المؤلفون: Päivi J. Rajala-Schultz, Andrew Mack, Jeffrey T. LeJeune, Thomas E. Wittum, Julie A. Funk, Andrew S. Bowman

المصدر: Veterinary microbiology. 124(3-4)

مصطلحات موضوعية: Chlortetracycline, Salmonella, Veterinary medicine, medicine.drug_class, Swine, Antibiotics, Colony Count, Microbial, Microbial Sensitivity Tests, medicine.disease_cause, Microbiology, Feces, Random Allocation, Antibiotic resistance, Stocking, Drug Resistance, Bacterial, medicine, Confidence Intervals, Odds Ratio, Animals, Animal Husbandry, Antibacterial agent, Population Density, Swine Diseases, Salmonella Infections, Animal, General Veterinary, biology, Salmonella enterica, General Medicine, biology.organism_classification, Animal Feed, Anti-Bacterial Agents, Logistic Models, Multivariate Analysis, Salmonella enterica subsp. enterica, Female, medicine.drug

الوصف: The objective of this research was to determine the effect of stocking density and inclusion of subtherapeutic chlortetracycline in the diet on Salmonella fecal prevalence and antimicrobial resistance in growing swine. A 2 × 2 factorial design was employed on a privately owned commercial swine farm. Four finisher rooms were included in the study. Two of the rooms received 50 g/tonnes of chlortetracycline in the ration, two rooms received no antimicrobials in the feed. In each room, alternate pens were assigned to either high stocking density (0.60 m 2 /pig) or low stocking density (0.74 m 2 /pig). Pigs were placed in the finisher rooms at 10 weeks of age and followed for 6 weeks. Individual fecal samples were collected from the floors of each pen and cultured once weekly. Antimicrobial resistance phenotypes were determined. Data were analyzed using multilevel, multivariable logistic regression. Pigs fed chlortetracycline were at increased odds (OR 6.88, 95% CI 2.77–17.12) to shed Salmonellae . No other associations between treatments (CTC and stocking density) and Salmonella prevalence or reduced susceptibility to antimicrobials were identified. Variance in the odds of a fecal sample to be positive was distributed mostly at the lowest level, the individual fecal sample. The increased risk of shedding associated with inclusion of subtherapeutic chlortetracycline in swine diets is discordant with previous results by our group, suggesting farm or strain specific factors may impact this association. Understanding this risk may provide a potential intervention for controlling Salmonella pre-harvest.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::009b77ad26adc0ff90faf416ebb67ed2Test
https://pubmed.ncbi.nlm.nih.gov/17482387Test

المؤلفون: Julie A. Funk, Andrew S. Bowman, Andrew Mack

المصدر: International Conference on the Epidemiology and Control of Biological, Chemical and Physical Hazards in Pigs and Pork.

مصطلحات موضوعية: Veterinary medicine, food.ingredient, food, biology, Inoculation, Herd, Becton dickinson, Agar, Outbreak, Yersinia, Yersinia enterocolitica, biology.organism_classification, Feces

