Neu3 neuraminidase induction triggers intestinal inflammation and colitis in a model of recurrent human food-poisoning.

Intestinal inflammation is the underlying basis of colitis and the inflammatory bowel diseases. These syndromes originate from genetic and environmental factors that remain to be fully identified. Infections are possible disease triggers, including recurrent human food-poisoning by the common foodborne pathogen Salmonella enterica Typhimurium (ST), which in laboratory mice causes progressive intestinal inflammation leading to an enduring colitis. In this colitis model, disease onset has been linked to Toll-like receptor-4-dependent induction of intestinal neuraminidase activity, leading to the desialylation, reduced half-life, and acquired deficiency of anti-inflammatory intestinal alkaline phosphatase (IAP). Neuraminidase (Neu) inhibition protected against disease onset; however, the source and identity of the Neu enzyme(s) responsible remained unknown. Herein, we report that the mammalian Neu3 neuraminidase is responsible for intestinal IAP desialylation and deficiency. Absence of Neu3 thereby prevented the accumulation of lipopolysaccharide-phosphate and inflammatory cytokine expression in providing protection against the development of severe colitis.

Inhibitory Effects of Carrageenans on Endotoxin-Induced Inflammation.

The inhibitory effects of carrageenans (CRGs) on lipopolysaccharide (LPS) induced inflammation in a mouse model of endotoxemia and in complex therapy of patients with enteric infections of Salmonella etiology were studied. The atomic force microscopy (AFM) examination of LPS and its mixture with CRGs showed that the LPS morphology is significantly changed under the action of κ- and κ/ß-CRGs. CRGs were able to increase the synthesis of anti-inflammatory interleukin 10 (IL-10) in vitro, and, at low concentrations, their activity in the mixture with LPS was higher. The protective effect of CRGs against Escherichia coli LPS was studied in vivo by monitoring the biochemical and pathomorphological parameters. The κ- and κ/ß-CRGs and food supplement "Carrageenan-FE" increased the nonspecific resistance of mice to E. coli LPS at the expense of the inhibition of processes of thymus involution, adrenals hypertrophy, thyroid atrophy, hypercorticoidism, glycogenolysis, and lactate acidosis. The estimation of the therapeutic action of food supplement Carrageenan-FE in complex therapy of patients with enteric infections of Salmonella etiology is given. Carrageenan-FE restores the system of hemostasis and corrects some biochemical indicators and parameters in the immune systems of patients. These results allow us to hope for the practical application of CRGs for lowering the endotoxemia level in patients under the development of the infectious process caused by Gram-negative bacteria.

Lymph node colonization dynamics after oral Salmonella Typhimurium infection in mice.

An understanding of how pathogens colonize their hosts is crucial for the rational design of vaccines or therapy. While the molecular factors facilitating the invasion and systemic infection by pathogens are a central focus of research in microbiology, the population biological aspects of colonization are still poorly understood. Here, we investigated the early colonization dynamics of Salmonella enterica subspecies 1 serovar Typhimurium (S. Tm) in the streptomycin mouse model for diarrhea. We focused on the first step on the way to systemic infection -- the colonization of the cecal lymph node (cLN) from the gut -- and studied roles of inflammation, dendritic cells and innate immune effectors in the colonization process. To this end, we inoculated mice with mixtures of seven wild type isogenic tagged strains (WITS) of S. Tm. The experimental data were analyzed with a newly developed mathematical model describing the stochastic immigration, replication and clearance of bacteria in the cLN. We estimated that in the beginning of infection only 300 bacterial cells arrive in the cLN per day. We further found that inflammation decreases the net replication rate in the cLN by 23%. In ccr7(-/-) mice, in which dendritic cell movement is impaired, the bacterial migration rate was reduced 10-fold. In contrast, cybb(-/-) mice that cannot generate toxic reactive oxygen species displayed a 4-fold higher migration rate from gut to cLN than wild type mice. Thus, combining infections with mixed inocula of barcoded strains and mathematical analysis represents a powerful method for disentangling immigration into the cLN from replication in this compartment. The estimated parameters provide an important baseline to assess and predict the efficacy of interventions.

Composition of Herba Pogostemonis water extract and protection of infected mice against Salmonella Typhimurium-induced liver damage and mortality by stimulation of innate immune cells.

