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At least 55 records · Page 3Linked to original sources
PubMed2006

Therapeutic value of a Lactobacillus gasseri and Bifidobacterium longum fixed bacterium combination in acute diarrhea: a randomized, double-blind, controlled clinical trial.

A multicenter, parallel-group, randomized, double-blind, active-controlled clinical trial, involving 169 outpatients at 9 centers, was conducted to assess the efficacy of a fixed bacterium combination of Lactobacillus gasseri and Bifidobacterium longum in the therapy of acute diarrhea. In particular, this clinical trial was designed to prove equivalent therapeutic efficacy of a fixed bacterium combination versus an exhaustive investigated mono-bacterium medicinal product. All patients, free to carry on usual daily activities, received 1 capsule 3 times a day of either a fixed bacterium combination of Lactobacillus gasseri and Bifidobacterium longum or Enterococcus faecium mono-bacterium. All treatments were continued for a maximum of 6 days in line with the normal course of acute diarrhea. Primary efficacy criterion was the severity and duration of diarrhea assessed by the ensemble of stool frequency as change from baseline and stool consistency at trial Day 2, 3 and 4, and time in days until normal bowel function (recovery). The median duration of diarrhea was 2.70 days versus 2.67 days (fixed bacterium combination of Lactobacillus gasseri and Bifidobacterium longum versus mono-bacterium Enterococcus feacium). The total mean difference of duration of diarrhea was 0.072 days. This result can be considered equivalent. However, the proportion of patients with complete recovery tended to be higher in the fixed bacterium combination group (92.6% versus 87.1%) resulting in a number needed to treat (NNT) of 18.1. The fixed bacterium combination reduced the number of unformed stools by 80% and the mono-bacterium by 75% during the first 2 days of treatment. Both treatments were well tolerated. Oral therapy with a fixed combination of Lactobacillus gasseri and Bifidobacterium longum shortens the duration and decreases the severity of acute self-limiting diarrhea in adults comparable to an effective mono-bacterium medicinal product. It therefore appears to be a useful and safe treatment for this disease.

Acute Disease↗
PubMed2000

[The effects of tea polyphenols on the adherence of cariogenic bacterium to the salivary acquired pellicle in vitro].

OBJECTIVE: It has been proved that tea polyphenols (TP) can inhibit the sucrose-dependent adherence of oral cariogenic bacterium to the tooth surface. This study is carried on to investigate the effects of tea polyphenols on the preliminary adherence of main cariogenic bacterium to salivary acquired pellicle and reveal the anticarious mechanisms of tea polyphenols further. METHODS: The hydroxyapatites were coated by saliva to form S-HA, an in-vitro model of experimental pellicle. Streptococcus mutans 3a3 and Actinomyces viscosus ATCC 19246 were chosen as the main cariogenic bacterium, and the microorganisms were radiolabelled by growing them in TPY culture medium supplemented with 3H-thymidine. Tea polyphenols solution was prepared, the concentrations of which were 0.5, 1.0, 2.0 and 4.0 mg/ml respectively. Two parts of inhibited adherence tests were done with TP-treated S-HA or TP-treated bacterium. In the first one, S-HA was immerged into the TP solution of different concentrations for 1 h before the attachment of bacterium. In the other, the bacterium were mixed with the TP solution for 1 h and then centrifuged and washed before bound to S-HA. The whole process was carried on in KCl buffer solution. The number of 3H-thymidine-labelled bacterium which attached to S-HA were determined by scintillation counting. RESULTS: In both the two parts of this study, tea polyphenols solution, the concentrations of which were changed from 1.0 to 4.0 mg/ml, could decrease the number of S. mutans 3a3 and A. viscosus ATCC 19246, and the inhibition rates rose with the increase of the concentrations of TP solution. But the inhibitory effects of 0.5 mg/ml TP solution were inconsistent in different tests. The results showed that 1.0-4.0 mg/ml TP solution could inhibit the attachments of S. mutans and A. viscosus to S-HA effectively. The inhibitory functions of tea polyphenols were so obvious that in some experiments, while the concentrations of TP solution were changed from 2.0 to 4.0 mg/ml, the number of 3H-thymidine-labelled bacterium which attached to S-HA was even less than that of the same bacterium which attached to naked HA. CONCLUSION: Tea polyphenols can inhibit the preliminary adherence of Streptococcus mutans and Actinomyces viscosus to S-HA effectively. TP may prevent enamel from caries by decreasing the adherence of main cariogenic bacterium to salivary acquired pellicle.

