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PubMedDate not supplied

Microbiological status of cosmonauts during orbital spaceflights on Salyut and Mir orbital stations.

The main feature of the human-microorganism eco-system forming in the environment of manned space vehicles is the periodic accumulation of the potential for pathogenicity. This process is characterized by the activation of opportunistic pathogens, representatives of which grow in large number within the system, settle in various niches, and demonstrate expansion, intruding into microbiocenoses of open biotopes of humans who, until contamination, have been clean of these microorganisms. Clones (similar to hospital strains) arising out of these populations exhibit the ability to spread "epidemically" within isolated teams.

Aerospace Medicine↗
PubMed2001

Comparison of the sialic acid binding activity of transmissible gastroenteritis coronavirus and E. coli K99.

Transmissible gastroenteritis coronavirus (TGEV) and Escherichia coli K99 are both enteropathogenic for pigs with infections being most severe in neonate animals. For both microorganisms, a sialic acid binding activity has been shown to be an essential pathogenicity factor. Here we demonstrate with haemagglutination and haemagglutination-inhibition assays that TGEV and E. coli K99 differ in their sialic acid binding activities with respect to the type and amount of sialic acid residues required on the erythrocytes surface as well as with respect to the type of sialoglycoconjugate preferentially recognized. Intestinal mucins from piglets (12-14 days old) and adult animals were shown to inhibit TGEV to the same extent. From our results we conclude that E. coli K99 and TGEV interact with different sialoglycoconjugates to establish an intestinal infection. The implications for the enteropathogenicity of TGEV are discussed.

Age Factors↗
PubMed1994

Bacteriophages presence in human faeces of healthy subjects and patients with gastrointestinal disturbances.

The variation of the content of enteric bacteria and their bacteriophages in faeces from the different types of diarrhoeal processes has been studied. A total of 122 samples of human faeces from both healthy individuals and patients with diarrhoeal diseases of functional or infectious origin were tested. Detection rates for all microbial parameters tested decreased in the faeces of individuals with functional gastrointestinal disturbances. On the contrary, no significant differences of the microbial detection frequency was observed in faeces containing pathogenic microorganisms compared to faeces of healthy subjects. Human faeces were a poor source of F-specific, Salmonella, and Bacteroides bacteriophages, whereas specific Escherichia coli phages were isolated in most samples tested. Coliphage concentrations in faeces of healthy individuals were not directly correlated with levels of faecal coliforms. On the basis of their high correlation, faecal streptococci and coliphages were the most adequate indicators of the intestinal ecosystem variations in subjects with diarrhoeal processes.

Bacteriophages↗
PubMed2003

The effect of a probiotic Enterococcus faecium product in diets of healthy dogs on bacteriological counts of Salmonella spp., Campylobacter spp. and Clostridium spp. in faeces.

An experiment was conducted to determine the effects of a probiotic on selected faecal bacteria of healthy dogs under different feed and environmental conditions. For the study 12 dogs kept in households were used for an 18-day supplementation with a patented commercially available strain of E. faecium NCIB 10415 (Enteroferm). In order to minimize losses the probiotic product was orally applicated once a day before meals at a dose of 2 g per dog (9.2 x 10(9) CFU). The faeces were collected before the beginning of the supplementation and at the end of the 18-day application period. In order to exclude contamination, all faeces were taken rectally. Before and at the end of the experimental period total Salmonella spp., Campylobacter spp. and Clostridium spp. counts were determined in fresh faeces using selective media. It was demonstrated that the 18-day application of the probiotic E. faecium product induced modifications on the gastrointestinal microflora in all dogs. While Salmonella spp. and Campylobacter spp. counts were in majority of the dogs higher than before the application. Clostridium spp. counts were significantly reduced in 10 of 12 dogs. According to the guidelines for the evaluation of the efficiency of microorganisms in dogs a relevant efficacy effect was supported by this data. However, a beneficial effect of the probiotic product on healthy dogs remains questionable.