GC-MS analysis of a hot water extract of Herba Pogostemonis (HP) revealed the presence of 131 compounds. HP slightly inhibited Salmonella Typhimurium bacteria in culture and stimulated uptake of the bacteria into RAW 264.7 murine macrophage cells as indicated by both increased fluorescence from internalized FITC-dextran and increased colony-forming unit (CFU) counts of the lysed macrophages. Postinfection, the HP-treated cells showed lower bacterial counts than the control. HP elicited altered morphology, elevated inducible NO synthase (iNOS) mRNA, and reduced pro-inflammatory cytokine expression in macrophage cells. Salmonella induced increased expression of iNOS mRNA, cognate polypeptides, and NO. Histology of mice infected with a sublethal dose (1 × 10(4) CFU) of Salmonella showed that intraperitoneally administered HP protected against necrosis of the liver, a biomarker of in vivo salmonellosis. The lifespan of mice infected with a lethal dose (1 × 10(5) CFU) was significantly extended. These results suggest that the activity of HP against bacterial infection in mice occurs through the activation of innate immune macrophage cells. The relationship of composition of HP to bioactivity is discussed.

Development of a fermented goats' milk containing Lactobacillus rhamnosus: in vivo study of health benefits.

BACKGROUND: Lactobacillus rhamnosus CRL1505, a strain of goats' milk origin, is able to stimulate mucosal immunity and protect immunocompetent mice from intestinal and respiratory infections. RESULTS: In this work we developed and characterized a fermented goats' milk containing L. rhamnosus CRL1505, and we demonstrated in a model of immunosuppression in mice that the final dairy product preserves the immunomodulatory properties of the strain. L. rhamnosus CRL1505 survived the manufacturing process of fermented milk and maintained a viability of 10(6) cfu g(-1) during storage. The fermented goats' milk was accepted by 90.48% of the panelists and was considered as having an acid taste and pleasant aroma. We also demonstrated that the developed product, used as a supplement during the repletion of immunocompromised malnourished mice, was effective in accelerating the recovery of clinical parameters altered by malnutrition and to induce increased resistance against intestinal and respiratory infections. CONCLUSION: Goats' milk fermented with L. rhamnosus CRL1505 could be manufactured as an alternative probiotic dairy product since this new food has the ability to stimulate the common mucosal immune system and to improve defenses against respiratory and intestinal infections.

Impact of dietary components on chicken immune system and Salmonella infection.

Salmonella enterica serovars are facultative intracellular pathogens that may cause serious illness in poultry and humans. Human infection by two common serovars, Salmonella enteritidis (SE) and Salmonella typhimurium (ST) usually occurs via food-borne transmission. Consumption of raw or undercooked contaminated eggs usually causes SE infection, while ST is transmitted by contaminated chicken meat. There are several reports on dietary interventions, including fatty acid modifications, probiotic or prebiotic treatment on the immune system and/or Salmonella clearance in chickens. The aim of this review is to compile the information on the role of major dietary components on chicken immune system and Salmonella clearance. This may help design better poultry nutrition to lower Salmonella infection in chickens and, therefore, reduce human salmonellosis.

Reactive joint symptoms following an outbreak of Salmonella typhimurium phage type 135a.

OBJECTIVE: To quantify the incidence and clinical features of reactive arthritis (ReA) developing in a cohort exposed to an outbreak of Salmonella typhimurium phage type 135a, and factors affecting host susceptibility to ReA. METHODS: A screening questionnaire was mailed to 493 patients with confirmed Salmonella infection. Musculoskeletal symptoms and extraarticular manifestations of ReA were quantified. Positive responders with joint pain were invited to participate further, with a detailed history, examination, and investigations including HLA-B27 status. RESULTS: A total of 261/461 (57%) subjects responded to the questionnaire, with 23/54 adults (43%) and 41/207 children (20%) reporting joint symptoms. Although joint pains were less common in children compared with adults, those children affected usually had eye (34%) or mucocutaneous (37%) symptoms. The incidence of ReA was 14.6%, with adults more frequently affected (24%) than children (12%). This may be an underestimate given the large proportion of children involved. Associated clinical features were similar to previous studies, with the distribution of arthritis affecting the lower limbs predominantly in an oligoarticular pattern, as were the extraarticular manifestations and enthesopathy. We found 17% of subjects were HLA-B27 positive, and 55% were still symptomatic after 6 months. CONCLUSION: In an Australian cohort study of a S. typhimurium phage type 135a outbreak, joint symptoms were common, affecting 25% of subjects. The incidence of ReA of 14.6% and the clinical features were comparable to previous studies. There was a small effect of HLA-B27 status on the development of ReA.

