Risk of Escherichia coli O157:H7, Non-O157 Shiga Toxin–Producing Escherichia coli, and Campylobacter spp. in Food Animals and Their Products in Qatar

2015 ◽  
Vol 78 (10) ◽  
pp. 1812-1818 ◽  
Author(s):  
HUSSNI O. MOHAMMED ◽  
KORANA STIPETIC ◽  
AHMED SALEM ◽  
PATRICK McDONOUGH ◽  
YUNG FU CHANG ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Cross Sectional Study ◽  
Campylobacter Coli ◽  
Escherichia Coli O157 ◽  
Cross Sectional ◽  
Fecal Samples ◽  
E Coli ◽  
Cattle Feces ◽  
Campylobacter Spp

Escherichia coli O157:H7, non-O157 E. coli, and Campylobacter spp. are among the top-ranked pathogens that threaten the safety of food supply systems around the world. The associated risks and predisposing factors were investigated in a dynamic animal population using a repeat-cross-sectional study design. Animal and environmental samples were collected from dairy and camel farms, chicken processing plants, and abattoirs and analyzed for the presence of these pathogens using a combination of bacterial enrichment and real-time PCR tests without culture confirmation. Data on putative risk factors were also collected and analyzed. E. coli O157:H7 was detected by PCR at higher levels in sheep and camel feces than in cattle feces (odds ratios [OR], 6.8 and 21.1, respectively). Although the genes indicating E. coli O157:H7 were detected at a relatively higher rate (4.3%) in fecal samples from dairy cattle, they were less common in milk and udder swabs from the same animals (1 and 2%, respectively). Among the food adulterants, E. coli O103 was more common in cattle fecal samples, whereas O26 was more common in sheep feces and O45 in camel feces compared with cattle (OR, 2.6 and 3.1, respectively). The occurrence of E. coli in the targeted populations differed by the type of sample and season of the year. Campylobacter jejuni and Campylobacter coli were more common in sheep and camel feces than in cattle feces. Most of the survey and surveillance of E. coli focused on serogroup O157 as a potential foodborne hazard; however, based on the PCR results, non-O157 Shiga toxin–producing E. coli serotypes appeared to be more common, and efforts should be made to include them in food safety programs.

Detection of cytolethal distending toxin and other virulent factors in Escherichia coli samples from animal livestock, retail foods and gastroenteritis human cases in Qatar

2020 ◽  
Author(s):  
Adriana Morales Gómez ◽  
Nilda N. Valenzuela ◽  
Kenlyn E. Peters ◽  
Ahmed Salem ◽  
Ali Sultan ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Food Products ◽  
Cross Sectional Study ◽  
Toxin Gene ◽  
Cytolethal Distending Toxin ◽  
Cross Sectional ◽  
E Coli ◽  
Polymerase Chain ◽  
Retail Food

Cytolethal distending toxin (CDT) is a heterotrimeric AB-type genotoxin produced by several clinically important bacterial pathogens. To better understand the risk of CDT within the food supply and human gastroenteritis patients in Qatar, we investigated the frequency of the CDT gene (cdtB) among Escherichia coli (E. coli) strains recovered from food products, animal livestock, and human gastroenteritis patients. In this cross-sectional study, E. coli isolates were screened for cdtB using polymerase chain reaction (PCR). cdtB positive strains were further examined for E. coli cdtB gene types (cdt I, cdt II, cdt III, cdt IV and cdtV), serotypes O157: H7, and non-O157 Shiga toxin-producing E. coli O26, O45, O103, O111, O121, and O145. Screening for other virulent factors, stx (Shiga toxin gene) and eae (gene that encodes intimin) genes were also performed. The cdtB gene was detected in E. coli isolates sourced from all three groups; animal livestock (17%), retail foods (8%), and human gastroenteritis patients (3%). Although the incidence of cdtB gene harboring E. coli is relatively low among gastroenteritis patients, there is still a risk of infection from animal reservoirs as well as retail food products. Among the three groups, E. coli isolates from humans had the lowest occurrence of cdtB, stx, eae, and O157: H7. Furthermore, we advise implementing monitoring at the food production and preparation level.

