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PubMed1982

[Principles of decontaminating the small intestine with bacterial preparations in experimental antibiotic dysbacteriosis].

Introduction of antibiotic-resistant bifidobacterial and lactobacterial strains, separately or together, does not decrease the degree and duration of contamination of the small intestine by enterobacteria after oral administration of antibiotics in large doses. The use of antibiotic-resistant bifidobacterial and lactobacterial strains allows one to decrease contamination of the small intestine by enterobacteria, resulting from the administration of antibiotics in near-therapeutic doses. The therapeutic effectiveness of bacterial preparations with respect to antibiotic dysbacteriosis has been found to depend on the level of resistance to the administered antibiotic. Antibiotic-resistant strains of bifidobacteria decrease the number of opportunistic microorganisms in the intestine in cases of dysbacteriosis caused by irradiation and administration of antibiotics.

Actinomycetaceae↗
PubMed1987

[Local immune reaction in human intestinal spirochetosis].

The pathogenetic and clinical importance of intestinal spirochaetes in man is still unresolved. In 12 patients mainly presenting with mild diarrhoea, light and electron microscopy demonstrated massive spirochaetal infestation of the colonic mucosa (spirochaetosis). There were several hitherto unreported features: spirochaetes adhered not only to the surface epithelium of the intestine but were also present within epithelial cells and subepithelial macrophages; many partially degranulated mast cells were noted within the epithelium; there was a marked increase of IgE plasma cells within the lamina propria. In control biopsies intraepithelial mast cells were absent and IgE cells occurred only sporadically. Penetration of the microorganisms into the intestinal mucosa may be responsible for this unusual immune response. Spirochaetes, symptoms and findings disappeared after antibiotic therapy. The authors therefore suggest that intestinal spirochaetosis can cause clinical symptoms in man, and that spirochaetes should not invariably be considered harmless commensals.

Colonic Diseases↗
PubMed1982

The normal human anaerobic microflora.

Anaerobic bacteria are prevalent among the bacterial populations of the human body, particularly on mucous membrane surfaces. The major sites with a rich anaerobic normal microflora are the mouth, the gastrointestinal tract and the female genital tract. The oral cavity harbours more than 300 different bacterial species. The concentrations of bacteria in saliva are 10(8) to 10(9) colony forming units/ml and anaerobic bacteria outnumber aerobic bacteria by 10:1. On the tooth surfaces, the concentrations of bacteria are 10(10) to 10(11) cfu/ml with a predominance of anaerobes. Bacterial concentrations in gingival scrapings are 10(11) to 10(12) cfu/ml with anaerobic bacteria outnumbering aerobic bacteria by 1000:1. In the saliva and on the tongue surface, the predominant anaerobic bacteria are cocci, while in the gingival crevice large concentrations of gram-negative rods are recovered. Microorganisms found in the upper intestinal tract are different from those in the lower intestinal tract. In the stomach and the proximal small bowel, the microorganisms found as normal flora are a reflection of the oral flora. Bacterial concentrations in this region are 10(2)-10(5) cfu/ml intestinal content. In the colon, bacterial concentrations of 10(11)-10(12) cfu/g faeces are found. About 500 different bacterial species are recovered in the lower intestine. The most common anaerobic microorganisms are bifidobacteria, lactobacilli and bacteroides. Recent studies have used quantitative techniques for analyses of the vaginal flora and it has been found that anaerobic bacteria outnumber aerobic bacteria in the vagina by approximately 10:1. The most prevalent bacteria are peptococci, present in counts of 10(7)-10(8) cfu/ml. Lactobacilli, corynebacteria, eubacteria and bacteroides are also isolated.

Anaerobiosis↗
PubMed2006

[Investigation and analysis of the bacteria community in silkworm intestine].

Majority of the environmental microorganisms are still unculturable. To shed a light on the bacteria community in the silkworm intestine more completely, culture-dependent and culture-independent methods were used to perform the investigation. As the latter, 16s rRNA gene was amplified and a library was constructed by using the meta-genomic DNA extracted from the bacteria in the silkworm intestine as template. Restriction fragment length polymorphism (RFLP) method was used to screen recombinants originated from different bacteria, and the nucleotide sequences were determined. A BLAST searching in the GenBank and an analysis on phylogenesis were performed. The taxonomy of these bacteria and their physiological function to silkworm were speculated. Results showed that the bacteria in silkworm intestine are mainly belong to the genera Arthrobacter, Lactobacillus, Pseudomonas, Escherichia, Micrococcus, Bacillus, and Staphylococcus. They may play important roles to the host silkworm in the utilization of their food mulberry and disease prevention. Both the culture-dependent and culture-independent methods have their advantages and disadvantages, and they are complemented with each other.

