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At least 19 recordsLinked to original sources
PubMed1987

[Occurrence and incidence of bacteria in the area of drinking water with antagonistic relations to indicator bacteria].

During a period of 8 months about 3000 drinking water samples derived from different water works and distribution systems around the area of the city Bonn were examined for colony count, E. coli and coliform bacteria and bacteria suppressing the growth of E. coli and S. faecalis. A modified agar diffusion test was used for the determination of antagonistic substances. Bacteria which revealed an antagonistic activity were isolated and identified. The majority of water samples (81.9% of the samples examined for antagonistic bacteria against E. coli) contained no bacteria in 1 ml and therefore were not examined for antagonistic substances. Only 2.5% of the samples had bacterial counts greater 100 per ml. In 64.2% of the samples examined for bacteria antagonistic to S. faecalis, no counts were found and 2.4% had counts greater 100. The occurrence of fecal indicators was very low in samples with low colony forming units (cfu). At counts greater than 100 we found E. coli within 30.6% and coliform bacteria in 38.8% of the samples examined for bacteria showing antagonistic activity against E. coli. E. coli and coliform bacteria were determined in 24.2% and 33.3% of the samples examined for antagonistic bacteria against S. faecalis. 20% of the samples with colony counts between 1 to 10 contained bacteria showing antagonistic activity against E. coli and at counts greater than 100 they were found in 57.1% of the samples. On the other hand, the quantity of samples with suppression of S. faecalis was 10 to 20% lower and reached a maximum of 39.4% at cfu greater 100. Most of the isolated antagonistic strains belong to the genus Pseudomonas and even 57.8% of the inhibitory strains against E. coli and 26.5% against S. faecalis were found to be P. fluorescens.

Bacteriological Techniques↗
PubMed1987

Urease activity of adherent bacteria and rumen fluid bacteria.

In experiments on six sheep fed on a low nitrogen diet (3.7 g N/day), urease (EC 3.5.1.5) activity (nkat X mg-1 bacterial dry weight) 3 h after feeding was found to be highest in the bacteria adhering to the rumen wall (13.25 +/- 2.10), lower in the rumen fluid bacteria (8.96 +/- 1.35) and lowest in the bacteria adhering to feed particles in the rumen (5.69 +/- 2.13). The urease activity of bacteria adhering to the rumen wall and of the rumen fluid bacteria of six sheep fed on a high nitrogen diet (21 g N/day) was significantly lower than in sheep with a low N intake and in both cases was roughly the same (3.81 +/- 1.37 and 3.76 +/- 1.02 respectively); it was lowest in bacteria adhering to feed particles in the rumen (1.92 +/- 0.90). It is concluded from the results that the urease activity of rumen fluid bacteria and of bacteria adhering to the rumen wall and to feed particles in the rumen is different and that it falls significantly in the presence of a high nitrogen intake. From the relatively high ureolytic activity of bacteria adhering to the rumen wall in the presence of a low nitrogen intake it is assumed that this is one of the partial mechanisms of the hydrolysis of blood urea entering the rumen across the rumen wall and of its reutilization in the rumen-liver nitrogen cycle in ruminants.

Animal Feed↗
PubMed1971

Platelet interaction with bacteria. II. Fate of the bacteria.

Several common strains of bacteria have been studied to determine their influence on human and rabbit platelets in vitro. Bacteria at a nominal ratio of 1:1 were added to platelets in their native plasma or to platelets in a balanced salt solution. The platelet-bacterial interaction was examined by nephelometry and by sequential light microscopy of fixed specimens taken at key points in the reaction. The results support the following conclusions: (1) Bacteria that were potent stimuli of the platelet aggregation reaction were incorporated in large numbers into the forming platelet aggregates. (2) Bacteria sequestered within platelet aggregates remained in direct contact with the aggregated platelet mass for up to 1 hour in vitro and during this time showed no morphologic changes by light microscopy. (3) Plateletbacterial interaction produced clumping of the bacteria but no demonstrable killing of the microorganisms. (4) Collagen-platelet interaction resulted in release of platelet products that were capable of clumping bacteria but were not lethal to them. (5) Rabbit and human platelets showed no species differences in plateletbacterial interaction. (6) Washed platelets interacted with bacteria without added serum factors but the addition of serum accelerated the aggregation reaction.

Animals↗
PubMed1992

Human bactericidal/permeability-increasing protein and a recombinant NH2-terminal fragment cause killing of serum-resistant gram-negative bacteria in whole blood and inhibit tumor necrosis factor release induced by the bacteria.

