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PubMed1998

Cross-species induction and enhancement of antimicrobial activity produced by epibiotic bacteria from marine algae and invertebrates, after exposure to terrestrial bacteria.

Antibiotic producing marine bacteria isolated from surfaces of the marine alga Fucus vesiculosus and the nudibranch Archidoris pseudoargus were exposed to live cells of Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and heat-killed cells of Staph. aureus. Twelve out of the 16 marine strains tested showed enhanced antimicrobial activity towards Staph. aureus, E. coli and Ps. aeruginosa following this exposure. Three out of seven strains tested showed enhanced antimicrobial activity when exposed to Ps. aeruginosa and three out of seven strains showed enhanced antimicrobial activity when exposed to E. coli. These results suggest that production of antimicrobial compounds by marine bacteria can be induced by the presence of terrestrial bacteria. This appears to be the first example of cross-species induction and enhancement of antimicrobial activity in marine bacteria and has important implications for the design of antibiotic screening assays and for an understanding of microbial competition in the environment.

Animals↗
PubMed2003

Detection of bacteria in WBC-reduced PLT concentrates using percent oxygen as a marker for bacteria growth.

BACKGROUND: The risk of receiving a PLT concentrate (PC) contaminated with bacteria may be 1000-fold greater than that of pathogenic viral transmission, yet surveillance for this risk is not generally practiced. A novel bacteria detection system (BDS) that overcomes the limitations of current systems is described. The BDS monitors percent oxygen (%O2) in air above aliquots of PCs that have been filtered to remove the confounding effect of respiring PLTs and residual WBCs. STUDY DESIGN AND METHODS: One-day-old WBC-reduced whole-blood-derived PCs (WBPCs) were inoculated with bacteria at 100 to 500 CFU per mL. After 30 minutes, 2- to 3-mL aliquots were processed through a PLT-reducing filter into a sample pouch containing sodium polyanethol sulfonate and entrained air. After incubation at 35 degrees C for at least 24 hours, the %O2 was measured within the pouch. Noninoculated WBC-reduced WBPCs (n = 155), confirmed free of bacteria by routine culture, were tested in a like manner. Results from the latter group of WBC-reduced WBPCs were used to distinguish contaminated from noncontaminated units. RESULTS: After a 24-hour incubation at 35 degrees C, 195 (96.5%) of the 202 sample pouches obtained from inoculated units were detected by the BDS. After an additional 6 hours at room temperature, those that remained and were tested were found positive. None of the noninoculated controls produced a positive reading. CONCLUSION: The BDS is easy to use and provides good levels of sensitivity and specificity.

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↗
PubMed1984

Antibiotic action on phagocytosed bacteria measured by a new method for determining viable bacteria.

Antibiotics such as rifampin that act on phagocytosed bacteria have clinical advantages. The investigation of such intraphagocytic activity of antibiotics is, however, hampered by the time-consuming and cumbersome procedures necessary for enumerating viable bacteria. We have developed a semiautomatic biophotometric method for this purpose that permits the processing of relatively large numbers of samples. Using this method with Staphyloccus aureus Wood 46 as a test organism, we studied the dose dependence of the activities of a number of antibiotics against intraphagocytic bacteria. We could confirm the very good intracellular activity of rifampin. Its activity at low concentrations was slightly better against intracellular than against extracellular bacteria. In contrast, clindamycin and erythromycin, both of which have been reported to accumulate within phagocytes, did not exhibit a correspondingly enhanced intracellular activity, erythromycin being active intracellularly only at high concentrations. Clindamycin and vancomycin were effective against intracellular organisms, but only at relatively high concentrations owing to their low bactericidal activity against S. aureus Wood 46. Penicillin G, ampicillin, gentamicin, and streptomycin exhibited no useful intracellular activity. These results demonstrate that radioactive accumulation studies of antibacterial agents are not sufficient to show intracellular activity. Intracellular activity must be demonstrated in a functional test, preferably with graded concentrations of the test substance.

Anti-Bacterial Agents↗
PubMed1963

Lipid metabolism of rumen ciliates and bacteria. II. Uptake of fatty acids and lipid analysis of Isotricha intestinalis and rumen bacteria with further information on Entodinium simplex.

