Heat stress (HS) may result in economic losses to pig producers across the USA and worldwide. Despite significant advancements in management practices, HS continues to be a challenge. In this study, an in-feed antibiotic (carbadox, CBX) and antibiotic alternatives ( [XPC], and [SGX] fermentation products) were evaluated in a standard pig starter diet as mitigations against the negative effects of HS in pigs. A total of 100 gilts were obtained at weaning (6.87 ± 0.82 kg BW, 19.36 ± 0.72 d of age) and randomly assigned to dietary treatments (2 rooms/treatment, 2 pens/room, 6 to 7 pigs/pen). After 4 wk of dietary acclimation, half of the pigs in each dietary group (1 room/dietary treatment) were exposed to repeated heat stress conditions (RHS; daily cycles of 19 h at 25°C and 5 h at 40°C, repeated for 9 d), and the remaining pigs were housed at constant thermal neutral temperature (25°C, [NHS]). Pigs subjected to RHS had elevated skin surface temperature ( < 0.05; average 41.7°C) and respiration rate ( < 0.05; 199 breaths per minute (bpm) during HS, and overall reduced ( < 0.05) BW, ADG, ADFI, and G:F regardless of dietary treatment. Independent of diet, RHS pigs had significantly shorter ( < 0.05) jejunum villi on d 3 and d 9 compared to NHS pigs. Heat stress resulted in decreased villus height to crypt depth ratio (V:C) in pigs fed with control diet with no added feed additive (NON) and CBX diets at d 3, whereas the pigs fed diets containing XPC or SGX showed no decrease. Transcriptional expression of genes involved in cellular stress (, , , ), tight junction integrity (, , ), and immune response (, , and ) were measured in the ileum mucosa. Pigs in all dietary treatments subjected to RHS had significantly higher ( < 0.05) transcript levels of and , and an upward trend ( < 0.07) of mRNA expression. RHS pigs had higher ( < 0.05) transcript levels of and in NON diet, in XPC and CBX diets, and in SGX diet compared to the respective diet-matched pigs in the NHS conditions. Neither RHS nor diet affected peripheral natural killer () cell numbers or NK cell lytic activity. In conclusion, pigs subjected to RHS had decreased performance, and supplementation with fermentation products in the feed (XPC and SGX) protected pigs from injury to the jejunum mucosa.

Bra.chy.spi'ra. Gr. adj.brachysshort; L. fem. n.spiraa coil, spiral; N.L. fem. n.Brachyspiraa short spiral, describing a bacterium that resembles a short spiral.Spirochaetes / Spirochaetia / Spirochaetales / Brachyspiraceae / BrachyspiraBrachyspiraspirochetes are helical shaped bacteria withregular coiling patterns. Cells measure 2–11 µm by 0.2–0.4 µm. Unicellular, but dividing pairs and occasional chains of three or more cells can be observed in growing cultures. Under unfavorable growth conditions, spherical or round bodies are formed. Gram‐stain negative.Obligately anaerobic, aerotolerant. Cell ends may be blunt or pointed. Cells have a typical spirochete cell ultrastructure, consisting of an outer sheath, helical protoplasmic cylinder, and internal flagella in the space between the protoplasmic cylinder and outer sheath. Brachyspire cells have 8–30 flagella per cell depending on the species (flagellar number usually correlates with cell size and species of smaller cells have fewer flagella). Flagella attach subterminally in equal numbers at each cell end, wrap around the protoplasmic cylinder, and their free ends overlap in the middle of the cells. Flexing and creeping motility at 22°C; translational movement in liquids at 37–42°C. Cultured anaerobically on commercially available media (trypticase soy or brain heart infusion broths) containing a carbohydrate growth substrate and supplemented with defibrinated blood or animal (calf) serum. Grows at 36–42°C, optimally at 37–39°C. Population doubling times on glucose in broth cultures are 1–5 h (not reported forBrachyspira aalborgi). Chemoorganotrophic, using various carbohydrates for growth.Possess NADH oxidase for reducing molecular oxygen. Consume oxygen during growth in culture broth beneath a 1%oxygen atmosphere. Acetate, butyrate, H2, and CO2are major endproducts of glucose metabolism. Higher amounts of H2than CO2are produced. Weakly hemolytic except forBrachyspira hyodysenteriaewhich exhibits β‐hemolysis (strongly hemolytic). Associated with animal and human hosts. Some species are pathogenic.The genusBrachyspirais distinguished from other spirochete genera based on 16S rRNA gene sequences.Brachyspiraspecies share high 16S rRNA sequence similarity with each other. Species can be differentiated by DNA–DNA relative reassociation and MLEE (multilocus enzyme electrophoresis) analyses. Similar to other spirochete genera,Brachyspirais insensitive to the antibiotic rifampin.DNA G+C content(mol%): 24.5–27.1 (Tm).Type species:Brachyspira aalborgiHovind‐Hougen, Birch‐Andersen, Henrik‐Nielsen, Orholm, Pedersen, Teglbjaerg and Thaysen 1 9 8 3, 896VP(Effective publication: Hovind‐Hougen, Birch‐Andersen, Henrik‐Nielsen, Orholm, Pedersen, Teglbjaerg and Thaysen 1982, 1135VP.).

