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Lethbridge, Canada

Stanford K.,Agriculture Center | Hannon S.,Feedlot Health Management Services Ltd. | Booker C.W.,Feedlot Health Management Services Ltd. | Jim G.K.,Feedlot Health Management Services Ltd.
Foodborne Pathogens and Disease | Year: 2014

To evaluate the efficacy of a type-III secreted proteins vaccine and a Lactobacillus-acidophilus-based direct-fed microbial (DFM) for controlling Escherichia coli O157:H7, cattle (n=864) were allocated to the following groups: DFM, finishing diets containing 109 colony-forming units (CFU)/animal/day L. acidophilus and Propionibacterium freudenreichii; VAC, finishing diets and 2mL intramuscular injection of vaccine at allocation and 28 days later; or CON, finishing diets only. Cattle within replicates were stratified by initial levels of E. coli O157:H7 and randomized to experimental groups, with 30 pens allocated on June 15, 2011 (AS1), 18 pens allocated on June 28, 2011 (AS2), and 18 cattle per pen. Rectal fecal samples and perineal swabs were collected at 28-day intervals until shipment to slaughter (103-145 days on trial). Numbers of cattle with enumerable E. coli O157:H7 (≥1.6 CFU/g feces) were reduced in AS1 and AS2 by VAC (p=0.008), although interventions had no impact on numbers of E. coli O157:H7 shed. For AS1, VAC reduced prevalence of E. coli O157:H7 in feces (p=0.03) and perineal swabs (p=0.04) in the feeding period but not at shipment to slaughter. For AS2, prevalence of E. coli O157:H7 was not reduced in either feces or perineal swabs by VAC at any time. For AS1, DFM reduced prevalence of E. coli O157:H7 in perineal swabs (p=0.01) during the feeding period. For AS2, DFM increased E. coli O157:H7 detection in feces (p=0.03) and perineal swabs (p=0.01) at shipment to slaughter. Seventy-five percent of AS1 E. coli O157:H7 isolates had only stx1, while 87% of AS2 isolates had stx1 and stx2 genes. Of the two interventions, VAC shows the most potential for pre-harvest control of E. coli O157:H7, but due to variable efficacy of both DFM and VAC, additional product development is necessary to ensure more consistent pre-harvest control of E. coli O157:H7. © 2014 Mary Ann Liebert, Inc. Source

Aslam M.,Agriculture and Agri Food Canada | Stanford K.,Agriculture Center | McAllister T.A.,Agriculture and Agri Food Canada
Letters in Applied Microbiology | Year: 2010

Aims: To characterize antimicrobial resistance (AMR) and determine the seasonal prevalence of Escherichia coli O157:H7 isolated from commercial feedlots. Methods and Results: Escherichia coli O157:H7 were isolated from faecal and oral samples collected at monthly intervals from three commercial feedlots over a 12-month period. A total of 240 isolates were characterized using pulsed-field gel electrophoresis (PFGE) technique. A subset of 205 isolates was analysed for AMR using Sensititre system and AMR genes (tet, sul and str) by PCR. Seven PFGE clusters (≥90% Dice similarity) were identified, and two clusters common to all three feedlots were recovered year-round. The majority of isolates (60%) were susceptible to all antimicrobials and were closely related (P < 0.001), whereas isolates with unique AMR patterns were not related. The prevalences of AMR from feedlots A, B and C were 69%, 1% and 38%, respectively. Resistance to tetracycline (69%) and sulfisoxazole (68%) was more prevalent in feedlot A than other two feedlots. The presence of strA and strB genes was linked in the majority of isolates, and tet(A) and tet(B), and sul1 and sul2 genes were present individually. Escherichia coli O157:H7 were genetically diverse during summer and fall, and strains from winter and spring months were more closely related. Conclusions: Antimicrobial resistance was more common in E. coli O157:H7 obtained from two of the three commercial feedlots, and the phenotypic expression of resistance was correlated with the presence of resistant genes. A highly diverse E. coli O157:H7 population was found during summer and fall seasons. Significance and Impact of the Study: Information would help understanding the dynamics of AMR in E. coli O157:H7 from commercial feedlots. © 2010 Her Majesty the Queen in Right of Canada, as represented by the Ministry of Agriculture and Agri-Food Canada. Source

