Showing papers in "Microbial Ecology in Health and Disease in 2006"

Health and nutritional properties of probiotics in fish and shellfish

Abstract: The use of chemotherapeutic agents as an infection control measure has become questionable because of the evolution of antimicrobial resistance among pathogenic bacteria. One of the alternatives to antibiotics in disease control could be the use of probiotics as biological control agents. This review describes the state of the art of probiotic research in preventing and controlling infectious diseases in aquaculture, with a description of the mechanisms of action involved.

Methanogenic archaea in adult human faecal samples are inversely related to butyrate concentration

Abstract: Background : We have examined the relationship between the presence and numbers of methanogenic archaea in the faeces of humans and levels of the short chain fatty acids (SCFAs), especially butyrate, to gain insight into factors that may influence bowel health. In doing so, we have carried out the first cultivation-independent, molecular analysis of methanogen diversity and abundance in the human gastrointestinal tract. Materials and methods : The faeces of eight healthy individuals on their normal diets were collected weekly over a 12 week period. DNA was extracted from the faeces and PCR-based assays, using methanogen-specific 16S rRNA gene primer sets, were used in conjunction with denaturing gradient gel electrophoresis (DGGE) to identify and enumerate methanogens present. Results : Methanogens were detected in all faecal samples from five of the eight individuals tested. Three distinct methanogen phylotypes were found, with two or three phylotypes present in some individuals. DNA sequencing of DGGE bands indicated that all phylotypes were closely related to Methanobrevibacter smithii (99-100%). Real-time PCR analyses revealed that faecal methanogen numbers varied significantly between individuals and over time by up to two orders of magnitude. Concentrations of acetate, butyrate and propionate in faeces also varied significantly between individuals and with time. There was a negative correlation between mean faecal butyrate concentration and methanogen abundance (R=-0.729, p<0.05, n=8), but no significant relationship existed for acetate, propionate or total SCFAs, and no relationship was found between total bacterial abundance and pH, SCFA concentration or methanogen abundance. Conclusion : As butyrate appears to be an important mediator of colonic health, the inverse relationship with methanogens uncovered here suggests that methanogens may be useful biomarkers of bowel health. Key words: methanogens, butyrate, colorectal cancer

Newly identified vitamin K-producing bacteria isolated from the neonatal faecal flora

Abstract: Fat-soluble vitamin K is an essential component of the blood clotting process. Menaquinones are the naturally occurring form of vitamin K identified in bacteria. Lipid extracts were made from three bacteria originally isolated from the human neonatal gut and identified as Enterobacter agglomerans, Serratia marcescens and Enterococcus faecium. Following preparative thin layer chromatography (TLC), the lipid extracts were subjected to liquid chromatography-mass spectrometry (LC-MS) analysis. Peak analysis of the LC-MS data showed that the three bacteria produce various forms of menaquinone.

Effect of miso soup containing Natto on the composition and metabolic activity of the human faecal flora

Abstract: This study investigated the effect of consumption of miso soup containing natto (natto miso soup) over 14 days on the bacterial flora and metabolic activity of the faeces of healthy volunteers (age range 2159 years). No marked change in the number of total bacteria was observed throughout the experimental period. During intake, the numbers of Bacillus and Bifidobacterium were increased (p<0.05), whereas numbers of Enterobacteriaceae were decreased (p<0.05) and numbers of lecithinase-positive clostridia (including Clostridium perfringens ) tended to decrease. Faecal acetic and propionic acids were increased (p<0.05) while faecal indole, p-cresol, ammonia and sulfide were lowered (p<0.05) during the intake period. Faecal moisture was increased and faecal pH was decreased during the intake period, although they were not significantly different. These results indicate that consumption of natto miso soup improved the intestinal environment of the volunteers. Key words: Natto (fermented soybean product), faecal bacteria, faecal metabolic activity

Growth inhibition of Aeromonas species by lactic acid bacteria isolated from salmonids

Abstract: Six lactic acid bacteria isolated from salmonids and identified as Lactococcus lactis subsp. lactis , Lactococcus lactis subsp. cremoris , Lactobacillus curvatus , Leuconostoc mesenteroides , Lactobacillus sakei and Carnobacterium maltaromaticum were found to inhibit the growth of several Aeromonas species. These results suggest that these strains could be suitable as biological control agents in aquaculture.

