Todd R Callaway

..We have evaluated the microbiome from the feces of 20 commercial, lactating dairy cows...

..This review explores the ecology behind the efficacy of these products against pathogens found in food animals, including those that enter the food chain and impact human consumers...

..54 genera, respectively). Overall, the microbial diversity was least and Lactobacillius populations were not found in the hens undergoing feed withdrawal, which could explain much of these hens' sensitivity to colonization by Salmonella...

..Data from researchers across North America indicate that diet does impact STEC/EHEC populations in cattle prior to slaughter; however the economic, logistic and practical impacts of dietary changes must be examined and accounted for...

..coli O157:H7 were reduced (P < 0.05) by inclusion of both 5 and 10% OP diets. Our results demonstrate that orange peel products can be used as a preharvest intervention strategy as part of an integrated pathogen reduction scheme...

..These results indicate that phages (predator) populations may vary along with Salmonella (prey) populations; and that phages could potentially be used as a food safety pathogen reduction strategy in swine...

..Using bTEFAP, the normal microbiota of cattle were examined using modern molecular methods to understand how diets affect gastrointestinal ecology and the gastrointestinal contribution of the microbiome to animal health and production...

..Further research needs to be performed to determine the most efficacious dosing regimens and the most effective combinations of phages targeting the diverse Salmonella population found in swine before they can enter the food supply...

..10) in any of the studies due to relatively low inoculated E. coli O157:H7 ruminal populations. Our results demonstrate that phage can be used as a preharvest intervention as part of an integrated pathogen reduction scheme...

..05) than non-treated controls. Quantification of fermentation end-products produced and H(2) balance estimates indicate that fermentation efficiencies were not compromised by the nitro-treatments...

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..Further research is warranted to determine if the optimization of dosage of nitroethane or related nitrocompouds can maintain the enteropathogen control and anti-methanogen effect in fed steers...

..Under the conditions of our study, we concluded that ribotyping is not as discriminatory as PCR for speciation, and that a phenotypic trait such as antimicrobial resistance cannot always be predicted within the same genotype...

..29). Our results suggest that the rumen environment and its microbial population are less favorable for the growth of Campylobacter and that concentrate diets may provide a more hospitable lower gastrointestinal tract for Campylobacter...

..coli O157:H7, and only modest differences (decreases) in Salmonella prevalence with no apparent affect on antimicrobial susceptibility of fecal coliform isolates...

..05) Salmonella but not necessarily E. coli concentrations. 2-Nitro-1-propanol and 2-nitroethanol exhibited inhibitory activity against Salmonella and E. coli by an undetermined mechanism, even in the absence of added chlorate...

..5 and 9 mM nitroethane compared to numbers recovered from controls or monensin-containing treatments, which may explain ruminal adaptation to lower nitroethane treatments...

..coli at 24 h, but may be useful when the reducing equivalents are limiting as in waste holding reservoirs or composting systems required for intense animal production...

..coli O157:H7 and Salmonella. Because ractopamine is currently approved to be fed to finishing cattle and swine immediately before slaughter, any potential for decreasing foodborne pathogens has exciting food safety implications...

..20) to control levels. Understanding the mechanisms underlying the seasonality of this important foodborne pathogen will enable the implementation of effective control strategies when it is most prevalent...

..Our results indicate that the role of ionophores in the dissemination of antibiotic resistance genes through the intestinal Enterococcus spp. appears to be limited...

..coli O157:H7 and Salmonella and wool can be a source of carcass contamination; however, in-plant processing procedures and intervention strategies were largely effective in preventing carcass contamination...

..Results of the current research indicate that the weaning of dairy calves does not increase the prevalence of pathogenic bacteria or substantially modify antimicrobial susceptibility profiles of these bacteria...

..These results suggest that nitro-treatment inhibited formate dehydrogenase/formate hydrogen lyase and hydrogenase activity...

..05) by > or =10 mM dicarboxylic acid addition. These results confirm that dicarboxylic acids can modify ruminal fermentation, but they do not affect populations of critical foodborne pathogens...

..faecium strains was due to factors other than the two-component cytolysin...

..05) by 48, but not 24, hours posttreatment than those from the group treated with 6.5 mg 2NPOH per bird. These results demonstrate the inhibitory activity of 2NPOH against Salmonella Typhimurium in vivo...

..The presence of multiple serotypes and genotypes in the herd suggests multiple contamination sources. However, there was no conclusive effect of lactation status of the cows on Salmonella genotypic shedding...

..0% (P = 0.02) and 23.5% skatole production, respectively, and a decrease of 14.9% indole at 6 h, but an increase in indole production of 81.1% at 24 h...

..Results of this research suggest the incidence of MDR Salmonella, found primarily in hutch calves and cattle in the sick-fresh pen, is low in comparison to the overall Salmonella prevalence...

..Melatonin treatment had no effect (p > 0.10) on daily fecal shedding, luminal content concentrations, or in the percentage of gastrointestinal tract tissue positive for the inoculated strain of E. coli O157:H7...

