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PubMed1994

The role of systemic antibodies against intestinal Escherichia coli in the prevention of bacterial translocation of Escherichia coli in a burn model in mice.

Bacterial translocation (BT) from the gastrointestinal (GI) tract has been proposed to play a role in the pathogenesis of septic complications in severely burned patients. It is well known that severely ill patients such as thermally injured patients may acquire new potential pathogenic microorganisms in the GI tract. Because these patients have no antibodies directed against these acquired microorganisms, BT may be facilitated in these patients. To investigate this hypothesis in a burn model, a study was performed in which two groups of C3H-HeN mice underwent a different period of intestinal overgrowth by a single neomycin-resistant (NR) Escherichia coli strain after oral neomycin-bacitracin treatment. Group I underwent a short period (5 days) and group II experienced a long period (44 days) of intestinal overgrowth before a thermal injury was executed. Two days postburn, plasma antibody titers of IgA, IgG, and IgM isotype against NR E. coli were measured by indirect immunofluorescence (IIF) and BT to various organs was determined by culturing. Although there were no significant differences of BT to organs between the groups, the IgG antibody titer against the NR E. coli strain was significantly increased in group II. Antibody titers of IgA and IgM were not significantly different between the groups. Titers of plasma antibodies of IgG isotype against the intestinal NR E. coli did not correlate with BT. We conclude that increased IgG titers against the NR E. coli used are the result of a longer intestinal overgrowth period and are not associated with prevented or decreased BT.

Animals↗
PubMed2005

Uptake and presentation of orally administered antigens.

The mucosae of the gastrointestinal tract are continuously exposed to a myriad of antigens and microorganisms that the immune system has to discriminate between dangerous and harmless. Entry of pathogenic microorganisms occurs mainly via M cells that are concentrated in the follicle-associated epithelium overlying the Peyer's Patches (PPs). M cells are very selective and do not allow entry of all microorganisms. We have recently described an additional mechanism by which dendritic cells (DCs) can monitor the contents of the intestinal lumen. DCs send dendrites outside the epithelium, like periscopes. It is not clear whether this mechanism is constitutively active or is induced in response to signals from epithelial cells that have been in contact with pathogens or high numbers of non pathogenic bacteria in the lumen. Therefore, deciphering the signals that are released by epithelial cells after the encounter with mucosal antigens is of paramount importance to understand the ability of the DCs to respond to the different antigens and to mount immune or tolerogenic responses.

Administration, Oral↗
PubMed2001

Protection from gastrointestinal diseases with the use of probiotics.

Probiotics are nonpathogenic microorganisms that, when ingested, exert a positive influence on the health or physiology of the host. They can influence intestinal physiology either directly or indirectly through modulation of the endogenous ecosystem or immune system. The results that have been shown with a sufficient level of proof to enable probiotics to be used as treatments for gastrointestinal disturbances are 1) the good tolerance of yogurt compared with milk in subjects with primary or secondary lactose maldigestion, 2) the use of Saccharomyces boulardii and Enterococcus faecium SF 68 to prevent or shorten the duration of antibiotic-associated diarrhea, 3) the use of S. boulardii to prevent further recurrence of Clostridium difficile-associated diarrhea, and 4) the use of fermented milks containing Lactobacillus rhamnosus GG to shorten the duration of diarrhea in infants with rotavirus enteritis (and probably also in gastroenteritis of other causes). Effects that are otherwise suggested for diverse probiotics include alleviation of diarrhea of miscellaneous causes; prophylaxis of gastrointestinal infections, which includes traveler's diarrhea; and immunomodulation. Trials of gastrointestinal diseases that involve the ecosystem are currently being performed, eg, Helicobacter pylori infections, inflammatory bowel disease, and colon cancer.

Bifidobacterium↗
PubMed2000

Probiotic immunomodulation in health and disease.

Probiotics, microorganisms that have a favorable influence on physiologic and pathological processes of the host by their effect on the intestinal flora, may play a role in improving human health. One of the putative effects is the modulation of immune function. Thus, the mucosal immune system and methods to assess its function are reviewed briefly. Probiotic modulation of humoral, cellular and nonspecific immunity is reviewed, with emphasis placed on immune response in disease models. There are very few reports of human intervention studies with probiotics. However, some of the possible future directions for research with respect to probiotics, immunity, and human health are discussed. Although the application of probiotics has demonstrated trends with respect to altered aspects of immune response, the underlying mechanisms by which that occurs are unclear.