الوصف: The objective of this study was to describe the prevalence of Yersinia enterocolitica (YE) in different swine production phases. In this cross-sectional study, individual pigs on eight farrowto-finish farms were sampled for YE by collection of both feces and oral-pharyngeal swabs. Samples were cultured with a three-week cold enrichment followed by culture onto selective media. Presumptive YE isolates were confirmed as YE and assayed for the presence of the ail gene using a multiplex PCR. A pig was considered positive if either the fecal sample or oral-pharyngeal swab tested positive. Of the 2321 pigs sampled, 141(6.1%) were YE positive and of those,109 were ail positive (77.3 % of YE isolates). There was a consistent trend of increasing prevalence with maturity. These results represent the first on-farm description of YE in US herds providing first step for future studies to understand the epidemiology of YE in US market swine. Introduction Yersinia enterocolitica is a food borne pathogen which causes an estimated 96,000 human illnesses in the United States each year (Mead et al., 1999). While the bacterium has been found in a variety of food and environmental samples, swine are the only food animals that regularly harbor pathogenic Y. enterocolitica (Kapperud, 1991). Thus swine and pork products have been implicated as the primary reservoir of pathogenic Y. enterocolitica. Recent outbreaks in the US have been related to the preparation and consumption of chitterlings (pig intestines). (Anonymous, 1990; Anonymous, 2003) Of particular food safety concern is the ability for Y. enterocolitica to grow at refrigeration temperatures and survive repeated freezing and thawing.(Toora et al., 1992) Previous studies of Y. enterocolitica have investigated swine at harvest (Hanna et al., 1980; Harmon et al., 1984) but little research has focused on the epidemiology of Y. enterocolitica at the farm level. Understanding the on-farm epidemiology of Y. enterocolitica is the first step towards identifying risk factors and potential interventions in swine production that may decrease the risk of product contamination during harvest and processing. The objective of this study was to describe the prevalence of Y. enterocolitica in different production phases on swine farms. Methods A cross-sectional study to survey individual pigs for the presence of Y. enterocolitica was undertaken on eight farrow-to-finish swine operations in Ohio. On each farm, during a onetime visit, gestating sows (G), farrowing sows (S), their suckling piglets (P), nursery pigs (N), and finishing pigs (F) were cultured for the presence of Y. enterocolitica. When possible, the youngest (1) and oldest animals (2) within each phase were sampled. The number of pigs sampled in each production phase was calculated in order to estimate prevalence with 95% confidence and a 610% confidence interval based on previous estimates in the literature of 25% prevalence in swine at harvest. This sampling scheme resulted in the sampling of 2321 pigs from May to August 2003. Fecal samples (10g) and oral-pharyngeal swabs were collected and tested for each animal with the exceptions of 1) sows in the farrowing room where oral-pharyngeal swabs were not collected and 2) in the cases where 10g of feces could not be collected (i.e. piglets under 10 weeks of age) rectal swabs were used in place of a fecal sample. Animals were considered positive if either the fecal or oral-pharyngeal sample tested positive for Y. enterocolitica. Samples were cultured according to the gold standard method of three-week cold enrichment in phosphate buffered saline (PBS) (Aleksic et al., 1999). Briefly, swabs were placed into 10mL of PBS and fecal samples were diluted at a 1:10 ratio with PBS (EMD Chemicals Inc.). Swab and fecal samples were incubated for 3 weeks at 4°C. Following enrichment, 10μL of the inoculated PBS was streaked onto Yersinia Selective Agar (CIN) plates (Becton Dickinson and Company). Plates were incubated at 25°C for 48 hours before being examined for colonies resembling Y. enterocolitica. Colonies having morphologies typical of Y. enterocolitica were tested on Kligler’s Iron Agar (KIA) (Becton Dickinson and Company) slants and urease broth (Becton Dickinson and Company). Colonies that produced an alkaline slant with an acid butt on the KIA within 24 hours and an alkaline urease broth reaction within 48 hours were classified as presumptive Y. enterocolitica. Presumptive Y.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::1e9957c2872042fd9d830edaba9683dfTest
https://doi.org/10.31274/safepork-180809-743Test

المؤلفون: Andrew Mack, Julie A. Funk, Andrew S. Bowman

المصدر: International Conference on the Epidemiology and Control of Biological, Chemical and Physical Hazards in Pigs and Pork.

مصطلحات موضوعية: Chlortetracycline, Salmonella, food.ingredient, business.industry, Virkon, Contamination, medicine.disease_cause, Antimicrobial, food, Animal science, Medicine, Agar, business, Barn (unit), Feces, medicine.drug