High frequency of reactive joint symptoms after an outbreak of Salmonella enteritidis.

OBJECTIVE: To study reactive symptoms following an outbreak of Salmonella enteritidis that occurred after a dinner party held January 15, 1999, in Copenhagen, Denmark. An epidemiological study pointed toward a dish of minced raw salmon, in which one of the constituents was unboiled eggs as the likely cause of the outbreak. Remnants of this dish were not available for bacteriological exam. METHOD: All 94 guests and kitchen staff members were mailed a questionnaire about gastrointestinal, joint, and eye symptoms. Nonrespondents were contacted by telephone. Thirty-five individuals delivered blood samples for serological analysis mean 90 days (range 60-186) after the exposure. RESULTS: Answers were obtained from all participants and 91 were regarded as Salmonella exposed. Male/female ratio was 40/51, mean age 49 years. Fifty-two reported diarrhea (57%), 49 abdominal pain (54%), 33 fever (36%), and 12 vomiting (13%). Eight (9%) delivered stool samples, and all were positive for S. enteritidis. Seventeen fulfilled predefined criteria of reactive arthritis/arthralgia (ReA), and of these 13 had had enterocolitis. Joint pain from knees and ankles was most frequently reported. The mean duration of diarrhea among the patients reporting joint symptoms was 7.5 days, while in the group of patients with enterocolitis without joint symptoms it was 4.1 days (p = 0.00047). Three participants, all from the ReA group, reported ocular redness and irritation compatible with conjunctivitis. Although there was a trend to higher IgG anti-Salmonella antibody levels among the patients with ReA the difference was not significant. CONCLUSION: Reactive joint symptoms after food-borne Salmonella infection may be more frequent than previously thought. The duration of diarrhea is strongly correlated with the occurrence of joint symptoms.

Radiossensibilidade de Salmonella spp e Vibrio parahaemolyticus incorporadas artificialmente por ostras (Crassostrea brasiliana) / Salmonella spp and Vibrio parahaemolyticus radiosensibility artificially incorporated by oysters (Crassostrea brasiliana)

A irradiação é considerada um dos processos tecnológicos mais eficientes na redução de microrganismos patogênicos e deteriorantes dos alimentos. As ostras são moluscos bivalves que, frequentemente, são consumidas cruas, sendo consideradas importantes veículos de microrganismos patogênicos, devido à sua capacidade de filtração. O objetivo deste estudo foi avaliar a radiossensibilidade de Salmonella spp e Vibrio parahaemolyticus incorporadas artificialmente por ostras (Crassostrea brasiliana). As ostras foram submetidas ao tratamento de radiação gama com doses variando entre 0,5 kGy a 3,0 kGy. Os valores de D10 variaram de 0,44 kGy a 0,55 kGy para Salmonella spp e de 0,15 kGy a 0,19 kGy para Vibrio parahaemolyticus...

Interferon-gamma plays a critical role in intestinal immunity against Salmonella typhimurium infection.

Salmonella bacteria are a major cause of food-borne infectious diarrhoea and there is great interest in understanding the pathogenesis of Salmonella infection and in vaccine development. Potential vaccines include the aromatic mutants of S. typhimurium. Such non-lethal Aro mutants have also been useful for studying Salmonella infections in mouse models. Studies of systemic infection, using these Aro mutants, in both normal and cytokine gene knockout mice, indicate that interferon-gamma (IFN-gamma) plays a key role in the resolution of Salmonella infection. The present studies have investigated the outcome of oral infection in mice with attenuated Salmonella because this infection route mimics natural infection in humans. In IFN-gamma gene knockout (IFN-gamma-/-) mice, intestinal immunity was impaired and oral challenge resulted in disseminated septicaemia 2 weeks later. No dissemination of infection was seen in wild-type mice. In wild-type mice, both CD4 and CD8 cell numbers increased in the gut following Salmonella challenge, together with increased expression of major histocompatibility complex (MHC) II and vascular cell adhesion molecule-1 (VCAM-1). No such changes were seen in IFNgamma-/- mice. Following oral challenge, antilipopolysaccharide (LPS) and antiphosphoryl choline antibodies increased by more than 100-fold in both serum and faecal pellet extracts of IFNgamma-/- mice compared with wild-type mice. Our data show that IFN-gamma production is essential for resolution of enteric Salmonella infection and that antibody has little effect on this process.

