Ileocecal Nodes Research Articles

Maximum Diameter of Ileocecal Lymph Nodes Measured Using Abdominal Ultrasonography Allows for the Discrimination of Yersinia pseudotuberculosis Infection from Kawasaki Disease.

This study aimed to determine whether the maximum diameter of ileocecal lymph nodes measured using abdominal ultrasonography is useful for differentiating Yersinia pseudotuberculosis infection from Kawasaki disease in the acute phase. The optimal maximum diameter cutoff of the ileocecal lymph nodes was also explored to optimize differentiation between these 2 diseases. We included pediatric patients <15 years old who met the diagnostic criteria for Kawasaki disease. Stool culture testing, loop-mediated isothermal amplification of stool specimens, and serological diagnosis were performed to confirm the presence or absence of Y. pseudotuberculosis infection. Of the 122 patients included in the analysis, 17 were confirmed to have Y. pseudotuberculosis infection and 105 were not. The age (in months), white blood cell count, C-reactive protein level, prediction score (risk score) for nonresponse to intravenous immunoglobulin, and number of intravenous immunoglobulin doses did not differ significantly between the Y. pseudotuberculosis-positive and -negative groups. The maximum diameter of ileocecal lymph nodes was 6.0 (5.5-9.5) mm in the Y. pseudotuberculosis-positive group and 3.0 (2.5-3.8) mm in the Y. pseudotuberculosis-negative group (numbers presented as median, interquartile range), with a significantly larger diameter in the Y. pseudotuberculosis-positive group (P < 0.01, Mann-Whitney U test), suggesting potency of ultrasonography. In patients meeting the diagnostic criteria for Kawasaki disease, the possibility of Y. pseudotuberculosis infection is significantly higher if the maximum ileocecal lymph node diameter ≥5.1 mm. Its sensitivity and specificity being 100%, and 89.5%, respectively.

Appendiceal goblet cell adenocarcinoma with perineural invasion extending into the ileocecal lesion

BackgroundAppendiceal goblet cell adenocarcinoma (GCA) is a rare subtype of primary appendiceal adenocarcinoma with an incidence of 1–5 per 10,000,000 people per year. Appendiceal tumors are often diagnosed after appendectomy for acute appendicitis. Notably, however, there is currently no standard treatment strategy for GCA, including additional resection. We report a case of appendiceal GCA with perineural extension into the cecum, in which ileal resection was considered effective.Case presentationA 41-year-old man was diagnosed with acute appendicitis and underwent appendectomy. Histopathological findings revealed GCA (T3, Pn1). He was referred to our hospital for additional resection. Preoperative examination indicated a diagnosis of GCA cT3N0M0. Laparoscopic ileocecal resection and D3 lymph node dissection were performed 2 months after initial appendectomy. The patient had a good postoperative course and was discharged 8 days after surgery. Histopathological findings showed a GCA invading the cecum, despite an intact appendiceal stump, no lymph node metastasis, no vascular invasion, and no horizontal extension into the submucosa. Direct invasion of the tumor through the serosa was not observed, but perineural extension was conspicuous in the cecum, suggesting that the GCA extended into the cecum via perineural invasion. The resection margins were negative. The patient has survived free of recurrence for a year after ileocecal resection.ConclusionsThe current patient was diagnosed with appendiceal GCA following appendectomy for acute appendicitis. Despite intact of appendiceal stump and no evidence of lymph node or distant metastasis, he underwent laparoscopic ileocecal resection and D3 lymph node dissection 2 months after initial appendectomy, with a favorable outcome. Despite the detection of perineural invasion, the patient declined adjuvant therapy. This case suggests that extensive resection may be required in patients with appendiceal GCA, but the role of adjuvant therapy remains unclear.