ABSTRACT A novel Coriobacteriaceae bacterium (strain 68-1-3) was isolated from the ileum of the swine intestinal tract using a selective mucus-based medium. Here we present the finished genome sequence for the swine commensal, totaling 1.97 Mb in size.

The human food chain begins with upwards of 1,000 species of bacteria that inhabit the intestinal tracts of poultry and livestock. These intestinal denizens are responsible for the health and safety of a major protein source for humans. The use of antibiotics to treat animal diseases was followed by the surprising discovery that antibiotics enhanced food animal growth, and both led to six decades of antibiotic use that has shaped food animal management practices. Perhaps the greatest impact of antibiotic feeding in food animals has been as a selective force in the evolution of their intestinal bacteria, particularly by increasing the prevalence and diversity of antibiotic resistance genes. Future antibiotic use will likely be limited to prudent applications in both human and veterinary medicine. Improved knowledge of antibiotic effects, particularly of growth-promoting antibiotics, will help overcome the challenges of managing animal health and food safety.

Thymol is a natural product that exhibits antimicrobial activity in vitro but in vivo results indicate that absorption within the proximal alimentary tract precludes its delivery to the distal gut. Presently, the anti-Campylobacter activity of thymol was compared against that of thymol-β-d-glucopyranoside, the latter being resistant to absorption. When treated with 1 mM thymol, Campylobacter coli and jejuni were reduced during pure or co-culture with a β-glycoside-hydrolysing Parabacteroides distasonis. Thymol-β-d-glucopyranoside treatment (1 mM) did not reduce C. coli and jejuni during pure culture but did during co-culture with P. distasonis or during mixed culture with porcine or bovine faecal microbes possessing β-glycoside-hydrolysing activity. Fermentation acid production was reduced by thymol-β-d-glucopyranoside treatment, indicating that fermentation was inhibited, which may limit its application to just before harvest. Results suggest that thymol-β-d-glucopyranoside or similar β-glycosides may be able to escape absorption within the proximal gut and become activated by bacterial β-glycosidases in the distal gut.

Bovine papillomatous digital dermatitis (DD) is the leading cause of lameness in dairy cattle and represents a serious welfare and economic burden. Found primarily in high production dairy cattle worldwide, DD is characterized by the development of an often painful red, raw ulcerative or papillomatous lesion frequently located near the interdigital cleft and above the bulbs of the heel. While the exact etiology is unknown, several spirochete species have been isolated from lesion material. Four isolates of Treponema phagedenis-like spirochetes were isolated from dairy cows in Iowa. Given the distinct differences in host, environmental niche, and disease association, a closer analysis of phenotypic characteristics, growth characteristics, and genomic sequences of T. phagedenis, a human genitalia commensal, and the Iowa DD isolates was undertaken.

To identify bacteria with potential for influencing gut health, 980 anaerobes were cultured from the swine intestinal tract and analyzed for butyrate production. Fifteen isolates in the order Clostridiales produced butyrate and had butyryl coenzyme A (CoA):acetate CoA transferase activity. Three of the isolates grew on mucin, suggesting an intimate association with host intestinal mucosa.

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The persistence and spread of antibiotic resistance, in conjunction with decreased profitability of new antibiotics, have created the dangerous prospect of ineffective therapies against bacterial diseases. National strategies aimed at discovery, development, and definition of the mechanisms of effective antibiotic alternatives, especially for agricultural applications, should be encouraged.