Lactobacilli and bifidobacteria lectins as possible signal molecules regulating intra- and inter-population bacteria-bacteria and host-bacteria relationships. Part I. Methods of bacterial lectin isolation, physico-chemical characterization and some biological activity investigation

Abstract: Lectins (natural or artificial nonimmunoglobulin origin proteins/glycoproteins) are able to bind noncovalently with carbohydrate targets. Lectins and lectin-like substances of lactobacilli (L. acidophilus K3III24; 100ash; NK1; L. plantarum 8RA3) and bifidobacteria (B. adolescentis MC42; B gallinarum, B. bifidum 1) have been investigated. Bacteria were grown in semi-anaerobic conditions in a casein-yeast broth. Medium was microfiltrated and ultrafiltrated for isolation of 30 kDa compounds which were then separated by isoelectric focusing in polyacrylamide gel in the presence of urea and sucrose. Components isolated were electrotransferred to immobillon P. Blots obtained were then treated with a set of biotinylated artificial linear homopolysaccharides revealed by streptavidin-peroxidase conjugate. Chemiluminescence registration of peroxidase bound to blots was performed using the ‘BioChemi System’ camera. A spectrum of different polysaccharide-binding individual components reacting with such homopolymers a...

Vaginal microbiota in healthy women and patients with bacterial vaginosis and nonspecific vaginitis

Abstract: According to Russian classification, bacterial vaginosis (BV) and nonspecific vaginitis (NSV) are two different clinical conditions. The vaginal microbiota was evaluated in 200 women (50 healthy pregnant women (HPW) during the first trimester, 100 patients with BV and 50 patients with NSV). The samples received from both healthy women (121 samples) and patients (BV 241 samples, NSV 136 samples) contained lactobacilli (96.5%), peptostreptococci (52.2%), streptococci (36.4%), bifidobacteria (48.2%), and propionibacteria (34.3%). Other microorganisms (bacteroides, enterobacteria, yeasts, staphylococci) were recovered by culture in 1.2-27.8% of samples. The most common microorganisms found in the vaginal discharge samples of women with BV and NSV were opportunistic pathogens (staphylococci 32.3%, enterococci 17.5%, enterobacteria 28.2%, candida 21.3%, peptostreptococci 64.2%, peptococci 38.8%, gram-negative anaerobic bacteria 29.4%). In most cases, more than one species of microorganisms were present (simultaneously representatives of 1-3 (NSV) or 3-5 (BV) species). The vaginal lactobacillus content in healthy women was log 7-9 cfu/ml. The total number of vaginal lactobacilli in the samples from BV and NSV women was reduced by up to log 6-7 cfu/ml and log 3-4 cfu/ml, respectively; 41.9% of NSV samples contained 3 cfu/ml of lactobacilli. All vaginal aerobic microorganisms isolated from the patients were resistant to 9 or more of 22 antibiotics tested. Microorganisms isolated were evaluated for their ability to restore nitrate and nitrite (Grees reagent) and to produce arginine decarboxylase (Moeller medium with arginine). Nitrate and nitrite reductases were produced by 25-28% of vaginal microbe strains isolated from HPW, 61-64% strains isolated from patients with NSV and 51-55% of those with BV (mostly belonging to enterobacteria, peptostreptococci, bacteroides, candida, and some others). Arginine decarboxylase activity was found in 41%, 53.4%, and 49.5% of strains isolated from these groups of women, respectively. The results obtained allow us to suppose that the determination of activity of enzymes investigated in vaginal strains or vaginal discharges may be used as additional diagnostic or screening tests for the predictive value of vaginal microbial ecology imbalance in BV and NSV. Key words: vaginal microbial ecology, vaginosis, nonspecific vaginitis, antimicrobial resistance, nitrate reductase, nitrite reductase, arginine decarboxylase