The bactericidal/permeability-increasing protein (BPI) of neutrophils and BPI fragments neutralize the effects of isolated Gram-negative bacterial lipopolysaccharides both in vitro and in vivo. Since endotoxin most commonly enters the host as constituents of invading Gram-negative bacteria, we raised the question: Can BPI and its bioactive fragments also protect against whole bacteria? To determine whether the bactericidal and endotoxin-neutralizing activities of BPI/fragments are expressed when Gram-negative bacteria are introduced to the complex environment of whole blood we examined the effects of added BPI and proteolytically prepared and recombinant NH2-terminal fragments on: (a) the fate of serum-resistant encapsulated Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa that survive the antibacterial actions of whole blood and (b) the ability of these bacteria to trigger cytokine release. Added BPI in nanomolar concentrations killed each of three encapsulated strains of E. coli and in closely parallel fashion inhibited tumor necrosis factor (TNF) release. Holo-BPI and its NH2-terminal fragment were equipotent toward a rough LPS chemotype K1-encapsulated strain, but the fragment was substantially more potent than holo-BPI toward two encapsulated smooth LPS chemotype strains. TNF release induced by K. pneumoniae and P. aeruginosa was also inhibited by both holo-BPI and fragment but, at the protein concentrations tested, P. aeruginosa was killed only by the fragment and K. pneumoniae was not killed by either protein. The bactericidal action of BPI/fragment toward E. coli is inhibited by C7-depleted serum, but accelerated by normal serum, indicating that BPI, acting in synergy with late complement components, enhances extracellular killing of serum-resistant bacteria. Thus, BPI and an even more potent NH2-terminal fragment may protect against Gram-negative bacteria in the host by blocking bacterial proliferation as well as endotoxin-mediated effects, not only as components of the intracellular antibacterial arsenal of the neutrophil, but also as potentially therapeutic extracellular agents.

Antimicrobial Cationic Peptides↗
PubMed1992

Efficacy of burning, tillage, and biocides in controlling bacteria released at field sites and effects on indigenous bacteria and fungi.

Decontamination treatments of burning and biocide application, alone and in combination with tillage, were evaluated for their ability to reduce populations of bacteria applied to the leaves of plants in field plots. In addition, the effects of these control methods on indigenous leaf and soil bacteria and fungi were assessed. Field plots of bush beans (Phaseolus vulgaris), sprayed with the bacterium Pseudomonas syringae, Pseudomonas fluorescens, or Erwinia herbicola, received the following treatments: (i) control, (ii) tillage, (iii) burning, (iv) burning plus tillage (burn-tillage), (v) Kocide (cupric hydroxide), (vi) Kocide plus tillage, (vii) Agri-Strep (streptomycin sulfate), and (viii) Agri-Strep plus tillage. Leaves and soil from the plots were sampled at 1 day before and at 1, 3, 7, 10, 14, 21, and 30 days after application of the decontamination treatments. The burn and burn-tillage treatments produced the most significant reductions in bacterial populations. The Agri-Strep treatment was more effective than the Kocide treatment in eliminating applied bacteria, but neither biocide produced consistent or persistent control. In contrast, the tillage treatment, alone or in combination with the Agri-Strep or Kocide treatments, had a short-term stimulatory effect and increased populations of applied bacteria and also levels of indigenous fungi and bacteria. Agri-Strep and Kocide treatments caused significant reductions in indigenous bacterial populations up to 14 days after application and in indigenous fungal populations on day 7 after application. Our results suggest that conventional plant disease control methods may not provide satisfactory control of genetically engineered microorganisms and indicate a need for further development of effective and selective methods to control release microorganisms at field sites.

Agriculture↗
PubMed1991

Competition for hydrogen by human faecal bacteria: evidence for the predominance of methane producing bacteria.

Studies of sludge have shown that some species of sulphate reducing bacteria outcompete methane producing bacteria for the common substrate H2. A similar competition may exist in human faeces where the methane (CH4) producing status of an individual depends on the faecal concentration of sulphate reducing bacteria. To determine if non-methanogenic faeces outcompete CH4 producing faeces for H2, aliquots of each type of faeces were incubated alone or mixed together, with or without addition of 10% H2 and/or 20 mmol/l sulphate. Methane producing faeces consumed H2 significantly more rapidly and reduced faecal H2 tension to a lower value compared with non-methanogenic faeces. The mixture of the two types of faeces yielded significantly more CH4 than CH4 producing faeces alone (mean (SD) 8.5 (1.3) v 2.9 (0.45) mmol/l of homogenate per 24 hours, p less than 0.01). Faecal sulphide concentrations were similar in CH4 producing and non-producing homogenates both before and after 24 hours of incubation. The addition of sulphate to the homogenates did not significantly influence CH4 production or sulphide formation. Our results suggest that in human faeces methane producing bacteria outcompete other H2 consuming bacteria for H2.