Escherichia coli O157 and non-O157 Shiga Toxin–Producing Escherichia coli in Fecal Samples of Finished Pigs at Slaughter in Switzerland

2006 ◽  
Vol 69 (2) ◽  
pp. 260-266 ◽  
Author(s):  
M. KAUFMANN ◽  
C. ZWEIFEL ◽  
M. BLANCO ◽  
J. E. BLANCO ◽  
J. BLANCO ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Escherichia Coli O157 ◽  
Strongly Correlated ◽  
Fecal Samples ◽  
E Coli ◽  
High Prevalence ◽  
Strain Testing ◽  
Typical Epec ◽  
Uremic Syndrome

Fecal samples from 630 slaughtered finisher pigs were examined by PCR to assess the shedding of Escherichia coli O157 (rfbE) and Shiga toxin–producing E. coli (STEC, stx). The proportion of positive samples was 7.5% for rfbE and 22% for stx. By colony hybridization, 31 E. coli O157 and 45 STEC strains were isolated, and these strains were further characterized by phenotypic and genotypic traits. Among E. coli O157 strains, 30 were sorbitol positive, 30 had an H type other than H7, and none harbored stx genes. Intimin (eae), enterohemolysin (ehxA), EAST1 (astA), and porcine A/E–associated protein (paa) were present in 10, 3, 26, and 6% of strains. Among them, one eae-γ1–positive O157:H7 strain testing positive for ehxA and astA and two eae-α1–positive O157:H45 strains were classified as enteropathogenic E. coli (EPEC). The O157:H45 EPEC harbored the EAF plasmid and the bfpA gene, factors characteristic for typical EPEC. The isolated STEC strains (43 sorbitol positive) belonged to 11 O:H serotypes, including three previously reported in human STEC causing hemolytic uremic syndrome (O9:H−, O26:H−, and O103:H2). All but one strain harbored stx2e. The eae and ehxA genes, which are strongly correlated with human disease, were present in only one O103:H2 strain positive for stx1 and paa, whereas the astA gene was found more frequently (14 strains). High prevalence of STEC was found among finisher pigs, but according to the virulence factors the majority of these strains seem to be of low virulence.

Seasonal Prevalence of Escherichia coli O157:H7 in Beef Cattle Feces†

2006 ◽  
Vol 69 (12) ◽  
pp. 3018-3020 ◽  
Author(s):  
M. J. ALAM ◽  
L. ZUREK
Keyword(s):  
Escherichia Coli ◽  
Beef Cattle ◽  
Shiga Toxin ◽  
Bacterial Colonization ◽  
Feedlot Cattle ◽  
Escherichia Coli O157 ◽  
Human Pathogen ◽  
E Coli ◽  
Cattle Feces ◽  
Shiga Toxin 2

Cattle are an asymptomatic reservoir of Escherichia coli O157:H7, but the bacterial colonization and shedding patterns are poorly understood. The prevalence and shedding of this human pathogen have been reported to be seasonal with rates typically increasing during warm months. The objectives of this study were (i) to assess the prevalence of E. coli O157:H7 in feces of feedlot cattle in Kansas during summer, fall, and winter months, and (ii) to characterize E. coli O157:H7 by screening for virulence factors. Of 891 fecal samples collected, 82 (9.2%) were positive for E. coli O157:H7. No significant differences in prevalence were detected among summer, fall, and winter months. The highest monthly prevalence (18.1%) was detected in February. All tested isolates were positive for stx2 (Shiga toxin 2) and eaeA (intimin) genes; 14 isolates (12.8%) also carried stx1. Our results indicate the prevalence of E. coli O157:H7 in beef cattle feces is not necessarily season dependent.