Administration, Oral↗
PubMed1980

Determination of vitamin K in foods: a review.

Vitamin K receives less dietary attention and fewer assays in foods than other fat-soluble vitamins. It is widely distributed in foods, usually at low concentrations. The human requirement is small. Intestinal bacteria synthesize vitamin K, which presumably helps provide the metabolic requirements for vitamin K. An RDA for vitamin K has not been published, but infants fed milk-substitute formulas risk vitamin K deficiency and it is recommended that those formulas contain supplemental vitamin K. Vitamin K in foods includes phylloquinone (K1) found in plants and several menaquinones (K2) found in animals and synthesized by microorganisms. Many vitamin K methods were developed primarily to identify forms present and determine their relative bioactivities. Until recently bioassays with chicks were the only practical methods to determine vitamin K content of foods. Various physicochemical methods have been developed to determine vitamins K in pure solutions, concentrates, and pharmaceuticals. Because of low concentrations of vitamin K in foods and the extensive purifications of extracts required, there has been only limited use of physicochemical methods, such as column chromatography, thin-layer chromatography, and high-performance liquid chromatography, with foods; the latter method perhaps offers the greatest possibilities for further development.

Animals↗
PubMed1993

Impact of the fluoroquinolones on gastrointestinal flora.

A number of studies have been performed to evaluate the effect of the fluoroquinolones on gastrointestinal flora. The fluoroquinolones have only slight or no effect on the oropharyngeal flora, except when Neisseria, Haemophilus or Branhamella spp. are present. Studies have consistently shown that Gram-negative facultative bacteria of the lower intestinal flora are strongly suppressed during administration of these agents. Total faecal anaerobes are generally unchanged. The effect of the fluoroquinolones on Gram-positive bacteria is more variable with mild to moderate suppression reported with some agents. In view of the high faecal concentrations of the fluoroquinolones, the general lack of effect on anaerobes is surprising; it may be attributable to the large number of microorganisms found in faeces and faecal binding of the fluoroquinolones. Several recent studies suggest that the effects of some fluoroquinolones on faecal anaerobes and Gram-positive cocci may be more profound in certain patient populations such as bone marrow transplant recipients and patients undergoing gastrointestinal surgery. Colonisation with yeasts and the emergence of resistant bacterial strains have been reported during or after fluoroquinolone administration in some studies. Future studies will need to investigate the effect of the newer agents with greater activity against anaerobes and Gram-positive cocci on the gastrointestinal flora and to continue surveillance for resistant organisms.

Anti-Infective Agents↗
PubMed1991

[Some clinical aspects of therapeutic administration of iron preparations in childhood: iron and infections].

Iron is one of the most important metals for living organisms. There are many different reasons for an iron deficiency, which can lead to an iron deficiency anemia and can be treated by iron-containing drugs. But there are also some reasons leading to an iron overload, which can impair the defense against bacterial infections. An anemia in the course of an infection is usually not a result of iron deficiency but a physiological reaction against the invading microorganisms. A treatment with iron-containing drugs is only indicated in the case of an undoubtedly proven iron deficiency.

Anemia, Hypochromic↗
PubMed2005

An immunomodulatory molecule of symbiotic bacteria directs maturation of the host immune system.

The mammalian gastrointestinal tract harbors a complex ecosystem consisting of countless bacteria in homeostasis with the host immune system. Shaped by evolution, this partnership has potential for symbiotic benefit. However, the identities of bacterial molecules mediating symbiosis remain undefined. Here we show that, during colonization of animals with the ubiquitous gut microorganism Bacteroides fragilis, a bacterial polysaccharide (PSA) directs the cellular and physical maturation of the developing immune system. Comparison with germ-free animals reveals that the immunomodulatory activities of PSA during B. fragilis colonization include correcting systemic T cell deficiencies and T(H)1/T(H)2 imbalances and directing lymphoid organogenesis. A PSA mutant of B. fragilis does not restore these immunologic functions. PSA presented by intestinal dendritic cells activates CD4+ T cells and elicits appropriate cytokine production. These findings provide a molecular basis for host-bacterial symbiosis and reveal the archetypal molecule of commensal bacteria that mediates development of the host immune system.