Animals↗
PubMedDate not supplied

Bone and joint infection with Arizona hinshawii: report of a case and a review of the literature.

The Arizona group of gram-negative enteric microorganisms is closely related to the genus Salmonella. Arizona infection is common in avian and reptilian species. Whereas Arizona intestinal infection has been observed in humans, extraintestinal disease has infrequently been described. A case of a 23-year-old woman with systemic lupus erythematosus and sickle cell trait who acquired Arizona hinshawii osteomyelitis and septis arthritis is presented. The patient recovered after treatment with ampicillin and cephalosporins. Three previously described cases of bone and/or joint infection with Arizona are summarized. Because Arizona species frequently ferment lactose, it is possible that they are discarded from fecal isolates by bacteriology laboratories. It is conceivable that many intestinal and extraintestinal infections are either overlooked or mistakenly identified.

Adult↗
PubMed1984

Distribution and effects of a defined six-member murine-derived microflora in gnotobiotic gerbils.

The gnotobiotic gerbil was selected as a model with which to study the effects of colonization with a defined microflora on organ morphology, histology, and selected blood biochemical parameters. Gerbils were maintained germfree for 13 months but failed to reproduce, presumably because of the enlarged cecum. A colony of gnotobiotic gerbils that was associated with a bacterial flora consisting of Lactobacillus brevis, Streptococcus faecalis, Staphylococcus epidermidis, Bacteroides vulgatus, Enterobacter aerogenes, and a Fusobacterium sp. was established. These gnotobiotic gerbils had smaller ceca than germfree gerbils and proved capable of reproduction. Except for the presence of large numbers of Bacteroides organisms in the stomach and greater numbers of S. epidermidis in gnotobiotic gerbils, the number and location of gastrointestinal bacteria were similar in conventional and gnotobiotic gerbils. Bacteroides sp. was the second most predominant microorganism present in gnotobiotic gerbils, whereas clostridia were reported to be the second most predominant microorganism in conventional gerbils. Microscopic examination of direct-impression smears indicated that fusobacteria were present on mucosal surfaces. Intestines of gnotobiotic gerbils weighed twice as much as the intestines of conventional gerbils. Intestinal tissue water weight values from conventional and gnotobiotic gerbils were similar. Histological examination of gerbil intestinal tissue revealed no cellular hypertrophy and no evidence of inflammation in gnotobiotic gerbil intestines. Spleens of gnotobiotic gerbils showed no germinal center stimulation. Statistical differences in total serum glucose, serum protein, and hematocrit levels were found between conventional and gnotobiotic gerbils.

Aerobiosis↗
PubMed2005

Microarray analysis and motif detection reveal new targets of the Salmonella enterica serovar Typhimurium HilA regulatory protein, including hilA itself.

DNA regulatory motifs reflect the direct transcriptional interactions between regulators and their target genes and contain important information regarding transcriptional networks. In silico motif detection strategies search for DNA patterns that are present more frequently in a set of related sequences than in a set of unrelated sequences. Related sequences could be genes that are coexpressed and are therefore expected to share similar conserved regulatory motifs. We identified coexpressed genes by carrying out microarray-based transcript profiling of Salmonella enterica serovar Typhimurium in response to the spent culture supernatant of the probiotic strain Lactobacillus rhamnosus GG. Probiotics are live microorganisms which, when administered in adequate amounts, confer a health benefit on the host. They are known to antagonize intestinal pathogens in vivo, including salmonellae. S. enterica serovar Typhimurium causes human gastroenteritis. Infection is initiated by entry of salmonellae into intestinal epithelial cells. The expression of invasion genes is tightly regulated by environmental conditions, as well as by many bacterial factors including the key regulator HilA. One mechanism by which probiotics may antagonize intestinal pathogens is by influencing invasion gene expression. Our microarray experiment yielded a cluster of coexpressed Salmonella genes that are predicted to be down-regulated by spent culture supernatant. This cluster was enriched for genes known to be HilA dependent. In silico motif detection revealed a motif that overlaps the previously described HilA box in the promoter region of three of these genes, spi4_H, sicA, and hilA. Site-directed mutagenesis, beta-galactosidase reporter assays, and gel mobility shift experiments indicated that sicA expression requires HilA and that hilA is negatively autoregulated.