P-269 Malignant tumors of the appendix: A retrospective study

Malignant tumors of the appendix are a rare group of tumors often found fortuitously during surgical removal of the appendix, representing approximately 2% of appendectomy specimens. Our objective was to describe the clinico-pathological characteristics of appendicular tumors, the therapeutic modalities proposed and patient’s evolution after treatment. We conducted a retrospective review of 52 patients diagnosed with malignant tumors in the Medical Oncology department at Mohamed VI University Hospital, Marrakech, Morocco between 2012 and 2021. The clinical, biological, radiological, therapeutic and evolution data were collected. The median age was 50 years. The sex ratio was 0.7. Right lower quadrant pain was a constant complaint, followed by constipation, abdominal bloating and/or distension and vomiting. The diagnostic was based on ultrasound and/or abdominal scan. A complementary colonoscopy was proposed for 4 patients. An appendicectomy for performed on all patients after suspecting an acute appendicitis, an appendicular mucocele or for a diagnostic exploration. 42% (22 cases) were found to have a low-grade appendicular mucinous tumor, 34% a mucinous adenocarcinoma (including 5 patients with pseudomyxoma peritonei) and 24% (12 cases) an neuroendocrine tumor. 36% had localized only in the appendix while 64% were already metastatic. The therapeutic management was based on an additional surgical revision by right hemi-colectomy with ileocecal resection and lymph node dissection in 32% (17 cases), while 3% (2 cases) had undergone cytoreductive surgery with intravenous chemotherapy-peritoneal. Adjuvant chemotherapy was indicated to patients with a localized tumor with R0 and positive lymph node dissection which is the case in 7 patients. Palliative chemotherapy was proposed for metastatic patients with an unresectable tumor 26% (14 cases). 55% were under medical surveillance and screening, and 24% of patients relapsed. 21% (11 cases) were lost to follow-up. Appendicular malignant tumors represent a wide histological spectrum with various clinical subtypes, early diagnosis conditioning its management. Multidisciplinary molecular tumor boards are recommended.

Bacillus-Based Direct-Fed Microbial Reduces the Pathogenic Synergy of a Coinfection with Salmonella enterica Serovar Choleraesuis and Porcine Reproductive and Respiratory Syndrome Virus.

ABSTRACTViral respiratory infections predispose lungs to bacterial coinfections causing a worse outcome than either infection alone. Porcine reproductive and respiratory syndrome virus (PRRSV) causes pneumonia in pigs and is often associated with bacterial coinfections. We examined the impact of providing weanling pigs a Bacillus-based direct-fed microbial (DFM) on the syndrome resulting from infection with either Salmonella enterica serotype Choleraesuis alone, or in combination with PRRSV. Nine days after the bacterial challenge, Salmonella was isolated from ileocecal lymph nodes of all challenged pigs regardless of DFM treatment. Compared to the single bacterial challenge, the dual challenge with Salmonella and PRRSV resulted in a pathogenic synergy exhibited by a higher rate of Salmonella colonization in the lung and a more extensive and severe interstitial pneumonia. Provision of DFM to dually challenged pigs reduced the rate of lung colonization by Salmonella, eliminated or reduced the presence of PRRSV in the lung, and reduced the extent and severity of gross lung pathology. Dually challenged pigs that received DFM had increased concentrations of interleukin 1 (IL-1) and IL-8 in lung lavage fluids, accompanied by increased expression in their blood cells of nucleotide-binding oligomerization domain receptor 2 (NOD2) and triggering receptor expressed in myeloid cells 1 (TREM-1) molecules. These changes in pulmonary inflammatory cytokine production and increased expression of NOD2 and TREM-1 suggest that the DFM exerted a systemic modulating effect on innate immunity. These observations are consistent with the notion that tonic stimulation by gut-derived microbial products can poise innate immunity to fight infections in the respiratory tract.

Differentiation of Yersinia enterocolitica enteritis from other bacterial enteritides by ultrasonography: A single-center case–control study

The diagnosis of Yersinia enterocolitica (Ye) enteritis is not easy because detection from stool culture is more difficult for Ye than for other bacterial enteritides. The establishment of characteristic ultrasonographic findings for Ye enteritis would help improve the detection rate of Ye enteritis along with performance of several cold cultures. This would facilitate appropriate selection of antibiotics based on antimicrobial susceptibility testing and contribute to a more accurate understanding of local public health. This study aimed to retrospectively compare ultrasonographic findings and clinical features between children with Ye enteritis and other bacterial enteritides. We identified patients treated for Ye enteritis (Ye group; n=27) or other bacterial enteritides (Other enteritis group; n=29) between 2014 and 2018. Ultrasonographic findings (including mean maximum diameter and mean major-minor axis ratio of ileocecal lymph nodes, wall thickness of the terminal ileum, and presence of a pericecal hyperechoic region), clinical symptoms, and laboratory findings at first visit were compared between groups. No difference in mean maximum diameter of ileocecal lymph nodes was seen between groups. However, mean major-minor axis ratio of ileocecal lymph nodes was lower in the Ye group than in the Other enteritis group (p<0.001). Presence of a pericecal hyperechoic region was more frequent in the Ye group than in the Other enteritis group (p<0.001). The combined presence of a mean ileocecal lymph node major-minor axis ratio <1.51 and a pericecal hyperechoic region offered 100% sensitivity. Characteristic ultrasonographic findings identified in this study may improve ultrasonographic differentiation of Y. enterocolitica enteritis from other bacterial enteritides.