scholarly journals Detection of Escherichia coli O157:H7 and Shiga toxin 2a gene in pork, pig feces, and clean water at Jagalan slaughterhouse in Surakarta, Central Java Province, Indonesia

2019 ◽  
Vol 12 (10) ◽  
pp. 1584-1590
Author(s):  
Maria Kristiani Epi Goma ◽  
Alvita Indraswari ◽  
Aris Haryanto ◽  
Dyah Ayu Widiasih
Keyword(s):  
Escherichia Coli ◽  
Food Safety ◽  
Shiga Toxin ◽  
Water Samples ◽  
Animal Origin ◽  
Clean Water ◽  
Escherichia Coli O157 ◽  
Fecal Samples ◽  
E Coli ◽  
Pork Samples

Background and Aim: The feasibility assessment of food products on the market becomes one of the milestones of food safety. The quality of food safety of animal origin especially pork need to get attention and more real action from the parties related and concerned. Since pork is also a source of transmission for the contagion of foodborne disease so that the study of the existence of several agents in the pork and its products become the benchmark of safety level. This study aimed to isolate, identify, and detect the Shiga toxin 2a (stx2a) gene from Escherichia coli O157:H7 in pork, pig feces, and clean water in the Jagalan slaughterhouse. Materials and Methods: A total of 70 samples consisting of 32 pork samples, 32 pig fecal samples, and 6 clean water samples were used to isolate and identify E. coli O157:H7 and the stx2a gene. Isolation and identification of E. coli O157:H7 were performed using culture on eosin methylene blue agar and Sorbitol-MacConkey agar media and confirmed molecularly with polymerase chain reaction to amplify the target genes rfbE (317 bp) and fliC (381 bp). The isolates, which were identified as E. coli O157:H7, were investigated for the stx2a gene (553 bp). Results: The results of this study show that of the total collected samples, E. coli O157:H7 was 28.6% in Jagalan slaughterhouse and consisted of 25% of pork samples, 31.25% of pig fecal samples, and 33.3% of clean water samples. The isolates that were identified to be E. coli O157:H7 mostly contained the stx2a gene, which was equal to 75%, and consisted of seven isolates from pork samples, seven isolates from fecal samples, and one isolate from clean water samples. Conclusion: E. coli O157:H7 was found in 28.6% of pork, pig feces, and clean water in Jagalan slaughterhouse and 75% of identified E. coli O157:H7 contained the stx2a gene.

Validation and Application of a Real-Time PCR Assay Based on the CRISPR Array for Serotype-Specific Detection and Quantification of Enterohemorrhagic Escherichia coli O157:H7 in Cattle Feces†

2018 ◽  
Vol 81 (7) ◽  
pp. 1157-1164 ◽  
Author(s):  
LANCE W. NOLL ◽  
RACHEL CHALL ◽  
PRAGATHI B. SHRIDHAR ◽  
XUMING LIU ◽  
JIANFA BAI ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Real Time ◽  
Shiga Toxin ◽  
Culture Method ◽  
Qpcr Assay ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Cattle Feces ◽  
Crispr Array ◽  
Detection And Quantification

