2 Adapted from Rezac et al. (2014b). Data collected at commercial packing plants in Kansas and Texas. 3 Adapted from Rezac et al. (2014a). Data collected at a commercial packing plant in the Great Lakes region.4 Normal = Liver free from abscesses; A-= Liver with 1 to 2 small abscesses; A = Liver with 2 to 4 large abscesses or multiple small abscesses; A+ = Liver with multiple large abscesses, abscesses adhered to diaphragm, abdominal organs or both, or open or ruptured abscesses.5 Numbers in parentheses are percentage of total abscesses.

No abstract

Copper, an essential micronutrient, is supplemented in the diet at elevated levels to reduce morbidity and mortality and to promote growth in feedlot cattle. Gut bacteria exposed to copper can acquire resistance, which among enterococci is conferred by a transferable copper resistance gene (tcrB) borne on a plasmid. The present study was undertaken to investigate whether the feeding of copper at levels sufficient to promote growth increases the prevalence of the tcrB gene among the fecal enterococci of feedlot cattle. The study was performed with 261 crossbred yearling heifers housed in 24 pens, with pens assigned randomly to a 2؋2 factorial arrangement of treatments consisting of dietary copper and a commercial linseed meal-based energy protein supplement. A total of 22 isolates, each identified as Enterococcus faecium, were positive for tcrB with an overall prevalence of 3.8% (22/576). The prevalence was higher among the cattle fed diets supplemented with copper (6.9%) compared to normal copper levels (0.7%). The tcrB-positive isolates always contained both erm(B) and tet(M) genes. Median copper MICs for tcrB-positive and tcrB-negative enterococci were 22 and 4 mM, respectively. The transferability of the tcrB gene was demonstrated via a filtermating assay. Multilocus variable number tandem repeat analysis revealed a genetically diverse population of enterococci. The finding of a strong association between the copper resistance gene and other antibiotic (tetracycline and tylosin) resistance determinants is significant because enterococci remain potential pathogens and have the propensity to transfer resistance genes to other bacteria in the gut.

Copper, as copper sulfate, is increasingly used as an alternative to in-feed antibiotics for growth promotion in weaned piglets. Acquired copper resistance, conferred by a plasmid-borne, transferable copper resistance (tcrB) gene, has been reported in Enterococcus faecium and E. faecalis. A longitudinal field study was undertaken to determine the relationship between copper supplementation and the prevalence of tcrB-positive enterococci in piglets. The study was done with weaned piglets, housed in 10 pens with 6 piglets per pen, fed diets supplemented with a normal (16.5 ppm; control) or an elevated (125 ppm) level of copper. Fecal samples were randomly collected from three piglets per pen on days 0, 14, 28, and 42 and plated on M-Enterococcus agar, and three enterococcal isolates were obtained from each sample. The overall prevalence of tcrB-positive enterococci was 21.1% (38/180) in piglets fed elevated copper and 2.8% (5/180) in the control. Among the 43 tcrB-positive isolates, 35 were E. faecium and 8 were E. faecalis. The mean MICs of copper for tcrB-negative and tcrB-positive enterococci were 6.2 and 22.2 mM, respectively. The restriction digestion of the genomic DNA of E. faecium or E. faecalis with S1 nuclease yielded a band of ϳ194-kbp size to which both tcrB and the erm(B) gene probes hybridized. A conjugation assay demonstrated cotransfer of tcrB and erm(B) genes between E. faecium and E. faecalis strains. The higher prevalence of tcrB-positive enterococci in piglets fed elevated copper compared to that in piglets fed normal copper suggests that supplementation of copper in swine diets selected for resistance.Copper is an essential trace element required for vital biological functions in both prokaryotic and eukaryotic cells (29). The growth response in piglets to copper is independent ofand in addition to-the response to commonly used antibiotics in the feed (16). Copper in excess concentrations is toxic to cells because it induces the production of intracellular reactive oxygen radicals, which inactivate cell components such as nucleic acids, lipids, and proteins (32). Therefore, cells tightly regulate intracellular copper concentrations to avoid toxicity (43). The copper homeostasis mechanism has been well studied in certain Gram-positive bacteria, such as Enterococcus hirae, Lactococcus lactis, and Bacillus subtilis (45). The normal intracellular copper concentration is maintained by the copYZAB operon, where copA and copB encode copper transport ATPases responsible for the influx and efflux of copper, respectively. The copY gene acts as a copper-responsive repressor and copZ encodes a copper chaperone (46). Some bacteria acquire resistance to copper, which may be either chromosome mediated (17) or plasmid mediated (31). A plasmid-borne gene, designated as transferable copper resistance (tcrB) and homologous to copB of the copYZAB operon, was reported in E. faecium and E. faecalis isolated from piglets, calves, poultry, and humans in Denmark (2). In Denmark, the plasmid also carries the genes erm(...

Thymus vulgaris Linn. is a medicinal and culinary herb from the Southern European region known for its antiinfective, cardioprotective, gastroprotective, anti-inflammatory, and immunomodulatory activities since the Egyptian era. The reported pharmacological activities of T. vulgaris L. include antibacterial, antioxidant, antiinflammatory, antiviral, and anti-cancerous activities. In this review, a comprehensive approach is put forth to scrutinize and report the available data on phytochemistry, ethnopharmacology, pharmacology, and toxicology of the plant. The different extracts and essential oil obtained from the plant have been assessed and reported to treat ailments like microbial infections, inflammation, non-communicable diseases like cancer, and sexually transmitted diseases like HIV-1 and Herpes. The literature review has also indicated the use of volatile oils, phenolic acids, terpenoids, flavonoids, saponins, steroids, tannins, alkaloids, and polysaccharides in pharmacotherapy. Applications of these compounds including antidiabetic, anti-Alzheimer's, cardio, neuro and hepatoprotective, anti-osteoporosis, sedative, immunomodulatory, antioxidant, anti-tyrosinase, antispasmodic, antinociceptive, gastroprotective, anticonvulsant, antihypertensive, antidepressant, anti-amnesia, and anti-helminthic activities have been mentioned. Further, based on research gaps, recommendations have been provided to evaluate T. vulgaris L. systematically to develop plant-based drugs, nutraceuticals, and to evaluate their clinical efficiency and safety.