Colonization of preterm gnotobiotic piglets with probiotic Lactobacillus rhamnosus GG and its interference with Salmonella Typhimurium.

A balanced microbiota of the gastrointestinal tract (GIT) is a prerequisite for a healthy host. The GIT microbiota in preterm infants is determined by the method of delivery and nutrition. Probiotics can improve the GIT microbiota balance and suitable animal models are required to verify their harmlessness. Preterm gnotobiotic piglets were colonized with Lactobacillus rhamnosus GG (LGG) to evaluate its safety and possible protective action against infection with an enteric pathogen, Salmonella Typhimurium (ST). Clinical signs (anorexia, somnolence, fever and diarrhea), bacterial interference and translocation, intestinal histopathology, transcriptions of claudin-1, occludin and interferon (IFN)-γ, intestinal and systemic protein levels of interleukin (IL)-8, IL-12/23 p40 and IFN-γ were compared among (i) germ-free, (ii) LGG-colonized, (iii) ST-infected and (iv) LGG-colonized and subsequently ST-infected piglets for 24 h. Both LGG and ST-colonized the GIT; LGG translocated in some cases into mesenteric lymph nodes and the spleen but did not cause bacteremia and clinical changes. ST caused clinical signs of gastroenteritis, translocated into mesenteric lymph nodes, the spleen, liver and blood, increased claudin-1 and IFN-γ transcriptions, but decreased occludin transcription and increased local and systemic levels of IL-8 and IL-12/23 p40. Previous colonization with LGG reduced ST colonization in the jejunum and translocation into the liver, spleen and blood. It partially ameliorated histopathological changes in the intestine, reduced IL-8 levels in the jejunum and plasma and IL-12/23 p40 in the jejunum. The preterm gnotobiotic piglet model of the vulnerable preterm immunocompromised infant is useful to verify the safety of probiotics and evaluate their protective effect.

Interference of Bifidobacterium choerinum or Escherichia coli Nissle 1917 with Salmonella Typhimurium in gnotobiotic piglets correlates with cytokine patterns in blood and intestine.

The colonization, translocation and protective effect of two intestinal bacteria - PR4 (pig commensal strain of Bifidobacterium choerinum) or EcN (probiotic Escherichia coli strain Nissle 1917) - against subsequent infection with a virulent LT2 strain of Salmonella enterica serovar Typhimurium were studied in gnotobiotic pigs after oral association. The clinical state of experimental animals correlated with bacterial translocation and levels of inflammatory cytokines [a chemokine, interleukin (IL)-8, a proinflammatory cytokine, tumour necrosis factor (TNF)-α and an anti-inflammatory cytokine, IL-10] in plasma and intestinal lavages. Gnotobiotic pigs orally mono-associated with either PR4 or EcN thrived, and bacteria were not found in their blood. No significant inflammatory cytokine response was observed. Mono-association with Salmonella caused devastating septicaemia characterized by high levels of IL-10 and TNF-α in plasma and TNF-α in the intestine. Di-associated gnotobiotic pigs were given PR4 or EcN for 24 h. Subsequently, they were infected orally with Salmonella and euthanized 24 h later. Pigs associated with bifidobacteria before Salmonella infection suffered from severe systemic infection and mounted similar cytokine responses as pigs infected with Salmonella alone. In contrast, EcN interfered with translocation of Salmonella into mesenteric lymph nodes and systemic circulation. Pigs pre-associated with EcN thrived and their clinical condition correlated with the absence of IL-10 in their plasma and a decrease of TNF-α in plasma and ileum.

Innate immune response in the gut against Salmonella - review.

Innate immunity is shaped by a complex of redundant and pleiotropic factors that ensure recognition, alert and suppression of pathogens. Innate immune responses in the gut are complicated by the requirement of parallel tolerance to commensal microflora predominating in cell numbers and species. In normal individuals, the intestinal mucosa together with relevant lymph nodes represents a robust barrier against systemic spread of non-typhoid Salmonella. Contemporary insights into these defense mechanisms are reviewed.

Cytokine response to Escherichia coli in gnotobiotic pigs.

One-week-old-germ-free pigs were inoculated with 10(8) CFU of E.coli bacteria-either commensal 086 strain or virulent 055 strain for 1 d. Bacteria were counted in the small intestine, mesenteric lymph nodes, blood and lungs. The O55 strain reached higher levels in circulation and lungs. IL-8, IL-10 and TNF-alpha concentrations were determined by ELISA in plasma and intestinal washes . No difference in cytokine levels was found between control germ-free pigs and their counterparts associated with commensal O86 strain in spite of its high concentration in the gut and circulation.

Attenuated aroA Salmonella enterica serovar Typhimurium does not induce inflammatory response and early protection of gnotobiotic pigs against parental virulent LT2 strain.