The total lipid and free fatty acid contents of Isotricha intestinalis, Entodinium simplex, and the rumen bacterial flora of the respective protozoa were determined. Warburg manometric data showed that the sodium salts of tributyrin, oleic, and acetic acids stimulated gas production in I. intestinalis, whereas tributyrin was stimulatory with E. simplex and less active with oleic and acetic acids. Rumen bacteria provided fatty acids produced lower manometric gaseous increases when compared with the protozoa. Volatile fatty acids were produced by I. intestinalis and rumen bacteria with tributyrin, but not with tripalmitin. Sodium oleate gave little volatile fatty acid response with I. intestinalis or rumen bacteria. Washed suspensions of I. intestinalis and rumen bacteria concentrated C(14)-labeled oleic, palmitic, stearic, and linoleic acids within the cells during short incubation periods. Autoradiographs demonstrated the conversion of C(14)-labeled oleic, palmitic, stearic, linoleic, and acetic acids in the rumen protozoa and bacterial cells.

Animals↗
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↗
PubMed1982

Effect of leukocyte hydrolases on bacteria XVI. Activation by leukocyte factors and cationic substances of autolytic enzymes in Staphylococcus aureus: modulation by anionic polyelectrolytes in relation to survival of bacteria in inflammatory exudates.

The mechanisms involved in the activation of autolytic enzymes in Staphylococcus aureus, by leukocyte extracts, cationic proteins, phospholipase A2, amines, and membrane-damaging agents was studied in a resting cell system as well as by growing staphylococci. The bacteria were labeled with [14C]N-acetylglucosamine and were subjected to a variety of agents either in 0.1 M acetate buffer, pH 5.0, or in phosphate buffer, pH 7.4. While intact log-phase cultures were found to undergo partial autolysis at pH 5.0 and almost complete lysis at pH 7.4, both heat-killed bacteria and bacterial cell walls were completely resistant to autolysis in buffers. Autolysis at pH 5.0 can be further activated by leukocyte extracts, nuclear histone, crystalline ribonuclease, egg-white and human lysozyme, phospholipase A2, as well as by spermine, spermidine, and polymyxins B and E. The addition of viable log-phase bacteria to radiolabeled heat-killed staphylococci or to radiolabeled cell walls which had been cleaned off autolytic enzymes resulted in degradation of the radiolabeled targets. The data suggest that the various inducers of autolysin activation caused leakage of autolytic enzymes from the intact bacteria which attacked the depolymerized the bacterial cell walls. Anionic polyelectrolytes like heparin, dextran sulfate, suramine, polyglutamic acid, and liquid (polyanethole sulfonic acid) markedly inhibited both spontaneous and induced lysis. Staphylococci which had grown in the presence of anionic polyelectrolytes became highly resistant to lysis triggered by any of the inducers of autolysis. Since inflammatory exudates are known to be rich in anionic polyelectrolytes, it is suggested that the prolonged survival of intact bacterial cells in such a milieu may be due to the inactivation of autolytic enzymes. It is also postulated that the degradation of certain bacterial species following phagocytosis or extracellular degradation may not be the result of the action of hydrolytic enzymes but rather the result of activation by leukocyte factors of autolytic enzymes which lead to bacteriolysis.

Bacteriolysis↗
PubMed2003

Assessment of fluorescent-labeled bacteria for evaluation of in vivo uptake of bacteria (Vibrio spp.) by crustacean larvae.

Available methods to study crustacean digestive tract colonization by bacteria are laborious, time-consuming, and do not permit in vivo assays and observation. This paper reports on a rapid and consistent technique to apply a fluorescent label to bacteria, which can then be presented to filter-feeding crustacea such as Artemia and penaeid larvae for later in situ bacterial distribution observation. Three luminescent Vibrio spp. were stained and observed inside Artemia nauplii, shrimp zoea and mysis stages, Vibrio harveyi type strain ATCC 14126, M(1) (pathogenic) and Ea (non-pathogenic). Factors such as dye (DTAF) concentration, exposure time/temperature and sonication time were evaluated. Viability of the dye and stained bacteria were tested at 4, -20 and -70 degrees C storage temperatures for up to 81 days. Results show that 4 and -20 degrees C storage temperatures are not recommended. At -70 degrees C, both bacteria and dye are optimally preserved. Monodispersed fluorescent-labeled bacterial cells can be observed inside the digestive tract of crustacean larvae at a density of inoculation as high as 5.2 x 10(6) CFU ml(-1). After 2 to 4 h, some leaching occurs, increasing difficulty in observation, although after 24 h, it is still possible to observe monodispersed FLB inside the digestive tract of crustacean larvae. Autofluorescence may complicate observation when filter-feeding crustacean larvae are co-fed with microalgae.

Animals↗
PubMed2001

Metabolic and functional properties of lactic acid bacteria in the gastro-intestinal ecosystem: a comparative in vitro study between bacteria of intestinal and fermented food origin.

