Oral probiotic administration attenuates postexercise inflammation in horses.

Probiotics are commonly incorporated into equine diets to impart health and performance benefits; however, peer-reviewed evidence supporting their efficacy in horses is limited. Interestingly, bacteria from the Bacillus genus are gaining interest for their unique ability to impact metabolic, immune, and inflammatory pathways. The objective of this trial was to evaluate a selection of Bacilli for their role in altering the inflammatory response in horses to exercise. Eighteen horses were utilized in a randomized cross-over trial. Horses were randomly assigned to one of 6 starting treatments including a negative and positive control, and groups that received one of 4 probiotics (Bacillus coagulans GBI-30, 6086, Bacillus subtilis-1, Bacillus subtilis-2, or Bacillus amyloliquefaciens) top dressed to their daily ration at a rate of 8 billion CFU/d mixed into dried whey powder. All horses received a similar base diet of grass hay offered at 2.0% of bodyweight daily along with 4.54 kg of a commercially available textured horse feed. Each 3-wk phase of the trial consisted of a 2-wk dietary acclimation followed by a 1-wk exercise challenge and sample collection. Between phases, horses were offered only their base diet. On the day of exercise, horses were offered their 0700 ration and then subjected to a 2-h standardized exercise test. Blood samples were obtained prior to starting exercise and then again at 0, 2, 4, 6, 8, 24, 48, and 72-h postexercise. Horses in the positive control group were administered 0.23 mg/kg BW flunixin meglumine immediately following the 0-h sampling. Samples were analyzed for serum amyloid A (SAA), interleukin-6 (IL-6), and prostaglandin E2 (PGE2) concentrations. Data were evaluated via ANOVA using the MIXED procedure in SAS 9.4. Exercise-induced inflammation as evidenced by SAA, IL-6, and PGE2 increases postexercise. Horses consuming B. coagulans GBI-30, 6086 had reduced production of SAA, IL-6, and PGE2 compared to all other probiotic-fed groups and the negative control (P < 0.001). The positive control successfully ameliorated the postexercise inflammatory response. These data highlight the potential for B. coagulans GBI-30, 6086 to be incorporated into equine rations as a method to support optimal response to exercise or other inflammation-inducing challenges. Additional research is ongoing to elucidate the methodology by which these results occur.

Identification and characterization of the causative agents of Focal Ulcerative Dermatitis in commercial laying hens.

Focal Ulcerative Dermatitis (FUDS) is an emerging dermatological disease that affects cage-free laying flocks, it is characterized by the development of a lesion on the dorsum of the birds; FUDS is sporadic in nature and can result in a drop in egg production and up to 50% of cumulative mortality. A total of two cage-free flocks (flock 1: no history of FUDS; flock 2: birds affected with FUDS) from a commercial laying hen operation in the mid-west U.S. were sampled in this study. The microbial composition of skin, cloacal, cecal, and ileal samples from each bird was characterized through next generation sequencing (NGS). Results identified Staphylococcus aureus and Staphylococcus agnetis as the potential causative agents of FUDS, being the most predominant in FUDS positive birds. These results were confirmed by plating, with both staphylococci as the only pathogens isolated from lesions of FUDS positive birds. A total of 68 confirmed Staphylococcus isolates from skin and environmental samples were further analyzed by whole genome sequencing (WGS) for the presence of antimicrobial resistance (AMR) genes and virulence factors that could have contributed to the development of FUDS. Forty-four-point one-two percent of the isolates had between one and four acquired AMR genes encoding for macrolides, lincosamides, spectrogramines, and beta-lactams resistance. Six classes of virulence factors associated with adherence, enzyme, immune evasion, secretion system, toxin, and iron uptake were identified. The antimicrobial effect of 4 proprietary Bacillus Direct Fed Microbial (DFM) combinations was evaluated against the Staphylococcus aureus and Staphylococcus agnetis isolates, by agar well-diffusion (AWD) assay and competitive exclusion (CE) on broth culture. Through this antimicrobial screening, a particular two-strain combination of Bacillus pumilus was identified as the most effective inhibitor of both staphylococci. A customized Bacillus pumilus product is being used at different farms with history of FUDS resulting in the successful inhibition of both Staphylococcus aureus and Staphylococcus agnetis, decreasing FUDS mortalities, and improving harvestable eggs.

A Systematic Approach to Identify and Characterize the Effectiveness and Safety of Novel Probiotic Strains to Control Foodborne Pathogens.

A total of 44 lactic acid bacteria (LAB) strains originally isolated from cattle feces and different food sources were screened for their potential probiotic features. The antimicrobial activity of all isolates was tested by well-diffusion assay and competitive exclusion on broth against Salmonella Montevideo, Escherichia coli O157:H7 and Listeria monocytogenes strain N1-002. Thirty-eight LAB strains showed antagonistic effect against at least one of the pathogens tested in this study. Improved inhibitory effect was observed against L. monocytogenes with zones of inhibition up to 24 mm when LAB overnight cultures were used, and up to 21 mm when cell-free filtrates were used. For E. coli O157:H7 and Salmonella maximum inhibitions of 12 and 11.5 mm were observed, respectively. On broth, 43 strains reduced L. monocytogenes up to 9.06 log10 CFU/ml, 41 reduced E. coli O157:H7 up to 0.84 log10 CFU/ml, and 32 reduced Salmonella up to 0.94 log10 CFU/ml 24 h after co-inoculation. Twenty-eight LAB isolates that exhibited the highest inhibitory effect among pathogens were further analyzed to determine their antimicrobial resistance profile, adhesion potential, and cytotoxicity to Caco-2 cells. All LAB strains tested were susceptible to ampicillin, linezolid, and penicillin. Twenty-six were able to adhere to Caco-2 cells, five were classified as highly adhesive with > 40 bacterial cells/Caco-2 cells. Low cytotoxicity percentages were observed for the candidate LAB strains with values ranging from -5 to 8%. Genotypic identification by whole genome sequencing confirmed all as members of the LAB group; Enterococcus was the genus most frequently isolated with 21 isolates, followed by Pediococcus with 4, and Lactobacillus with 3. In this study, a systematic approach was used for the improved identification of novel LAB strains able to exert antagonistic effect against important foodborne pathogens. Our findings suggest that the selected panel of LAB probiotic strains can be used as biocontrol cultures to inhibit and/or reduce the growth of L. monocytogenes, Salmonella, and E. coli O157:H7 in different matrices, and environments.

Draft Genome Sequence of Enterococcus faecium Strain J19, Isolated from Cabbage.

Herein, we report the draft genome sequence of a newly discovered probiotic strain, Enterococcus faecium J19, which was isolated from cabbage. Strain J19 has shown antagonistic effects against the human foodborne pathogen Listeria monocytogenes in coculture and in different food matrices.

Draft Genome Sequence of Lactobacillus salivarius L28 Isolated from Ground Beef.

In this report, we describe the draft genome sequence of a newly discovered probiotic strain, Lactobacillus salivarius L28. L. salivarius L28 demonstrates antagonistic effects against human foodborne pathogens, including Escherichia coli O157:H7, Salmonella spp., and Listeria monocytogenes, in coculture experiments and food matrices.