental contamination by faeces of shedding cattle contributed to transmission over timescales longer than 3 days and preliminary evidence that higher stocking density increased the risk of transmission.

Monitoring Escherichia coli O157:H7 in Inoculated and Naturally Colonized Feedlot Cattle and Their Environment

2005 ◽  
Vol 68 (1) ◽  
pp. 26-33 ◽  
Author(s):  
K. STANFORD ◽  
S. J. BACH ◽  
T. H. MARX ◽  
S. JONES ◽  
J. R. HANSEN ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Feedlot Cattle ◽  
Mitigation Strategies ◽  
Escherichia Coli O157 ◽  
Feeding Period ◽  
Sample Collection ◽  
E Coli ◽  
Challenge Study ◽  
On Farm ◽  
Feed Samples

On-farm methods of monitoring Escherichia coli O157:H7 were assessed in 30 experimentally inoculated steers housed in four pens over a 12-week period and in 202,878 naturally colonized feedlot cattle housed in 1,160 pens on four commercial Alberta feedlots over a 1-year period. In the challenge study, yearling steers were experimentally inoculated with 1010 CFU of a four-strain mixture of nalidixic acid–resistant E. coli O157:H7. After inoculation, shedding of E. coli O157:H7 was monitored weekly by collecting rectal fecal samples (FEC), oral swabs (ORL), pooled fecal pats (PAT), manila ropes (ROP) orally accessed for 4 h, feed samples, water, and water bowl interface. Collection of FEC from all animals per pen provided superior isolation (P < 0.01) of E. coli O157:H7 compared with other methods, although labor and animal restraint requirements for fecal sample collection were high. When one sample was collected per pen of animals, E. coli O157:H7 was more likely to be detected from the ROP than from the FEC, PAT, or ORL (P < 0.001). In the commercial feedlot study, samples were limited to ROP and PAT, and E. coli O157:H7 was isolated in 18.8% of PAT and 6.8% of ROP samples. However, for animals that had been resident in the feedlot pen for at least 1 month, isolation of E. coli O157:H7 from ROP was not different from that from PAT (P = 0.35). Pens of animals on feed for <30 days were six times more likely to shed E. coli O157:H7 than were animals on feed for >30 days. However, change in diet did not affect shedding of the organism (P > 0.23) provided that animals had acclimated to the feedlot for 1 month or longer. Findings from this study indicate the importance of introduction of mitigation strategies early in the feeding period to reduce transference and the degree to which E. coli O157:H7 is shed into the environment.

Quantitative Determination of the Role of Lettuce Leaf Structures in Protecting Escherichia coli O157:H7 from Chlorine Disinfection

2001 ◽  
Vol 64 (2) ◽  
pp. 147-151 ◽  
Author(s):  
KAZUE TAKEUCHI ◽  
JOSEPH F. FRANK
Keyword(s):  
Escherichia Coli ◽  
Leaf Surface ◽  
Dead Cell ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Chlorine Disinfection ◽  
Sytox Green ◽  
Tissue Surface ◽  
Confocal Scanning

Viability of Escherichia coli O157:H7 cells on lettuce leaves after 200 mg/liter (200 ppm) chlorine treatment and the role of lettuce leaf structures in protecting cells from chlorine inactivation were evaluated by confocal scanning microscopy (CSLM). Lettuce samples (2 by 2 cm) were inoculated by immersing in a suspension containing 109 CFU/ml of E. coli O157: H7 for 24 ± 1 h at 4°C. Rinsed samples were treated with 200 mg/liter (200 ppm) chlorine for 5 min at 22°C. Viability of E. coli O157:H7 cells was evaluated by CSLM observation of samples stained with Sytox green (dead cell stain) and Alexa 594 conjugated antibody against E. coli O157:H7. Quantitative microscopic observations of viability were made at intact leaf surface, stomata, and damaged tissue. Most E. coli O157:H7 cells (68.3 ± 16.2%) that had penetrated 30 to 40 μm from the damaged tissue surface remained viable after chlorine treatment. Cells on the surface survived least (25.2 ± 15.8% survival), while cells that penetrated 0 to 10 μm from the damaged tissue surface or entered stomata showed intermediate survival (50.8 ± 13.5 and 45.6 ± 9.7% survival, respectively). Viability was associated with the depth at which E. coli O157:H7 cells were in the stomata. Although cells on the leaf surface were mostly inactivated, some viable cells were observed in cracks of cuticle and on the trichome. These results demonstrate the importance of lettuce leaf structures in the protection of E. coli O157:H7 cells from chlorine inactivation.