ABSTRACT Several real-time quantitative PCR (qPCR) assays have been developed for detection and quantification of Escherichia coli O157:H7 in complex matrices by targeting genes for serogroup-specific O-antigen (rfbEO157), H7 antigen, and one or more major virulence factors (Shiga toxin and intimin). A major limitation of such assays is that coamplification of H7 and virulence genes in a sample does not signal association of those genes with the O157 serogroup. Clusters of regularly interspaced short palindromic repeats (CRISPR) polymorphisms are highly correlated with certain enterohemorrhagic E. coli (EHEC) serotypes, including O157:H7, and the presence of genes for Shiga toxin (stx1 and stx2) and intimin (eae). Our objectives were to develop and validate a qPCR assay targeting the CRISPR array for the detection and quantification of EHEC O157:H7 in cattle feces and to evaluate the applicability of the assay for detection of and comparison with a four-plex qPCR assay targeting rfbEO157, stx1, stx2, and eae genes and a culture method. Detection limits of the CRISPRO157:H7 qPCR assay for cattle feces spiked with pure cultures were 2.1 × 103 and 2.3 × 100 CFU/g before and after enrichment, respectively. Detection of E. coli O157 in feedlot cattle fecal samples (n = 576) was compared among the CRISPRO157:H7 qPCR assay, culture method, and four-plex qPCR assay. The CRISPRO157:H7 qPCR detected 42.2% of the samples (243 of 576 samples) as positive for E. coli O157:H7, compared with 30.4% (175 samples) by the culture method. Nearly all samples (97.2%; 560 samples) were positive for rfbEO157 by the four-plex PCR, but 21.8% (122 of 560 samples) were negative for the stx and/or eae genes, making it unlikely that EHEC O157:H7 was present in these samples. Cohen's kappa statistic indicated a fair and poor agreement beyond that due to chance between the CRISPR assay and the culture method and four-plex assay, respectively. This novel qPCR assay can detect the EHEC O157:H7 serotype in cattle feces by targeting CRISPR polymorphisms.

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

2017 ◽  
Vol 80 (5) ◽  
pp. 848-856 ◽  
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.

scholarly journals Seasonal Prevalence of Shiga Toxin–Producing Escherichia coli, Including O157:H7 and Non-O157 Serotypes, and Salmonella in Commercial Beef Processing Plants†

2003 ◽  
Vol 66 (11) ◽  
pp. 1978-1986 ◽  
Author(s):  
GENEVIEVE A. BARKOCY-GALLAGHER ◽  
TERRANCE M. ARTHUR ◽  
MILDRED RIVERA-BETANCOURT ◽  
XIANGWU NOU ◽  
STEVEN D. SHACKELFORD ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Escherichia Coli O157 ◽  
Seasonal Prevalence ◽  
Fecal Samples ◽  
E Coli ◽  
Beef Processing ◽  
Beef Carcasses ◽  
Processing Plants ◽  
Antimicrobial Interventions

The seasonal prevalence of Escherichia coli O157:H7, Salmonella, non-O157 E. coli (STEC), and stx-harboring cells was monitored at three Midwestern fed-beef processing plants. Overall, E. coli O157:H7 was recovered from 5.9% of fecal samples, 60.6% of hide samples, and 26.7% of carcasses sampled before the preevisceration wash. This pathogen also was recovered from 1.2% (15 of 1,232) of carcasses sampled at chilling (postintervention) at approximate levels of <3.0 cells per 100 cm2. In one case, the E. coli O157:H7 concentration dropped from ca. 1,100 cells per 320 cm2 at the preevisceration stage to a level that was undetectable on ca. 2,500 cm2 at the postintervention stage. The prevalence of E. coli O157:H7 in feces peaked in the summer, whereas its prevalence on hide was high from the spring through the fall. Overall, Salmonella was recovered from 4.4, 71.0, and 12.7% of fecal, hide, and preevisceration carcass samples, respectively. Salmonella was recovered from one postintervention carcass (of 1,016 sampled). Salmonella prevalence peaked in feces in the summer and was highest on hide and preevisceration carcasses in the summer and the fall. Non-O157 STEC prevalence also appeared to vary by season, but the efficiency in the recovery of isolates from stx-positive samples ranged from 37.5 to 83.8% and could have influenced these results. Cells harboring stx genes were detected by PCR in 34.3, 92.0, 96.6, and 16.2% of fecal, hide, preevisceration carcass, and postintervention carcass samples, respectively. The approximate level of non-O157 STEC and stx-harboring cells on postintervention carcasses was ≥3.0 cells per 100 cm2 for only 8 of 199 carcasses (4.0%). Overall, the prevalence of E. coli O157:H7, Salmonella, and non-O157 STEC varied by season, was higher on hides than in feces, and decreased dramatically, along with pathogen levels, during processing and during the application of antimicrobial interventions. These results demonstrate the effectiveness of the current interventions used by the industry and highlight the significance of hides as a major source of pathogens on beef carcasses.