Actinomyces viscosus↗
PubMed2000

[The effects of tea polyphenols on the adherence of cariogenic bacterium to the collagen in vitro].

OBJECTIVE: In the first phase of our study, it has been proved that tea polyphenols (TP) can inhibit the preliminary adherence of oral cariogenic bacterium to salivary acquired pellicle. This study is carried on to investigate the effects of tea polyphenols on the preliminary adherence of main cariogenic bacterium to collagen I and reveal the anticarious mechanisms of tea polyphenols further. METHODS: Tea polyphenols solution was prepared firstly, the concentrations of which were 0.5, 1.0, 2.0 and 4.0 mg/ml. An in-vitro model of experimental pellicle(C-HA) was formed by immerging the hydroxyapatites in 250 micrograms/ml collagen I solution for 1 h. Streptococcus mutans 3a3, Actinomyces viscosus ATCC 19246 and Lactobacillus ATCC 4546 were chosen as the main cariogenic bacterium and radiolabelled by growing them in TPY culture medium supplemented with 3H-thymidine. Two parts of inhibited adherence tests were done with TP-treated C-HA or TP-treated bacterium respectively. In the first one, C-HA was immerged into the TP solution of different concentrations for 1 h before the attachment of bacterium. In the other, the bacterium were mixed with the TP solution for 1 h and then centrifuged and washed before bound to C-HA. KCl buffer solution provided a steady condition to the whole process. Finally, the number of 3H-thymidine-labelled bacterium which attached to C-HA were determined by scintillation counting. RESULTS: In both the two parts of this study, tea polyphenols solution, the concentrations of which were changed from 1.0 to 4.0 mg/ml could inhibit the attachments of S. mutans 3a3, A. viscosus ATCC 19246 and Lactobacillus ATCC 4546 to C-HA effectively, and the inhibition rates rose with the increase of the concentrations of TP solution. But the inhibitory effects of 0.5 mg/ml TP solution were inconsistent in different tests. The inhibitory functions of tea polyphenols were so prominent that in some experiments, while the concentrations of TP solution were higher than 2.0 mg/ml, the number of 3H-thymidine-labelled bacterium which attached to C-HA was even less than that of the same bacterium which attached to naked HA. These results showed that TP had the remarkable inhibitory efficiency on the attachments of S. mutans, A. viscosus and Lactobacillus to C-HA. CONCLUSION: Tea polyphenols can inhibit the preliminary adherence of Streptococcus mutans, Actinomyces viscosus and Lactobacillus to C-HA effectively. TP may prevent dentine from caries by decreasing the adherence of main cariogenic bacterium to collagen.

Actinomyces viscosus↗
PubMed2001

[Influence of surface roughness of pure titanium on accumulation of bacterium].