Animals↗
PubMed2000

Effect on the human normal microflora of oral antibiotics for treatment of urinary tract infections.

Oral administration of antibiotics for treatment of urinary tract infections (UTIs) can cause ecological disturbances in the normal intestinal microflora. Poorly absorbed drugs can reach the colon in active form, suppress susceptible microorganisms and disturb the ecological balance. Suppression of the normal microflora may lead to reduced colonization resistance with subsequent overgrowth of pre-existing, naturally resistant microorganisms, such as yeasts and Clostridium difficile. New colonization by resistant potential pathogens may also occur and may spread within the body or to other patients and cause severe infections. It is therefore important to learn more about the ecological effects of antibacterial agents on the human microflora. The impact on intestinal microorganisms of oral antibiotics used for the treatment of UTIs is reviewed here. Ampicillin, amoxycillin and co-amoxiclav suppress both the aerobic and anaerobic intestinal microflora with overgrowth of ampicillin-resistant Enterobacteriaceae. Pivmecillinam also affects the intestinal microflora, suppressing Escherichia coli, but does not have a major effect on the anaerobic microflora. Several orally administered cephalosporins, such as cefixime, cefpodoxime, cefprozil and ceftibuten, reduce the number of Enterobacteriaceae and increase the number of enterococci. Colonization with C. difficile has also been observed. Fluoroquinolones eliminate or strongly suppress intestinal Enterobacteriaceae, but affect enterococci and anaerobic bacteria only slightly. When antimicrobial agents are prescribed for the treatment of UTIs, not only the antimicrobial spectrum of the agent but also the potential ecological disturbances, including the risk of emergence of resistant strains, should be considered.

Journal Article↗
PubMed2000

Effect on the human normal microflora of oral antibiotics for treatment of urinary tract infections.

Oral administration of antibiotics for treatment of urinary tract infections (UTIs) can cause ecological disturbances in the normal intestinal microflora. Poorly absorbed drugs can reach the colon in active form, suppress susceptible microorganisms and disturb the ecological balance. Suppression of the normal microflora may lead to reduced colonization resistance with subsequent overgrowth of pre-existing, naturally resistant microorganisms, such as yeasts and Clostridium difficile. New colonization by resistant potential pathogens may also occur and may spread within the body or to other patients and cause severe infections. It is therefore important to learn more about the ecological effects of antibacterial agents on the human microflora. The impact on intestinal microorganisms of oral antibiotics used for the treatment of UTIs is reviewed here. Ampicillin, amoxycillin and co-amoxiclav suppress both the aerobic and anaerobic intestinal microflora with overgrowth of ampicillin-resistant Enterobacteriaceae. Pivmecillinam also affects the intestinal microflora, suppressing Escherichia coli, but does not have a major effect on the anaerobic microflora. Several orally administered cephalosporins, such as cefixime, cefpodoxime, cefprozil and ceftibuten, reduce the number of Enterobacteriaceae and increase the number of enterococci. Colonization with C. difficile has also been observed. Fluoroquinolones eliminate or strongly suppress intestinal Enterobacteriaceae, but affect enterococci and anaerobic bacteria only slightly. When antimicrobial agents are prescribed for the treatment of UTIs, not only the antimicrobial spectrum of the agent but also the potential ecological disturbances, including the risk of emergence of resistant strains, should be considered.

Administration, Oral↗
PubMed2002

Host-dependent zonulin secretion causes the impairment of the small intestine barrier function after bacterial exposure.