Commissioned by President Dwight Eisenhower in 1958 and opened with a dedication ceremony in December 1961, the USDA, Agricultural Research Service (ARS), National Animal Disease Center (NADC) celebrated its 50-year anniversary in November 2011. Over these 50 years, the NADC established itself among the world's premier animal health research centers. Its historic mission has been to conduct basic and applied research on selected endemic diseases of economic importance to the U.S. livestock and poultry industries. Research from NADC has impacted control or management efforts on nearly every major animal disease in the United States since 1961. For example, diagnostic tests and vaccines developed by NADC scientists to detect and prevent hog cholera were integral in the ultimate eradication of this costly swine disease from the U.S. Most major veterinary vaccines for critical diseases such as brucellosis and leptospirosis in cattle, porcine respiratory and reproductive syndrome (PRRS), porcine parvovirus and influenza in swine had their research origins or were developed and tested at the NADC. Additional discoveries made by NADC scientists have also resulted in the development of a nutritional approach and feed additives to prevent milk fever in transition dairy cattle. More recently, NADC's archive of historic swine influenza viruses combined with an established critical mass of influenza research expertise enabled NADC researchers to lead an effective national research response to the pandemic associated with the novel 2009 H1N1 influenza virus. This review commemorates some of the key animal health contributions in NADC's first 50 years, recaps the newly completed modernization of the center into new facilities, and offers highlights of the ongoing research that will define NADC's mission going forward.

Antibiotics have been administered to agricultural animals for disease treatment, disease prevention, and growth promotion for over 50 y. The impact of such antibiotic use on the treatment of human diseases is hotly debated. We raised pigs in a highly controlled environment, with one portion of the littermates receiving a diet containing performance-enhancing antibiotics [chlortetracycline, sulfamethazine, and penicillin (known as ASP250)] and the other portion receiving the same diet but without the antibiotics. We used phylogenetic, metagenomic, and quantitative PCR-based approaches to address the impact of antibiotics on the swine gut microbiota. Bacterial phylotypes shifted after 14 d of antibiotic treatment, with the medicated pigs showing an increase in Proteobacteria (1-11%) compared with nonmedicated pigs at the same time point. This shift was driven by an increase in Escherichia coli populations. Analysis of the metagenomes showed that microbial functional genes relating to energy production and conversion were increased in the antibiotic-fed pigs. The results also indicate that antibiotic resistance genes increased in abundance and diversity in the medicated swine microbiome despite a high background of resistance genes in nonmedicated swine. Some enriched genes, such as aminoglycoside O-phosphotransferases, confer resistance to antibiotics that were not administered in this study, demonstrating the potential for indirect selection of resistance to classes of antibiotics not fed. The collateral effects of feeding subtherapeutic doses of antibiotics to agricultural animals are apparent and must be considered in cost-benefit analyses.

A novel anaerobic, mesophilic, amino-acid-fermenting bacterium, designated strain CL-84T, was isolated from the swine intestinal tract on mucin-based media. Cells were curved rods (0.8–1.2×3.5–5.0 µm), stained Gram-negative and were non-motile with no evidence of spores. Strain CL-84T produced acetate, propionate, formate and butyrate as the end products of metabolism when grown on serine. Optimum growth occurred at 39 °C and pH 6.5. The major cellular fatty acids were iso-C15 : 0, iso-C15 : 0 3-OH, iso-C17 : 0 and C16 : 0, distinguishing strain CL-84T from closely related species. The DNA G+C content of strain CL-84T was 55.1 mol%. 16S rRNA gene sequence analysis showed that strain CL-84T shared 90–95 % similarity with characterized genera within the phylum Synergistetes , family Synergistaceae . Phylogenetic analysis showed that strain CL-84T was related to, but distinct from, Cloacibacillus evryensis . Based on these findings, we propose that strain CL-84T represents a novel species of the genus Cloacibacillus . We further propose the name Cloacibacillus porcorum sp. nov. be designated for this species. The type strain is CL-84T ( = DSM 25858T = CCUG 62631T). An emended description of the genus Cloacibacillus is provided.

Salmonella continues to be a significant human health threat, and the objective of this study was to identify microorganisms with the potential to improve porcine food-safety through their antagonism of Salmonella. Anaerobic culture supernatants of 973 bacterial isolates from the gastrointestinal tract and feces of swine were screened for their capacity to inhibit the growth of Salmonella enterica serovar Typhimurium. Growth inhibition of 1000-fold or greater was observed from 16 isolates, and 16S rRNA sequencing identified the isolates as members of the genera Mitsuokella, Escherichia/Shigella, Anaerovibrio, Selenomonas, and Streptococcus. Four isolates were identified as Mitsuokella jalaludinii, and the mechanism of Salmonella Typhimurium growth inhibition by M. jalaludinii was further investigated. M. jalaludinii stationary phase culture supernatants were observed to significantly inhibit growth, and featured the production of lactic, succinic, and acetic acids. Aerobic and anaerobic S. Typhimurium growth was restored when the pH of the culture supernatants (pH 4.6) was increased to pH 6.8. However, S. Typhimurium growth in fermentation acid-free media was the same at pH 4.6 and pH 6.8 - indicating a synergistic effect between fermentation acid production and low pH as the cause of S. Typhimurium growth inhibition. Furthermore, exposure of S. Typhimurium to M. jalaludinii culture supernatants inhibited Salmonella invasion of HEp-2 cells by 10-fold. The results identify M. jalaludinii as a possible inhibitor of Salmonella growth and invasion in swine, and thus a potential probiotic capable of improving food safety.