الوصف: The objective of this study was to evaluate the effect of stringent cleaning and subtherapeutic chlortetracycline (CTC) on Salmonella enterica (SE) prevalence in market age swine. Twenty-four finisher barns from one farm were enrolled in a 2X2 factorial study design. Treatments included 1) assignment to a “stringent” or standard cleaning protocol and 2) inclusion of 50g of CTC/ton of feed or no feed antimicrobials. Barn swab samples were obtained preand post-cleaning for SE detection. Post-cleaning aerobic plate counts (APC) were collected. Feces were collected to determine SE prevalence pre-market. The stringent cleaning protocol resulted in decreased mean APC post-cleaning, but there was no difference in isolation of SE from the barn environment between cleaning protocols. Pigs housed in barns that received CTC had decreased odds of being SE positive, but there was no difference in the odds of a pig being SE positive between cleaning protocols. Introduction Contamination of the barn environment with Salmonella enterica (SE) has been suggested to be an important risk factor for SE infection in swine. All-in, all-out production practices with cleaning and disinfection between groups is often utilized to aid in the control of production impairing illnesses in swine. However, the effectiveness of these practices on the prevalence of SE is not clear. Relatively high SE prevalence has been reported on US farms that utilize all-in, allout pig flow with cleaning and disinfection between groups.(Davies et al., 1998; Davies et al., 1997; Funk et al., 2001; Funk and Gebreyes, 2004) Subtherapeutic antimicrobial use, in particular for the purpose of growth promotion, is under increasing scrutiny regarding its contribution to antimicrobial resistance in human pathogens. It is currently unclear what the effect of subtherapeutic antimicrobial use has on the prevalence of SE. Few on-farm clinical trials evaluating the effect of subtherapeutic antimicrobials on SE prevalence have been conducted. Previous research regarding SE shedding and antimicrobial resistance subsequent to antimicrobial therapy have been conducted in laboratory facilities involving experimental infection with S. enterica (Abou-Youssef et al., 1979; Baggesen et al., 1999; Dealy and Moeller, 1976; Delsol et al., 2003; Ebner and Mathew, 2000; Evangelisti et al., 1975; Girard et al., 1976; Gutzmann et al., 1976; Jacks et al., 1988; Jones et al., 1983; Mathew et al., 2002; Wilcock and Olander, 1978; Williams et al., 1978). The goal of this study is to determine the effect of stringent cleaning and the use of subtherapeutic CTC on the prevalence of SE in market ready swine. Materials and Methods One production company with 24 finisher barns at six different production sites (4 barns per site) was selected. Entry criteria was willingness to participate and proximity to the laboratory as substantial investment in travel and labor were required. The study was a 2X2 factorial design. Treatments included 1) assignment to a “stringent” or standard cleaning protocol and 2) inclusion of 50g of CTC/ton of feed or no feed antimicrobials. Prior to the cleaning of any barns 30 environmental swabs were taken to get a baseline of SE contamination in the environment. These samples were taken using a 4x4 swab that was moistened in 30ml of buffered peptone water (BPW). The samples originated from surfaces throughout the barn including; gates, feeders, waters, overhead pipes and air vents, fans, the floor and the entry door. Samples were transported to the lab on ice and cultured for SE using standard methods. Briefly, 100ml of BPW was added to each sample and incubated at 37°C for 18-24 hours. Following incubation 100μl was transferred to 9.9ml of Rappaport-Vassiliadis Broth (RV) and incubated at 42°C for 18-24 hours. Finally samples were struck onto XLT-4 agar and compared to control strains. The suspected positive samples were confirmed using Triple Sugar Iron agar slants and urea broth incubated at 37°C for 18-24 hours. Following the environmental sampling barns were then cleaned according to their randomly assigned protocol. The standard protocol, which was conducted by the farm personnel, included a cold water soak, followed by cold water pressure wash (2500 psi), and ended with the application of Virkon-S applied using the pressure washer. The farm personnel estimated that the standard protocol required a single person 12-13 hours to complete. The stringent protocol, conducted by laboratory personnel, started with the same cold water soak, which was then followed with a hot water (180-190°F) high pressure wash (4000 psi). Barn equipment such as gates, feeders, and waters were hand scrubbed during this same time period

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::599b38b0f03a9fadabade97ec3d9b8c7Test
https://doi.org/10.31274/safepork-180809-760Test

المؤلفون: Andrew Mack, Julie A. Funk

المصدر: International Conference on the Epidemiology and Control of Biological, Chemical and Physical Hazards in Pigs and Pork.

مصطلحات موضوعية: Salmonella, Veterinary medicine, Titer, Salmonella antibody, medicine, Herd, Biology, medicine.disease_cause, Feces

الوصف: ORAL PRESENTATIONS test results. In other words, although single sera, which have Salmonella antibody concentrations around the cut-off point, can be recognized as positive with one test and negative with the other test or vice versa, the three tests can be used, since less than 10% of the sera tested over years in Germany, have Salmonella antibody concentrations around the cut-off point (around 70% have very low titers, and about 15% have quite high titers, which are always correctly identified by all three tests as negative or positive). This means that the risk that a set of sera is categorized differently by using another test out of the three tests is so low that it can be neglected in the light of the overall goal of the German Salmonella Monitoring and Reduction Programme: Identifying via an ongoing semiquantitative estimation the herds with the relatively highest risk of introducing zoonotic Salmonella spec. into the food production chain to be able to implement measures for a) reducing the crosscontamination of Salmonella spec. in the slaughter plant and b) reducing the salmonella load of swine herds identified as high risk herds. Finding the herds with the relatively highest salmonella risk, at which cut-off point ever, will be performed by all three tests at a comparative herd sensitivity level.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::32ab2c883f05156370a701bbe81ae7d2Test
https://doi.org/10.31274/safepork-180809-469Test