Yersinia Enterocolitica.

Yersinia Enterocolitica.

292 The effect of pharmacological zinc on oral Salmonella vaccine efficacy

Abstract Pharmacological zinc (2,000-3,000 ppm) is commonly fed to nursery pigs to improve health and growth due to its antimicrobial and anti-inflammatory properties. The objective was to test if pharmacological zinc at time of oral Salmonella vaccination impeded vaccine efficacy. Sixty-four weaned pigs (5.1±0.7 kg BW) were used in a 2 x 2 factorial design. The diets were control (CON) or zinc (3,000 ppm for 1 week, 2,000 ppm for 2 weeks, and no additional zinc for 1 week [ZN]). On d 2 pigs were orally vaccinated for Salmonella with 1 of 2 commercially available vaccines, resulting in 4 treatments (CON1, CON2, ZN1, ZN2; n = 16/treatment). On d 28, n = 8 pigs/treatment were randomly selected and enrolled in a S. Typhimurium challenge study. On d 35 post-weaned, all pigs were inoculated with 108 cfu of a field S. Typhimurium isolate. Pig performance, febrile response, fecal shedding and serology was assessed over a 7-d challenge period. On dpi 7 all pigs were euthanized, and colon contents and ileocecal lymph nodes were collected for culture. The effect of nursery diet, vaccine and their interaction was assessed. Pigs were confirmed Salmonella culture positive at dpi 2 and 6 pigs were culture positive from the ileocecal lymph nodes at dpi 7. Salmonella-specific antibody titers (S/P) increased (P &amp;lt; 0.001) from dpi 0 (0.31) to 7 (2.01), and a time-by-vaccine interaction was reported (P &amp;lt; 0.05). Irrespective of diet and vaccine, core temperatures increased from 39.5°C (dpi 0) to 39.7°C (dpi 2) before decreasing (P = 0.02). Over the challenge period, ADG did not differ (0.67, 0.64, 0.61, 0.62 kg/d, CON1, CON2, ZN1, ZN2, respectively, P = 0.654). Furthermore, ADFI and G:F did not differ by diet or vaccine (P &amp;gt;0.05). In conclusion, pharmacological Zn did not inhibit efficacy of oral Salmonella vaccines.

Effect of a High Proportion of Rye in Compound Feed for Reduction of Salmonella Typhimurium in Experimentally Infected Young Pigs.

Public health concerns and the potential for food-borne zoonotic transmission have made Salmonella a subject of surveillance programs in food-producing animals. Forty-two piglets (25 d of age and initially 7.48 kg) were used in a 28 d infection period to evaluate the effects of a high proportion of rye on reducing Salmonella Typhimurium. Piglets were divided into two diet groups: control diet (wheat 69%) and experimental diet (rye 69%). After a one-week adaptation period, all piglets were orally infected with Salmonella Typhimurium (107 log CFU/mL; 2mL/pig). Salmonella in fecal shedding were evaluated at day 1, 3, 5, 7 and then weekly after infection. At the end of the experimental period (at day 28 after infection), the piglets were euthanized to sample feces, cecal digesta contents and ileocecal lymph nodes to determine the bacterial counts of Salmonella. The results suggest that the bacterial counts in the experimental group fed rye diets showed evidence of reducing Salmonella fecal shedding from day 14 onwards and decreasing the number of Salmonella in cecal digesta. However, the translocation of Salmonella in ileocecal lymph nodes was not affected. Furthermore, feed intake, weight gain and feed conversion did not differ between the groups (p > 0.05).

Pathogenicity and Competitive Fitness of Salmonella enterica Serovar 4,[5],12:i:- Compared to Salmonella Typhimurium and Salmonella Derby in Swine.