New principles in ecological regulation – features from the oral cavity

Abstract: The ecology of the mouth is unique. The mouth consists of teeth, saliva and crevicular fluid, not present elsewhere in the body. It has several habitats with distinct microfloras. Even a tooth has several ecological locales. Dental plaque (dental biofilm), is a diverse microbial community with channels and voids. It is accumulated most easily in protected areas, i.e. the approximal and crevicular areas of teeth. These areas also have the largest diversity of oral bacteria. Altogether 771 bacterial species have been detected in the oral cavity. More than 50% of the microflora has not yet been cultured in dental caries, periodontitis and the healthy mouth. While saliva is the most important nutrient for supragingival plaque, the serum-like gingival crevicular fluid nourishes the diverse microbiota of the gingival crevice/periodontal pocket. Development of biofilmmediated diseases probably follows ecological changes in the local milieu, implying that potentially pathogenic members, being sparse under healthy conditions, multiply at the cost of non-pathogenic members due to selective pressures (ecological plaque hypothesis). A number of factors may initiate this local perturbation, such as biofilm, nutrition, pH and redox potential. Also the metabolism of biofilm members can modify physical and chemical properties of the surroundings, promoting disease. The ecological plaque hypothesis implies that plaque-mediated diseases may be prevented/treated by re-establishing the local microbial homeostasis, e.g. through fluoride, sub-MIC levels of antimicrobial agents, change in the alkalinogenic potential of the biofilm, sugar substitutes, treatment of mothers with antimicrobial sealants during the childhood window of Streptococcus mutans infectivity, vaccines, surface modification of oral surfaces, transgenic repair of salivary glands, and interference with quorum sensing and two-component systems in biofilms. Ecological intervention may also be achieved through replacement therapy and probiotics. Key words: oral ecology, oral cavity, dental biofilm

In vitro modulatory effects of colonic microflora by olive oil iridoids.

Abstract: The Mediterranean diet, rich in fruits, vegetables, and grains as well as olive oil and olives, has been associated with a lower risk of coronary heart disease and cancer The beneficial role of olive oil has been related to its fatty acid composition and the presence of phenolic compounds The present research aimed to study the biological activity of some olive oil iridoids, such as hydroxytyrosol and tyrosol, as microbial inhibitors and their in vitro effects on modulation of human intestinal microflora Among the tested strains, Bifidobacterium longum , Lactobacillus salivarius , and Bacteroides vulgatus showed the highest sensitivity to the tested compounds; however, the inhibitory effect of iridoids seemed to be more effective when a mix of olive oil iridoids, instead of pure hydroxytyrosol, was used The fermentation experiments showed that olive oil iridoids modulate the intestinal microflora, leading to a higher production of total short chain fatty acids and in particular of butyrate These are important conditions well known to be associated with a protective effect against colon cancer development Key words: olive oil iridoids, hydroxytyrosol, intestinal microflora, semi-continuous culture system

Antibiotic resistance profiles and integrons in Enterobacteriaceae from the riverside of Evros-Ardas with respect to chemical and waste pollution