Long-term prognosis of reactive salmonella arthritis.

OBJECTIVES: Reactive joint complications triggered by salmonella gastroenteritis are increasingly reported, but the outcome and long term prognosis of the patients is incompletely known. This study looked at the prognosis of salmonella arthritis in patients hospitalised in 1970-1986. METHODS: Hospital records from two hospitals in southern Finland were screened for patients with the discharge diagnosis of salmonellosis or reactive, postinfectious arthritis or Reiter's disease. For the patients with confirmed diagnosis of reactive salmonella arthritis, data about the acute disease were collected from the hospital records. A follow up study was performed. RESULTS: There were 63 patients (28 women, 35 men, mean age 36.5 years) with salmonella arthritis. Urethritis occurred in 27%, eye inflammation in 13%, and low back pain in 44% of the patients. HLA-B27 was present in 88%. More men than women were HLA-B27 positive. HLA-B27 positive patients had higher erythrocyte sedimentation rate (mean 80.9 v 46.5 mm 1st h, p = 0.0180). Also, extra-articular features and radiological sacroiliitis were seen only in HLA-B27 positive patients. A follow up study was performed on 50 patients mean 11.0 (range 5-22 years) later. Twenty patients had recovered completely. Ten patients had mild joint symptoms, 11 patients had had a new acute transient arthritis, and five acute iritis. Eight patients had developed chronic spondyloarthropathy. Radiological sacroiliitis was seen in six of 44 patients, more frequently in male than in female patients (32% v 0%; p = 0.0289). Recurrent or chronic arthritis, iritis or radiological sacroiliitis developed only in HLA-B27 positive patients. CONCLUSION: Joint symptoms are common after reactive salmonella arthritis. HLA-B27 contributes to the severity of acute disease and to the late prognosis.

Serologic testing for reactive arthritis.

The objective of the study was to determine the sensitivity and specificity of quantitative serum antibody response to Salmonella enteritidis lipopolysaccharide (LPS) as a diagnostic test for post-Salmonella reactive arthritis (ReA). In a single food-source outbreak of Salmonella enteritidis, serum was collected from dysenteric individuals with and without ReA at 6, 12, and 24 months post infection. Serum was also collected from control patients with no prior exposure to Salmonella infection. Quantitative measurements of isotypic antibodies to Salmonella enteritidis LPS were performed by an ELISA. Sensitivity and specificity of quantitative isotypic antibody levels over time were plotted on receiver operator characteristic (ROC) curves. Serum IgG and IgA anti-LPS were found to be present in higher levels in the ReA patients than in controls. Using the optimal cutoff of 0.10 selected from an ROC curve, IgG anti-LPS is 88% sensitive and 94% specific, and IgA anti-LPS is 75% sensitive and 100% specific. We conclude that IgA anti-LPS is both sensitive and specific in distinguishing prior exposure to Salmonella LPS in ReA patients compared to unexposed controls.

[The function of the humoral antiendotoxic systems in patients with acute intestinal infections]. / Sostoianie nekotorykh gumoral'nykh antiéndotoksicheskikh sistem u bol'nykh s ostrymi kishechnymi infektsiiami.

The authors propose an original approach to the problem of intoxication syndrome observed in patients with acute intestinal infections (AII). They focus on such endogenic humoral antiendotoxic systems as Re-hemotype glycolipid antibodies and high-density lipoproteins. The titers of Re-antibodies in patients with light and moderate AII at the height of intoxication remained within control levels, whereas in patients with a severe AII course the titers values remained low throughout 7 days of the follow-up. Indometac administration induced changes in the antibodies formation. Lipoprotein endotoxin-binding activity persisted at low levels to the end of 7-day follow-up. Mechanisms involved in changing functional activity of the body antiendotoxic systems are considered.

