A Potential New Risk Factor for Stroke: Streptococcus Mutans With Collagen-Binding Protein.

BACKGROUND: Among human oral bacteria, particular kinds of Streptococcus mutans (SM) known as dental caries pathogens contain a collagen-binding protein, Cnm, and show platelet aggregation inhibition and matrix metalloproteinase-9 activation. We have previously reported that these strains may be a risk factor for intracerebral hemorrhage. As a major sample-providing hospital, we report the clinical details, including intracranial aneurysms and ischemic stroke. METHODS: After the study received approval from the Ethical Committee, 429 samples of whole saliva were obtained from patients who were admitted to or visited our hospital between February 16, 2010, and February 28, 2011. The study cohort comprised 48 patients with cardioembolic stroke (CES), 151 with non-CES infarct, 54 with intracerebral hemorrhage (ICH), 43 with ruptured intracranial aneurysm (RIA), and 97 with unruptured intracranial aneurysm (UIA). Cultured SM was identified as Cnm-positive when the corresponding gene was positive. The results were compared with those from 79 healthy volunteers. Relationships between Cnm-positive SM and known risk factors, including hypertension, diabetes, hyperlipidemia, smoking, and alcohol consumption, were analyzed. RESULTS: A statistically significant high Cnm-positive rate was observed in patients with CES, non-CES infarct, ICH, and RIA (P = 0.002, 0.039, 0.013, and 0.009, respectively). There were no relationships between Cnm-positive SM and known risk factors. CONCLUSIONS: Specific types of oral SM can be a risk factor for cardioembolic infarct, intracerebral hemorrhage, and intracranial aneurysm rupture. Further study is needed.

In-vitro interaction of L-dopa with bacterial adhesins of Helicobacter pylori: an explanation for clinicial differences in bioavailability?

OBJECTIVES: Recent investigations on the pharmacokinetics of levodopa (L-dopa) indicated that the presence of Helicobacter pylori in patients with Parkinson's disease, orally treated with L-dopa, influences the absorption of this compound, which consequently leads to decreased plasma levels. Therefore this work aims to study a potential in-vitro interaction of L-dopa with H. pylori and its surface adhesins. METHODS: Solutions containing L-dopa of different concentrations were incubated with H. pylori at different bacterial densities and time intervals. Free L-dopa was quantified from the incubation supernatants by HPLC. A flow cytometric assay with fluorescence labelled H. pylori was used to investigate the influence of L-dopa on the bacterial adhesion of H. pylori: FITC-labelled bacteria were pre-incubated with L-dopa, followed by incubation with gastric epithelial cells (AGS cells) and FACS quantification of adhering bacteria. KEY FINDINGS: Evaluation of time- and concentration-dependent incubation experiments indicated a significant decrease in L-dopa concentrations when coming into contact with H. pylori. The reduction in L-dopa concentrations was determined as 47 to 12%, referred to the initial starting concentration, with time-dependency and dependency of the H. pylori density. FITC-labelled H. pylori, pre-incubated with differing L-dopa concentrations, were shown to have a significantly reduced bacterial adhesion to AGS cells, with a maximum reduction of 22 +/- 9%. These results demonstrate a direct interaction of L-dopa with the outer membrane proteins of H. pylori responsible for the adhesion to gastric epithelial cells. By this interaction the unbound L-dopa concentration in bacterial suspension was strongly reduced. CONCLUSIONS: This study suggests a potential in-vitro interaction of L-dopa with H. pylori adhesins, confirming the clinical changes found in pharmacokinetics of L-dopa therapy by H. pylori-positive patients with Parkinson's disease.

Yersinia pseudotuberculosis induces transcytosis of nanoparticles across human intestinal villus epithelium via invasin-dependent macropinocytosis.

Crohn's disease is characterized by a defect in intestinal barrier function, where bacteria are considered the most important inflammation-driving factor. Enteric bacteria, including E. coli and Yersinia spp, affect tight junctions in enterocytes, but little is known about bacterial effects on the transcellular pathway. Our objective was to study the short-term effects of Y. pseudotuberculosis on uptake of nanoparticles across human villus epithelium. Monolayers of human colon epithelium-derived Caco-2 cells and biopsies of normal human ileum were studied after 2 h exposure to Y. pseudotuberculosis expressing (inv+) or lacking (inv-) the bacterial adhesion molecule, invasin. Transepithelial transport of fluorescent nanoparticles (markers of transcytosis) was quantified by flow cytometry, and mechanisms explored by using inhibitors of endocytosis. Epithelial expressions of beta1-integrin and particle uptake pathways were studied by confocal microscopy. The paracellular pathway was assessed by electrical resistance (TER), mannitol flux, and expression of tight junction proteins occludin and caludin-4 by confocal microscopy. Inv+ Y. pseudotuberculosis adhered to the apical surface of epithelial cells and induced transcytosis of exogenous nanoparticles across Caco-2 monolayers (30-fold increase, P<0.01) and ileal mucosa (268+/-47% of control; P<0.01), whereas inv bacteria had no effect on transcytosis. The transcytosis was concentration-, particle size- and temperature-dependent, and possibly mediated via macropinocytosis. Y. pseudotuberculosis also induced apical expression of beta1-integrin on epithelial cells. A slight drop in TER was seen after exposure to inv+ Y. pseudotuberculosis, whereas mannitol flux and tight junction protein expression was unchanged. In summary, Y. pseudotuberculosis induced apical expression of beta1-integrin and stimulated uptake of nanoparticles via invasin-dependent transcytosis in human intestinal epithelium. Our findings suggest that bacterial factors may initiate transcytosis of luminal exogenous particles across human ileal mucosa, thus presenting a novel mechanism of intestinal barrier dysfunction.

