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PubMed1978

[Stable paper indicator systems for rapid identification of microorganisms].

The authors prepared under experimental-industrial conditions paper indicator systems for the express identification of microbes, including carbohydrate discs (by the method of Nikitin et al.), and newly worked out types for the determination of the activity of cytochromoxidase, urease, indol formation, and indicator amino acid decarboxylases (lysin, ornithin, arginine). The use of paper indicator discs proved to be expedient for rationalization of laboratory diagnosis of bacterial intestinal infections.

Bacteria↗
PubMedDate not supplied

The intestinal immune system and its relation to disease.

The essential protective structure against the heavy enteric antigenic burden, the gut mucosa, prevents penetration of noxious agents, but allows a minimal exchange of large molecules and particles between the gut lumen and the 'milieu intérieur' of the body. M cells in the follicle-associated epithelium of the gut, ideal gateways for the presentation of enteric antigens to the cells of the gut-associated lymphoid tissue (GALT), are also weak links in the mucosal barrier, and may provide access for various microorganisms. The afferent limb of the GALT consists of distinct aggregates of lymphoid cells located in Peyer's patches, the vermiform appendix and the solitary lymphatic follicles, and of the mesenteric lymph nodes. The efferent limb subsumes the diffusely scattered mucosal leukocytes, mainly lymphocytes and plasma cells. Intraepithelial and mucosal T lymphocytes are instrumental in launching local immune responses, producing lymphokines, and in the specific lysis of virally infected cells. Antigenic stimulation of the GALT results in local secretion of antibodies, or in suppression of systemic immunologic responses to ingested antigens ('oral tolerance'). Poorly controlled mucosal immune responses result in organ-specific diseases. Extranodal lymphomas that mimic structures of the GALT may arise on a background of inflammatory or immunologic (autoimmune) disorders.

Appendix↗
PubMed1999

Colonization and clearance of environmental microbial agents upon intranasal exposure of strain C3H/HeJ mice.

Environmental dissemination of biotechnology agents is becoming a common practice. Most applications use historically innocuous species; however, potential health effects of individual products are not scrutinized unless they contain genetically engineered microorganisms. In order to investigate possible health concerns, four surrogate microbial agents were studied in vivo. Male C3H/HeJ (endotoxin-resistant) mice were administered intranasally (i.n.) with approximately 10(7) Pseudomonas aureofaciens, Burkholderia cepacia, P. fluorescens, or P. putida. To determine clearance of the dosed bacterial strains, lungs, small intestine, large intestine, cecum, mesenteric lymph nodes (MLN), spleen, and liver were homogenized individually, plated, and dilutions inoculated onto selective media. Pseudomonas fluorescens and P. putida were eliminated from the lungs by 2 d posttreatment, and P. aureofaciens was not detected in the lungs by 5 d posttreatment. Burkholderia cepacia was reisolated from the lungs and cecum for the experimental duration (14 d). Translocation to extraintestinal sites (MLN, spleen, and liver) also occurred. Burkholderia cepacia was recovered from the MLN for 10 d after treatment of mice. Pulmonary exposure to several bacterial strains resulted in unexpected mortality. Pseudomonas aureofaciens was lethal at the lowest dose (8.26 x 10(6) CFU/ mouse), while P. fluorescens and B. cepacia were fatal at higher doses (6.15 x 10(8) CFU/mouse and 1.34 x 10(8) CFU/mouse, respectively). By using the model described in this study, human safety issues can be more easily addressed and evaluated.

Administration, Intranasal↗
PubMed1988

Microbial invasion: a covert activity?

In contrast to nonpathogenic microorganisms that exist happily in biofilms on various organic and inorganic surfaces, many pathogenic microbes have the additional ability to invade host tissues by inducing their own endocytosis and transport across normally protective barriers. This phenomenon, designated "parasite-directed endocytosis," has been observed with a variety of surfaces (intestinal, genital, nasopharyngeal, and tracheal epithelium) as well as in endothelial cells. The mechanisms involved in invasion may involve a single factor as described for some species of Yersinia, or may require multiple factors as observed in Shigellae. For the majority of pathogens, the molecular mechanisms of invasion are not well understood (e.g., Neisseria gonorrhoeae). Because parasite-directed endocytosis is reminiscent of receptor-mediated endocytosis, it is quite possible that some pathogens engage in biologic mimicry by producing a molecule that resembles a natural host ligand, for which there is a host cell receptor. Such a masquerade may allow some microbes to enter the host's inner sanctum covertly in a manner analogous to the Trojan horse, rather than overtly by destroying the mucosa and entering host tissues directly. Whereas this hypothesis is speculative at present, bacteria that produce molecules resembling insulin, calmodulin, and chorionic gonadotropin have been described.