Amino Acid Motifs↗
PubMed2001

Human defensin 5 is stored in precursor form in normal Paneth cells and is expressed by some villous epithelial cells and by metaplastic Paneth cells in the colon in inflammatory bowel disease.

BACKGROUND AND AIMS: Intestinal epithelial cell derived antimicrobial peptides of the defensin family may play a major role in host defence against microorganisms. Our aims were to (i) isolate, characterise, and investigate the processing of human defensin 5 (HD-5) in normal Paneth cells and (ii) investigate expression of HD-5 in active inflammatory bowel disease (IBD). METHODS: Antiserum raised against chemically synthesised putative mature HD-5 was used for immunohistochemistry and purification of HD-5 from extracts of normal terminal ileal crypts. RESULTS: In normal and Crohn's disease terminal ileum, HD-5 immunoreactivity was seen in Paneth cells and in some villous epithelial cells. Normal colonic mucosa did not express HD-5 but HD-5 immunoreactivity was seen in cells in the colonic crypt region of many IBD samples. N-terminal amino acid sequence analysis of HD-5 purified from normal terminal ileal Paneth cells consistently showed the predicted sequence of the precursor form of the peptide. Following stimulation of isolated intact normal terminal ileal crypts, a truncated form of HD-5, with the N-terminal sequence GEDNQLAIS, was detected in the supernatant. CONCLUSIONS: (i) HD-5 is present only in the precursor form in normal terminal ileal Paneth cells and is processed to the mature form during and/or after secretion, (ii) some villous epithelial cells express HD-5, and (iii) HD-5 is expressed by metaplastic Paneth cells in the colon in IBD.

Animals↗
PubMed1998

Protective function of proteins and lipids in human milk.

Human milk provides the infant with protection against infectious diseases. This protection is conferred through several mechanisms: specific antibody targeted protection against pathogens in the infant's environment (through milk IgA, IgG, and IgM) and broad-spectrum, nonspecific protection provided through several distinct mechanisms. These are: bactericidal effects (lactoferrin), bacteriostatic action (lactoferrin, lysozyme), lysis of microorganisms (lysozyme), antiviral effects (lactoferrin, products of milk fat digestion), antiprotozoan activity (free fatty acids produced during gastric and intestinal digestion of milk fat), and ligand action (inhibition of Helicobacter pylori adhesion to gastric mucosa by kappa-casein). In addition to these protective functions of the proteins and lipids of human milk, several enzymes present in human milk might provide protection by generating components that are bactericidal (bile salt dependent lipase, peroxidase), prevent inflammatory reactions (platelet-activating factor acetylhydrolase), or protect the integrity of milk proteins (antiproteases).

Anti-Infective Agents↗
PubMed2005

Outbreak of avian mycobacteriosis in a flock of two-year-old domestic pigeons (Columba livia f. domestica).

This report describes an outbreak of avian mycobacteriosis in a flock of 100 two-yr-old pigeons. Over a 6-mo period, the sick pigeons showed cachexia followed by death. In Columbiformes classic tubercles rarely develop, but in these affected pigeons granulomatous nodular lesions of various sizes, containing numerous acid-fast bacilli, were found in the internal organs. The lesions were observed in the liver, spleen, intestine, bone marrow, ovary, and oviduct. Despite their breeding age, atrophy was also found in the ovary and oviduct. Microorganisms belonging to Mycobacterium avium complex were identified in the affected tissues by polymerase chain reaction.

Aging↗
PubMed2001

[Factors for individualization of treating postoperative wound complications in stomach cancer patients].

Since gram-negative aerobic and anaerobic microorganisms constitute at present the largest fraction of microflora in surgical patients, the chances of their translocation from the intestines due to impaired anticolonization resistance of the body are becoming stronger. Evidence is presented to demonstrate the dynamics of postoperative infestation of wounds in patients operated on for stomach cancer.

Female↗
PubMedDate not supplied

[Toxoplasmosis: historical summary and bibliographic review].

A chronologic description of the principal events and discoveries related to toxoplasmosis from 1908 when the causal agent was discovered up to date is performed. The main data with a parasitic interest are summarized, and the endodiogenic multiplication is explained. The cat is the definitive host for this protozoan. Its evolutive cycle in the intestinal epithelium of this domestic animal is commented. The oocyst is recognized as the main infecting form of this microorganism. The classical concepts of congenital and acquired histoplasmosis are briefly exposed. A brief comment of the ophthalmic and gyneco-obstetric complications from the disease is made. Possible relationships between toxoplasmic adenopathies and neurotic states in psychiatry are emphasized.