Abstract: Objective: The aim of this study was to evaluate the presence of Enterobacteriaceae in different locations of the Evros-Ardas river ecosystem at the borderline of Greece-Turkey. Materials and methods: Usual filter methods were applied for the collection of water samples from the riverside subjected to waste and/or borderline polluted stream. Sampling was accomplished during 3 months, from January to March. A total of 150 strains were isolated and identified by API Me´rieux. The antibiotic resistance profiles were performed according to CLSI; phylogeny analysis was performed by RAPD (random amplification polymorphic DNA analysis); integron class I, II and III were detected by PCR amplification of integrases I and II by using degenerated primers. The detection of the classes of integrons was performed after RsaI digestion of the PCR products and agarose gel electrophoresis. The antibiotic gene cassettes were also generated by PCR. Results : In all, 90% of the isolates were usual environmental strains without antibiotic resistance. Resistance to ampicilllin, amoxicillin, and/or ampicillin/sulbactam and several cephalosporins was detected in 12 strains. Resistance to tetracycline and chloramphenicol was observed in two isolates; resistance to nalidixic acid and to fluoroquinolones was detected in three strains. Finally, resistance to sulfamethoxazole and trimethoprim was observed in four isolates. Integron class I was detected in four isolates and class II in two of them. Several profiles were identified by RAPD and some unique types. Conclusion : It has been shown that plasmids containing b-lactamase, tetracycline and chloramphenicol genes as well as integron class I and II contribute to the pathogenic profiles of the isolates of the region. According to our results four locations represented environmental niches of pathogenic and antibiotic-resistant Enterobacteriaceae, namely the locations Ardas, Elaia bridge, Rizia and Kastanies and Evros Nea Vissa. Further investigation must be undertaken to control the microbial pollution of the riverside in Evros. Key words: antibiotic resistance, Enterobacteriaceae, integron, pollution

Diurnal variation in the concentration of methane in the breath of methane producers

Abstract: Aims: The aim of this study was to examine diurnal variation in the concentration of methane in the breath of methane producers and to clarify the mechanism of methane production in enterobacterial flora. Subjects and methods : The study was performed on 11 methane producers (students) with a methane concentration of 5 ppm or more in their breath. Methane in the breath and hydrogen concentrations were measured simultaneously using an exhalation gas analyzer, and diurnal variations were followed. Results : Four diurnal variation patterns were observed in 11 methane producers. Pattern A, methane varies at a higher concentration than hydrogen; pattern B, methane and hydrogen vary in parallel at almost the same level; pattern C, hydrogen varies at a higher concentration than methane; and pattern D, methane concentration varies at a low level of 5 ppm or less. In the case of patterns A and B, the concentrations of methane and hydrogen were in a positive correlation (p<0.02). From the standpoint of dynamic correlation with variations in concentration (-ppm and +ppm), a significant correlation in variations of methane and hydrogen existed in pattern B only (p<0.01). Conclusion : Methane producers comprise those of pattern A, where methanogens are preponderant; pattern B, where methanogens exist together with hydrogen-producing bacteria; and pattern C, where methanogens are inferior. In the case of pattern B, the concentration of methane and hydrogen varies in mutual correlation. Key words: Methane in breath, methanogens, methane producers, diurnal variation type, enterobacterial flora

Stress modifies the vaginal flora in cyclic female rats

Abstract: The understanding of the pathogenesis of vaginitis is directly dependent upon the factors which promote the colonization by bacterial genital microflora. Disruption of the bacterial barrier function afforded by the predominant microflora can lead to colonization by pathogenic or opportunistic pathogenic subdominant species. The present study focused on the effects of stress on the bacteria of the vaginal flora. For this purpose two types of psychological stress were employed: acute and subacute mild unpredictable stress. Estimation of the vaginal flora of 22 Wistar rats was performed according to the distinct phases of the estrous cycle: PE (proestrous), E (estrous), ME (metestrous), and DE (diestrous). Bacteria isolated from the vaginal flora were identified following Bergey’s Manual criteria. Escherichia coli, Clostridium , and Clostridium perfringens (vegetative and spore forms), showed increased numbers at PE-E after acute and subacute stress. Enterococcus was increased after acute stress, in all stages, while S treptococcus was increased after acute stress only at ME-DE. Staphylococcus aureus was detected at ME-DE only after stress. Staphylococcus epidermidis seemed to be predominant, but not influenced by stress at PE-E. However, it was detected in increased numbers at ME-DE after stress. Fusobacterium was detected at low levels in all phases and remained unaffected after exposure to stress. Both types of stress increased the numbers of Bacteroides at PE-E. Finally, the absence of Lactobacillus was noticed at PE-E 24 h after acute and subacute mild unpredictable stress, while Lactobacillus was decreased at ME-DE 72 h after stress. Hormonal fluctuations during the different phases of the estrous cycle may be associated with alterations in the vaginal flora. The data showed that stress acting on the vaginal flora and its immunity potential may contribute to disturbances of the natural balance in the area by altering the numbers of several bacteria that belong to the vaginal microflora. Continuous research on the factors that regulate the vaginal microflora is considered as essential, to prevent complications in infections that may be caused by indigenous microorganisms. Key words: stress, vaginal flora, clostridium, lactobacillus