Pathogenicity of foodborne Salmonella.

Salmonella remains a leading etiological agent in bacterial foodborne diseases. Although human salmonellosis generally presents as a self-limiting episode of enterocolitis, the disease can degenerate into chronic and debilitating conditions. Antibiotic treatment of uncomplicated salmonellosis is contra-indicated because it tends to prolong the carrier state. Clinical management of systemic infections with newer drugs such as third-generation cephalosporins and quinolones is most promising, particularly in light of the increasing resistance of Salmonella to the traditional ampicillin, chloramphenicol and trimethoprim sulfamethoxazole therapeutic agents. Research into the development of effective vaccines from avirulent auxotrophic or from virulence plasmid-cured strains may ultimately facilitate the control of salmonellosis in human populations and in various agricultural sectors. Human salmonellosis reflects the outcome of a confrontation between humoral and cellular immune responses of the host, and virulence determinants of the invasive pathogen. Following an adhesion-dependent attachment of salmonellae to lumenal epithelial cells, the invasive pathogen is internalized within an epithelial cell by a receptor-mediated endocytotic process. Cytotoxin localized in the bacterial cell wall suggestively may facilitate Salmonella entry into the epithelial layer. Cytoplasmic translocation of the infected endosome to the basal epithelial membrane culminates in the release of salmonellae in the lamina propria. During this invasive process, Salmonella secretes a heat-labile enterotoxin that precipitates a net efflux of water and electrolytes into the intestinal lumen. Although non-typhoid salmonellae generally precipitate a localized inflammatory response in deeper tissues via lymphatics and capillaries, and elicit a major immune response. Current research efforts have focused on the molecular characterization and role of virulence plasmids and chromosomal genes in Salmonella pathogenicity.

HLA class I-related impairment in IL-2 production and lymphocyte response to microbial antigens in reactive arthritis.

The contribution of certain Gram-negative bacteria and host HLA class I Ag to the development of reactive arthritis (ReA)3 has strong epidemiologic support but the pathogenesis of the arthritis is unknown. An outbreak of Salmonella typhimurium afforded the opportunity to compare the immune response to the organism between those who developed ReA (ReA+, n = 11) with those who did not (ReA-, n = 12). Of the 11 ReA+ patients, 4 were B27-positive and 6 were B7-positive; of the ReA- patients none was B27- or B7-positive. The causative pathogen S. typhimurium phage 22 was used to examine PBL proliferation by [3H]thymidine incorporation. Impairment in lymphocyte response to S. typhimurium in ReA+ compared with ReA- was demonstrated by: i) lower stimulation index (1.9 +/- 0.3 for ReA+, 5.7 +/- 0.6 for ReA-, p less than 0.01); ii) lower in vitro Ig production; and iii) lower Ag-induced IL-2 production. Mixing experiments did not demonstrate a soluble suppressor factor in ReA+ supernatants. Thus, after infection with S. typhimurium there is an impairment in cellular immunity that has correlates in immunogenetic and clinical features of the infected population.

[Cellular immunity factors in salmonellosis and food toxinfections]. / Sostoianie faktorov kletochnogo immuniteta pri sal'monelleze i pishchevykh toksikoinfektsiiakh.

A complex immunological examination of 68 salmonellosis patients and 227 patients with alimentary toxinfections of unknown etiology has been made in the process of their treatment by rehydration therapy. At the acute period of the disease, irrespective of its nosologic form, cellular immunity has been suppressed. Cell-mediated immunity factors have been shown to depend on the severity of the disease.

[Antibody avidity indices of the saliva and serum antibodies in salmonellosis patients]. / Izuchenie pokazatelei avidnosti antitel sliuny i syvorotochnykh antitel u bol'nykh sal'monellezami.

The avidity characteristics of salivary and serum antibodies have been determined in 179 salmonellosis patients by means of the indirect hemagglutination inhibition test. These investigation have shown that, in contrast to serum antibodies, no changes occur in the avidity of salivary antibodies in the course of the disease. This is due to the fact that secretory antibodies belong to IgA which have no tendency to ripening. The regularities thus established reflect the role of secretory and serum antibodies in the pathogenesis of Salmonella infections.