Metabolic and functional properties of probiotic lactic acid bacteria (LAB) in the human gastro-intestinal ecosystem may be related to certain beneficial health effects. In this study, lactobacilli of either intestinal or fermented food origin were compared in their capability to survive low pH and bile, in their metabolic activity in the presence of bile salts and mucins, as well as in their potential to attach to enterocyte-like CaCO-2 cells. Food fermenting bacteria especially strains of the species Lactobacillus plantarum showed high tolerance to the consecutive exposure to hydrochloric acid (pH 1.5-2.5) and cholic acid (10 mM). Growth in and deconjugation of glycocholic (5 mM) and taurocholic acids (5 mM), as demonstrated for all lactobacilli of intestinal origin, was detected for food fermenting strains of the species L. plantarum, but not L. paracasei and L. sakei. Degradation of mucins was not observed for lactobacilli. Adhesion to the intestinal epithelial cell line CaCO-2 was demonstrated for several food fermenting bacterial strains in vitro. Soluble factors in the spent culture supernatants from intestinal and fermented food lactobacilli but not staphylococci cross reacted and synergized with cell wall components to promote adhesion to CaCO-2 cells. A competitive role of fecal bacteria on the adhesion of lactobacilli to CaCO-2 cells was demonstrated. In conclusion we have shown that metabolic and functional properties of intestinal lactobacilli are also found in certain bacteria of fermented food origin.

Bacterial Adhesion↗
PubMedDate not supplied

Hypothesis on the role of sub-clinical bacteria of the endometrium (bacteria endometrialis) in gynaecological and obstetric enigmas.

Unexplained infertility, recurrent abortion, dysfunctional uterine bleeding, pelvic pain, premenstrual syndrome, premature labour, placental insufficiency and pre-eclampsia are examples of common obstetric and gynaecological problems that frequently defy adequate explanation. Bacterial vaginosis, a non-inflammatory condition, is associated with premature labour, but antibiotics administered topically provide less effective prophylaxis than those administered orally. This would indicate that bacterial vaginosis might be a marker for significant genital tract bacteria, but some pathology is dependent on micro-organisms ascending out of reach of topical antibiotics. The author was led to consider the hypothesis that micro-organisms, possibly those associated with bacterial vaginosis, surreptitiously inhabit the uterine cavity (bacteria endometrialis) where they are culprits of some common gynaecological and obstetric enigmas. The objective of this review is to provide an initial theoretical examination of this hypothesis. Bacteria in the endometrium have been associated with infertility. Antiphospholipids have been linked to recurrent miscarriage and pre-eclampsia and with infections including Mycoplasma. Pre-eclampsia might be explained by an exaggerated host response to intrauterine micro-organisms or bacterial toxins. The hypothesis that one common factor, bacteria endometrialis, could provide a plausible explanation for a variety of obstetric and gynaecological mysteries is particularly intriguing. There is sufficient evidence to justify further investigation.

Bacterial Infections↗
PubMed1993

Photon emission by bacteria challenged with phenylacetaldehyde. A possible distinction between gram-positive and gram-negative bacteria.

With all bacteria tested, addition of phenylacetaldehyde leads to light emission. The latter is markedly stronger with gram-negative bacteria, presumably because they possess a thinner wall and an extra external lipophilic membrane. Consistent with this explanation, the bactericidal effect of phenylacetaldehyde is also stronger with gram-negative bacteria. The spectrum of the emitted light shows maximal emission in the 500 nm region and is very similar to that observed when a protein (bovine serum albumin), free amino acids or isopropylamine reacts with phenylacetaldehyde.

Acetaldehyde↗
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↗
PubMed2001

Competition among three predominant ruminal cellulolytic bacteria in the absence or presence of non-cellulolytic bacteria.

Competition among three species of ruminal cellulolytic bacteria - Fibrobacter succinogenes S85, Ruminococcus flavefaciens FD-1 and Ruminococcus albus 7 - was studied in the presence or absence of the non-cellulolytic ruminal bacteria Selenomonas ruminantium or Streptococcus bovis. Co-cultures were grown under either batch or continuous conditions and populations were estimated using species-specific oligonucleotide probes to 16S rRNA. The three cellulolytic species co-existed in cellobiose batch co-culture, but inclusion of either Sel. ruminantium or Str. bovis yielded nearly a monoculture of the non-cellulolytic competitor. In cellobiose chemostats, R. albus completely dominated the triculture, but R. flavefaciens became predominant over F. succinogenes and R. albus when Sel. ruminantium was co-inoculated into the chemostats. Similar effects on competition were observed in the presence of Str. bovis at a lower (0.021 h(-1)), but not at a higher (0.045 h(-1)) dilution rate. In cellulose batch co-cultures, R. albus was more abundant than both F. succinogenes and R. flavefaciens, regardless of the presence of the non-cellulolytic species. Co-existence among the three cellulolytic species was observed in almost all cellulose chemostats, but Sel. ruminantium altered the relative proportions of the cellulolytic species. R. albus and R. flavefaciens were found to produce inhibitors that suppressed growth of R. flavefaciens and F. succinogenes, respectively. These data indicate that interactions among cellulolytic bacteria, while complex, can be modified further by non-cellulolytic species.