ABSTRACT Organically raised swine had high fecal populations of chlortetracycline (CTC)-resistant (growing at 64 μg CTC/ml) Escherichia coli , Megasphaera elsdenii , and anaerobic bacteria. By comparison, CTC-resistant bacteria in feral swine feces were over 1,000-fold fewer and exhibited lower taxonomic diversity.

AbstractBrachyspira species are anaerobic spirochetes inhabiting intestinal tracts of animals and humans. Several species cause transmissible intestinal diseases of swine and birds. This unit describes methods for the isolation of Brachyspira from fecal samples, cultivation on liquid and solid media, and long term and short term preservation of Brachyspira species. Curr. Protoc. Microbiol. 22:12D.1.1‐12D.1.14. © 2011 by John Wiley & Sons, Inc.

The primary objective of this study was to determine whether or not Spiroplasma mirum would be capable of producing lesions of transmissible spongiform encephalopathy (TSE) when inoculated in raccoons (Procyon lotor) and, if that was possible, to compare the clinicopathological findings with those of transmissible mink encephalopathy (TME) in the same experimental model. For this purpose, 5 groups (n = 5) of raccoon kits were inoculated intracerebrally with either S. mirum and/or TME. Two other groups (n = 5) of raccoon kits served as sham-inoculated controls. All animals inoculated with TME, either alone or in combination, showed clinical signs of neurologic disorder and were euthanized within 6 mo post-inoculation (MPI). None of the carcasses revealed gross lesions. Spongiform encephalopathy was observed by light microscopy and the presence of abnormal disease-causing prion protein (PrP(d)) was detected by immunohistochemistry (IHC) and Western blot (WB) techniques in only the raccoons administered TME. Raccoons inoculated with Spiroplasma, but not administered TME agent, were euthanized at 30 MPI. They did not show clinical neurologic signs, their brains did not have lesions of spongiform encephalopathy, and their tissues were negative for S. mirum by polymerase chain reaction (PCR) and for PrP(d) by IHC and WB techniques. The results of this study indicate that Spiroplasma mirum does not induce TSE-like disease in raccoons.

ABSTRACT Megasphaera elsdenii is a lactate-fermenting, obligately anaerobic bacterium commonly present in the gastrointestinal tracts of mammals, including humans. Swine M. elsdenii strains were previously shown to have high levels of tetracycline resistance (MIC=64 to >256 μg/ml) and to carry mosaic (recombinant) tetracycline resistance genes. Baby pigs inherit intestinal microbiota from the mother sow. In these investigations we addressed two questions. When do M. elsdenii strains from the sow colonize baby pigs? Can five antibiotic-sensitive M. elsdenii strains administered intragastrically to newborn pigs affect natural colonization of the piglets by antibiotic-resistant (AR) M. elsdenii strains from the mother? M. elsdenii natural colonization of newborn pigs was undetectable (<104 CFU/g [wet weight] of feces) prior to weaning (20 days after birth). After weaning, all pigs became colonized (4 × 105 to 2 × 108 CFU/g feces). In a separate study, 61% (76/125) of M. elsdenii isolates from a gravid sow never exposed to antibiotics were resistant to chlortetracycline, ampicillin, or tylosin. The inoculation of the sow's offspring with mixtures of M. elsdenii antibiotic-sensitive strains prevented colonization of the offspring by maternal AR strains until at least 11 days postweaning. At 25 and 53 days postweaning, however, AR strains predominated. Antibiotic susceptibility phenotypes and single nucleotide polymorphism (SNP)-based identities of M. elsdenii isolated from sow and offspring were unexpectedly diverse. These results suggest that dosing newborn piglets with M. elsdenii antibiotic-sensitive strains delays but does not prevent colonization by maternal resistant strains. M. elsdenii subspecies diversity offers an explanation for the persistence of resistant strains in the absence of antibiotic selection.

In Antimicrobial Drugs—Chronicle of a Twentieth Century Medical Triumph, author David Greenwood describes the contributors and contributions to the revolution in infectious disease therapy which took place 1900 to 1980. During those years, the convergence of organic chemistry, industrial fermentation technology, clinical medicine, and disease microbiology produced hundreds of life-saving antimicrobials.