Animals↗
PubMed2002

A group-specific PCR assay for the detection of Helicobacteraceae in human gut.

BACKGROUND: Enterohepatic Helicobacter species are emerging pathogens, which are increasingly isolated from humans with enteric diseases. Nevertheless, current methods to detect Helicobacteraceae in the human gut have significant limitations. METHODS: Based on 16S-rRNA gene alignments and computer aided primer analysis a set of group-specific PCR primers was designed. The evaluation of the PCR assay was performed using 36 ATCC reference strains and intestinal biopsies from 10 patients with defined gastric Helicobacter pylori status. The amplification products derived from clinical samples were cloned and subsequently analyzed by DNA sequencing. Sensitivity of the PCR-assay was determined by spiking previously negative tested samples with decreasing amounts of Helicobacter DNA. RESULTS: The analysis of the ATCC reference strains revealed amplification products in all 14 Helicobacter strains and Wolinella succinogenes, 21 other microorganisms representing negative controls did not produce PCR fragments. Four out of the 10 patient-derived samples were positive. Three of them represented H. pylori-derived DNA confirming the gastric H. pylori infection in these patients. In the fourth patient, who was suffering from Crohn's disease, H. pullorum was identified. The sensitivity of the PCR assay was 0.1 pg of Helicobacter-derived DNA representing about 40 bacteria. CONCLUSION: The novel PCR assay described here is an important new tool in rapid and sensitive assessment for the presence of Helicobacteraceae in human gut.

DNA Primers↗
PubMed2004

Screening of dairy yeast strains for probiotic applications.

To evaluate the potential of yeasts of dairy origin as probiotics, we tested 8 species including Candida humilis, Debaryomyces hansenii, Debaryomyces occidentalis, Kluyveromyces lactis, Kluyveromyces lodderae, Kluyveromyces marxianus, Saccharomyces cerevisiae, and Yarrowia lipolytica, isolated from commercial blue cheese and kefir. Strains were randomly selected from each species and tested for their ability to adhere to human enterocyte-like Caco-2 cells in culture. Among the 8 species, K. lactis showed higher adhesive ability than K. marxianus, K. lodderae, and D. hansenii. The other 4 species were poorly adhesive. All species other than K. marxianus and C. humilis were resistant to acidic conditions. In the presence of bile acid, growth inhibition was undetectable when incubation was carried out at 27 degrees C; however, it was evident for C. humilis and a strain of D. occidentalis when incubated at 37 degrees C. Moreover, the influence of proteinase treatment of living cells of K. lactis and K. lodderae on their adhesion to Caco-2 cells was evaluated. Although a slight reduction was recognized when K. lactis was treated with proteinase K, the influence of intestinal protease treatments of pepsin followed by trypsin was negligible. These results indicated that a proteinaceous factor was unlikely to be involved in adhesion of K. lactis and K. lodderae to Caco-2 cells. No stimulation of IL-8 synthesis by Caco-2 cells was recognized in the presence of K. lactis. In conclusion, K. lactis was the most attractive to continue study for use as probiotic microorganisms.

Animals↗
PubMed1990

Pathogenesis of colonization and infection in a neonatal surgical unit.

Nosocomial infection with aerobic Gram-negative bacilli is a major cause of morbidity and mortality in neonates. Few prospective studies have been undertaken in neonatal surgical units to investigate colonization and infection rates and the pathogenesis of infection. We prospectively studied 40 infants admitted to a neonatal surgical unit. Ninety-eight percent became colonized in throat/intestine with aerobic Gram-negative bacilli. Thirty-five percent developed infections, with wound and surface infections predominant (61%). Ninety-one percent of infections were caused by Gram-negative bacilli or yeasts. Severe infections (septicemia, pneumonia, meningitis) occurred in 13% of infants. The mortality rate was 5%. In all infections, the pathogenesis was found to be endogenous, and in most, three stages were distinguishable. Neonates always acquired potentially pathogenic organisms in throat/intestine (stage 1) before colonization (stage 2) and infection (stage 3) of other systems occurred. Reduction of digestive tract colonization by these potentially pathogenic microorganisms by means of successful selective decontamination may therefore reduce subsequent infection.