Comparison of Two Sampling Methods for Escherichia coli O157:H7 Detection in Feedlot Cattle

2005 ◽  
Vol 68 (8) ◽  
pp. 1724-1728 ◽  
Author(s):  
M. L. KHAITSA ◽  
M. L. BAUER ◽  
P. S. GIBBS ◽  
G. P. LARDY ◽  
D. DOETKOTT ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Sampling Methods ◽  
Feedlot Cattle ◽  
Sampling Time ◽  
Escherichia Coli O157 ◽  
Confounding Factors ◽  
Rank Tests ◽  
E Coli ◽  
Signed Rank ◽  
Sampling Times

Two sampling methods (rectoanal swabs and rectal fecal grabs) were compared for their recovery of Escherichia coli O157:H7 from feedlot cattle. Samples were collected from 144 steers four times during the finishing period by swabbing the rectoanal mucosa with cotton swabs and immediately obtaining feces from the rectum of each individual steer. The number of steers with detectable E. coli O157:H7 increased from 2 of 144 (1.4%) cattle on arrival at the feedlot to 10 of 144 (6.9%) after 1 month, 76 of 143 (52.8%) after 7 months, and 30 of 143 (20.8%) at the last sampling time before slaughter. Wilcoxon signed-rank tests indicated that the two sampling methods gave different results for sampling times 3 and 4 (P < 0.05) but not for sampling time 2 (P = 0.16). Agreement between the two sampling methods was poor (kappa < 0.2) for three of the four sampling times and moderate (kappa = 0.6) for one sampling time, an indication that in this study rectoanal swabs usually were less sensitive than rectal fecal grabs for detection of E. coli O157:H7 in cattle. Overall, the herd of origin was not significantly associated with E. coli O157:H7 results, but the weight of the steers was. Further investigation is needed to determine the effects of potential confounding factors (e.g., size and type of swab, consistency of feces, site sampled, and swabbing technique) that might influence the sensitivity of swabs in recovering E. coli O157:H7 from the rectoanal mucosa of cattle.

Fecal Shedding of Escherichia coli O157:H7 in North Dakota Feedlot Cattle in the Fall and Spring

2006 ◽  
Vol 69 (5) ◽  
pp. 1154-1158 ◽  
Author(s):  
MARGARET L. KHAITSA ◽  
MARC L. BAUER ◽  
GREGORY P. LARDY ◽  
DAWN K. DOETKOTT ◽  
REDEMPTA B. KEGODE ◽  
...  
Keyword(s):  
United States ◽  
Escherichia Coli ◽  
North Dakota ◽  
The United States ◽  
Extreme Weather ◽  
Early Spring ◽  
Feedlot Cattle ◽  
Escherichia Coli O157 ◽  
Fecal Shedding ◽  
E Coli