Animals↗
PubMed2002

Diversity and phylogenetic analysis of bacteria in the mucosa of chicken ceca and comparison with bacteria in the cecal lumen.

We reported the first attempt to describe mucosa-associated bacterial populations in the chicken ceca by molecular analysis of 16S rRNA genes. Bacteria in the mucosa were highly diverse but mainly Gram-positive with low G+C. Fusobacterium prausnitzii and butyrate-producing bacteria comprised the largest groups among 116 cloned sequences. Twenty five percent of the clones had less than 95% homology to database sequences. Many sequences were related to those of uncultured bacteria identified in human feces or the bovine rumen. Terminal restriction fragment length polymorphism (T-RFLP) analysis revealed some differences between bacterial populations present in the mucosa and lumen of ceca. Greater resolution of bacterial population was obtained using a culture-independent approach rather than a culture-based approach.

Animals↗
PubMed1995

Application of antisera raised against sulfate-reducing bacteria for indirect immunofluorescent detection of immunoreactive bacteria in sediment from the German Baltic Sea.

Polyclonal rabbit antisera raised against sulfate-reducing bacteria (SRB) could detect several distinct populations of bacteria in sediment from the German Baltic Sea. The depth distribution of immunoreactive bacteria was determined by an indirect immunofluorescence filter method. Anti-Desulfovibrio desulfuricans DSM 1926 serum showed maximum bacterial numbers at a depth of 18 cm, with a concentration of 60 x 10(6) cells cm-3. With anti-Desulfovibrio baculatus DSM 2555 serum, counts were highest at the same depth, approaching 0.7 x 10(6) cells cm-3. Other significantly smaller populations were observed. Anti-SRBStrain 1 (lactate,vibrio) maxima were at 0 to 4 cm and at 17 to 18 cm. Anti-SRBStrain 2 (lactate,vibrio) serum showed several local maxima. Anti-SRBStrain 3 (lactate,oval) serum detected one single peak at a depth of 10 to 12 cm. Also determined were rates of sulfate reduction, total bacterial counts by acridine orange staining, and the viable counts by dilution series on anaerobic lactate medium. The total bacterial counts were highest (180 x 10(6) cells cm-3) at 3 to 4 cm and dropped to 24 x 10(6) cells cm-3 at 10 to 11 cm but showed additional local maxima reaching 140 x 10(6) cells cm-3 at a depth of 17 to 18 cm. Viable counts probable number) were above 10(5) CFU cm-3 at 0 to 3.6 cm but remained below 10(3) CFU at 7.2 to 18 cm. The sulfate reduction rate was maximal (107 nmol cm-3 day-1) at a depth of 1 to 2 cm, dropped to 10 nmol cm-3 day-1 at 12 to 13 cm, and reached 38 nmol cm-3 day-1 at 17 to 18 cm.

Antibodies, Bacterial↗
PubMed2005

Comparison of psychro-active arctic marine bacteria and common mesophillic bacteria using surface-enhanced Raman spectroscopy.

Psychro-active bacteria, important constituents of polar ecosystems, have a unique ability to remain active at temperatures below 0 degrees C, yet it is not known to what extent the composition of their outer cell surfaces aids in their low-temperature viability. In this study, aqueous suspensions of five strains of Arctic psychro-active marine bacteria (PAMB) (mostly sea-ice isolates), were characterized by surface-enhanced Raman spectroscopy (SERS) and compared with SERS spectra from E. coli and P. aerigunosa. We find the SERS spectra of the five psychro-active bacterial strains are similar within experimental reproducibility. However, these spectra are significantly different from the spectra of P. aeruginosa and E. coli. We find that the relative intensities of many of the common peaks show the largest differences reported so far for bacterial samples. An indication of a peak was found in the PAMB spectra that has been identified as characteristic of unsaturated fatty acids and suggests that the outer membranes of the PAMB may contain unsaturated fatty acids. We find that using suspensions of silver colloid particles greatly intensifies the Raman peaks and quenches the fluorescence from bacterial samples. This technique is useful for examination of specific biochemical differences among bacteria.

Adaptation, Physiological↗