Animals↗
PubMedDate not supplied

[An analysis of the physiological activity of organic compounds of ozokerite obtained by its biotransformation by naftusia water microorganisms].

A possibility to obtain physiologically active substances by means of biotransformation of natural carbohydrate raw material-ozokerite using the saprophite groups of microorganisms isolated from the medicinal water naftusia has been studied. It is shown that microorganisms metabolise ozokerite with following formation of the whole spectrum of water-soluble substances, activators and inhibitors of Na, K-ATPase, cholopoiesis stimulators being found among them. A conclusion has been made that using microorganisms inhabiting water naftusia can obtain from ozokerite organic substances conditioning physiologic activity of this medicinal water.

Animals↗
PubMed1997

Effect of preventive administration of a nonpathogenic Escherichia coli strain on the colonization of the intestine with microbial pathogens in newborn infants.

In a randomized, double-blind study, 27 healthy newborn infants were colonized with the nonpathogenic Escherichia coli strain Nissle 1917 (E. coli DSM 6601, Mutaflor) during the first 5 days of life by daily oral inoculation of 1 ml of a suspension with 10(8) living cells. A second group of 27 newborns, used as controls, received a placebo suspension (1 ml of phosphate-buffered saline) instead. Stool samples were taken on days 1, 2, 3, 5, and 21, and 6 months after birth. All samples were examined for the presence of the nonpathogenic E. coli strain and of pathogenic and potentially pathogenic microorganisms. The administered E: coli strain was detected in the stools of the colonized newborns from day 2 and remained present throughout the study in more than 90% of these infants. Colonization with true and potential bacterial pathogens was significantly reduced in infants receiving E. coli strain Nissle 1917 compared to the placebo group--both with respect to numbers of pathogens and to the spectrum of species.

Acinetobacter↗
PubMed1981

Use of nonabsorbable markers for gastrointestinal contents in in vivo measurement of magnesium bioavailability.

Magnesium absorption from five leafy vegetables was measured in rats using 28Mg as an extrinsic label and polyethylene glycol (PEG) and chromium-mordanted vegetable fibers (cr-mordants) as unabsorbable markers of soluble and particulate gut and fecal contents, respectively. The test meals used in this investigation were identical to those used in a previous test in which we found: a) that stable 26Mg biologically incorporated into the vegetables was freely exchangeable with an extrinsic 28Mg tracer; b) PEG consistently preceded Cr-mordants in transit through the gut; and c) fecal Mg isotope excretion 12 hours after the test meal was inadequate for measurement of Mg absorption. Accordingly, in the present investigation, all measurements in feces and gut contents were made 24 hours after the test meal. By that time an average of greater than 60% of the ingested PEG had been excreted. Magnesium-28 excretions, estimated under these conditions, were 4-5% less than they would have been had fecal PEG excretion been 100%. The discrepancy was due to partial separation of PEG and Mg in the lower gastrointestinal tract (GIT), possibly due to sequestration of Mg by microorganisms. That Mg must have entered an insoluble phase in the lower GIT was born out by the observation that little or no Mg absorption occurred in the cecum or colon. As before, Cr-modants lagged behind PEG and unabsorbed 28Mg, and thus do not seem suitable to monitoring intestinal transit of Mg.

Absorption↗
PubMed2000

Oligosaccharides in human milk: structural, functional, and metabolic aspects.

Research on human milk oligosaccharides (HMOs) has received much attention in recent years. However, it started about a century ago with the observation that oligosaccharides might be growth factors for a so-called bifidus flora in breast-fed infants and extends to the recent finding of cell adhesion molecules in human milk. The latter are involved in inflammatory events recognizing carbohydrate sequences that also can be found in human milk. The similarities between epithelial cell surface carbohydrates and oligosaccharides in human milk strengthen the idea that specific interactions of those oligosaccharides with pathogenic microorganisms do occur preventing the attachment of microbes to epithelial cells. HMOs may act as soluble receptors for different pathogens, thus increasing the resistance of breast-fed infants. However, we need to know more about the metabolism of oligosaccharides in the gastrointestinal tract. How far are oligosaccharides degraded by intestinal enzymes and does oligosaccharide processing (e.g. degradation, synthesis, and elongation of core structures) occur in intestinal epithelial cells? Further research on HMOs is certainly needed to increase our knowledge of infant nutrition as it is affected by complex oligosaccharides.