Animal- and Truckload-Level Associations between Escherichia coli O157:H7 in Feces and on Hides at Harvest and Contamination of Preevisceration Beef Carcasses†

2010 ◽  
Vol 73 (6) ◽  
pp. 1030-1037 ◽  
Author(s):  
M. E. JACOB ◽  
D. G. RENTER ◽  
T. G. NAGARAJA
Keyword(s):  
Escherichia Coli ◽  
Cross Sectional Study ◽  
Mitigation Strategies ◽  
Escherichia Coli O157 ◽  
Sectional Study ◽  
Cross Sectional ◽  
Factors Affecting ◽  
E Coli ◽  
Beef Carcasses ◽  
Carcass Contamination

Cattle feces and hides contribute to carcass contamination with Escherichia coli O157:H7, ultimately impacting beef safety. Primary objectives of our cross-sectional study were to evaluate associations among fecal, hide, and preevisceration carcass prevalence of E. coli O157:H7 and to assess factors affecting carcass contamination. Fecal, hide, and preevisceration carcass samples were collected from up to 32 cattle on each of 45 truckloads presented to a midwestern U.S. abattoir. Enrichment and selective culture were used to assess fecal, hide, and carcass prevalence, and direct plating was used to identify cattle shedding high levels of E. coli O157:H7 in feces. Fecal, hide, and carcass prevalence of E. coli O157:H7 within truckload were significantly correlated (P < 0.05) with each other. Enriched fecal sample prevalence was 13.8%, and high shedder prevalence was 3.3%; 38.5% of hides and 10.5% of carcasses were positive for E. coli O157:H7. We used logistic regression to assess animal- and truckload-level variables affecting the probability of carcasses testing positive for E. coli O157:H7. All truckload-level predictors significantly affected the probability of an E. coli O157:H7–positive carcass, including presence of a high shedder within the truckload (odds ratio [OR] = 4.0; confidence interval [CI], 1.6 to 10.1), high (>25%) within-truckload fecal prevalence (OR = 19.3; CI, 4.7 to 79.0), and high (>50%) within-truckload hide prevalence (OR = 7.7; CI, 3.1 to 19.6). The only significant animal-level predictor was having a positive hide (OR = 1.6; CI, 1.0 to 2.6). Our results suggest that preharvest interventions for reducing E. coli O157:H7 contamination of carcasses should focus on truckload (cohort)–level and hide mitigation strategies.

Multiplex Quantitative PCR Assays for the Detection and Quantification of the Six Major Non-O157 Escherichia coli Serogroups in Cattle Feces†

2016 ◽  
Vol 79 (1) ◽  
pp. 66-74 ◽  
Author(s):  
P. B. SHRIDHAR ◽  
L. W. NOLL ◽  
X. SHI ◽  
B. AN ◽  
N. CERNICCHIARO ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Quantitative Pcr ◽  
Foodborne Pathogens ◽  
Virulence Genes ◽  
Target Genes ◽  
Culture Methods ◽  
Fecal Samples ◽  
E Coli ◽  
Cattle Feces ◽  
Before And After