Bacterial Infections↗
PubMedDate not supplied

[Bacteriology of abdominal pus in 43 cases of acute appendicitis and appendiceal abscess at the Ivrea-Castellamonte Hospital, isolation of aerobic and anaerobic bacteria and drug sensitivity].

A retrospective study on the microbiology of abdominal pus from acute appendicitis or peritonitis was carried out by the authors. A total of 45 specimens were examined, 38 of them (84.4%) where found to be positive, of which 29 (76.3%) were polymicrobial and 9 (23.7%) were monomicrobial. The most represented species were Escherichia coli (28.4%), Bacteroides fragilis (7.8%), Streptococcus milleri (7.8%), Bacteroides oralis (3.9%) and Pseudomonas aeruginosa (3.9%). The polymicrobial associations more represented include Bacteroidaceae, Enterobacteriaceae and streptococcus genus. The most active drugs in vitro were found to be Piperacillin and Chloramphenicol, Cephalosporin (cefotaxime, ceftriaxone and cefoxitin) showed a good capability of being active against isolated microorganisms although they were less effective when used against anaerobic microorganisms then aerobic ones. On the contrary, Rifampicin, Metronidazole and Clindamycin were found to be quite effective against the anaerobes.

Abscess↗
PubMed1998

Autoimmunity, immunodeficiency and mucosal infections: chronic intestinal inflammation as a sensitive indicator of immunoregulatory defects in response to normal luminal microflora.

Despite the fact that target antigens and the genetic basis of several autoimmune diseases are now better understood, the initial events leading to a loss of tolerance towards self-components remain unknown. One of the most attractive explanations for autoimmune phenomena involves various infections as possible natural events capable of initiating the process in genetically predisposed individuals. The most accepted explanation of how infection causes autoimmunity is based on the concept of "molecular mimicry" (similarity between the epitopes of an autoantigen and the epitopes in the environmental antigen). Infectious stimuli may also participate in the development of autoimmunity by inducing an increased expression of stress proteins (hsp), chaperones and transplantation antigens, which leads to abnormal processing and presentation of self antigens. Superantigens are considered to be one of the most effective bacterial components to induce inflammatory reactions and to take part in the development and course of autoimmune mechanisms. It has long been known that defects in the host defense mechanism render the individual susceptible to infections caused by certain microorganisms. Impaired exclusion of microbial antigens can lead to chronic immunological activation which can affect the tolerance to self components. Defects in certain components of the immune system are associated with a higher risk of a development of autoimmune disease. The use of animal models for the studies of human diseases with immunological pathogenesis has provided new insights into the influence of immunoregulatory factors and the lymphocyte subsets involved in the development of disease. One of the most striking conclusion arising from work with genetically engineered immunodeficient mouse models is the existence of a high level of redundancy of the components of the immune system. However, when genes encoding molecules involved in T cell immunoregulatory functions are deleted, spontaneous chronic inflammation of the gut mucosa (similar to human inflammatory bowel disease) develops. Surprisingly, when such immunocompromised animals were placed into germfree environment, intestinal inflammation did not develop. Impairment of the mucosal immune response to the normal bacterial flora has been proposed to play a crucial role in the pathogenesis of chronic intestinal inflammation. The use of immunodeficient models colonized with defined microflora for the analysis of immune reactivity will shed light on the mode of action of different immunologically important molecules responsible for the delicate balance between luminal commensals, nonspecific and specific components of the mucosal immune system.

Animals↗
PubMed2006

Metagenomics: the role of the microbiome in cardiovascular diseases.

