ERIC-PCR fingerprinting-based community DNA hybridization to pinpoint genome-specific fragments as molecular markers to identify and track populations common to healthy human guts

Bacterial populations common to healthy human guts may play important roles in human health. A new strategy for discovering genomic sequences as markers for these bacteria was developed using Enterobacterial Repetitive Intergenic Consensus (ERIC)-PCR fingerprinting. Structural features within microbial communities are compared with ERIC-PCR followed by DNA hybridization to identify genomic fragments shared by samples from healthy human individuals. ERIC-PCR profiles of fecal samples from 12 diseased or healthy human and piglet subjects demonstrated stable, unique banding patterns for each individual tested. Sequence homology of DNA fragments in bands of identical size was examined between samples by hybridization under high stringency conditions with DIG-labeled ERIC-PCR products derived from the fecal sample of one healthy child. Comparative analysis of the hybridization profiles with the original agarose fingerprints identified three predominant bands as signatures for populations associated with healthy human guts with sizes of 500, 800 and 1000 bp. Clone library profiling of the three bands produced 17 genome fragments, three of which showed high similarity only with regions of the Bacteroides thetaiotaomicron genome, while the remainder were orphan sequences. Association of these sequences with healthy guts was validated by sequence-selective PCR experiments, which showed that a single fragment was present in all 32 healthy humans and 13 healthy piglets tested. Two fragments were present in the healthy human group and in 18 children with non-infectious diarrhea but not in eight children with infectious diarrhea. Genome fragments identified with this novel strategy may be used as genome-specific markers for dynamic monitoring and sequence-guided isolation of functionally important bacterial populations in complex communities such as human gut microflora.

[Helicobacter pylori infection in developing countries]

Helicobacter pylori infection is probably the most common bacterial infection in the world. The pathogenicity of this bacteria has been recognized since 1989 in the developed world where prevalence is 20 to 40%. Its role in gastric and duodenal disease is certain and its low recurrence rate justifies eradication. In the developing world prevalence of Helicobacter pylori infection is over 80% with contamination being maximal in children. Transmission is oro-oral and even feco-oral. Crowded living conditions is the determinant factor. Helicobacter pylori infection exhibits special features in developing world. The prevalence of gastroduodenal disease varies according to geographic area independently of the prevalence of Helicobacter pylori infection and stomach cancer is uncommon. In newborns Helicobacter pylori infection seems to be the primary event for chronic malnutrition and diarrhea syndrome with failure to thrive. In practice detection of Helicobacter pylori is difficult in the developing world and presumptive treatment is always followed by recurrence. In the future active or passive immunization will be the solution.

[The pharyngeal viral flora in dystrophic infants 0 to 1 years of age with acute respiratory diseases]

Pharyngeal viral flora was studied in 0-1-year-old dystrophic children with acute infections of the upper respiratory tract and with interstitial pneumopathy. Influence of the dystrophic factor on the qualitative and quantitative aspects of the viral flora is discussed.

Failure to thrive, wasting syndrome, and immunodeficiency in rabies: a hypophyseal/hypothalamic/thymic axis effect of rabies virus

Studies of rabies virus in several animal models consistently showed hypothalamic infection, hypophyseal infection, dramatic growth impairment (in the form of failure to thrive), wasting syndrome, and immune depletion. Rabies virus infection was studied through routine monoclonal antinucleocapsid antibody immunofluorescence and through a peroxidase-antiperoxidase immunoperoxidase method. The latter was modified to detect the in situ production of growth hormone by uninfected and rabies virus-infected adeno-a-pituicytes (with confirmation of the results both in vivo and in vitro). Infection with rabies virus made the specialized pituicytes produce less growth hormone. Growth before rabies virus infection and its reduction due to infection were investigated in a linear regression model. The fit was statistically significant (P less than .05) in all species studied: mouse, rat, rabbit, cow, and cat. Immune depression was studied in terms of alterations in the immunotopography of the thymus and also the specific T- and B-cell homing areas of the spleen (although spleen data are not presented here). On the basis of these results and a thorough review of wasting syndromes encountered in other diseases, a primary failure to thrive and an ensuing wasting syndrome were described and characterized for rabies, and their origin was assigned to a dysfunction of the hypophyseal/hypothalamic/thymic axis associated with at least (but not necessarily only) one of the centrally controlled growth hormones.

Use of cloned probes to detect Epstein-Barr viral DNA in tissues of patients with neoplastic and lymphoproliferative diseases

Cloned fragments of the Epstein-Barr virus (EBV) genome were used to examine tissues from 145 patients for the presence of EBV DNA by two techniques: (1) nucleic acid hybridization of cell spots from which the DNA had been extracted in situ and (2) hybridization of DNA that had been transferred to nitrocellulose by Southern blotting. EBV DNA was found in tissues from four adults and five children with American Burkitt's lymphoma, infectious mononucleosis, lymphoma following bone marrow transplant, central nervous system lymphoma, nasopharyngeal carcinoma, and fatal polyclonal B-cell lymphoma following mononucleosis; two patients also had chronic pneumonitis, failure to thrive, and abnormal immune function. Six of the nine patients whose tissues contained EBV DNA had a demonstrable or presumed associated immunologic disorder. EBV DNA was not found in normal tissues or in a variety of hematologic neoplasms and other disorders. Nucleic acid hybridization methods can be used for the routine examination of the association of EBV with lymphomas and other lymphoproliferative syndromes occurring in immunodeficient individuals.