Bifidobacterium↗
PubMed1986

Recolonization and colonization resistance of the large bowel after three methods of preoperative preparation of the gastrointestinal tract for elective colorectal surgery.

The impact of three current types of preoperative large bowel preparation on the microbial flora and the colonization resistance (CR) was investigated in 15 volunteers. In the first group a whole gut irrigation was performed without administration of antibiotics (group WGI). In the second group 0.5 g/l metronidazole and 1 g/l neomycin was added to the irrigation fluid (group WGI + AB). A whole gut irrigation with prior oral administration of 1 l mannitol 10% was performed in the third group. The antibiotic prophylaxis in this group consisted of two doses of 80 mg gentamicin i.v. and 500 mg metronidazole orally 24 h after lavage (group Mann + AB). One hour after the mechanical cleansing procedure was finished all volunteers were orally contaminated with one dose of an Escherichia coli test strain. The aerobic faecal reduction due to the cleansing procedure was 2-3 logs, while for the anaerobes it was 4-5 logs. The anaerobic flora in group WGI recovered within 24 h, while the aerobes showed a transient 'overgrowth' for the period of 2 days. The overgrowth of aerobes in group WGI + AB was observed for more than a week and the total numbers of aerobes started gradually to decline after the anaerobic flora had reached pretreatment levels at day three or four. Despite the normal numbers of anaerobes present 24 h after treatment, overgrowth of E. coli was seen in the group Mann + AB, probably due to residual mannitol left in the intestinal tract. The test strain of E. coli was excreted for a period of 1 week by the volunteers in the groups WGI and Mann + AB, but it was isolated for more than 10 weeks in the group WGI + AB. It is thought that all three methods of preoperative large bowel preparation decreased the CR of the gastrointestinal tract because of a disturbance of the interaction between aerobic and anaerobic microorganisms and alterations of the colonic wall. The anaerobic microflora, however, appeared to be primarily responsible for the maintenance of the CR. Antimicrobial prophylaxis should consist of a high dose, short term, systemic antibiotic regimen, not only because an adequate serum level of an appropriate drug at the time of operation substantially decreases the incidence of postoperative septic complications but also because a systemic regimen scarcely influences the CR of the gastrointestinal tract. beta-Aspartylglycine appeared to be a specific but not very sensitive marker for decreased CR.

Adult↗
PubMed2000

Molecular studies of the intestinal mucosal barrier physiopathology using cocultures of epithelial and immune cells: a technical update.

Peyer's patch lymphocytes cocultured with Caco-2 cells trigger the phenotypic conversion of enterocytes into cells that express morphological and functional M-cell properties. We report a technical update for setting up this model, which will enable the study of M-cell biology, the identification by biochemical approaches of molecules involved in the interaction of microorganisms with M cells, and the development of vectors that would efficiently target the mucosal immune system.

Animals↗
PubMed2000

Influence of breastmilk on the development of resistance to intestinal colonization in infants born at the Atma Jaya Hospital, Jakarta.

A study of intestinal colonization resistance (CR) in breastfed versus formula-fed newborns at 4 intervals after birth in Jakarta, Indonesia, is described. To measure the intestinal CR for gram-negative enterobacilli, mean values of Enterobacteriaceae concentrations and mean numbers of Enterobacteriaceae biotypes were determined. The CR values found in this study show, that in all 4 sampling periods, at < 1, 2, 4 and 6 months, the mean concentration of Enterobacteriaceae was somewhat lower in the breastfed group than in the formula-fed group (only significant at 6 months). This means that the intestinal CR of the breastfed group may have been slightly higher than that in the formula-fed group. In both study groups, the CR was lower in the second and fourth month than soon after birth and at 6 months. For epidemiological reasons, comparison was performed of the Enterobacteriaceae biotypes found in samples from mother and child. The data show that, in the first sampling period, regardless of the theoretical possibility of a 'more intense (skin) contact' during breastfeeding (which might promote transfer of also microorganisms), the breastfed infants had a significantly lower percentage of identical Enterobacteriaceae biotypes than did the formula-fed group. This could possibly be ascribed to a higher CR in the breastfed group. Determination of the concentration of Enterococcus species was found applicable to reproducibly measure the CR in the newborns at 6 months and in the mother-group.