Since 2014, Salmonella 4,[5],12:i:- has emerged as the most common serovar of Salmonella enterica identified from swine samples submitted to veterinary diagnostic laboratories in the United States. To compare the pathogenicity of S. 4,[5],12:i:- in swine to the known pathogenic Salmonella Typhimurium and lesser pathogenic Salmonella Derby, 72 pigs (20 per Salmonella serovar treatment and 12 controls) were inoculated with either S. Typhimurium, S. 4,[5],12:i:-, S. Derby, or sham-inoculated and followed for up to 28 days thereafter via rectal temperature, fecal scoring, and fecal culture. Animals were euthanized on days 2, 4, or 28 to determine the gross and histopathologic signs of disease and tissue colonization. The results clearly demonstrate that for the isolates selected, serovar 4,[5],12:i:- possesses similar ability as serovar Typhimurium to cause clinical disease, colonize the tonsils and ileocecal lymph nodes, and be shed in the feces of infected swine past resolution of clinical disease. To compare the competitive fitness of S. 4,[5],12:i:- to S. Typhimurium in swine when co-infected, 12 pigs were co-inoculated with equal concentrations of both S. Typhimurium and S. 4,[5],12:i and followed for up to 10 days thereafter. When co-inoculated, serovar 4,[5],12:i:- was consistently detected in the feces of a higher percentage of pigs and at higher concentrations than serovar Typhimurium, suggesting an increased competitive fitness of 4,[5],12:i:- relative to serovar Typhimurium when inoculated simultaneously into naïve pigs. Whole genome sequencing analysis of the isolates used in these studies revealed similar virulence factor presence in all S. 4,[5],12:i:- and S. Typhimurium isolates, but not S. Derby, providing additional evidence for similar pathogenicity potential between serovars 4,[5],12:i:- and Typhimurium. Altogether, this data strongly supports the hypothesis that S. 4,[5],12:i:- is a pathogen of swine and suggests a mechanism through increased competitive fitness for the increasing identification of Salmonella 4,[5],12:i:- in swine diagnostic samples over the past several years.

Evaluation of group vaccination of sows and gilts against Salmonella Typhimurium with an attenuated vaccine in subclinically infected pig herds

Subclinical Salmonella Typhimurium infections occur frequently in pigs and constitute a major risk for human salmonellosis. With the currently available control measures, Salmonella Typhimurium infections in pigs remain difficult to control. Vaccination has been proposed to be an effective tool to control infections at farm level. In the current study, the effect of group vaccination of sows and gilts against Salmonella Typhimurium is evaluated on Salmonella prevalence in fecal and overshoe samples and ileocecal lymph nodes, and on serology in the sows and their offspring in three subclinically infected pig farms.In each farm, all sows and gilts were vaccinated twice, three weeks apart, with an attenuated histidine-adenine auxotrophic vaccine (Salmoporc®, IDT Biologika). From three months after the group vaccination onwards, all sows were given a booster dose three weeks before every farrowing. The farms were monitored bacteriologically and serologically from 12 months before until 15 months after the group vaccination.After group vaccination, no significant effect was detected in the prevalence of Salmonella Typhimurium in the fecal and overshoe samples collected in the sows (before: 2 %, after: 0 %) and their offspring at 18 weeks (before: 17 %, after: 11 %) and at 26 weeks of age (before: 15 %, after: 7 %), and when combining the results of the offspring at 18 and 26 weeks of age (before: 16 %, after: 9 %). Also, no significant effect was detected in the prevalence of Salmonella Typhimurium positive lymph nodes of sows (before and after: 0 %) and their offspring (before: 4 %, after: 7 %). Regarding serology, the mean S/P-ratios of the sows were significantly higher after the group vaccination, compared to before group vaccination (before: 1.50, after: 2.32, p < 0.001). The mean S/P-ratios of the offspring at slaughter age were significantly lower after the group vaccination, compared to before group vaccination (before: 1.71, after: 1.04, p = 0.001).In conclusion, group vaccination of sows and gilts resulted in a more beneficial serological status of the offspring, but did not significantly decrease Salmonella Typhimurium excretion and lymph node contamination.

Translocation of Orally Inoculated Salmonella Following Mild Immunosuppression in Dairy Calves and the Presence of the Salmonella in Ground Beef Samples