Counter-attacking pandemic H5N1 bird influenza by counter-pandemic

Abstract: The Kermack-McKendrick (KM) (1927) epidemiological equations are used to analyse different pandemic scenarios. The infection rate constant and the withdrawal rate constant of infected individuals for the Spanish influenza pandemic (1918- 1920) are found by curve fitting the solution of the KM equations to the historical data for the number of dead and the number of infected individuals during the pandemic. Hypothetically assuming the very same parameters for hypervirulent strains of H5N1 influenza virus (with 50% lethality), our simulations reveal that the latter (without vigorous countermeasures) can infect the total world population during a period of 20-30 days, with a mortality of 50% of the total world population. The short time it takes before the pandemic is over precludes the use of new vaccines that are developed only after a pandemic has started. We examine a logistically more feasible method of achieving rapid immunization after a pandemic has started (and if prefabricated vaccines cannot be used either because they are not effective or for logistic reasons): the influence of a counter-pandemic running ahead and immunizing the population before the hypervirulent H5N1 virus attacks. We find that the counter-pandemic can significantly reduce the total death toll during a pandemic with a hypervirulent strain of H5N1 influenza virus, provided that its infectivity at a population level is much larger than for the hypervirulent virus. This can be achieved if everything possible is done to hinder geographic dispersal of the hypervirulent virus (e.g. immediate cessation of all international passenger traffic, immediate cessation of all ordinary road traffic, house quarantine) at the same time as dispersal of the ‘vaccine virus’ is deliberately facilitated by sending it around in a similar way as for a vaccine, but seeding it only in every local population and not in every person as for ordinary vaccine. From a logistic point of view this might be the only feasible method of achieving immunization of a significant proportion of the population in poor countries with poor infrastructure during the very short time interval available before the superpathogen itself normally would be expected to arrive. However, mortality caused by a counter-pandemic virus will probably be higher than during an ordinary influenza epidemic, especially among elderly and malnourished persons. Vaccination, using vaccines that have been prefabricated and stored before the start of an eventual pandemic, should therefore be the preferred method of achieving immunization whenever logistically feasible. Key words: Spanish flu pandemic, avian influenza, mathematical modeling, prefabricated vaccines, counter-pandemic, epidemics, epidemiology, infection, simulations

β-Glucuronidase activity in germ-free, monoassociated and conventional mice

Abstract: The establishment of β -glucuronidase activity was investigated in intestinal contents from gnotobiotic mice monoassociated either with Lactobacillus rhamnosus ATCC 53103 (LGG) or with Escherichia coli X7 for different periods of time. Additionally, the enzyme activity was investigated after the animals had been conventionalized. Neither the monoassociated animals nor the conventionalized animals had reached normal levels of β -glucuronidase activity after the colonization period (3 and 7 days, or 7 and 14 days, respectively). A great inter-individual variation of the enzyme activity was observed in the group that was conventionalized for longer (14 days), mainly in the caecum. These results indicate a very slow establishment of the β -glucuronidase activity in the intestinal tract of mice after exposure to either individual bacterial strains or exclusively to the environment. Key words: β -glucuronidase, intestinal microbial enzymes, germ-free mice, gnotobiotic mice, monoassociation