Bacteria, Anaerobic↗
PubMed1986

The presence of bacteria in the oral epithelium in periodontal disease. II. Immunohistochemical identification of bacteria.

Serial histological sections of gingiva obtained from each of six advanced adult periodontitis, two localized juvenile periodontitis and two periodontally healthy patients were used for specific identification of bacteria within the oral epithelium and adjacent connective tissue. Healthy gingival biopsies served as controls. Sections from patients and control biopsies were Gram-stained and also screened with antibacterial sera associated with the peroxidase immunocytochemical technique for specific bacterial identification. The "Pop-off" electron microscopic technique was also used to further demonstrate the bacterial nature of peroxidase-stained material. In addition, the possible correlation between bacteria and areas of possible reduced keratinization was investigated. The results showed that sections of orthokeratinized healthy gingiva did not contain bacteria. Gram-stained sections from diseased sites contained large numbers of bacteria in the oral epithelium and adjacent connective tissue. Bacteroides gingivalis and to a lesser extent Capnocytophaga gingivalis were found in periodontitis, and Actinobacillus actinomycetemcomitans was found in juvenile periodontitis when the immunoperoxidase technique was used. The bacterial nature of peroxidase-stained material was confirmed by the "pop-off" technique. In the disease biopsies, bacterial presence was correlated with areas of reduced amounts of keratin suggesting that the oral epithelium may be a portal of entry for bacteria into gingival tissues.

Actinobacillus↗
PubMed1979

A simple method for the separation of tissue-cultured plant cells from unbound bacteria: a demonstration of acquired affinity for bacteria by cells of soy bean.

Tissue-cultured cells of soy bean, grown in liquid medium and then transferred to an agar substratum in so-called tissue chambers, showed an affinity for the binding of applied bacteria (Klebsiella pneumoniae). This binding, which became greater as the plant cells remained on the agar for up to 10 days, was manifested as an increasing resistance of the bacteria to be washed from the plant cells in a standard, gentle and reproducible procedure devised for this purpose. The number of bacteria firmly bound to the cells was determined by the use of 32P-labelled bacteria and was largely independent of the concentration of bacteria in the suspension applied to the tissue-cultured cells.

Adsorption↗
PubMed1992

Isolation and identification of intestinal bacteria from Japanese tree frog (Hlya japonica) with the special reference to anaerobic bacteria.

The bacteria in the large intestines of eight Japanese tree frogs (Hlya japonica) were enumerated by using an anaerobic culture system. The microorganisms at approximately 3.1 x 10(9) bacteria per g (wet weight) of intestinal contents were present in the intestine of all the frogs tested. No difference of the total bacteria in the frog intestine was observed between two different incubation-temperatures (room temperature and 37 degrees C). Eleven genera and 16 species were isolated from the frog intestine. In most frogs, Bacteroides (B.) caccae and B. vulgatus were detected as the predominant organisms. Escherichia coli was also present in greater numbers in the intestine. Other bacteria isolated at high dilutions were strict anaerobes, including Fusobacterium and Clostridium. Enterococcus faecalis was frequently isolated from the frog intestine. However, four genera of Bifidobacterium, Eubacterium, Peptostreptococcus, and Lactobacillus were not isolated from the frog intestine.

Animals↗
PubMed1978

Oxygen and "strictly anaerobic" intestinal bacteria. II. Oxygen metabolism in strictly anaerobic bacteria.

Oxygen metabolism of "strictly anaerobic" intestinal bacteria was investigated and compared in 25 strains. Washed cell suspensions of all the bacterial strains, in which growth in a medium initially equilibrated with a gas mixture consisting of 5% O2, 5% CO2, and 90% N2 was almost the same as under anaerobic conditions, absorbed O2 at high rate. Such O2 uptake was inhibited by NaN3. Most strains in which growth was inhibited either partially or completely in the same oxygenic condition absorbed O2 at a comparably low rate, and in many cases, such O2 uptake was not inhibited by NaN3. However, in a certain strain incapable of growth in the initial presence of dissolved O2, absorption of O2 was as high as that in some aerobic bacteria, and it was inhibited by NaN3. Little interrelationship was found between the degree of oxygen tolerance and the activities of NADH-peroxidase, H2O2-splitting reaction or superoxide dismutase. A slight interrelationship seems to be present in the case of NADH oxidase even though many exceptions were recognized. All the strains studied had the activities of superoxide dismutase, the absence of which has been regarded as the enzymatic basis of strict anaerobiosis of "strictly anaerobic" bacteria. Some strict anaerobes had high an activity of this enzyme as some aerobic bacteria. The differences in the levels of this activity seem to have some interrelationship not with differences in the degree of oxygen tolerance but with those in the genus to which every strain belongs taxonomically.