Reuter T.,Agriculture Center | Alexander T.W.,University of Vermont | McAllister T.A.,Agriculture and Agri Food Canada
Applied and Environmental Microbiology | Year: 2011

Safe disposal of dead livestock and contaminated manure is essential for the effective control of infectious disease outbreaks. Composting has been shown to be an effective method of disposal, but no information exists on its ability to contain diseases caused by spore-forming bacteria, such as Bacillus anthracis. Duplicate composters (east and west), each containing 16 dead cattle, were constructed (final capacity, 85,000 kg). Spores (10 7 CFU/g manure) of Bacillus licheniformis and Bacillus thuringiensis were mixed with autoclaved feedlot manure and placed in either sterile vials or porous nylon bags. Compost temperatures in the west composter were slightly higher than in the east composter. Viable B. thuringiensis spores were reduced to ≤10 2 CFU in all samples after 112 days but were isolated from bags (west composter) at ≤10 2 and at 10 5 CFU (east composter) after 230 days. In contrast, B. licheniformis was at ≤10 2 CFU in vials (west composter) after 112 days but remained at 10 6 CFU after 230 days (east composter). Similarly, B. licheniformis in bags was not detected after 230 days in the west composter but remained at 10 7 CFU in the east composter. Our study suggests that spore viability was reduced in the west composter by exposure to compost and elevated temperatures over time. Different temperature profiles may explain why spores remained viable in the east structure but were largely rendered nonviable in the west structure. Under practical conditions, variation in composting microclimates may preclude the complete inactivation of Bacillus spores, including those of B. anthracis, during composting. However, composting may still have merit as a method of biocontainment, reducing and diluting the transfer of infectious spores into the environment. © 2011, American Society for Microbiology. Source

Stanford K.,Agriculture Center | Koohmaraie M.,Forest Laboratories | Gill C.O.,Agriculture and Agri Food Canada
Journal of Food Protection | Year: 2013

Due to the expense of monitoring multiple serotypes of Escherichia coli at slaughter, a study was conducted at a beef abattoir in southern Alberta to determine relationships between E. coli and E. coli O157:H7 on hides. Swab samples were collected from carcasses immediately prior to hide removal over 8 weeks in summer (n = 591) and winter (n = 686). Detection of E. coli was highest in summer (P , 0.05), although detection of E. coli O157:H7 did not differ by season. Numbers of E. coli did not vary by season, but were affected by slaughter plant hygiene schedules. E. coli O157:H7 was more likely (P , 0.001) to be detected on hides of carcasses with the most E. coli (.3.5 log CFU/50 cm2). For E. coli ,3.5 log CFU/50 cm2, the likelihood of detecting E. coli O157:H7 did not differ. Consequently, for 83% of carcasses, there was no relationship between numbers of E. coli and detection of E. coli O157:H7 on hides. Copyright ©, International Association for Food Protection. Source

Philips Lighting has collaborated with The University of Arizona Controlled Environment Agriculture Center (CEAC) to test energy efficient ways to grow food that will help feed astronauts on missions to the moon, Mars and beyond. A recent study, conducted over a nine week period, found that replacing water-cooled high-pressure sodium (HPS) systems with energy efficient LED lighting from Philips in a prototype lunar greenhouse resulted in an increased amount of high-quality edible lettuce while dramatically improving operational efficiency and use of resources. Lettuce grown under Philips LED modules achieved up to 54 grams/kWh of fresh weight, edible lettuce compared to lettuce grown under a high pressure sodium system which achieved only 24 grams/kWh of fresh weight, edible lettuce. This represents an energy savings of 56%.

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