BACKGROUND & AIMS: Enteric infections have been implicated in the pathogenesis of both food intolerance and autoimmune diseases secondary to the impairment of the intestinal barrier. On the basis of our recent discovery of zonulin, a modulator of small-intestinal tight junctions, we asked whether microorganisms might induce zonulin secretion and increased small-intestinal permeability. METHODS: Both ex vivo mammalian small intestines and intestinal cell monolayers were exposed to either pathogenic or nonpathogenic enterobacteria. Zonulin production and changes in paracellular permeability were monitored in Ussing chambers and micro-snapwells. Zonula occludens 1 protein redistribution after bacteria colonization was evaluated on cell monolayers. RESULTS: Small intestines exposed to enteric bacteria secreted zonulin. This secretion was independent of either the species of the small intestines or the virulence of the microorganisms tested, occurred only on the luminal aspect of the bacteria-exposed small-intestinal mucosa, and was followed by a decrease in small-intestinal tissue resistance (transepithelial electrical resistance). The transepithelial electrical resistance decrement was secondary to the zonulin-induced tight junction disassembly, as also shown by the disengagement of the protein zonula occludens 1 protein from the tight junctional complex. CONCLUSIONS: This zonulin-driven opening of the paracellular pathway may represent a defensive mechanism, which flushes out microorganisms and contributes to the host response against bacterial colonization of the small intestine.

Animals↗
PubMed2006

Triclosan and antimicrobial resistance in bacteria: an overview.

Triclosan is a widely used biocide that is considered as an effective antimicrobial agent against different microorganisms. It is included in many contemporary consumer and personal health-care products, like oral and dermal products, but also in household items, including plastics and textiles. At bactericidal concentrations, triclosan appears to act upon multiple nonspecific targets, causing disruption of bacterial cell wall functions, while at sublethal concentrations, triclosan affects specific targets. During the 1990s, bacterial isolates with reduced susceptibility to triclosan were produced in laboratory experiments by repeated exposure to sublethal concentrations of the agent. Since 2000, a number of studies have verified the occurrence of triclosan resistance amongst dermal, intestinal, and environmental microorganisms, including some of clinical relevance. Of major concern is the possibility that triclosan resistance may contribute to reduced susceptibility to clinically important antimicrobials, due to either cross-resistance or co-resistance mechanisms. Although the number of studies elucidating the association between triclosan resistance and resistance to other antimicrobials in clinical isolates has been limited, recent laboratory studies have confirmed the potential for such a link in Escherichia coli and Salmonella enterica. Thus, widespread use of triclosan may represent a potential public health risk in regard to development of concomitant resistance to clinically important antimicrobials.

Anti-Bacterial Agents↗
PubMed1992

[Occurrence of Campylobacter coli in a central boar breeding facility in Thuringia].

Investigating the cause of an outbreak of mild diarrhoea in a boar rearing unit with about 750 animals, C. coli was found in all diseased animals, i.e. it was isolated from the intestines of culled boars and from faeces samples; often the amount of C. coli was very high. The intragastric application of C. coli to 5 weaning pigs (about 35 kg) resulted in the shedding of large numbers of C. coli via the faeces at days 3 and 5 post infectionem only. The development of the animals was undisturbed during the 17 days of the experiment. Carrying out follow-up investigation, C. coli was isolated at least once per animal from all healthy animals (n = 40) from the 3 farms, delivering young boars to the unit. C. coli is regarded as an opportunistic microorganism in the intestines of swine, able to cause diarrhoea only when combined with infection-promoting factors. In the case presented, these factors were nitrate-enriched water, changes in the composition of feed and the rapid shift from winter conditions to a warm spring.

Animals↗
PubMed1997

[The current concepts of the influence of lactobacilli on the immune system of the human body].

The review summarizes experimental and clinical data about the influence of Lactobacillus on the immune system. A conclusion is made that the effect of Lactobacillus is a multifactor process. After entering the intestinal tract live microorganisms or biologically active substances produced by them may activate specific and nonspecific systems of microorganism protection. Experimental and clinical data about the action of Lactobacillus as adjuvants to the humoral immune response are presented. The mechanisms of anticancerogenic action of Lactobacillus and their cell wall components are analyzed in detail. The prospects for the use of Lactobacillus as probiotics in medicine are considered. The conclusion about positive value of the multifactor action of these microorganisms on the human immune system is made, since no negative effects are evoked by the discussed mechanisms of specific effect of Lactobacillus. This opens wide possibilities for the development of application schemes of probiotics from lactobacillus for the stimulation of several functions of the immune system, creation a new forms of antitumor drugs and combination of them with oral vaccines for improving their immunogenicity.