OBJECTIVE: The aim of this investigation was to evaluate the influence of surface roughness of pure titanium on adhesion of bacterium. METHODS: A total of six edentulous volunteers with healthy oral mucosa participated in an in vivo study. Four kinds of pure Titanium testing pieces with different surfaces were fixed in the polished surface of upper complete dentures and the other in the tissue surface of the dentures. After 6-month wearing the dentures, the amount and species of bacterium adhered on pure Titanium were examined. RESULTS: (1) Individual difference had a significant influence on amount of bacterium adhered on pure Titanium, but had no relation to species of bacterium according to Gram's staining. (2) To the same patient, with the increase of roughness, bacterium adhered on samples improved in amount (P < 0.01), but remained the same in composition. Wrinkly samples collected more bacterium than plane samples and exhibited G- coccus beside G+ coccus. Comparing two samples with same roughness, the one with roughness on the tissue surface of the denture collected less bacterium than that on the polished surface (P < 0.01), and predominantly presented G- rod bacterium and coccus, which was completely different to that on the polished surface. CONCLUSION: From the perspective of benefit to periodontal tissue, plane surface should be adopted when framework of pure Titanium is made, and polishing of the prosthesis after being modified should be paid more attention, especially on the tissue surface.

Bacteria↗
PubMed1997

Evaluating Children in the Ukraine for Colonization With the Intestinal Bacterium Oxalobacter formigenes, Using a Polymerase Chain Reaction-based Detection System.

Background: Oxalobacter formigenes is a recently discovered anaerobic bacterium residing in the gastrointestinal tracts of most vertebrates, including humans. Evidence suggests that this bacterium plays an important symbiotic relationship with its hosts by regulating oxalic acid homeostasis. Oxalic acid is a ubiquitous toxic by-product of metabolism associated with numerous pathologic conditions, including hyperoxaluia, cardiac myopathy and conductance disorders, kidney stones, and even death. Despite the potential importance of O. formigenes in several major health disorders, the difficulty in culturing, isolating, and identifying this fastidious anaerobe has limited research of its disease associations. Because O. formigenes must use two unique enzymes to catabolize oxalic acid, this bacterium appeared to be a suitable model for DNA-based identification, thereby circumventing the labor-intensive procedures currently used. Methods and Results: In this study, genus- and group-specific oligonucleotide sequences were designed corresponding to homologous regions residing in the oxc gene that enodes for oxalyl-coenzyme A decarboxylase. A polymerase chain reaction (PCR)-based amplification of the 5'end of this gene directly from genomic DNA isolated from various strains of O. formigenes was used to show that the genus- and group-specific oligonucleotide probes could identify and subgroup the bacterium. Field testing of this PCR-based detection system with 100 fecal cultures collected from children aged 0-12 years demonstrated the ease and efficacy with which O. formigenes can now be identified. Furthermore, these latter data provide a profile for the natural colonization of a human population with this intestinal bacterium. Conclusions: Development and use of this PCR-based detection system permit the rapid identification and classification of the gut-associated bacterium O. formigenes, thereby circumventing the need for the more labor-intensive and lengthy method currently used. The first field test of this detection system indicates that humans apparently do not become colonized with O. formigenes until they begin crawling about in the environment. Furthermore, studies investigating the association between several disorders (eg, kidney stones, irritable bowel syndrome, and hyperoxaluria) and the absence of the bacterium from the gut will now prove far easier.

Journal Article↗
PubMed2005

Molecular characterization of the nonphotosynthetic partner bacterium in the consortium "Chlorochromatium aggregatum".

Phototrophic consortia represent valuable model systems for the study of signal transduction and coevolution between different bacteria. The phototrophic consortium "Chlorochromatium aggregatum" consists of a colorless central rod-shaped bacterium surrounded by about 20 green-pigmented epibionts. Although the epibiont was identified as a member of the green sulfur bacteria, and recently isolated and characterized in pure culture, the central colorless bacterium has been identified as a member of the beta-Proteobacteria but so far could not be characterized further. In the present study, "C. aggregatum" was enriched chemotactically, and the 16S rRNA gene sequence of the central bacterium was elucidated. Based on the sequence information, fluorescence in situ hybridization probes targeting four different regions of the 16S rRNA were designed and shown to hybridize exclusively to cells of the central bacterium. Phylogenetic analyses of the 1,437-bp-long sequence revealed that the central bacterium of "C. aggregatum" represents a so far isolated phylogenetic lineage related to Rhodoferax spp., Polaromonas vacuolata, and Variovorax paradoxus within the family Comamonadaceae. The majority of relatives of this lineage are not yet cultured and were found in low-temperature aquatic environments or aquatic environments containing xenobiotica or hydrocarbons. In CsCl-bisbenzimidazole equilibrium density gradients, genomic DNA of the central bacterium of "Chlorochromatium aggregatum" formed a distinct band which could be detected by quantitative PCR using specific primers. Using this method, the G+C content of the central bacterium was determined to be 55.6 mol%.