ObjectivesThe objective of this study was to determine if immunosuppression altered Salmonella (SAL) translocation from the GI tract subsequently contaminating the carcass during fabrication.Materials and MethodsWeaned Holstein steer calves (n = 20; BW = 102 ± 2.7 kg) received dexamethasone (DEX; n = 10; 0.5mg/kg BW), a synthetic glucocorticoid, or saline (CON; n = 10; 0.5mg/kg BW) for 4 d (from d –1 to d 2) via a jugular catheter prior to oral inoculation of nalidixic acid resistant Salmonella Typhimurium (3.4×106 CFU/animal) via milk replacer on d 0. Fecal swabs were obtained daily to ensure SAL infection. Blood was collected to assess hematological markers of immunosuppression. Upon harvest (d 5), the ileum, cecal content, lymph nodes (ileocecal, mandibular, popliteal and prescapular), and synovial (stifle, coxofemoral, and shoulder) swabs were collected for the isolation of the inoculated strain of SAL. The trim obtained during fabrication was then ground separating both fore and hind quarters of each carcass. Ground beef samples were collected using a random grab method then combined for a composite sample for each fore quarter and each hind quarter for every carcass. The sample were diluted with 225ml of PBSResultsFollowing inoculation, 100% of DEX calves shed the experimental strain of SAL for 5 d, 90% of CON calves shed from d 1 to 3, and 100% of CON calves shed from d 4 to 5. A treatment by tissue interaction (P &lt; 0.01) was observed for SAL in tissues collected at harvest. Greater (P &lt; 0.001) concentrations of SAL were quantified from the cecum of DEX calves (3.86 ± 0.37 log10 CFU) than CON (1.37 ± 0.37 log10 CFU); There was no difference in SAL concentrations between DEX and CON calves in ileal tissue (P = 0.07), nor ileocecal (P = 0.57), mandibular (P = 0.12), popliteal (P = 0.99), or prescapular (P = 0.83) lymph nodes. Salmonella was isolated from the stifle joint of one calf in the CON group; however, SAL was not isolated from any other joint fluids sampled. The prevalence of SAL in the ground beef samples was recovered in 7 of the 80 (8.75%) samples taken. This is important to note as it was 3.3% of swabs collected from the CON treatment and the opportunity exists for stifle joint fluid to come in contact with meat during hind quarter fabrication.ConclusionThe observed data suggests that the grab method for ground beef sampling may not be a correct quantification of overall presence of SAL in a ground beef sample. Therefore, further studies are needed to determine the effectiveness of pathogen sampling methods on ground beef.

198 An in vivo model to investigate the effects of host stress and Salmonella typhimurium infection on nursery pigs

Abstract In animals, the sympathoadrenal and hypothalamic-pituitary-adrenal axis release chemicals that can act on and alter host microbiota. Therefore, the objectives of this study were to investigate if host stress (via adrenocorticotropin and catecholamine challenge) would increase the severity of a salmonella typhimurium infection. A total of 32 nursery pigs (7.6 ± 1.5 kg BW) were selected and split into treatment groups using a 2 x 2 factorial design to examine the impacts of stress hormone challenge, S. Typhimurium challenge, and their interaction. The resulting treatment groups (n = 8 pigs/treatment) were: 1) non-challenged controls (CON), 2) stress challenged, S. Typhimurium negative (CAT), 3) stress challenge negative, S. Typhimurium challenged (SAL), and 4) stress challenged, S. Typhimurium challenged (CAT+SAL). On days post inoculation (dpi) -1, the stress challenge was initiated and continued daily until dpi 4. The stress challenge consisted of an adrenocorticotropin injection (intramuscular, 0.2 IU/kg BW), a norepinephrine injection (intramuscular, 45 μg/kg BW), and an oral drench of L-DOPA (50 mg/kg BW). On dpi 0, pigs were inoculated with a field strain of S. Typhimurium. On dpi 5, plasma was collected and all pigs were necropsied for tissue collection. Plasma and colon samples were assayed for cortisol, norepinephrine, epinephrine, and dopamine. Colon contents and the ileocecal lymph node were cultured for S. Typhimurium. At dpi 5, plasma norepinephrine, epinephrine, and dopamine concentrations were increased (P &lt; 0.05) and plasma cortisol tended to be increased (P = 0.077) due to stress challenge. However, only colon dopamine concentrations were increased (P = 0.050) due to stress challenge. Further, CAT+SAL pigs didn’t have increased colon colonization of S. typhimurium or increased translocation to the ileocecal lymph node compared with SAL pigs. This suggests that host driven stress may not specifically exacerbate the severity of an S. Typhimurium infection.