Animals↗
PubMed1995

Identification of a new intestinal spirochete with pathogenicity for chickens.

Two intestinal spirochete isolates obtained from chickens with diarrhea were examined by electron microscopy, biochemical tests, rRNA gene restriction pattern analysis, and multilocus enzyme electrophoresis. One isolate (strain 91-1207/C1) was pathogenicity tested in vivo in chickens. The chicken spirochetes were morphologically indistinguishable from Serpulina innocens and Serpulina hyodysenteriae and phenotypically similar to S. innocens. However, the chicken spirochetes could be distinguished from S. innocens, S. hyodysenteriae, and other swine intestinal spirochetes by rRNA gene restriction pattern analysis and multilocus enzyme electrophoresis. In pathogenicity tests in 1-day-old chicks and 14-month-old hens, chicken spirochete 91-1207/C1 produced pale-yellow, watery cecal contents and mild lymphocytic typhlitis. These findings support the conclusion that avian intestinal spirochetes can be pathogenic to commercial poultry and that the microorganisms are different from intestinal spirochetes that infect pigs.

Animals↗
PubMed1992

[Prenatal risk factors and the status of local defense of the intestines in premature newborn infants].

A randomized study was made to examine certain characteristics of local immunity of the intestine (immunoglobulins in coprofiltrates, microbiocenosis) and the immunoglobulin composition of the milk of mothers to 108 premature breast-fed children of the first month of life. It has been established that toward the end of the second week of life, there was a remarkable decrease in the characteristics of secretory IgA (SIgA) in coprofiltrates of the newborn whose mothers suffered from gestosis (group 2) and in children born to mothers with infectious pathology (group 3) as compared to conventionally healthy premature children (group 1). The group 3 neonates showed a significantly less amount of IgG. According to the examinations made over time, the deficiency of secretory antibodies rose in group 2, declined in group 3, whereas the group 1 children manifested an increase in SIgA. The group 2 and 3 children demonstrated more profound dysbiotic disturbances, characterized by long persistence of opportunistic microorganisms and by the appearance in some cases of pathogenic microorganisms in the intestine. All this requires distinguishing risk groups and carrying out additional preventive and treatment measures in such children.

Dysgammaglobulinemia↗
PubMed1980

[Interest in gnotoxenic systems for the study of host-microbial flora of the digestive tract].

It is necessary to use experimental models in all studies of interactions between a host, its digestive tract microbial flora and the environment because these interactions are complex. The gnotoxenic animal, reared in an isolator as the axenic animal and harbouring a known microbial flora, constitutes either an analytic or mimetic experimental model. The gnotoxenic animal may be considered as an analytic model when used to determine which biotic or abiotic environmental factor of the host-animal plays a role in the intestinal ecosystem. The potential metabolic or immunologic role of a given bacterial strain in the intestinal ecosystem may be determined when the axenic animal is associated with this strain. The variation of the expression of the potential role of this strain in relation to the environment can be ascertained by diversifying the diet of the host or by introducing other bacterial strains into the intestinal ecosystem. The role of an association of strains in host physiology and host protection against potentially pathogenic target strains can also be studied using this analytic model. An analytic model is created by associating either isolated strains of the holoxenic or heated or diluted suspensions of holoxenic digestive tract flora. Axenic mice associated with these simplified flora are called meroxenic. The gnotoxenic animal is considered to be a mimetic model when it harbours a microbial flora isolated from an animal of a different species. The advantage of the mimetic model is that it provides an easy-to-use biological tool, i.e. gnotoxenic mice, to first determine the potential role of these microbial strains. The validity of the mimetic model is then tested by comparing gnotoxenic mice and gnotoxenic piglets or chickens. When all the gnotoxenic animals are given the same diet, this comparison permits an estimation of the animal-host role in the expression of the potential activities of microbial strains. The mimetic model, composed of gnotoxenic animals harbouring microbial strains of human origin, is the only experimental model which can be used to study the role of microorganisms in the intestinal ecosystem of man.

Animals↗
PubMed2005

Ability of Bifidobacterium strains with acquired resistance to bile to adhere to human intestinal mucus.