Anaerobiosis↗
PubMed1977

Studies on phosphate-solubilizing bacteria in soil and rhizosphere of different plants. I. Occurrence of bacteria, acid producers, and phosphate dissolvers.

Occurrence of bacteria (total), acid producing and phosphate dissolving micro-organisms in soil, rhizosphere, and rizoplane of Egyptian cotton, peas, or maize during their different growth phases was studied. The rhizosphere effects were generally positive and differed according to type of plant, growth phase of each special plant, and type of micro-organism under study. The high densities of bacteria, acid-producers, and phosphate-dissolvers in the rhizoplane samples suggest the conclusion that roots of the studied plants are colonized with these soil micro-organisms. The role of the micro-organism and the mechanism of the noted colonization is not fully understood yet. However, the presence of high numbers of bacteria in the rhizosphere zones of all plants is undoubtedly important, since they may convert organic and inorganic substances into available plant nutrients. The acidproducing organisms were greatly stimulated in the rhizosphere of all plants. Consequently, the production of acid, especially in alkaline soils such as in Egypt, may directly or indirectly react with insoluble inorganic compounds, converting their nutrient elements into available forms for the growing plants. But not all acid-producers are considered as phosphate-dissolvers. Therefore, the presence of high numbers of phosphate-dissolving bacteria in the rhizophere zones may explain how the growing plants can obtain their requirements in such alkaline soils.

Bacteria↗
PubMed1987

Can decreased phagocytosis and killing of autologous gram-positive bacteria explain the finding of gram-positive bacteria in "non-bacterial prostatitis"?

Immunological deficiency is seldom considered in the pathogenesis of chronic prostatitis, despite clinical symptoms of prostatic inflammation and occasionally also in other tissues. Investigations in three patients with severe bacterial prostatitis with Gram-positive bacteria in the prostatic secretion revealed a decreased phagocytotic activity of the polymorphonuclear leukocytes (PMN-cells) derived from patients' sera towards the autologous Gram-positive bacteria from their own prostatic secretions but not towards heterologous Gram-positive bacteria from other patients or controls. These observations indicate a hitherto unobserved, altered host-parasite interaction in patients with prostatitis possibly caused by Gram-positive bacteria.

Adult↗
PubMed1979

Effect of leukocyte hydrolases on bacteria. XV. Inhibition by antibiotics, metabolic inhibitors, and ultraviolet irradiation of the release by leukocyte extracts, trypsin, and lysozyme of lipopolysaccharide from gram-negative bacteria.

Leukocyte extracts, trypsin, and lysozyme are all capable of releasing the bulk of the LPS from S. typhi, S. typhimurium, and E. coli. Bacteria which have been killed by heat, ultraviolet irradiation, or by a variety of metabolic inhibitors and antibiotics which affect protein, DNA, RNA, and cell wall synthesis no longer yield soluble LPS following treatment with the releasing agents. On the other hand, bacteria which are resistant to certain of the antibiotics yield nearly the full amount of soluble LPS following treatment, suggesting that certain heatlabile endogenous metabolic pathways collaborate with the releasing agents in the release of LPS from the bacteria. It is suggested that some of the beneficial effects of antibiotics on infections with gram-negative bacteria may be the prevention of massive release of endotoxin by leukocyte enzymes in inflammatory sites.

Anti-Bacterial Agents↗
PubMed1991

Evidence that mycoplasmas, gram-negative bacteria, and certain gram-positive bacteria share a similar protein antigen.

It was demonstrated that mycoplasmas, gram-negative bacteria, and certain gram-positive bacteria share a similar protein antigen with a molecular weight ranging from 42,000 to 48,000. Western blotting (immunoblotting) with an antibody specific to a 43-kDa membrane protein of Mycoplasma fermentans showed the existence of this protein antigen in all Mycoplasma spp. tested (14 species), Acholeplasma laidlawii (1 strain), and gram-negative bacteria (8 species) but only in Staphylococcus aureus of four gram-positive species tested. Neither Ureaplasma urealyticum nor mammalian cell cultures showed any cross-reactions with this antibody. These proteins were found in both cytoplasmic and membrane fractions of mycoplasma cells but were not exposed on the surface of mycoplasmal or bacterial cells.