Cattle are an important reservoir of Escherichia coli O157:H7, which can lead to contamination of food and water, and subsequent human disease. E. coli O157:H7 shedding in cattle has been reported as seasonal, with more animals shedding during summer and early fall than during winter. North Dakota has relatively cold weather, especially in winter and early spring, compared with many other regions of the United States. The objective was to assess fecal shedding of E. coli O157: H7 in North Dakota feedlot cattle over the fall, winter, and early spring. One hundred forty-four steers were assigned randomly to 24 pens on arrival at the feedlot. Samples of rectal feces were obtained from each steer four times (October and November 2003, and March and April 2004) during finishing. On arrival (October 2003), 2 (1.4%) of 144 cattle were shedding E. coli O157:H7. The shedding increased significantly to 10 (6.9%) of 144 after 28 days (November 2003), to 76 (53%) of 143 at the third sampling (March 2004), and dropped significantly to 30 (21%) of 143 at the fourth (last) sampling (March 2004) before slaughter. Unfortunately, we were unable to sample the cattle during winter because of the extreme weather conditions. Sampling time significantly (P < 0.0001) influenced variability in E. coli O157:H7 shedding, whereas herd (P = 0.08) did not. The prevalence of E. coli O157:H7 shedding in North Dakota steers in fall and early spring was comparable to what has been reported in other parts of the United States with relatively warmer weather. Further research into E. coli O157:H7 shedding patterns during extreme weather such as North Dakota winters is warranted in order to fully assess the seasonal effect on the risk level of this organism.

Ecological Relationships between the Prevalence of Cattle Shedding Escherichia coli O157:H7 and Characteristics of the Cattle or Conditions of the Feedlot Pen†

2001 ◽  
Vol 64 (12) ◽  
pp. 1899-1903 ◽  
Author(s):  
DAVID SMITH ◽  
MARK BLACKFORD ◽  
SPRING YOUNTS ◽  
RODNEY MOXLEY ◽  
JEFF GRAY ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Feedlot Cattle ◽  
Escherichia Coli O157 ◽  
Water Tank ◽  
Weight Class ◽  
E Coli ◽  
Ecological Relationships ◽  
Average Body ◽  
Tank Water ◽  
Average Body Weight

This study was designed to describe the percentage of cattle shedding Escherichia coli O157:H7 in Midwestern U.S. feedlots and to discover relationships between the point prevalence of cattle shedding the organism and the characteristics of those cattle or the conditions of their pens. Cattle from 29 pens of five Midwestern feedlots were each sampled once between June and September 1999. Feces were collected from the rectum of each animal in each pen. Concurrently, samples of water were collected from the water tank, and partially consumed feed was collected from the feedbunk of each pen. Characteristics of the cattle and conditions of each pen that might have affected the prevalence of cattle shedding E. coli O157:H7 were recorded. These factors included the number of cattle; the number of days on feed; and the average body weight, class, and sex of the cattle. In addition, the temperature and pH of the tank water were determined, and the cleanliness of the tank water and the condition of the pen floor were subjectively assessed. The samples of feces, feed, and water were tested for the presence of E. coli O157:H7. E. coli O157:H7 was isolated from the feces of 719 of 3,162 cattle tested (23%), including at least one animal from each of the 29 pens. The percentage of cattle in a pen shedding E. coli O157:H7 did not differ between feedyards, but it did vary widely within feedyards. A higher prevalence of cattle shed E. coli O157:H7 from muddy pen conditions than cattle from pens in normal condition. The results of this study suggest that E. coli O157:H7 should be considered common to groups of feedlot cattle housed together in pens and that the condition of the pen floor may influence the prevalence of cattle shedding the organism.

Impact of Transportation of Feedlot Cattle to the Harvest Facility on the Prevalence of Escherichia coli O157:H7, Salmonella, and Total Aerobic Microorganisms on Hides

2007 ◽  
Vol 70 (1) ◽  
pp. 17-21 ◽  
Author(s):  
A. L. REICKS ◽  
M. M. BRASHEARS ◽  
K. D. ADAMS ◽  
J. C. BROOKS ◽  
J. R. BLANTON ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Feedlot Cattle ◽  
Lower Percentage ◽  
Escherichia Coli O157 ◽  
Sample Collection ◽  
Treatment Groups ◽  
E Coli ◽  
Sampling Locations ◽  
Before And After