Bacteriological evaluation of vaccination against Salmonella Typhimurium with an attenuated vaccine in subclinically infected pig herds

Subclinical infections with Salmonella Typhimurium occur frequently in pigs. They constitute a risk for human salmonellosis and are difficult to control with currently available control measures. Vaccination against Salmonella Typhimurium in pigs can be an effective tool to control Salmonella infections at farm level.In the present study, the efficacy of an attenuated Salmonella Typhimurium vaccine (Salmoporc®, IDT Biologika) to control Salmonella infections in pigs was evaluated in three subclinically infected pig herds. The effect on Salmonella excretion and the number of pigs positive for Salmonella Typhimurium field and vaccine strains in ileocecal lymph nodes at slaughter were evaluated using five different vaccination strategies: 1. vaccination of sows, 2. vaccination of sows and piglets, 3. vaccination of sows and fattening pigs, 4. vaccination of piglets, 5. vaccination of fattening pigs, which were all compared to a non-vaccinated control group (experimental group 6). Each vaccination strategy was implemented in each farm, during two consecutive production cycles of the same sows.The prevalence of Salmonella Typhimurium field strain excretion was low; in total, 4% of the fecal and overshoe samples collected in the non-vaccinated control group were Salmonella Typhimurium field strain positive. The excretion of Salmonella Typhimurium field strain did not significantly differ between farms, production cycles and experimental groups. Applying vaccination in either sows and piglets, sows and fattening pigs, or in piglets only, resulted in a significantly reduced number of Salmonella Typhimurium field strain positive lymph nodes of slaughter pigs in the second production cycle, but not in the first production cycle. Vaccination of sows and piglets resulted in the most consistent reduction of Salmonella Typhimurium field strain positive lymph nodes at slaughter. The vaccine strain was detected in the lymph nodes of 13 pigs at slaughter, indicating the possible persistence of the vaccine strain until slaughter.Because of limitations in the study design, and the variability between farms and production cycles, the results of the current observational study should be extrapolated with care. Nevertheless, the results provide evidence that applying vaccination against Salmonella Typhimurium in sows and piglets (preferred), sows and fattening pigs, and piglets only can support the control of Salmonella Typhimurium infections by decreasing the prevalence of Salmonella Typhimurium field strain positive lymph nodes at slaughter.

Microbiota of the Gut-Lymph Node Axis: Depletion of Mucosa-Associated Segmented Filamentous Bacteria and Enrichment of Methanobrevibacter by Colistin Sulfate and Linco-Spectin in Pigs.

Microorganisms are translocated from the gut to lymphatic tissues via immune cells, thereby challenging and training the mammalian immune system. Antibiotics alter the gut microbiome and consecutively might also affect the corresponding translocation processes, resulting in an imbalanced state between the intestinal microbiota and the host. Hence, understanding the variant effects of antibiotics on the microbiome of gut-associated tissues is of vital importance for maintaining metabolic homeostasis and animal health. In the present study, we analyzed the microbiome of (i) pig feces, ileum, and ileocecal lymph nodes under the influence of antibiotics (Linco-Spectin and Colistin sulfate) using 16S rRNA gene sequencing for high-resolution community profiling and (ii) ileocecal lymph nodes in more detail with two additional methodological approaches, i.e., cultivation of ileocecal lymph node samples and (iii) metatranscriptome sequencing of a single lymph node sample. Supplementation of medicated feed showed a local effect on feces and ileal mucosa-associated microbiomes. Pigs that received antibiotics harbored significantly reduced amounts of segmented filamentous bacteria (SFB) along the ileal mucosa (p = 0.048; 199.17-fold change) and increased amounts of Methanobrevibacter, a methanogenic Euryarchaeote in fecal samples (p = 0.005; 20.17-fold change) compared to the control group. Analysis of the porcine ileocecal lymph node microbiome exposed large differences between the viable and the dead fraction of microorganisms and the microbiome was altered to a lesser extent by antibiotics compared with feces and ileum. The core microbiome of lymph nodes was constituted mainly of Proteobacteria. RNA-sequencing of a single lymph node sample unveiled transcripts responsible for amino acid and carbohydrate metabolism as well as protein turnover, DNA replication and signal transduction. The study presented here is the first comparative study of microbial communities in feces, ileum, and its associated ileocecal lymph nodes. In each analyzed site, we identified specific phylotypes susceptible to antibiotic treatment that can have profound impacts on the host physiological and immunological state, or even on global biogeochemical cycles. Our results indicate that pathogenic bacteria, e.g., enteropathogenic Escherichia coli, could escape antibiotic treatment by translocating to lymph nodes. In general ileocecal lymph nodes harbor a more diverse and active community of microorganisms than previously assumed.