PURPOSE OF REVIEW: The human oral and intestinal microbiota interact with the host through poorly understood metabolic pathways. Investigation of such complex ecosystems and interactions has been difficult. In this paper, we assess the current evidence supporting the role of the microbiota as a significant determinant of cardiovascular disease risk. RECENT FINDINGS: The link between oral disease and cardiovascular disease was established about 15 years ago. The accumulated evidence supports, but does not prove a causal association between periodontal infection and cardiovascular disease and suggests some physiologically obvious connections between these pathologies, namely, inflammatory and immune responses, and hemostasis. Moreover, some studies have observed higher concentrations of total and LDL-cholesterol and triglycerides and lower concentrations of HDL-cholesterol in individuals with periodontitis before periodontal treatment. Likewise, recent reports suggest the influence of the gut microbiome in the risk of common age-related diseases such as cancer and potentially cardiovascular disease through modification of classical risk factors such as obesity, insulin resistance and plasma lipids. SUMMARY: The recognition that microorganisms may play an even more important role in maintaining human health than in generating diseases places metagenomics as one of the most relevant areas of future research. The knowledge of the hundreds of genomes that we host and their interaction with our own genome shall provide a much more complete understanding of the individual nutritional needs and may be an obligated part of future personalized healthcare approaches.

Cardiovascular Diseases↗
PubMed1988

[The significance of fiber for swine nutrition with special reference to HCl-treated straw meal].

The term crude fibre according to the Weend analysis method is insufficient for the nutrition of pigs as it does not comprise pentosanes. During the cooking process they are hydrolysed with diluted acid and do not remain in the crude fibre fraction. As stomach HCl can also hydrolyse pentosane (probably in shorter chains), they are well utilized by the microorganisms in the digestive tract (production of volatile fatty acids). Cereal bran and straw meal contain a particularly high quota of pentosanes in their fibre. The fibre fraction of the plant materials fulfills several functions in the digestive tract: absorption of water at the hydroxyl groups of cellulose and hemicellulose (higher absorption capacity of the digesta and improved passage rate); formation of volatile fatty acids (VFA) by the intestinal bacteria due to the fermentation of pentosanes and cellulose (positive influence of VFA on the mucosa of the intestinal walls); absorption of protein decomposition products (including amines) in the cavities of native plant scaffold substances and absorption of aromatic toxic substances (tyramine, phenol, cresol, tryptamine, indole, skatole, histamine etc.) in the lignin by means of VAN DER WAALS forces and further transport of the toxic substances until they are excreted in faeces. HCl treated straw meal is either a mixture of HCl and straw meal at a ratio of 20 kg half concentrated HCl (17% HCl) and 100 kg straw meal with or without heat treatment (steaming for ca. 30 min). The unsteamed product is called HCl straw meal, the steamed product partly hydrolysed straw meal (PHS). 5-10% HCl--straw meal was successfully used in the rearing of piglets after weaning. In addition to the above-mentioned significance of the scaffold substances for the digestive tract, the HCl improved the pH status in the stomach and the upper region of the small intestine. PHS neutralized with CaCO3 (up to pH 6-7) is suitable for breeding sows, boars, young sows and fattening pigs. PSM contains 25% reducing substances (reducing sugars) in the DM and serves the intestinal bacteria in the production of VFA. In the feeding of breeding sows in the phase of gestation 20-30% of the DM intake could be covered by PSM. The number of viable and rearable piglets was significantly higher than after conventional feeding. HCl--SM and PSM also provide advantages with regard to hygiene. They are not congested by fungi and can well be stored without neutralization.

Animal Feed↗
PubMedDate not supplied

[Clostridium difficile as an inducer of inflammatory diarrhea].