Why is the world so poorly prepared for a pandemic of hypervirulent avian influenza

Abstract: The world is now extremely poorly prepared to counter a possible pandemic of hypervirulent H5N1 influenza. Most countries are planning for nothing worse than the Spanish flu pandemic. It may be possible that this can in large measure be explained as a consequence of an epidemic of wishful thinking, which may already have infected the health authorities (and parts of the scientific community as well) in most countries in the world. However, it may also be possible that it can have happened as a consequence of too little contact between medical scientists and more general biologists (natural scientists) from disciplines such as ornithology, ecology and evolutionary biology. This may have led to a lack of proper understanding among medical scientists (and health bureaucrats) of the nature of evolutionary processes affecting influenza viruses, as regards the evolution of host species adaptation, infectivity and virulence properties, and also a lack of appreciation of the ways in which such forms of evolutionary adaptation depend on ecological boundary conditions that have radically changed, comparing the world in 2006 to the world in 1918. While the Spanish flu virus possibly might be compared to a one-headed monster, it may be possible that highly virulent varieties of H5N1 virus might better be compared to a three-headed one because there is evidence of at least three independent virulence factors connected with three different genes. It is highly unlikely that all of the high-virulence alleles will simultaneously mutate and disappear if and when the haemagglutinin gene changes so as to make the haemagglutinin molecule better adapted for the human-type (alpha-2,6-linked) receptor (which is a necessary prerequisite in order that a pandemic with H5N1 virus may start). It is more probable that evolutionary adaptation of the haemagglutinin of H5N1 viruses to the human-type receptor will happen without any simultaneous change in those other genetic properties that now are important for explaining the exceptionally high virulence of certain strains of avian-adapted H5N1 influenza virus. The change of the haemagglutinin molecule from avian adaptation to human adaptation must be expected to act as an additional virulence factor because it will enhance the total number of cells that can be infected (per host organism), increase the total rate of virus replication and potentiate the effects of the other virulence factors already present. The monster will then have four heads, not three, and case fatality rates must be expected to become even higher than they have been until now, perhaps reaching as high as 98-99% (at least in poor countries with less than optimal nutrition). Key words: avian influenza, virulence factors, virulence evolution, risk estimates, emergency preparedness

Prevention and treatment of urogenital infections and complications: lactobacilli's multi-pronged effects

Abstract: The association between depletion of vaginal lactobacilli and increased risk of various urogenital infections and complications such as preterm labor, has been known for some time. Restoration of depleted lactobacilli by administration of probiotic strains has been demonstrated in humans using Lactobacillus rhamnosus GR-1 and L. reuter i RC-14. These organisms also augment antibiotic efficacy, lessen the side effects of these drugs, and alleviate diarrhea in AIDS patients. The mechanisms appear to be multi-factorial, and include production of: (i) anti-microbial factors such as lactic acid, bacteriocins, hydrogen peroxide, (ii) biosurfactants or other components that affect pathogen colonization and biofilm formation, (iii) signalling compounds that influence pathogen virulence expression, and (iv) signalling compounds that modulate immunity. Recombinant strains have been produced that inhibit or kill HIV, offering hope for microbicide applications that can be self-used by women. As more information becomes available about the ‘normal’ versus ‘disease prone’ vaginal microbiota and strains that confer the most benefits, current and new probiotic remedies will potentially provide improved restorative and therapeutic options to lower the one billion urogenital infections currently afflicting women around the world. Key words: probiotics, lactobacillus, urogenital infections, mechanisms

The metabolism of phenobarbital, a drug used for epilepsy, by intestinal flora, Bifidobacterium adolescentis and Bifidobacterium bifidum