ABSTRACT Shiga toxin–producing Escherichia coli (STEC) serogroups O26, O45, O103, O111, O121, and O145, called non-O157 STEC, are important foodborne pathogens. Cattle, a major reservoir, harbor the organisms in the hindgut and shed them in the feces. Although limited data exist on fecal shedding, concentrations of non-O157 STEC in feces have not been reported. The objectives of our study were (i) to develop and validate two multiplex quantitative PCR (mqPCR) assays, targeting O-antigen genes of O26, O103, and O111 (mqPCR-1) and O45, O121, and O145 (mqPCR-2); (ii) to utilize the two assays, together with a previously developed four-plex qPCR assay (mqPCR-3) targeting the O157 antigen and three virulence genes (stx1, stx2, and eae), to quantify seven serogroups and three virulence genes in cattle feces; and (iii) to compare the three mqPCR assays to a 10-plex conventional PCR (cPCR) targeting seven serogroups and three virulence genes and culture methods to detect seven E. coli serogroups in cattle feces. The two mqPCR assays (1 and 2) were shown to be specific to the target genes, and the detection limits were 4 and 2 log CFU/g of pure culture–spiked fecal samples, before and after enrichment, respectively. A total of 576 fecal samples collected from a feedlot were enriched in E. coli broth and were subjected to quantification (before enrichment) and detection (after enrichment). Of the 576 fecal samples subjected, before enrichment, to three mqPCR assays for quantification, 175 (30.4%) were quantifiable (≥4 log CFU/g) for at least one of the seven serogroups, with O157 being the most common serogroup. The three mqPCR assays detected higher proportions of postenriched fecal samples (P < 0.01) as positive for one or more serogroups compared with cPCR and culture methods. This is the first study to assess the applicability of qPCR assays to detect and quantify six non-O157 serogroups in cattle feces and to generate data on fecal concentration of the six serogroups.

Long-Haul Transport and Lack of Preconditioning Increases Fecal Shedding of Escherichia coli and Escherichia coli O157:H7 by Calves†

2004 ◽  
Vol 67 (4) ◽  
pp. 672-678 ◽  
Author(s):  
S. J. BACH ◽  
T. A. McALLISTER ◽  
G. J. MEARS ◽  
K. S. SCHWARTZKOPF-GENSWEIN
Keyword(s):  
Escherichia Coli ◽  
Escherichia Coli O157 ◽  
Fecal Samples ◽  
Fecal Shedding ◽  
E Coli ◽  
Susceptibility To Infection

The effects of weaning and transport on fecal shedding of Escherichia coli and on E. coli O157:H7 were investigated using 80 Angus and 94 Charolais range steer calves blocked by breed and assigned to four treatments. The calves were or were not preconditioned before transport on commercial cattle liner to the feedlot via long (15 h) or short (3 h) hauling duration, yielding preconditioned long haul (P-L; n = 44), preconditioned short haul (P-S; n = 44), nonpreconditioned long haul (NP-L; n = 43), and nonpreconditioned short haul (NP-S; n = 43). Preconditioned calves were vaccinated and weaned 29 and 13 days, respectively, before transport. Nonpreconditioned calves were weaned 1 day before long or short hauling, penned for 24 h and hauled again for 2 h, and vaccinated on arrival at the feedlot. Fecal samples were collected from calves while on pasture, at weaning, at loading for transport, on arrival at the feedlot, twice in the first week, and on days 7, 14, 21, and 28 for enumeration of total E. coli (biotype 1) and detection of E. coli O157:H7. No calves were positive for E. coli O157:H7 before transport. Following transport, more (P < 0.005) NP-L calves (6 of 43) tested positive for E. coli O157:H7 than did P-L (1 of 44), NP-S (1 of 43), or P-S (0 of 44) calves, and on days 0, 1, 7, and 21, their levels of shedding of E. coli were higher (P < 0.005). The calves' susceptibility to infection from the environment (possibly the holding facilities or feedlot pens) was likely elevated by the stresses of weaning, transport, and relocation. Lack of preconditioning and long periods of transport (NP-L) increased fecal shedding of E. coli and E. coli O157:H7. Preconditioning may serve to reduce E. coli O157:H7 shedding by range calves on arrival at the feedlot.

Sign in / Sign up

Export Citation Format

Share Document