Gingipain-dependent interactions with the host are important for survival of Porphyromonas gingivalis.

Porphyromonas gingivalis, a major periodontal pathogen, must acquire nutrients from host derived substrates, overcome oxidative stress and subvert the immune system. These activities can be coordinated via the gingipains which represent the most significant virulence factor produced by this organism. In the context of our contribution to this field, we will review the current understanding of gingipain biogenesis, glycosylation, and regulation, as well as discuss their role in oxidative stress resistance and apoptosis. We can postulate a model, in which gingipains may be part of the mechanism for P. gingivalis virulence.

Safety and immunogenicity of two acellular pertussis vaccines with different pertussis toxoid and filamentous hemagglutinin content in infants 2-6 months old.

The optimal composition and antigen content of acellular pertussis vaccines is not known. Two vaccines with different quantities of pertussis toxoid (10 and 20 micrograms) and filamentous hemagglutinin (5 and 20 micrograms) and identical 69 kD protein (3 micrograms) and fimbriae 2 and 3 (5 micrograms) combined with diphtheria and tetanus toxoids were compared in a randomized, double-blind study in 2,050 infants undergoing their primary immunization series at 8 centers in the US and Canada. A 6:1 increased antigen to lower antigen allocation was used; 96% of infants received 3 doses and completed the study. A 'clinically significant' local reaction was reported in 3-6% of participants after each dose. Erythema was the most common reaction occurring in 3-5% of infants after the second or third dose. A clinically significant systemic adverse reaction was reported in 28-34% of vaccinees (or vaccinated children) after each dose; fever (7-18%) and fussiness (12-17%) were most common. There were no differences in adverse events between the 2 vaccine formulations. Antibody responses were measured in 292 infants at 1 center. At 7 months, geometric mean anti-filamentous hemagglutinin antibody titers were higher in recipients of the higher antigen content vaccine (p < 0.001) whereas recipients of the lower antigen content formulation had higher anti-fimbriae antibody (p < 0.001) and agglutinin titers (p < 0.05). No differences were detected in anti-pertussis toxin or other antibody responses between the formulations. We conclude that increasing the antigen content of the acellular pertussis vaccine had a variable effect on antibody response but was not associated with increased adverse reactions.

Relación entre cepas de enterobacterias manosa resistentes y presencia de células centelleantes en el sedimento urinario / Relation among enterobacteriaceae mannosa resistant isolates and glitter cells in the urinary sediments

La presencia de células con características especiales denominadas células centelleantes, en el sedimento urinario provenientes de infecciones urinarias producidas por cepas de enterobacterias que expresan fimbrias Pap, fue evaluada en este estudio. En 143 cepas de enterobacterias, la capacidad de adhesión fue analizada aglutinación de glóbulos rojos humanos grupo A suspendidos en buffer fosfato (PBS), para ver hemoaglutinación (HA), y con el agregado de D-manosa al 1 por ciento para detectar hemoaglutinación manosa-sensible (HAMS) o manosa resistente (HAMR). Escherichia coli presentó una diferencia significativa en el número de cepas que expresan fimbrias manosa resistente (MR):56 y las que expresan fimbrias manosa sensibles (MS):25. Las especies MR, fueron enfrentadas con glóbulos rojos humanos grupo P y eritrocitos de cerdo, utilizando como inhibidor de la hemoaglutinación el digalactósido (1-4) -ß-D galactopiranósido. No se estableció una diferencia notable en el número de cepas con fimbrias MR, que presentaron capacidad hemoaglutinante, frente a las dos especies de eritrocitos. Pero fue comparativamente mayor, el número de cepas con fimbrias Pap que aglutinaron glóbulos rojos humanos grupo P. La relación presencia de células centelleantes en el sedimento urinario y cepas de enterobacterias que expresan fimbrias MR, como agente etiológico del proceso infeccioso, fue significativamente mayor que la establecida por cepas con fimbrias MS (AU)

Relación entre cepas de enterobacterias manosa resistentes y presencia de células centelleantes en el sedimento urinario / Relation among enterobacteriaceae mannosa resistant isolates and glitter cells in the urinary sediments

La presencia de células con características especiales denominadas células centelleantes, en el sedimento urinario provenientes de infecciones urinarias producidas por cepas de enterobacterias que expresan fimbrias Pap, fue evaluada en este estudio. En 143 cepas de enterobacterias, la capacidad de adhesión fue analizada aglutinación de glóbulos rojos humanos grupo A suspendidos en buffer fosfato (PBS), para ver hemoaglutinación (HA), y con el agregado de D-manosa al 1 por ciento para detectar hemoaglutinación manosa-sensible (HAMS) o manosa resistente (HAMR). Escherichia coli presentó una diferencia significativa en el número de cepas que expresan fimbrias manosa resistente (MR):56 y las que expresan fimbrias manosa sensibles (MS):25. Las especies MR, fueron enfrentadas con glóbulos rojos humanos grupo P y eritrocitos de cerdo, utilizando como inhibidor de la hemoaglutinación el digalactósido (1-4) -ß-D galactopiranósido. No se estableció una diferencia notable en el número de cepas con fimbrias MR, que presentaron capacidad hemoaglutinante, frente a las dos especies de eritrocitos. Pero fue comparativamente mayor, el número de cepas con fimbrias Pap que aglutinaron glóbulos rojos humanos grupo P. La relación presencia de células centelleantes en el sedimento urinario y cepas de enterobacterias que expresan fimbrias MR, como agente etiológico del proceso infeccioso, fue significativamente mayor que la establecida por cepas con fimbrias MS