Clostridium difficile has been pointed out as an important agent of diarrheal diseases associated with antibiotic use. However, due to its complexity, the physiopathology of these diseases is only partially elucidated, although a series of scientific works has demonstrated the importance of toxins A and B in the pathogenesis of the inflammatory diarrhea induced by this microorganism. The inflammatory mechanisms involved in the biological activities of these toxins are complex. There are some studies demonstrating that toxin B has no enterotoxic activity in vivo. However, this toxin causes dose-dependent eletrophysiologic and morphologic modifications of human colonic mucosa in vitro. In addition, toxin B stimulates the synthesis of potent inflammatory mediators by monocytes and macrophages. The effects provoked by toxin A on the intestinal mucosa are quite evident and are characterized by intense fluid secretion and by inflammatory cell accumulation, such as macrophages, mast cells, lymphocytes and neutrophils, with the consequent release of mediators such as prostaglandins, leukotrienes, platelet activating factor, nitric oxide and cytokines.

Animals↗
PubMed1994

Small intestinal HIV-associated enteropathy: evidence for panintestinal enterocyte dysfunction.

To characterize the absorptive defect of AIDS enteropathy, we have used a D-xylose kinetic model of proximal absorption and correlated these findings with Schilling's test for cobalamin absorption, measurements of distal intestinal function. In addition, we compared findings between duodenal and jejunal biopsy and aspirations to determine whether additional information can be obtained by sampling the more distal site. Twelve consecutive patients with AIDS who had 3 to 14 loose bowel movements per day and two stool study results negative for pathogens, were admitted for study. D-xylose testing with oral and intravenous doses was used to determine the rate constants for D-xylose absorption, Ka, and the rate constant for nonabsorptive loss, Ko. Duodenal and distal duodenal-jejunal endoscopic aspirations and biopsies were also performed. Minimal histologic abnormalities were seen in either the proximal or distal biopsy sites. There were no significant differences in mucosal blunting, abnormalities of the enterocytes, lamina propria infiltrate, or presence of microorganisms between duodenal and distal duodenal-jejunal sites. Seventy-five percent had no identifiable pathogens. Ten of 12 patients had diminished Ka, elevated Ko, or both. Two patients had a normal Ka and Ko. Eight of 10 had an abnormal Schilling's test result. Percentage weight loss correlated negatively with Ka (r = 0.75; p = 0.013) and with Schilling's test results (r = 0.65; p = 0.043. Ka correlated positively with Schilling's test results (r = 0.82; p = 0.004).(ABSTRACT TRUNCATED AT 250 WORDS)

Absorption↗
PubMed1998

[Abscess of the psoas muscle: analysis of 11 cases and review of the literature].

BACKGROUND: Abscess of the psoas muscle (AP) is an infrequent disease of difficult diagnosis, developing spontaneously (primary AP) or by extension of a subjacent infection (secondary AP). In recent years changes have been observed in its etiology, advances in its diagnosis and modifications in the treatment schedules. METHODS: The cases of AP diagnosed from 1983-1996 were retrospectively studied. RESULTS: The cases included 11 AP, 5 (45%) primary and 6 (55%) secondary, of which the source of origin were: spondylitis in four, sacroiliac arthritis in one and intestinal in another. The clinical presentation was characterized by its prolonged course (evolution of symptoms greater than 30 days in 64% of the cases), with the most frequent symptoms being flank/abdominal pain (82%) and hip/inguinal pain (45%), with fever being presented in only 36%. The diagnostic profitability of echography and computerized tomography (CT) were 57% (4/7) and 91% (10/11), respectively. One case was diagnosed with magnetic resonance. The causal microorganisms were: Mycobacterium tuberculosis (36% of the cases), Staphylococcus aureus (18%), polymicrobian flora (18%) and Salmonella enteritidis, Streptococcus intermedius and Escherichia coli in 9% each. Eight cases (73%) underwent percutaneous (5 cases) and surgical (3 cases) drainage, with the evolution being favorable in 10 (91%) and death in one despite adequate medicosurgical treatment. CONCLUSIONS: The clinical presentation of AP is often unspecific, thereby delaying its diagnosis, and thus, CT is the procedure of choice. The tuberculous etiology continues to be frequent in our environment. Ultrasonographic or CT guided percutaneous drainage is a valid therapeutic alternative versus surgery.

Adolescent↗