Abbreviated identification scheme for Eschericia coli in swine feces

Antimicrobial susceptibility profiles of Escherichia coli (EC) are often used to monitor the effect of antimicrobial use regimens on the antimicrobial resistance (AR) reservoir in animal species. Epidemiological studies of AR may involve the identification of thousands of bacterial isolates, so complete biochemical identification of EC can be prohibitively expensive and time consuming. In this study an abbreviated biochemical scheme using colony phenotype and the indole test results in a sensitivity and specificity of 91.7% and 100% respectively for identification of EC as compared to a commercial biochemical identification kit. This abbreviated scheme results in over US$500 savings per 100 candidate EC isolates identified. These savings have significant benefits to the economics of conducting epidemiologic investigations of AR

Effect of chlortetracycline on the distribution of resistance genes

The objective of this study was to compare the distribution of tetracycline resistance genes in the Gram-negative fecal flora between swine that werer fed subtherapeutic chlortetracycline as compared to pigs that did not receive in feed antimicrobials

Prevalence of Yersinia enterocolitica across phases of swine production

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 farrow-to-finish farms were sampled for YE by collection of both feces and oral-pharyngeal swab

Association between Salmonella sp. and Yersinia enterocolitica infection in swine

Swine are known reservoirs for both Salmonella and Yersinia enterocolitica. Both are foodborne pathogens and can result in zoonotic disease if contamination of pork products occurs during harvest. The epidemiology of Y. enterocolitica and Salmonella in swine is not well understood. Previous reports from experimental studies in mice suggest that, vai quorum-sensing, Salmonella detects Y. enterocolitical signals, increasing Salmonella colonization

Effect of cleaning and subtherapeutic chlortetracycline on Salmonella

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

Molecular Epidemiology of Salmonella enterica and Subtyping Using Phenotypic and Genotypic Approaches

The aim of this study was to evaluate the discriminatory power of two phenotyping and three genotyping methods commonly used to subtype Salmonella in swine and other hosts. We found AFLP and PFGE to have the highest and comparable discriminatory power to each other. Among the 202 isolates analyzed in this study, using AFLP, 16 cluster types of S. Typhimurium were identified. Vertical spread in the production chain, from nursery to finishing farms and vertical as well as horizontal spread among finishing farms appeared to be important means of Salmonella serovar Typhimurium dissemination in swine units

Salmonella serovar distribution and risk factors associated with persistence of shedding in finishing pigs

The objectives of this study were to describe the Salmonella serovar distribution and to identify risk factors associated with serovar persistence in finisher pigs. A longitudinal study was conducted in 18 cohorts of pigs. Fecal culture and serotyping were conducted using standard methods

Differential translocation of Salmonella serovars to mesenteric lymph nodes of pigs

In observational studies of growing pigs in North Carolina, we cultured paired samples of mesenteric lymph nodes (MLN) and cecal contents for Salmonella using standard methods for selective enrichment and plating. Apparent Salmonella prevalence was higher among cecal (39.2%) than MLN (20.5%) samples from the same animals. Salmonella Typhimurium var. Copenhagen (STC) and S. Derby comprised 84% of all isolates at slaughter. For these two serovars we found an association between serovar and sample type. The odds of isolating STC from MLN rather than cecum were 5.7 (95%CI 3.0 to 10.7) times higher than the odds for S. Derby. The odds for isolating STC from MLN versus cecum were 58 times higher for groups where STC had been isolated from the pigs on farm than for groups where it was had not been detected on farm. These findings suggest biological differences among common group B Salmonella serovars in the pig

Quantifying tetracycline resistance

This study’s goal was to evaluate the impact of sub-therapeutic feeding of chlortetracycline (CTC) on the fecal concentration of tet(C), a gene that confers tetracycline resistance via an efflux mechanism. We developed a real-time quantitative PCR assay to measure the quantity of tet(C) in whole fecal DNA samples. The vast proportion of variability in tet(C) (91%) was associated with differences in concentration between the individual pigs, and there was no significant difference in the copy number of tet(C)/mg of feces between the treatment and control pigs (p\u3e0.05, linear regression, SPSS 11.0.5)

Effect of chlortetracycline on Salmonella and the fecal flora of swine

The goals of this study were to determine the impact of sub-therapeutic chlortetracycline in market swine diets on 1) the prevalence and antimicrobial resistance of Salmonella enterica 2) antimicrobial resistance of the aerobic Gram negative fecal flora. There was no significant difference in the prevalence or antimicrobial resistance of S. enterica isolates. For the gram-negative fecal flora, there was a statistically significant difference (p\u3c0.05) between treatment groups for the frequency of antimicrobial resistance in the gram negative flora with pigs receiving chlortetracycline having a greater frequency of isolates resistant tetracycline, gentamicin, and ceftriaxone, and a lesser proportion of isolates resistant to ampicillin