The hydrophobicity and capacity to adhere to human intestinal mucus of Bifidobacterium strains with acquired resistance to bile were assessed and compared with those of their more sensitive original strains. The resistant variants used were previously obtained [Int. J. Food Microbiol. 82 (2003) 191; Int. J. Food Microbiol. 94 (2004) 79] by progressive adaptation of originally more sensitive strains to gradually increasing concentrations of bile. In five out of the seven groups of original and bile-resistant variants tested the resistant strains showed higher adhesion levels to human mucus (range between 1.4- and 4-fold) than their corresponding original strains. However, in the presence of physiologic concentrations of bile (0.3%, w/v) the adhesion level of all Bifidobacterium strains dropped between 7% and 74%, depending on the strain. In spite of this, the adhesion capability of three bile-resistant variants remained higher than that of their originals. Hydrophobicity evidenced considerable variability; in four out of the seven bile-resistant strains it was higher than in the original strains, although no direct correlation between adhesion and hydrophobicity could be established. It was concluded that the acquisition of bile resistance by our Bifidobacterium strains promoted changes in hydrophobicity and in the adhesion of these microorganisms to human intestinal mucus.

Adaptation, Physiological↗
PubMed1977

Reduced mercury excretion with feces in germfree mice after oral administration of methyl mercury chloride.

When methyl mercury chloride was administered orally the amount of mercury excretion with feces of germfree mice was noticeably lower than that of the control mice. Germfree mice excreted 24 percent of the administered mercury within 10 days of administration while the control mice excreted 46 percent. Mercury retention in the organs of germfree mice was slightly higher than in the control mice. These results suggest that the existence of microorganisms in animal intestines are concerned with mercury excretion in the animal body.

Animals↗
PubMed1984

Reactions of nitrosochloramphenicol in blood.

It has been suggested that nitrosochloramphenicol (NOCAP), a possible metabolite of chloramphenicol (CAP), may be involved in CAP-induced aplastic anemia. We found that NOCAP was rapidly eliminated from human blood in vitro (more than 90% in less than 15 sec). Analysis of the different reactions showed that 5% of NOCAP was covalently bound to plasma proteins, mainly to albumin, the remainder being metabolized in red cells. The most important reaction in red cells was the very rapid adduct formation with GSH (k = 5,500 M-1S-1), yielding presumably a semimercaptal which either isomerized to a sulfinamide (GSONHCAP, k = 0.05 s-1) or was thiolytically cleaved by another GSH molecule with formation of the hydroxylamine (NHOHCAP) and GSSG (k = 7.1 M-1S-1). Another important elimination reaction was the covalent binding of NOCAP to the SH groups of hemoglobin (k = 5M-1S-1), also yielding a sulfinamide. Besides these reactions with thiols, NOCAP was enzymatically reduced to NHOHCAP in the presence of NADPH (Km NADPH = 10(-5) M; Km NOCAP = 10(-4) M; Vmax = 2 mumole/min per ml). This reaction was only effective at NOCAP concentrations below 10(-4)M, probably because of limited NADPH-regeneration. Further reduction of NHOHCAP to NH2CAP was a slow process which did not exceed 0.5 nmole/min per ml. NH2CAP was mainly formed from GSONHCAP, a reaction which depended on NADPH and the presence of hemolysate, indicating an enzymatic reaction. In contrast to smaller nitrosoarenes, NOCAP was a poor ligand for ferrohemoglobin (probably due to steric hindrance by its bulky molecule) and was therefore much more exposed to biotransformation. NOCAP and NHOHCAP formed ferrihemoglobin at a rate 5000 times slower than did phenylhydroxylamine. In contrast to NOCAP, NHOHCAP penetrated slowly the red cell membrane (4 about 5 min), and its disposition in blood was quite ineffective. From these data, it seems likely that most of the NOCAP formed by microorganisms in the intestine or produced in the liver, will be degraded in blood before it can reach the bone marrow.

Biological Transport↗
PubMed1987

Anti-Bacteroides fragilis substance from rhubarb.

Extracts of 178 Chinese herbs were screened for their antibacterial activity against Bacteroides fragilis a major anaerobic microorganism in the intestinal flora of humans. Only rhubarb root (Rheum officinale) was found to have significant activity and the purified active substance was identified as rhein.

Anthraquinones↗