..No treatment differences were observed in antimicrobial resistance patterns in any of the soil isolates examined. Results reported herein support the use of composted dairy manure as an environmentally friendly soil amendment...

..Other strategies rather than merely reducing antimicrobial usage are needed to combat the emergence of MDR bacteria...

..10) among treatments. Ionophore supplementation had no affect on fecal shedding of E. coli O157:H7 or Salmonella and a negligible impact on antimicrobial susceptibility patterns of fecal coliforms in beef calves...

..coli O157:H7 isolates. Results from these studies indicate that short-term ionophore feeding had very limited effects on E. coli and Salmonella shedding or on antimicrobial susceptibility in experimentally infected lambs...

..coli O157:H7 was 16.7 and 6.7% for the summer and winter collections, respectively. Results of this research do not support a correlation between vitamin D intake and E. coli O157:H7 shedding in cattle...

..jejuni, and that the majority of these isolates are sensitive to antibiotics...

..were also found in sampled water troughs, goats, and cattle (5.00%, 3.70%, and 1.25%, respectively). Further research examining pathogen distribution is needed to determine if white-tailed deer are a natural reservoir for these bacteria...

..Further research is needed to determine whether the antimicrobial activity of orange products against E. coli O157:H7 or Salmonella Typhimurium is expressed in the lower gastrointestinal tract...

..Overall, the concurrent use of several of these preslaughter intervention strategies could synergistically decrease human illnesses by providing for additional barriers in a multiple-hurdle approach to improving food safety...

..08) with the ractopamine treatment when data were pooled across replicates. Although further research is required to confirm these results, the potential food safety implications of this research are intriguing...

..20), concentrations were elevated in TRP-treated animals. The decrease in the number of positive fecal samples observed in the first experiment, may be related to gastrointestinal MEL, affected by the 10x, but not 1x MEL dose...

..1%). The current research showed minimal effects of beta-agonists on fecal shedding of E. coli O157:H7 and indicated that these compounds (fed immediately prior to slaughter) are not a cause for concern from a food safety standpoint...

..Our results demonstrate that orange peel and pellets are environmentally friendly and low-cost products that can be used as a pre-harvest intervention as part of an integrated pathogen reduction scheme...

..However, it is unclear whether this is because the pH of the lower gut destroys the AHL or because a lack of certain bacteria in the lower gut producing AHL...

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..On the basis of these results, preadaptation with SN followed by ECP supplementation immediately preharvest could be a potential strategy for the reduction of Salmonella Typhimurium in broilers...

..Rates of ruminal nitrotoxin metabolism can be enhanced by modifying the rumen environment through dietary manipulations, which suggests in vivo enrichment of competent nitrotoxin-metabolizing bacteria such as D. detoxificans...

..01) when examined across the entire experimental period. Results of this research indicate that the thyroid or its hormones may be involved in the seasonal shedding patterns of E. coli O157 in cattle...

..However, further research is needed to confirm these results...

..coli O157:H7 and Salmonella...

..The results of these studies support the concept that changes in the gastrointestinal tract microenvironment, such as those created during feed deprivation, encourage Salmonella Enteritidis virulence and susceptibility in molted hens...

..Acetate, the most predominant fatty acid produced, declined at the higher dilution rates, as did propionate. Ammonia production remained stable at the lowest dilution rates, but increased significantly at a dilution rates above 0.27/h...

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..To determine the prevalence of antimicrobial resistance among Salmonella isolated from a central Texas dairy calf farm that raises animals for dairy-beef production...

..05). Litters containing both TC and UC or both TC and US also shed Salmonella at lower rates than did litters in which only UC and US were present (P < 0.05)...

..Typhimurium, E. coli O157:H7 and Ent. faecalis. SIGNIFICANCE AND IMPACT OF THE STUDY: Results suggest that 2NPOH may be a useful antimicrobial supplement to reduce carriage of certain food-borne pathogens in food animals...

..Chlorate kills Escherichia coli O157:H7 and may be an effective feed additive for use in food animals. This study was designed to determine if development of chlorate-resistant E. coli O157:H7 strains was likely...

..52 log10 ST). This study suggested that incorporation of ECP in the drinking water 24 to 48 h prior to slaughter could reduce Salmonella contamination in broilers...

..Chlorate appears to be an effective method to reduce shiga toxin-producing E. coil (STEC) populations in food animals, but additional studies are warranted before it is used to control infections...

..coli O157:H7 in naturally infected cattle. However, a hyperthyroid state as observed postdosing might play a role in the seasonal shedding of E. coli O157:H7 in cattle...

..To examine the variability in faecal shedding of Salmonella and Escherichia coli O157:H7 in healthy lactating dairy cattle and to evaluate the genetic relatedness of Salmonella isolates...

..At present, neither chlorate nor the nitrocompounds have been approved as feed additives by the US Food and Drug Administration, and consequently they are not yet available for commercial use...

..This review emphasizes work with Escherichia coli O157:H7 to illustrate the various strategies...

..Therefore, it appears that chlorate supplementation is a viable potential strategy to reduce E. coli O157:H7 populations in cattle prior to harvest...