Base Composition↗
PubMed2006

Morphological and ultrastructural characterization of an unusual purple sulfur bacterium from a marine microbial-mat community.

An unusual purple sulfur bacterium present in the pink layer of the Ebro Delta microbial mats has been identified through the study of its ultrastructural features. As pure cultures of this bacterium have not been obtained, due to its inability to grow in axenic conditions, only enrichment cultures where it reached at least 90% of total biomass have been considered. In enrichment cultures, the cells are rods that are 5.4+/-0.6 microm wide and 11.0+/-2.1 microm long. The color of the cell suspensions is pink to pinkish-red. Cells are motile by means of a polar tuft of flagella and multiply by binary fission. This bacterium possesses an extensive internal photosynthetic membrane system consisting of stacks of lamellae, contains bacteriochlorophyll a and carotenoids of normal spirilloxanthin series and deposits sulfur intracellularly. In natural samples, the most abundant phototrophic purple sulfur bacterium developing in this ecosystem has the same kind of intracytoplasmic membrane system, but the cells differ slightly in size and arrangement, in that they are ovoid, 4.2+/-0.5 microm wide and 6.0+/-1.4 microm long, and can be seen forming irregular non-motile clumps which are embedded in slime. Differences observed between field samples and enrichment cultures suggest that environmental conditions may bring about changes in the phenotypic characteristics of the cells. The morphological characteristics of the described bacterium resemble those of large Chromatia. However, this bacterium differs from known species in this group, particularly in terms of its photosynthetic membrane system and in its light absorption properties.

Bacteriochlorophyll A↗
PubMed2004

Carbohydrates act as receptors for the periodontitis-associated bacterium Porphyromonas gingivalis: a study of bacterial binding to glycolipids.

In this study we show for the first time the use of carbohydrate chains on glycolipids as receptors for the periodontitis-associated bacterium Porphyromonas gingivalis. Previous studies have shown that this bacterium has the ability to adhere to and invade the epithelial lining of the dental pocket. Which receptor(s) the adhesin of P. gingivalis exploit in the adhesion to epithelial cells has not been shown. Therefore, the binding preferences of this specific bacterium to structures of carbohydrate origin from more than 120 different acid and nonacid glycolipid fractions were studied. The bacteria were labeled externally with (35)S and used in a chromatogram binding assay. To enable detection of carbohydrate receptor structures for P. gingivalis, the bacterium was exposed to a large number of purified total glycolipid fractions from a variety of organs from different species and different histo-blood groups. P. gingivalis showed a preference for fractions of human and pig origin for adhesion. Both nonacid and acid glycolipids were used by the bacterium, and a preference for shorter sugar chains was noticed. Bacterial binding to human acid glycolipid fractions was mainly obtained in the region of the chromatograms where sulfated carbohydrate chains usually are found. However, the binding pattern to nonacid glycolipid fractions suggests a core chain of lactose bound to the ceramide part as a tentative receptor structure. The carbohydrate binding of the bacterium might act as a first step in the bacterial invasion process of the dental pocket epithelium, subsequently leading to damage to periodontal tissue and tooth loss.

Carbohydrate Metabolism↗
PubMed2005

The first true obligately syntrophic propionate-oxidizing bacterium, Pelotomaculum schinkii sp. nov., co-cultured with Methanospirillum hungatei, and emended description of the genus Pelotomaculum.