Adult↗
PubMed1992

Microbic superinfection in relapse of inflammatory bowel disease.

To assess the association between symptomatic relapse of inflammatory bowel disease (IBD) and superinfection with enteropathogenic microorganisms, we determined prospectively the incidence of infections with enteropathogenic bacteria, protozoa, and helminths in patients with confirmed longstanding IBD. Sixty-four patients with IBD (49 with Crohn's disease [CD] and 15 with ulcerative colitis [UC]) were consecutively enrolled in the study when relapse occurred. Multiple biopsies for histological and microbiological investigations were taken from all patients who were evaluated by colonoscopy. Parallel stool specimens were investigated for the presence of enteropathogenic bacteria, protozoa, and helminths. In six patients, we detected Clostridium difficile or toxin B (five CD, one UC), in one patient Campylobacter jejuni (CD), and in another patient Salmonella typhimurium (UC). Enteropathogenic Escherichia coli were isolated from three patients. Investigation of biopsies for Mycobacteria, microscopic examination of stool samples for helminths, and immunofluorescence for chlamydia were negative in all patients. In summary, as we found enteropathogenic microorganisms so infrequently in patients with relapse of IBD, despite intensive microbiological screening by tissue sampling for detection of gut adherent bacteria, we believe that microorganisms play only a minor role in the exacerbation of IBD.

Adult↗
PubMed1976

Effect of truncal vagotomy on the bacterial flora in the duodenal juice on dogs.

The qualitative and quantitative changes in the bacterial flora of the duodenal juice after truncal vagotomy have been studied in self-control experiments in dogs. The intervention was followed by a rise in the bacterial count without a change in qualitative composition. It is suggested that the accumulation of microorganisms might contribute to the development of postoperative diarrhoea. The role of several partly clarified pathophysiological processes are pointed out.

Animals↗
PubMed2004

[A multi-center prospective study for antibiotic prophylaxis to prevent perioperative infections in urologic surgery].

In order to assess the ability of our protocol for antibiotic prophylaxis to prevent perioperative infections in urologic surgery, 1,353 operations of open and laparoscopic urologic surgery conducted in 21 hospitals between September 2002 and August 2003 were subjected to analyses. We classified surgical procedures into four categories by invasiveness and contamination levels: Category A; clean less invasive surgery, Category B; clean invasive or clean-contaminated surgery, Category C; surgery with urinary tract diversion using the intestine. Prophylactic antibiotics were administrated intravenously according to our protocol, such as Category A; first or second generation cephems or penicillins on the operative day only, Category B; first and second generation cephems or penicillins for 3 days, and Category C; first, second or third generation cephems or penicillins for 4 days. The wound conditions and general conditions were evaluated in terms of the surgical site infection (SSI) as well as remote infection (RI) up to postoperative day (POD) 30. The SSI rate highest (23.3%) for surgery with intestinal urinary diversion, followed by 10.0% for surgery for lower urinary tract, 8.9% for nephroureterctomy, and 6.0% for radical prostatectomy. The SSI rates in clean surgery including open and laparoscopic nephrectomy/adrenalectomy were 0.7 and 1.4%, respectively. In SSIs, gram-positive cocci such as methicillin-resistant Staphylococcus aureus (58.8%) or Enterobacter faecalis (26.5%) were the most common pathogen. Similarly, the RI rate was the highest (35.2%) for surgery using intestinal urinary diversion, followed by 16.7% for surgery for lower urinary tract, 11.4% for nephroureterctomy, and 7.6% for radical prostatectomy, while RI rates for clean surgery were less than 5%. RIs most frequently reported were urinary tract infections (2.6%) where Pseudomonas aeruginosa (20.3%) and Enterobacter faecalis (15.3%) were the major causative microorganisms. Parameters such as age, obesity, nutritional status (low proteinemia), diabetes mellitus, lung disease, duration of operation, and blood loss volume were recognized as risk factors for SSI or RI in several operative procedures. Postoperative body temperatures, peripheral white blood counts, C reactive protein (CRP) levels in POD 3 were much higher than those in POD 2 in cases suffering from perioperative infections, especially suggesting that CRP could be a predictable marker for perioperative infections.