Prevalences of Escherichia coli O157:H7, Salmonella, and total aerobic microorganisms were determined on the hides of beef feedlot cattle before and after transport from the feedyard to the harvest facility in clean and dirty trailers. Swab samples were taken from the midline and withers of 40 animals on each of 8 days before and after shipping. After samples were collected, animals were loaded in groups of 10 on upper and lower levels of clean and dirty trailers. Animals were unloaded at the harvest facility and kept in treatment groups for sample collection after exsanguination. Salmonella was found more often on hide swabs collected from the midline than on than samples collected from the withers from animals transported in both clean and dirty trailers. Salmonella was found on significantly more hide swabs collected at harvest from both sampling locations than on those collected at the feedyard, with no differences attributed to the type of trailer. At the feedyard, clean trucks had a lower percentage of Salmonella-positive samples than did dirty trucks before animals were loaded. However, after transport, both clean and dirty trucks had a similar prevalence of Salmonella. There were no differences in Salmonella prevalence on hides collected from animals transported on the top and bottom levels of clean and dirty trucks. E. coli O157:H7 was detected on less than 2% of the samples; therefore, no practical conclusions about prevalence could be drawn. Hides sampled at harvest had higher concentrations of aerobic microorganisms than did hides sampled at the feedyard, and concentrations were higher on the midline than on the withers. Although the prevalences of Salmonella and total aerobic microorganisms increased on hides after transport from the feedyard to the plant, this increase was not related to the cleanliness of the trailers or the location of the cattle in the trailers.

scholarly journals Preliminary Evidence that American Bullfrogs (Rana catesbeiana) Are Suitable Hosts for Escherichia coli O157:H7

2007 ◽  
Vol 73 (12) ◽  
pp. 4066-4068 ◽  
Author(s):  
Matthew J. Gray ◽  
Sreekumari Rajeev ◽  
Debra L. Miller ◽  
A. Chandler Schmutzer ◽  
Elizabeth C. Burton ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Rana Catesbeiana ◽  
Preliminary Evidence ◽  
Escherichia Coli O157 ◽  
E Coli

ABSTRACT We orally inoculated Rana catesbeiana tadpoles (n = 23) and metamorphs (n = 24) to test their suitability as hosts for Escherichia coli O157:H7. Tadpoles were housed in flowthrough aquaria and did not become infected. Metamorphs were housed in stagnant aquaria, and 54% tested positive through 14 days postinoculation, suggesting that they are suitable hosts for E. coli O157:H7.

Epidemiology of Escherichia coli O157 in Feedlot Cattle

1997 ◽  
Vol 60 (5) ◽  
pp. 462-465 ◽  
Author(s):  
DALE D. HANCOCK ◽  
DANIEL H. RICE ◽  
LEE ANN THOMAS ◽  
DAVID A. DARGATZ ◽  
THOMAS E. BESSER
Keyword(s):  
United States ◽  
Escherichia Coli ◽  
The United States ◽  
Feedlot Cattle ◽  
Escherichia Coli O157 ◽  
Fecal Samples ◽  
E Coli ◽  
Geographical Regions ◽  
Flagellar Antigen ◽  
Low Prevalence

Fecal samples from cattle in 100 feedlots in 13 states were bacteriologically cultured for Escherichia coli O157 that did not ferment sorbitol, lacked beta-glucuronidase, and possessed genes coding for Shiga-like toxin. In each feedlot 30 fresh fecal-pat samples were collected from each of four pens: with the cattle shortest on feed, with cattle longest on feed, and with cattle in two randomly selected pens. E. coli O157 was isolated from 210 (1.8%) of 11,881 fecal samples. One or more samples were positive for E. coli O157 in 63 of the 100 feedlots tested. E. coli O157 was found at roughly equal prevalence in all the geographical regions sampled. The prevalence of E. coli O157 in the pens with cattle shortest on feed was approximately threefold higher than for randomly selected and longest on feed pens. Of the E. coli O157 isolates found in this study, 89.52% expressed the H7 flagellar antigen. E. coli O157 was found to be widely distributed among feedlot cattle, but at a low prevalence, in the United States.

scholarly journals Longitudinal Study of Escherichia coli O157:H7 in a Beef Cattle Feedlot and Role of High-Level Shedders in Hide Contamination