A Gram-positive, spore-forming, syntrophic propionate-oxidizing bacterium, Pelotomaculum schinkii sp. nov. strain HH(T), was isolated as a co-culture with Methanospirillum hungatei JF-1(T) from anaerobic, freeze-dried granular sludge obtained from an upflow anaerobic sludge bed reactor treating sugar beet wastewater. The bacterium converted propionate to acetate in co-culture with Methanospirillum hungatei JF-1(T) or Methanobacterium formicicum MF(NT), but not in co-culture with Methanobrevibacter arboriphilus AZ. The organism could not be cultured axenically with any of the substrates tested and therefore can be considered as a (the first) true anaerobic syntrophic bacterium. The bacterium contained two distinct 16S rRNA gene sequences, with 96.8% sequence similarity, which were both expressed during syntrophic growth on propionate as revealed by fluorescent in situ hybridization. The most closely related organisms are Cryptanaerobacter phenolicus LR7.2(T), a bacterium that transforms phenol into benzoate, and Pelotomaculum thermopropionicum SI(T), a thermophilic, syntrophic propionate-oxidizing bacterium. Other related species belong to the Gram-positive, sulfate-reducing genus Desulfotomaculum. The type strain of Pelotomaculum schinkii is strain HH(T) (=ATCC BAA-615(T)=DSM 15200(T)).

Anaerobiosis↗
PubMed1998

Environmental occurrence of the Whipple's disease bacterium (Tropheryma whippelii).

Whipple's disease is a systemic disorder in which a gram-positive rod-shaped bacterium is constantly present in infected tissues. After numerous unsuccessful attempts to culture this bacterium, it was eventually characterized by 16S rRNA gene analysis to be a member of the actinomycetes. The name Tropheryma whippelii was proposed. Until now, the bacterium has only been found in infected human tissues, but there is no evidence for human-to-human transmission. Here we report the detection of DNA specific for the Whipple's disease bacterium in 25 of 38 wastewater samples from five different sewage treatment plants in the area of Heidelberg, Germany. These findings provide the first evidence that T. whippelii occurs in the environment, within a polymicrobial community. This is in accordance with the phylogenetic relationship of this bacterium as well as with known epidemiological aspects of Whipple's disease. Our data argue for an environmental source for infection with the Whipple's disease bacterium.

Actinobacteria↗
PubMed2001

Pathogenicity of Moraxella osloensis, a bacterium associated with the nematode Phasmarhabditis hermaphrodita, to the slug Deroceras reticulatum.

Moraxella osloensis, a gram-negative bacterium, is associated with Phasmarhabditis hermaphrodita, a nematode parasite of slugs. This bacterium-feeding nematode has potential for the biological control of slugs, especially the grey garden slug, Deroceras reticulatum. Infective juveniles of P. hermaphrodita invade the shell cavity of the slug, develop into self-fertilizing hermaphrodites, and produce progeny, resulting in host death. However, the role of the associated bacterium in the pathogenicity of the nematode to the slug is unknown. We discovered that M. osloensis alone is pathogenic to D. reticulatum after injection into the shell cavity or hemocoel of the slug. The bacteria from 60-h cultures were more pathogenic than the bacteria from 40-h cultures, as indicated by the higher and more rapid mortality of the slugs injected with the former. Coinjection of penicillin and streptomycin with the 60-h bacterial culture reduced its pathogenicity to the slug. Further work suggested that the reduction and loss of pathogenicity of the aged infective juveniles of P. hermaphrodita to D. reticulatum result from the loss of M. osloensis from the aged nematodes. Also, axenic J1/J2 nematodes were nonpathogenic after injection into the shell cavity. Therefore, we conclude that the bacterium is the sole killing agent of D. reticulatum in the nematode-bacterium complex and that P. hermaphrodita acts only as a vector to transport the bacterium into the shell cavity of the slug. The identification of the toxic metabolites produced by M. osloensis is being pursued.

Animals↗