Antibiotic Prophylaxis↗
PubMed1983

Scanning electron microscopy of soy protein-induced damage of small bowel mucosa in infants.

Observations are reported by scanning electron microscopy (SEM) of soy protein-induced villous atrophy and mucosal recovery in two infants aged 5 weeks and 4 1/2 months. Whereas, by light microscopy, the mucosal lesions appeared similar, i.e., a flat mucosa, their appearance by SEM was different: the damage appeared more severe in the younger infant, although there was a shorter period of exposure to soy protein. The mucosal architecture was restudied 6 weeks after the initial biopsy. The degree of mucosal reconstruction was more advanced in the older infant--the one who showed less severe damage by SEM on the first biopsy. Although these investigations by SEM of damaged small bowel mucosa in soy protein intolerance did not contribute definite information to clarify the pathogenesis of villous atrophy in this condition, the injury was consistent with a lectin-induced toxicity, similar to the one postulated for celiac disease. SEM seems eminently suited to study of the effect of interactions between environment and host at mucosal surfaces; and finer gradations of damage to small bowel mucosa can be determined better by SEM, while this is not possible by light microscopy. Of interest was the rather extensive colonization of the mucosal surface by microorganisms in one of the two patients. However, the contribution of microbial colonization to mucosal damage could not be assessed.

Biopsy↗
PubMed1997

[Enterococci in human environment].

Enterococci, formerly confounded with faecal streptococci, are recognized since the beginning of the century as being faecal in origin and are generally searched for in waste waters and food products; their detection may in fact indicate the presence of enteropathogenic organisms. Although nearly ubiquitous, their preferred ecological niche is the intestine sphere. Rejected in the environment by means of human faeces or animal dejecta, they are scattered afterwards in diverse niches. Once in the external environment, their survival is linked with their exceptional aptitude to resist or grow in hostile environments that are usually detrimental to the development of most mesophilic microorganisms. However, a certain ambiguity exists concerning their relationships with human beings. In fact, certain enterococcus strains or species are used in the elaboration of some milk products. Conversely, others are opportunists and may cause severe infections to people from infants to adults. Moreover, undergoing adaptation perpetually, they present a multiresistance pattern to antibiotics. Thus, the barrier that separates bacteria as nonoffensive contaminants from powerful pathogens appears most fragile, suggesting that people must systematically consider suspect the presence of enterococci in their near environment.

Animals↗
PubMedDate not supplied

[Serotypes of classical enteropathogenic Escherichia coli that produce changes in the small bowel ultrastructure and invasion of HeLa cells].

UNLABELLED: Enteropathogenic Escherichia coli (EPEC) is the main cause of diarrhea in infants up to one year of age in the majority of the developing countries. In vitro EPEC strains attach to HeLa or HEp-2 cells in a specific pattern called localized adherence (LA), which is correlated with 93% of the EPEC serotypes. In vivo, EPEC strains adhere intimately to cuplike projections of the apical enterocyte membrane causing localized destruction of the microvilli, described as an attaching and effacing lesion. PURPOSE: We showed the attaching-effacing lesions and intracellular penetration in the ultrastructural study of the small intestinal cells as well as in the HeLa cell assay by the following EPEC serotypes: O111ab:H2, O119:H6 and O18ab:H14. PATIENTS AND METHODS: These strains were isolated from the stools of three infants less than 2 years of age with watery diarrhea who were hospitalized for fluid and electrolyte repairment. In the three patients there were severe ultrastructural alterations of the enterocytes mainly shortening and destruction of the microvilli, and formation of cuplike pedestal lesions. There was also penetration of microorganisms into the cytoplasm of the enterocytes in the interior of endocytotic vesicles. The serotypes of EPEC were assayed with HeLa cells showing the formation of pedestals and penetration into the cytoplasm. CONCLUSION: The ultrastructural alterations of the small bowel observed in these patients represent an important indication of the possibility of perpetuation of the diarrhea, owing to either a secretory mechanism or malabsorption of the nutrients.

Acute Disease↗