Cytokine and inflammatory response against virulent LT2 strain and its attenuated aroA deletion mutant of Salmonella enterica serovar Typhimurium were compared in gnotobiotic pigs. Contrary to the parental strain, the auxotrofic mutant did not induce IL-1beta, IL-18, TNF-alpha, and IFN-gamma in the ileum and plasma 24h after the infection, did not cause pathological changes in ileal epithelium and mesenteric lymph nodes or immunoreactivity of gp91 phox and peroxynitrite and was not immunostained for GroEL stress protein. The absence of induction of proinflammatory cytokines may be a reason why aroA mutant was unable to elicit any inflammatory response and protect pigs against challenge with virulent LT2 strain administered 24h later.

Expression of inflammatory markers in pig amnion after intraamniotic infection with nonpathogenic or enteropathogenic Escherichia coli.

The pig amnion was in vivo intraamniotically infected with E. coli for 10 h at 80-85 d of gestation either with the nonpathogenic O86 strain or enteropathogenic O55 strain. TNF-alpha, IL-10, IL-1beta and IFN-gamma were determined in amniotic fluids by ELISA, the expression of cytokines and some other inflammatory markers was determined by immunohistochemistry. Intraamniotic infection induced high levels of TNF-alpha in amniotic fluids which correlated with bacterial virulence whereas IL-10 was induced only by O86. The IL-1beta level did not increase significantly and was expressed in all infected membranes. IFN-gamma was negligible or absent. TNF-alpha, IL-12p40, calprotectin, HSP65 and gp91phox were found by immunohistochemistry only in amnion membranes infected with the enteropathogenic strain 055.

Risks of different self-approach to health in an industrial city population.

INTRODUCTION: The results of a number of epidemiological studies found relationship between low socio-economic status (SES) and worse health status. OBJECTIVES: The goal of the study is the evaluation of the health status in inhabitants of an industrial city, their different approach to health and preventive measures in relation with lifestyle factors and socio-economic status (SES). METHODS: A structured questionnaire was elaborated, distributed to a random sample of some 3,000 aged 25-70 and collected by postal delivery. RESULTS: A total of 634 completed questionnaires were analysed. The subjective health status was reported as good in 75% of respondents; it was positively correlated with education (p < 0.001), negatively with age; worse subjective health was significantly more reported in people economically non-active (p < 0.001). More than a half of the study sample suffered a serious chronic disease, significantly more in men (p < 0.01), in the less educated (p < 0.001), and the prevalence increased with age (p < 0.001). The health status improved with the level of education and economic situation and worsened with age. A better health status was identified in women and economically active people. Women more frequently took care about their limit of weight (mostly for esthetical reasons), use more medicaments than men, they were more interested in protective health information (p < 0.01). The use of medicaments was reported significantly less in economically active respondents than in non-active. About half of respondents regularly underwent preventive medical examinations at their practitioner (significantly more men--p < 0.05, economically active people--p < 0.001, and married--p < 0.01). Diseased respondents in the sample were significantly more discontent, more often in a lack of psychological well-being and more passive in comparison with the group of healthy respondents. Contrary to prediction the behaviour of ill individuals was less risky as compared with healthy people. CONCLUSIONS: A significant relationship between the groups of healthy and ill respondents was found in respect to sex, age and all the SES factors (education, economic activity and economical situation of family) except for marital status and density of housing. The health status improved with the level of education and economic situation and worsened with age. A better health status was identified in women and economically active people.

Systemic and local cytokine response of young piglets to oral infection with Salmonella enterica serotype Typhimurium.

One-week-old breast-fed miniature piglets were orally infected either with virulent LT2 strain or with a non-virulent SF1591 rough mutant of Salmonella Typhimurium for 1 d. Both microorganisms were cultivated from mesenteric lymph nodes but not from the blood of infected piglets. Interleukins (IL) 1 beta, 8, 18, tumor necrosis factor alpha (TNF-alpha) and interferon gamma (IFN-gamma) were quantified by ELISA in plasma and washes of a terminal part of the small bowel. In plasma, cytokines were mostly missing in non-infected piglets and either missing or low in infected piglets. In the gut of non-infected piglets, IL-1 beta, IL-8 and IL-18 were detected whereas TNF-alpha and IFN-gamma were mostly missing. IFN-gamma levels highly increased (p < 0.05) after infection with nonvirulent salmonellae. The variability of cytokine levels in the gut of suckling piglets is discussed.

Escherichia coli administered into pig amniotic cavity appear in fetal airways and attract macrophages into fetal lungs.

Escherichia coli (2 x 10(4) bacteria) of the non-pathogenic O86 strain or enteropathogenic O55 strain were administered into the pig amniotic cavity at 79 to 86 days of gestation for six or ten hours. Translocation of bacteria into fetal lungs was confirmed by cultivation as well as by light and electron microscopy. Infection caused an influx of macrophages that were immunostained in cryostat sections by monoclonal antibody recognizing calprotectin.