Africa, Northern↗
PubMed1995

[Bacterial virulence factors and their role in the pathogenesis of pyogenic infections of the abdominal cavity and mediastinum].

Purulent peritonitis are caused predominantly by anaerobic bacteria which come from physiological intestinal flora. Mediastinitis is caused amidst other etiologic factors also by bacteria inhabiting the oropharyngeal region, as well as microorganisms causing diseases localized in the proximity of mediastinum. Anaerobic sporulating bacteria both Gram positive and negative cause often miscellaneous infections due to Staphylococcus aureus, Enterobacteriacae, Streptococcus, Enterococcus. It involves a group of bacteria which are able to produce a fibrin network in their proximity, to resist phagocytosis by their structures, to distruct the components of the complement system and immunoglobulins, to impair membranes of cells which leads by means of their factors of virulence to formation of defectuous immunity. Microbiological examination requires the material to be sent for anaerobic cultivation and the antimicrobial therapy must take into account its polymicrobic etiology. (Ref. 23.)

Abdomen↗
PubMed1982

Enhancement of the 7 alpha-dehydroxylase activity of a gram-positive intestinal anaerobe by Bacteroides and its significance in the 7-dehydroxylation of ursodeoxycholic acid.

The 7 alpha-dehydroxylation of chenodeoxycholic acid (CDCA) and cholic acid (CA) by a Eubacterium lentum-like intestinal anaerobe was specifically enhanced by the bacteroides present in mixed cultures and also by the addition to the growth medium of cell extracts from the bacteroides. The 7 alpha-dehydroxylating organism also possessed 7 alpha-hydroxysteroid dehydrogenase activity, and, in collaboration with a 7 beta-dehydrogenating organism, converted ursodeoxycholic acid (UDCA) into CDCA. Large quantities of lithocholic acids were produced from UDCA as well as CDCA in in vitro cocultures of these three kinds of microorganisms.

Anaerobiosis↗
PubMed1977

Effect of fosfomycin on the fecal microflora of man.

Use of broad-spectrum antibiotics is known to cause changes in the intestinal microflora of man. The present study was initiated to determine the effect of oral fosfomycin calcium on several groups of microorganisms indigenous to the gut. Data from this double-blind study indicate that 2 g of fosfomycin given daily in four divided doses for 28 days increased the incidence of soft stools. No significant changes in numbers of staphylococci or Candida were observed during treatment. Although there was no significant change in total coliforms, the numbers of E. coli decreased markedly from 10(5) to 10(2) organisms/g feces. Concurrent with this decrease, the Klebsiella-Enterobacter counts increased from 10(3) to 10(6) organisms/g feces. Two weeks posttreatment the E. coli and the Klebsiella-Enterobacter counts approached pretreatment levels. These observations are similar to those reported for ampicillin. During the course of treatment when the E. coli dropped precipitously the few surviving E. coli still were suceptible to fosfomycin as determined by an agar diffusion disc test.

Anti-Bacterial Agents↗
PubMed1997

Morphological injury of the intestinal mucosa and infection in patients with AIDS. The role of combined tissue and stool examination.

AIMS: To define the relationship between morphological injury of the intestinal mucosa and infections in AIDS patients. METHODS: Forty-nine AIDS patients were examined by upper gastrointestinal (GI) endoscopy and 8 of them also by lower GI endoscopy. Biopsy specimens, taken from the lower duodenum, esophagus and rectum, were studied by light (L.M.) and transmission electron microscopy (T.E.M.). Stool examination for microorganisms was routinely performed in all patients. RESULTS: Microorganisms were detected in 37 of the 49 patients (75.5%) by combined tissue and stool examination. The histological study revealed villous atrophy, inter- and intra-enterocyte oedema and epithelial degenerative changes in most of the patients whether or not they had detectable microorganisms. CONCLUSIONS: Combined methods (endoscopy, L.M. and T.E.M., studies of tissue samples, microbiological study of stool samples) may be used to improve the documentation of infections and morphological injury of the intestinal mucosa in AIDS patients.

AIDS-Related Opportunistic Infections↗