Efficacy of Clostridium butyricum as probiotic feed additive against experimental Salmonella Typhimurium infection in pigs

Salmonella Typhimurium (S. Typhimurium) infections in pigs constitute a risk for human salmonellosis. The use of probiotics may be a promising tool to reduce Salmonella infections in pigs. The present study investigated the efficacy of Clostridium butyricum (C. butyricum), at two different dosages, as probiotic feed additive against S. typhimurium infection in experimentally challenged pigs.After weaning, 35 Salmonella negative pigs were randomly divided into 4 groups;Negative control: no feed additive (n = 5), Positive control: no feed additive (n = 10), CB-H: ±2 × 106 CFU C. butyricum/g feed (n = 10), CB-L: ± 5 × 105 CFU C. butyricum/g feed (n = 10). Pigs were fed ad libitum with the experimental feed, including the probiotic feed additive according to the group, from arrival (day -7) until euthanasia (day 42). One week after arrival (day 0), pigs in the positive control group, CB-H and CB-L were orally inoculated with 2 × 108 CFU/mL nalidixic acid resistant S. typhimurium strain 112910a (1 mL/pig). Fecal excretion, serological response, intestinal carriage and prevalence of S. typhimurium positive ileocecal lymph nodes were evaluated.Under the present conditions, the probiotic feed additive C. butyricum did not significantly reduce fecal excretion, serological response, intestinal carriage and prevalence of S. typhimurium in the ileocecal lymph nodes in experimentally challenged pigs. Further research is needed to investigate the results under field conditions and to detect possible additional effects of the application of the probiotic for a longer time period.

Neuropeptides and lymphocyte populations in the porcine ileum and ileocecal lymph nodes during postnatal life.

The maturation-related changes in the concentrations of galanin (Gal), vasoactive intestinal polypeptide (VIP), substance P (SP) and somatostatin (Som), as well as in subpopulations of lymphocytes expressing antigens CD2 (lymphocytes T), CD4 (T helper), CD8 (T cytotoxic), CD21 (B lymphocytes), CD5-/CD8+ (NK cells) and TCRgamma/delta (gut mucosal/intraepitelial cells) were studied in the ileal Peyer’s patches and ileo-cecal lymph nodes in female pigs aged 3 days, 2 weeks, 4 weeks and 4 months. As regards neuropeptide concentrations statistically significant changes in the ileum and lymph nodes were found only in case of Gal and VIP. The concentrations of neuropeptides were significantly higher only in new-born animals. As regards the changes in subpopulations of lymphocytes, statistically significant changes were noticed only in 4-months old animals and were dealing only with CD2+ and TCRgamma/delta cells in the ileum as well as CD4+, CD8+, CD21+ and TCRgamma/delta in lymph nodes. The highest number of CD8+, CD21+ and TCRgamma/delta lymphocytes occurred in 4-months old animals.

Detection of Mycobacterium avium subsp. paratuberculosis in non-human primates.

Due to a sporadic occurrence of Mycobacterium avium subsp. paratuberculosis (MAP) in non-human primates (NHP), the susceptibility of different NHP to MAP should be investigated. Fecal and tissue samples (ileum, ileocecal lymph node, bone marrow) of 20 animals (seven species) were analyzed by IS900-based PCRs and sequenced. Samples of MAP PCR positive NHP were further cultivated. MAP DNA was detectable in two animals; the ileum of a cottontop tamarin and the bone marrow of a common marmoset. Cultivation of MAP failed. Sequence analysis revealed 100% homology to the MAP-K10 sequence. Pathohistological examinations offered no direct correlation to a MAP infection. MAP was detected for the first time in a common marmoset. But as both NHP suffered from other diseases, an asymptomatic infection with MAP was assumed. The detection of MAP in the bone marrow might play a role in establishing latent paratuberculosis, as known from tuberculosis.

Immunological findings associated with Argentinean strains of Mycobacterium avium subsp. paratuberculosis in bovine models