2009 ◽  
Vol 75 (20) ◽  
pp. 6515-6523 ◽  
Author(s):  
Terrance M. Arthur ◽  
James E. Keen ◽  
Joseph M. Bosilevac ◽  
Dayna M. Brichta-Harhay ◽  
Norasak Kalchayanand ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Longitudinal Study ◽  
Beef Cattle ◽  
Intervention Studies ◽  
High Density ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
High Level ◽  
Cattle Feedlot

ABSTRACT The objectives of the study described here were (i) to investigate the dynamics of Escherichia coli O157:H7 fecal and hide prevalence over a 9-month period in a feedlot setting and (ii) to determine how animals shedding E. coli O157:H7 at high levels affect the prevalence and levels of E. coli O157:H7 on the hides of other animals in the same pen. Cattle (n = 319) were distributed in 10 adjacent pens, and fecal and hide levels of E. coli O157:H7 were monitored. When the fecal pen prevalence exceeded 20%, the hide pen prevalence was usually (25 of 27 pens) greater than 80%. Sixteen of 19 (84.2%) supershedder (>104 CFU/g) pens had a fecal prevalence greater than 20%. Significant associations with hide and high-level hide (≥40 CFU/100 cm2) contamination were identified for (i) a fecal prevalence greater than 20%, (ii) the presence of one or more high-density shedders (≥200 CFU/g) in a pen, and (iii) the presence of one or more supershedders in a pen. The results presented here suggest that the E. coli O157:H7 fecal prevalence should be reduced below 20% and the levels of shedding should be kept below 200 CFU/g to minimize the contamination of cattle hides. Also, large and unpredictable fluctuations within and between pens in both fecal and hide prevalence of E. coli O157:H7 were detected and should be used as a guide when preharvest studies, particularly preharvest intervention studies, are designed.

Comparing Real-Time and Conventional PCR to Culture-Based Methods for Detecting and Quantifying Escherichia coli O157 in Cattle Feces

2014 ◽  
Vol 77 (2) ◽  
pp. 314-319 ◽  
Author(s):  
M. E. JACOB ◽  
J. BAI ◽  
D. G. RENTER ◽  
A. T. ROGERS ◽  
X. SHI ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Real Time ◽  
Positive Culture ◽  
Feedlot Cattle ◽  
Escherichia Coli O157 ◽  
Conventional Pcr ◽  
Culture Methods ◽  
E Coli ◽  
Cattle Feces ◽  
Culture Negative

Detection of Escherichia coli O157 in cattle feces has traditionally used culture-based methods; PCR-based methods have been suggested as an alternative. We aimed to determine if multiplex real-time (mq) or conventional PCR methods could reliably detect cattle naturally shedding high (≥104 CFU/g of feces) and low (~102 CFU/g of feces) concentrations of E. coli O157. Feces were collected from pens of feedlot cattle and evaluated for E. coli O157 by culture methods. Samples were categorized as (i) high shedders, (ii) immunomagnetic separation (IMS) positive after enrichment, or (iii) culture negative. DNA was extracted pre- and postenrichment from 100 fecal samples from each category (high shedder, IMS positive, culture negative) and subjected to mqPCR and conventional PCR assays based on detecting three genes, rfbE, stx1, and stx2. In feces from cattle determined to be E. coli O157 high shedders by culture, 37% were positive by mqPCR prior to enrichment; 85% of samples were positive after enrichment. In IMS-positive samples, 4% were positive by mqPCR prior to enrichment, while 43% were positive after enrichment. In culture-negative feces, 7% were positive by mqPCR prior to enrichment, and 40% were positive after enrichment. The proportion of high shedder–positive and culture-positive (high shedder and IMS) samples were significantly different from mqPCR-positive samples before and after enrichment (P < 0.01). Similar results were observed for conventional PCR. Our data suggest that mqPCR and conventional PCR are most useful in identifying high shedder animals and may not be an appropriate substitute to culture-based methods for detection of E. coli O157 in cattle feces.

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