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..To determine the effect of sprinklers on faecal shedding of Escherichia coli (E. coli) O157:H7 and Salmonella in lactating dairy cattle...

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..On the basis of these results, it appears that chlorate treatment can be an effective method for the reduction of E. coli O157:H7 populations in ruminant animals immediately prior to slaughter...

..7% compared with the controls. These studies suggest that incorporation of lactic acid in the drinking water during pretransport FW may reduce Salmonella and Campylobacter contamination of crops and broiler carcasses at processing...

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..coli O157:H7-challenged pigs with 200 mM chlorate caused reductions in gut concentrations of E. coli O157:H7; however, the reductions were not necessarily greater than those achieved with the 100 mM chlorate treatment...

..In conclusion, the role of wallows in disseminating Salmonella within an outdoor swine herd appears to be significant...

..coli O157 in humans in Mexico. However, further research is needed to verify prevalence throughout other regions of Mexico, as well as prevalence during other seasons of the year...

..Susceptibilities to 11 antimicrobial agents in the current study suggested somewhat reduced resistance than reported for other meat or animal toxinotype V isolates...

..coli and total coliforms, possibly due to stress, and these populations of bacteria may have potential utility as inexpensive, noninvasive indicators of handling-related stress in pigs...

..To determine if the purported deaminase inhibitors diphenyliodonium chloride (DIC) and thymol reduce the growth and survivability of Campylobacter...

..To examine the effects of ionophores on Salmonella and Escherichia coli O157:H7 in pure and mixed ruminal fluid cultures...

..During year 2 of the study, Salmonella was routinely cultured (although highly variable from month to month) from the cattle and the environment, although no outbreak of salmonellosis was observed...

..To examine the ability of flavophospholipol to inhibit bacterial conjugation between Escherichia coli donor and recipient pairs in vitro and in day-of-hatch chickens...

..aminophilum may be able to outcompete asaccharolytic C. jejuni for amino acid substrates and that this competitive ability was eliminated by addition on monensin...

..Performance measures and carcass traits did not differ between treatments (P > 0.10). Under our conditions, sprinkling cattle with water did not affect the incidence of zoonotic pathogens in feces or on hides...

..These experiments suggest that the ECP significantly reduces Salmonella colonization in commercial turkeys when administered prior to feed and water withdrawal...

..These results suggest that ECP administered to pigs just days before slaughter may reduce gut concentrations of Salmonella; however, the impacts of such reductions on slaughter hygiene have yet to be determined...

..Ruminal and (or) intestinal populations of E. coli O157:H7 may be influenced in livestock consuming endophyte-infected tall fescue, and these alterations could be due to the presence of ergot alkaloids in fescue plants...

..The most prevalent resistance patterns observed in this study were toward antimicrobial agents commonly used in cattle, while all Salmonella isolates were susceptible to ceftriaxone and ciprofloxacin, antibiotics used in human medicine...

..5% ECP compared with the controls. These results indicate broilers supplemented with feed </= 5% ECP or water ECP 7 d before slaughter reduced ST without affecting growth parameters...

..49) for HI-E and LO-E ewes. We conclude that short-term feeding of HI-E tall fescue seed may alter the concentrations of prolactin and NEFA, and may increase fecal shedding of E. coli O157:H7 in experimentally inoculated ewes...

..Results indicate that switching cattle from grain to forage could potentially reduce EHEC populations in cattle prior to slaughter; however the economic impact of this needs to be examined...

..Our results indicate that such bacteriophage are widespread in feedlot cattle, suggesting that further research into the ecological role of bacteriophage in the gastrointestinal tract is needed...

..To investigate the potential transfer of Escherichia coli O157:H7 and Salmonella from contaminated manure slurry into the tissue of tall fescue plants...

..05) in suspensions with added 2-nitro-l-propanol than in unsupplemented or nitroethane-supplemented suspensions, thus reiterating the superior inhibitory effect of 2-nitro-l-propanol...

..05) populations of E. coli O157:H7 at concentrations <0.1 microg/ml. These potent antimicrobial proteins may potentially provide an effective and environmentally sound preharvest strategy to reduce E. coli O157:H7 in food animals...

..A clear understanding of the key factors involved in Salmonella colonization in the avian GI tract has the potential to lead to better approach for more effective control of this foodborne pathogen...

..Results from the current research suggest that dosage with high levels of melatonin may exacerbate Salmonella Enteritidis infection in layers subjected to forced molt...

..An observed treatment by time after treatment interaction suggests the chlorate effect was concentration dependent. Chlorate treatment may provide a means to reduce foodborne pathogens immediately before harvest...

..Therefore it appears that ionophores will continue to play a significant role in improving the efficiency of animal production in the future...

..From our data, it appears that subclinical colonization with Salmonella enterica is relatively common on dairy farms and is represented by diverse serotypes on US dairy farms...

..These results suggest that inhibiting bacterial fat degradation may promote ruminal passage of total lipid, thereby providing greater proportions of beneficial unsaturated fat for incorporation into beef products...

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