Mycobacterium avium subspecies paratuberculosis (MAP) is the causative agent of ruminant paratuberculosis. The aim of this study was to evaluate the biological behavior of different Argentinean strains of MAP in two bovine infection models: macrophage (in vitro) and calf (in vivo) through the evaluation of early immune responses at the peripheral and local levels. Two MAP strains (A and C) were selected taking into account the different patterns of TNF-α and IL-10 secretion displayed by infected bovine macrophages in vitro. Two groups of calves were infected with 250mg of total wet weight live MAP: strain A infected group (MA, n=3), strain C infected group (MC, n=2). Another group of animals was mock-infected (MI, n=3). Infection was confirmed by MAP culture of feces and microscopic observation of granulomatous lesions in the gut tissue. All infected calves showed positive results in the DTH skin test. A significant increase in peripheral CD4CD25+ cells in MC group on day 150 was detected. The specific cellular immune response developed allowed the identification of the infection as early as 30days in the MA group. However, the percentage of CD8CD25+ cells was significantly increased on day 120 in MC group. Significant differences between groups in proliferation and cellular responses were also detected in ileocecal lymph node samples. In summary, the strains of MAP employed herein induced differential immune responses in peripheral cells, in the proliferative responses and in cell functionality at the local level. Our findings support the hypotheses that the in vitro behavior displayed by macrophages could be a tool to identify differences among MAP strains infecting bovines and that the host-pathogen interactions occurring upon infection are dependent on the strain of MAP involved.

A DIVA vaccine for cross-protection against Salmonella

Swine are often asymptomatic carriers of Salmonella spp., a leading cause of human bacterial foodborne disease. Vaccination against Salmonella is effective for protecting animal health and enhancing food safety. However, with >2500 Salmonella serovars, current vaccines for swine offer limited cross-protection against heterologous serovars. Also, existing vaccines can interfere with surveillance programs that monitor the Salmonella status of swine herds. To overcome Salmonella vaccine limitations, we rationally designed and constructed an attenuated Salmonella enterica serovar Typhimurium vaccine (BBS 866) by deleting multiple small regulatory RNA (sRNA) genes (omrA, omrB, rybB, micA, and invR) in combination with an rfaH mutation. We vaccinated swine intranasally at 3-weeks of age with PBS (mock-vaccinated), BBS 866 or BBS 202 (S. Typhimurium rfaH, Bearson et al., Front Vet Sci 2014;1:9.) and challenged at 7-weeks of age with virulent S. Choleraesuis, a swine pathogen. Vaccination with BBS 866 enhanced protection against S. Choleraesuis by significantly limiting the duration of fever, weight loss, the levels of circulating INFγ, and the total number of swine with S. Choleraesuis septicemia. Vaccination with either BBS 866 or BBS 202 significantly reduced S. Choleraesuis colonization of both systemic (spleen and liver) and gastrointestinal (Peyer's Patch, Ileocecal lymph nodes, and cecum) tissues. Similar to our earlier report for BBS 202, the BBS 866 vaccine strain can be used in swine without compromising the differentiation of infected from vaccinated animals (DIVA). Therefore, the attenuated S. Typhimurium BBS 866 strain, containing mutations in rfaH and multiple sRNAs, addresses the limitations of current Salmonella vaccines by providing cross-protection against Salmonella serovars in swine without interfering with established monitoring programs for Salmonella surveillance.

Effect of Organic Acids on Salmonella Shedding and Colonization in Pigs on a Farm with High Salmonella Prevalence

This study builds on the results of a previous study in which six commercial feed products based on organic acids were evaluated with respect to Salmonella contamination of piglets in an artificially challenged seeder model. In the present study, the efficacy of three of these commercial products was assessed for Salmonella reduction in fattening pigs on one closed farm with a natural high Salmonella prevalence. In each of four fattening compartments, one of the following feed treatments was evaluated during two consecutive fattening rounds: (i) butyric acid (active ingredients at 1.3 kg/ton of feed; supplement A1), (ii) a combination of short-chain organic acids (mixture of free acids and salts) and natural extracts (2.92 kg/ton; supplement A4), (iii) a 1:1 blend of two commercial products consisting of medium-chain fatty acids, lactic acid, and oregano oil (3.71 kg/ton; supplement A5+A6), and (iv) a control feed. On the farm, the Salmonella status of the fattening pigs was evaluated by taking fecal samples twice during the fattening period. At the slaughterhouse, samples were collected from the cecal contents and the ileocecal lymph nodes. Salmonella isolates were serotyped and characterized by pulsed-field gel electrophoresis. This farm had a particularly high number of pigs shedding Salmonella with a wide variety of sero- and pulsotypes. Only the feed blend based on the medium-chain fatty acids was able to significantly reduce Salmonella prevalence both on the farm and at the slaughterhouse. With this combined supplement, the Salmonella reduction in the feces at slaughter age, in cecal contents at slaughter, and the lymph nodes was 50, 36, and 67%, respectively, compared with the control animals. This promising finding calls for further investigation including cost-efficiency of this combined feed product and its effect on the animals.