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Selective digestive microbial decontamination (SDD) is hypothesized to benefit patients in intensive care (ICU) by suppressing Gram-negative potential pathogens from the colon without affecting the anaerobic intestinal microbiota. The purpose of this study was to provide more insight to the effects of digestive tract and oropharyngeal decontamination on the intestinal microbiota by means of a prospective clinical trial in which faecal samples were collected from ICU patients for intestinal microbiota analysis. The faecal samples were collected from ICU patients enrolled in a multicentre trial to study the outcome of SDD and selective oral decontamination (SOD) in comparison with standard care (SC). Fluorescent in situ hybridization (FISH) was used to analyze the faecal microbiota. The numbers of bacteria from different bacterial groups were compared between the three regimens. The total counts of bacteria per gram faeces did not differ between regimens. The F. prausnitzii group of bacteria, representing an important group among intestinal microbiota, was significantly reduced in the SDD regimen compared to the SC and SOD. The Enterobacteriaceae were significantly suppressed during SDD compared to both SOD and SC; enterococci increased in SDD compared to both other regimens. The composition of the intestinal microbiota is importantly affected by SDD. The F. prausnitzii group was significantly suppressed during SDD. This group of microbiota is a predominant producer of butyrate, the main energy source for colonocytes. Reduction of this microbiota is an important trade-off while reducing gram-negative bacteria by SDD. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study was to examine the effects of outer membrane vesicles (OMV) obtained from Porphyromonas gingivalis (Pg) on the growth and function of human gingival fibroblasts (HGF) and human umbilical vein endothelial cells (HUVEC). Methods: OMV were obtained from a cell-free growth medium of Pg ATCC 33277 by 40% NH2SO4 precipitation and ultracentrifugation. Cell proliferation was measured by ³H-thymidine incorporation into growing HGF and HUVEC. Endothelial cell function was determined by their capacity to form a network of capillary tubes on an extracellular matrix (ECM). Results; Proliferating HGF and HUVEC demonstrated a significant dose-dependent inhibition of ³H-thymidine uptake when cultured with 0 to 40 µg/ml of OMV protein. HGF and HUVEC showed an IC50 of growth of about 9.0 µg/ml and 4.5 µg/ml of OMV protein, respectively. Capillary tube formation by HUVEC cultured on an ECM was suppressed by 70% to 80% with 5 µg/ml OMV protein after 18 hours of incubation. The presence of proteolytic enzymes in the OMV did not contribute to capillary tube disruption, since blocking enzyme activity with specific inhibitors did not reduce the suppression of capillary tube formation. After heating at 90°C for 5 minutes, OMV significantly lost their capacity to suppress capillary tube formation. Conclusions: OMV significantly inhibit the proliferation of cultured HGF and HUVEC in a dose-dependent manner. OMV suppressed the capillary tube formation by cultured HUVEC. The factor(s) appeared to be a protein and not endotoxin because its inhibitory activity was markedly reduced by heat inactivation. These studies suggest that OMV contribute to chronic periodontitis by suppressing cell proliferation and revascularization in periodontal tissues. [ABSTRACT FROM AUTHOR]

Background: There have, been a number of reports of brain abscesses suggesting an odontogenic etiology. However, no efforts have been made to compare brain abscess isolates with isolates from the oral cavity using highly discriminative methods. We report a brain abscess caused by Streptococcus constellatus in an immunocompromised patient where oral infection (periodontitis) was suspected to be implicated. Methods: The brain abscess and oral isolates were compared by means of one phenotypic and three genetic (restriction fragment length polymorphism [RFLP], ribotyping, and random amplified polymorphic DNA [RAPD]) fingerprinting techniques. Results: The phenotypic method and RFLP showed identical profiles between brain and periodontal isolates, while ribotyping and RAPD showed very dose similarity, with only one band difference in one of the three ribotypes and in one of the three polymorphic RAPD. Conclusions: Gene transfer by genetic recombinational events in the periodontal pocket might have been responsible for the emergence of a strain variant of S. constellatus that had the potential to cause an abscess at a distant site (brain). The importance of odontogenic sources as potential foci of infection for brain abscesses is discussed. [ABSTRACT FROM AUTHOR]