Antigens, Bacterial↗
PubMed1991

Intestinal bacteria of newborn Ethiopian infants in relation to antibiotic treatment and colonisation by potentially pathogenic gram-negative bacteria.

The aerobic and anaerobic intestinal microflora of 60 newborn infants in Addis Ababa was studied. As opposed to earlier published studies from Stockholm, there were no consistent changes of the microflora attributable to antibiotic treatment. The reason why antimicrobial agents caused quantitatively smaller changes of the intestinal microflora in newborn infants in Addis Ababa than in Stockholm is not known, but may be due to antimicrobial inactivation, or marked, continuous ingestion of bacteria. Colonisation by potentially pathogenic gram-negative bacteria was coupled to a low isolation rate of bifidobacterium, but not of lactobacillus. This is consistent with the hypothesis that bifidobacterium might convey some kind of resistance to colonisation by and overgrowth of gram-negative bacteria in newborn infants. Similar results have previously been obtained in Stockholm. In comparison to 45 healthy infants in Stockholm, the Ethiopian infants had more enterococcus and lactobacillus and less staphylococcus and bacteroides during the first 2 weeks of life. After that time, the only difference was more frequent colonisation by lactobacillus in Addis Ababa.

Anti-Bacterial Agents↗
PubMed2025

Broad-spectrum antibacterial and antibiofilm activity of dandelion endophytic bacteria against multidrug-resistant bacteria.

Microbial secondary metabolites have long served as a key source of natural product-based drugs. This study evaluates the antibacterial, antibiofilm, and antioxidant activities of endophytic bacteria derived from dandelion, focusing on their effects against multidrug-resistant (MDR) clinical isolates. In total, 33 endophytic bacteria strains were isolated from Taraxacum ohwianum, representing 15 genera. Among these, 13 exhibited antibacterial activity, with 6 demonstrating efficacy against MDR clinical isolates. The endogenous strain Bacillus velezensis DR8 showed strong antibacterial activity against all three MDR strains tested and exerted inhibitory effects on the biofilm formation and dispersal of methicillin-resistant Staphylococcus aureus. Genome sequencing and antibiotics and secondary metabolite analysis shell analysis revealed that this strain harbors 12 biosynthetic gene clusters (BGCs) associated with secondary metabolite production. Of these, seven BGCs exhibited ≥ 80% similarity to known clusters, suggesting the potential to synthesize surfactin, difficidin, fengycin, bacillaene, macrolactin H, bacilysin, and bacillibactin. Overall, these findings indicate that endophytic bacteria from dandelion are a potential source of antibacterial compounds and biofilm formation inhibitors.

Endophytes↗
PubMed1991

Degradation of cellulose and forage fiber fractions by ruminal cellulolytic bacteria alone and in coculture with phenolic monomer-degrading bacteria.

We hypothesized that bacterial species capable of metabolizing phenolic monomers may act as catalysts for forage fiber breakdown by increasing microbial access to cell wall polysaccharides. Ruminal cellulolytic bacteria alone and in combination with phenolic-degrading bacteria were examined for differences in their ability to degrade fiber fractions of alfalfa or bromegrass. Electron micrographs of Fibrobacter succinogenes S85 cultured in combination with the ruminal phenolic-degrading organisms Eubacterium oxidoreducens G41 and Syntrophococcus sucromutans S195 indicated that bromegrass was degraded more extensively by the triculture than by the monoculture. The sequential detergent system was used to quantify the digestibility of fiber components from alfalfa and bromegrass. F. succinogenes incubated with the two phenolic-degrading organisms did not degrade more cell wall material than did F. succinogenes alone. However, with two other ruminal cellulolytic organisms, Clostridium longisporum B6405 and Ruminococcus albus B6403, greater (P less than .05, P less than .10, respectively) amounts of hemicellulose were degraded (72 h in vitro fermentation) from whole-plant alfalfa when E. oxidoreducens and S. sucromutants were combined with the cellulolytic species than when their monocultures were tested. Similar increases were not observed using a NDF preparation of alfalfa as the substrate. Based on these in vitro experiments, it does not seem that E. oxidoreducens and S. sucromutans play an important role in improving forage fiber degradation by cellulolytic ruminal bacteria.

Animals↗