Abstract: The metabolic capacity of the intestinal microflora and its influence on the human body are not fully understood. One area of interest is the metabolism of drugs used to treat disease. To gain a better understanding, major genera present in the intestine were tested for their ability to metabolize phenobarbital, a pharmaceutical drug used to treat epilepsy. We tested Bifidobacterium, Bacteroides , Enterococcus , Eubacterium, Clostridium, and Staphylococcus . Growth analysis at different concentrations of phenobarbital and gas chromatography-mass spectrometry analysis were used to determine the response and metabolism of phenobarbital. Our growth curve results demonstrated that the lag time for some bacteria was affected in the presence of high concentrations of phenobarbital. The generation time was also affected based on the concentration and specific bacterial type. Finally, it was shown that Bifidobacteirum adolescentis and Bifidobacterium bifidum were unique in metabolizing phenobarbital (reductively cleaved) into the compound alpha-ethyl-benezeneacetamide, which was an unexpected metabolite. The data demonstrate for the first time the ability of Bifidobacterium to metabolize phenobarbital into the potentially toxic metabolite alpha-ethyl-benezeneacetamide. The consequences of the generated metabolite may affect the surrounding intestinal bacterial population or the effectiveness of the drug in treating epilepsy. Key words: Bifidobacterium, phenobarbital, metabolism, anaerobe

Bifidobacterium may affect in vitro metabolism of daidzein by faecal flora from mice and a human male equol producer

Abstract: Recently, there has been great interest in the biological effects of equol, a metabolite of daidzein produced by intestinal flora. In this study, we used a newly isolated intestinal bacterium from healthy human faeces to investigate the effects of intestinal bacteria on the in vitro metabolism of daidzein by faecal flora in mice and a human male equol producer. The 16S rDNA partial sequence (1394 bp) of strain TM-20 that was isolated from infant faeces exhibited a 99% similarity to that of Bifidobacterium pseudocatenulatum . Therefore, this strain was identified as belonging to the genus Bifidobacterium . In faecal suspensions from mice, equol concentrations were significantly lower in the control faecal suspension than in the faecal suspension supplemented with the high concentration of strain TM-20. However, equol concentrations were significantly higher in the control faecal suspension than in the faecal suspension supplemented with the low concentration of strain TM- 20. In faecal suspensions from a human male equol producer, equol concentrations were lower in the control faecal suspension than in the faecal suspension supplemented with the high concentration of strain TM-20. However, equol concentrations were higher in the control faecal suspension than in the fecal suspension supplemented with the low concentration of strain TM-20. Metabolic activity of the faecal equol production in mice and humans may be changed by some types of bifidobacteria. To our knowledge, this is the first report of a Bifidbacterium sp. that is capable of changing the faecal equol production from daidzein in vitro. Key words: daidzein, equol, faecal flora, bifidobacteria

Use of genetically modified microbes for human health

Abstract: Sir , The publication by Ott et al. (1) restates the important, and topical, use of microbes in treating disease, in this case lymphoid immunodeficiencies. However, not everyone agrees that recombinant bacteria should be used in humans, and one particular submission to this journal called for a ban of such uses, a viewpoint that we wish to now strongly challenge (2).

Bowel cleansing with subsequent intake of Lactobacillus plantarum 299v does not change the composition of the faecal flora

Abstract: Aim: The intestinal flora may be washed out after bowel cleansing and may be beneficially influenced by probiotics during recolonization. In this randomized placebo-controlled double-blind study, the effect of bowel cleansing with or without subsequent inoculation by Lactobacillus plantarum 299v was assessed. Patients and methods : Patients who underwent bowel cleansing were included. After colonoscopy, patients consumed a drink with or without L. plantarum 299v (10 11 cfu/day). Faecal samples were collected: before bowel cleansing (week 0), the first sample after colonoscopy (week 1), after 2 and 4 weeks of consumption (week 2 and week 4), and 4weeks after cessation of the drinks (week 8).Total colony forming units (cfu) of bacteria per gram faeces were counted. Denaturing gradient gel electrophoresis (DGGE) was used to analyse the dominant flora, expressed as ‘similarity values’. Results : Twenty-two patients completed the study (12 probiotic, 10 placebo). The mean concentration of lactobacilli increased (p<0.05) from 4.7+-1.9 at week 0 to 6.59+-0.8 at week 2 in the probiotic group and returned back to 4.6+-1.4 at week 8 (p<0.05). DGGE profiles demonstrated high similarity values within subjects over time: mean value 86.5%+-2.6. No significant differences in similarity values were seen after bowel cleansing (week 2) or between probiotic and placebo groups. Conclusions: Although counts of faecal lactobacilli increased during probiotic consumption, no further changes in culture and DGGE results were observed. Therefore, the faecal flora can be considered as relatively stable over time: bowel cleansing or probiotic consumption had no major influence on the composition of the faecal flora. Key words: randomized double-blind placebo-controlled study, Lactobacillus plantarum 299v, probiotics, bowel cleansing procedure, PCR/DGGE

