The association between herd characteristics and salmonella prevalence in slaughter age pigs

Many factors have the potential to result in exposure of pigs to Salmonella and/or to increase the potential shedding at the time of slaughter. Observation of selected production systems has suggested that control of Salmonella may not occur using common disease management strategies, such as batch pig flow, as do many other diseases.\u27 A rational approach to Salmonella reduction would be to rank risk factors, to aid in selecting. We designed this study to assess risk factors of Salmonella status at slaughter

The association of antimicrobial resistance patterns and reported usage of antimicrobials in commercial growing pig production

The relationship between into microbial use and the development of resistance to antimicrobials has been demonstrated through both external models and has been observed clinically. However, the strength of this relationship in practical production systems has not been clearly quantified. We designed this study to examine the strength of the relationship between use of antimicrobials and the occurrence of antimicrobial resistence among Salmonella spp. collected from the same groups of growing pig

Antimicrobial resistance patterns of Salmonella isolates collected from slaughter age pigs

Salmonellae are ubiquitous in nature and are recovered from many animal species including swine. However, prevalence of specific serotypes can vary. Although carriage is often observed, fecal shedding can be sporadic (2). Salmonella, as well as other food borne pathogens, can be transferred from animals to the human population. However, since the federally mandated HACCP program has been implemented, a reduction in Salmonella among the major food animals has been observed

Segregated Early Weaning - Control of Food Safety Organisms

Segregated early weaning (SEW) is a production technology gaining widespread acceptance in the North American swine industry to reduce or eliminate vertical transmission for common bacterial and viral swine pathogens. Food safety concerns have been raised about a variety of zoonotic bacterial species (Salmonella, Yersinia, Campylobacter, Arcobacter and Listeria) known to colonize normal swine or to contaminate pork products. Because SEW technology functions to reduce swine pathogens it has been postulated that similar mechanisms could reduce important zoonotic bacteria at the production level. In this study we investigated the effect of SEW on the transmission of several zoonotic organisms in SEW swine and in conventional market swine. This study reports the first evaluation of SEW techniques to control zoonotic pathogens under commercial conditions

Prevalence and Antimicrobial Resistance of Salmonella, E. coli, and Campylobacter in Pigs from Swine Producing States in the United States

The purpose of the study was to determine the prevalence and antimicrobial susceptibility of Salmonella, Campylobacter and generic E. coli (commensal bacteria which may harbor antimicrobial resistance genes) from swine feces collected over one year from the top three swine producing states (Iowa, North Carolina, and Minnesota), which represent 51% of the total pig crop in the U.S, plus Ohio. The prevalence of Salmonella (n=462/4426), Campylobacter (n=994/1184) and E. coli (n=833/845) at the sample level was 10.4%, 98.6% and 83.6%, respectively

Prevalence, distribution, and molecular characterization of Salmonella recovered from swine finishing herds and a slaughter facility in Santa Catarina, Brazil.

Projeto: 04.10.06.001

Methicillin Resistant Staphylococcus aureus (MRSA) in market age pigs on-farm, at slaughter and retail pork

This study was conducted to determine the occurrence and prevalence of methicillin resistant Staphylococcus aureus (MRSA) in finishing pigs on-farm, at lairage and assess the likelihood of carriage at slaughter and retail levels. A cross-sectional study targeting ten cohorts of commercial swine farms was conducted for carriage of MRSA

Effects of some methodologic factors on detection of Salmonella in swine feces

Bacteriologic culture of feces for Salmonella continues to be a central component of epidemiologic studies. We conducted a series of experiments on fecal samples collected from commercial swine farms to evaluate the effects of several methodologic factors on detection of Salmonella. Factors examined included fecal sample storage (no storage, 4C, -15C) and fecal sample weight. In addition we compared the standard method (Method I) used in our laboratory [JOg feces/buffered peptone water pre-enrichment/selective enrichment in Rappaport Vassiliadis (RV) broth] with another method (Method 2) used by ourselves and others in the USA (=I g sample/primary enrichments in tetrathionate and Hajna GN broths/secondary enrichment in RV broth). Inunediate processing of samples yielded the best recovery of Salmonella, although storage at 4C for 6 days did not significantly reduce detection. Freezing of fecal samples resulted in significant reduction of detection. The weight of feces sampled had a marked linear effect on the detection of Salmonella using method I. Direct comparison of Method I and Method 2 indicated comparable results, with Method I tending to yield higher detection of Salmonella. However, when conducted on samples of equal weight, Method 2 had significantly better detection than Method I. The choice of methods can markedly affect the results of fecal sample culture. The preferred methodology for epidemiologic studies will be determined by many factors including logistics and cost. Our data highlight the imperfect sensitivity of culture methods, and the need for researchers to consider the sensitivity of their bacteriologic methods in the design and interpretation of field studies based on fecal culture

Distinct Peripheral Blood RNA Responses to Salmonella in Pigs Differing in Salmonella Shedding Levels: Intersection of IFNG, TLR and miRNA Pathways

Transcriptomic analysis of the response to bacterial pathogens has been reported for several species, yet few studies have investigated the transcriptional differences in whole blood in subjects that differ in their disease response phenotypes. Salmonella species infect many vertebrate species, and pigs colonized with Salmonella enterica serovar Typhimurium (ST) are usually asymptomatic, making detection of these Salmonella-carrier pigs difficult. The variable fecal shedding of Salmonella is an important cause of foodborne illness and zoonotic disease. To investigate gene pathways and biomarkers associated with the variance in Salmonella shedding following experimental inoculation, we initiated the first analysis of the whole blood transcriptional response induced by Salmonella. A population of pigs (n = 40) was inoculated with ST and peripheral blood and fecal Salmonella counts were collected between 2 and 20 days post-inoculation (dpi). Two groups of pigs with either low shedding (LS) or persistent shedding (PS) phenotypes were identified. Global transcriptional changes in response to ST inoculation were identified by Affymetrix Genechip® analysis of peripheral blood RNA at day 0 and 2 dpi. ST inoculation triggered substantial gene expression changes in the pigs and there was differential expression of many genes between LS and PS pigs. Analysis of the differential profiles of gene expression within and between PS and LS phenotypic classes identified distinct regulatory pathways mediated by IFN-γ, TNF, NF-κB, or one of several miRNAs. We confirmed the activation of two regulatory factors, SPI1 and CEBPB, and demonstrated that expression of miR-155 was decreased specifically in the PS animals. These data provide insight into specific pathways associated with extremes in Salmonella fecal shedding that can be targeted for further exploration on why some animals develop a carrier state. This knowledge can also be used to develop rational manipulations of genetics, pharmaceuticals, nutrition or husbandry methods to decrease Salmonella colonization, shedding and spread