Lactobacilli and bifidobacteria lectins as possible signal molecules regulating intra- and inter-population bacteria

Abstract: Lectins (natural or artificial nonimmunoglobulin origin proteins/glycoproteins) are able to bind noncovalently with carbohydrate targets. Lectins and lectin-like substances of lactobacilli (L. acidophilus K 3 III 24 ; 100ash; NK1; L. plantarum 8RA3) and bifidobacteria ( B . adolescentis MC42; B gallinarum, B. bifidum 1) have been investigated. Bacteria were grown in semi-anaerobic conditions in a casein-yeast broth. Medium was microfiltrated and ultrafiltrated for isolation of 30 kDa compounds which were then separated by isoelectric focusing in polyacrylamide gel in the presence of urea and sucrose. Components isolated were electrotransferred to immobillon P. Blots obtained were then treated with a set of biotinylated artificial linear homopolysaccharides revealed by streptavidin-peroxidase conjugate. Chemiluminescence registration of peroxidase bound to blots was performed using the ‘BioChemi System’ camera. A spectrum of different polysaccharidebinding individual components reacting with such homopolymers as mannan-alpha (phosphorylated or not), GalNAcalpha- polysaccharide of mucin-like-type or galactan-beta (sulfated or not)-binding was found in lactobacilli and bifidobacteria. Lactobacilli produced a more limited spectrum of lectins or lectin-like compounds with higher affinities to polysaccharides tested than bifidobacteria having more extended pI polysaccharide-binding activity spectrum. Interaction of isolated lectins with T and B lymphocytes, macrophages, and thrombocytes was demonstrated. The importance of lactobacilli and bifidobacteria lectins/lectin-like components and their effector complexes in cell mitoses, blood coagulation, aerobic metabolic reactions, and other biological activities is discussed. Key words: bacterial lectin, lactobacilli, bifidobacteria, bacterial communication, bacteriahost cross-talk, lectin isolation, lectin identification, lectin biological activity

Reply to ‘Use of genetically modified microbes for human health’

Abstract: Sir, Gregor Reid et al. (1) commented on our article, ‘Genetically modified probiotics should be banned’ (2), and promoted the use of genetically modified microbes for human health, which we shall address. We take issue first with the closing salvo of Reid et al. (1), which took the isolated words, ‘rogue’, ‘nasty’, and ‘warfare’, in our article out of context as representing sensationalism and a lack of common sense.

Probiotics and Helicobacter pylori infection

Abstract: Probiotics involving Lactobacillus, Bifidobacterium, Saccharomyces, Clostridium butyricum, etc have been reported to have inhibitory effects on Helicobacter pylori infections in in vitro and in vivo studies In addition, these probiotics have been reported to be effective in clinical studies; the patients treated with triple therapy combined with probiotics had a higher H pylori eradication rate than those with triple therapy only, and antibiotic-associated gastrointestinal side effects during H pylori eradication therapy were reduced in the patients treated with a probiotics supplemented regimen It was also reported that probiotic supplementation reduced side effects and permitted a slight improvement in eradicating H pylori in second-line eradication therapy