Composition Of Bacterial Flora Research Articles

A study on the existence of Vibrio cholerae non-O1 in the river.

The aim of the present study is Vibrio cholerae non-O1 existing in river. Bacteria are known to inhabit all kinds of environment. Vibrionaceae is widely distributed in environmental water. Vibrio spp. have been identified as a cause of toxicity in fish and shellfish. One condition affecting the survival of pathogenic microorganisms in environmental water is the salt concentration, and they have been reported to inhabit brackish water. However, V. cholerae non-O1 has also been detected in fresh water, and its properties suggest that it can survive in river water. Sampling was performed 4 times at 4 points during a 5-month period from July to November at about 1-month intervals from the Sagami River in 1985. River water bacteria were identified, and V. cholera non-O1 isolated. I investigated the relationship between the bacterial flora in river water and the detection of V. cholerae non-O1. There were significant differences in the composition of bacterial flora with and without the isolation of V. cholerae non-O1 (Chi-square test) (χ(2) = 24.70 > 22.0 (p = 0.005), df = 8). A correlation between changes in the composition of the river water bacterial flora and detection of V. cholerae non-O1 was identified. Therefore, V. cholerae non-O1 exists in the river.

Bacterial community structure in Apis florea larvae analyzed by denaturing gradient gel electrophoresis and 16S rRNA gene sequencing.

This study characterizes the colonization and composition of bacterial flora in dwarf Asian honeybee (Apis florea) larvae and compares bacterial diversity and distribution among different sampling locations. A. florea larvae were collected from 3 locations in Chiang Mai province, Thailand. Bacterial DNA was extracted from each larva using the phenol-chloroform method. Denaturing gradient gel electrophoresis was performed, and the dominant bands were excised from the gels, cloned, and sequenced for bacterial species identification. The result revealed similarities of bacterial community profiles in each individual colony, but differences between colonies from the same and different locations. A. florea larvae harbor bacteria belonging to 2 phyla (Firmicutes and Proteobacteria), 5 classes (Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Bacilli, and Clostridia), 6 genera (Clostridium, Gilliamella, Melissococcus, Lactobacillus, Saccharibacter, and Snodgrassella), and an unknown genus from uncultured bacterial species. The classes with the highest abundance of bacteria were Alphaproteobacteria (34%), Bacilli (25%), Betaproteobacteria (11%), Gammaproteobacteria (10%), and Clostridia (8%), respectively. Similarly, uncultured bacterial species were identified (12%). Environmental bacterial species, such as Saccharibacter floricola, were also found. This is the first study in which sequences closely related to Melissococcus plutonius, the causal pathogen responsible for European foulbrood, have been identified in Thai A. florea larvae.

Effect of dietary fructose polymers or sucrose on microbial fermentation, enzyme activity, ciliate concentration and diversity of bacterial flora in the rumen of rams

Five rumen-cannulated Polish Merino rams were used in a 5×5 Latin square design to investigate the effect of sucrose and polymers of fructose on the activity and characteristics of rumen protozoa and bacteria. The animals were fed concentrate and timothy hay containing either 33g or 163g fructan/kg. The low-fructan hay was supplied in the control diet and in the diets supplemented with sucrose and inulins. The high-fructan hay was the component of diet rich in timothy grass fructan. The control diet supplied 39.6g fructan/day. The remaining diet offered 195.6g of fructose-containing carbohydrates/day. The concentration of total SCFA was 7.2–9.5mM/100ml rumen fluid independently of diet and sampling time (P>0.05). The increase in sucrose or fructan contents lowered the proportions of acetate from 73.1 to 64.2mM/100mM (P≤0.002) and increased those of propionate and butyrate from 16.4 to 21.5 (P=0.003), and from 9.8 to 15.6mM/100mM (P≤0.004), respectively. The sampling time affected the proportions of propionate (P=0.01). The diets did not affect pH of rumen fluid except in the ration with timothy grass fructan (P=0.029).Irrespective of diet and sampling time (P≥0.05), the digestion velocities of timothy grass fructan, inulin, sucrose, starch, pectins, carboxymethylcellulose, and xylan were 1.3–2.9; 0.7–2.1; 4.8–9.6; 1.9–2.4, 0.3–0.5, 0.7–1.2, and 0.7–1.4mM reducing sugars/g dry matter (DM) of rumen fluid per hour, respectively. A positive correlation was found between the degradation rate of timothy grass fructan and inulin or sucrose (P≤0.045). The total number of ciliates was 261–475×103/ml, that of Entodinium, 231–439×103/ml. The concentrations of Epidinium, Isotricha and Dasytricha were 14–24×103/ml, 2.6–7.0×103/ml, and 3.2–8.1×103/ml, respectively (P≥0.05). The Diplodinium counts varied from 1.4 to 3.1×103/ml in control animals to 4.0–7.3×103/ml in sheep fed the diet rich in timothy grass fructan and Beneo P95 (P≤0.008). A postprandial decrease in the concentration of Diplodiniuum was found in animals fed the control ration and the rations rich in timothy grass fructan and Beneo HPX (P=0.017). It was stated that the sampling time influenced the composition of bacterial flora. The experiment showed that the applied doses of the examined carbohydrates did not affect the majority of the quantified parameters. The studies shall be continued using enlarged doses of fructose-containing carbohydrates.

Analysis of the Bacterial Flora in the Nasal Cavity and the Sphenoid Sinus Mucosa in Patients Operated on with an Endoscopic Endonasal Transsphenoidal Approach

The aim of this study was to analyze the bacterial flora in the nasal cavity and sphenoid sinus and evaluate the sensitivity of these bacteria to antibiotics that can be used to prevent postoperative meningitis. Bacteria of the preoperative nasal cavity and intraoperative sphenoid sinus mucosa were cultured and analyzed in 40 patients (20 men and 20 women; mean age, 52.2 years) who underwent endoscopic transsphenoidal surgery. The sensitivity of these bacteria to cephalosporin, a representative prophylactic antibiotic, was examined. Staphylococcus epidermidis was the most frequently detected species in both spaces; 24 (38.7%) of 62 isolates in the nasal cavity and 26 (37.1%) of 70 isolates in the sphenoid sinus. In contrast, Corynebacterium species were found mainly in the nasal cavity, and anaerobic bacteria were found only in the sphenoid sinus. Bacteria that were resistant to cephalosporin were found in the nasal cavity in 3.2% of patients and in the sphenoid sinus in 20% of patients. In conclusion, the composition of bacterial flora, including bacteria that are resistant to prophylactic antibiotics, differs between the nasal cavity and the sphenoid sinus.

Preliminary Analysis of Bacterial Flora in Turbot <i>Scophthalmus maximus</i> Cultured in Deep Well Seawater

The microbiological characters and composition of bacterial flora in fresh turbot Scophthalmus maximus were observed with qualitative and quantitative analysis. Samples of turbot fish were collected in the spring, summer and autumn of one year. The total amounts of bacteria from the culturing water, gills and skin were quantified as 3.46±2.4-3.82±1.2 log10cfu·ml-1, 5.19±2.3-6.28±1.7 log10cfu·ml-1 and 2.70±1.1-2.95±2.8 log10cfu·ml-1, respectively. The isolated strains and bacterial flora were identified and classified. The results showed that among 206 isolated strains, Gram-positive bacteria accounted for 18.9% of the total flora, and Gram-negative bacteria formed 82.4%, including predominant bacteria such as Staphylococcusaureus (12.6%), Serratia liquefaciens (10.7%), Enterobacter (19.4%) and Pseudomonas (8.3%). A large number of isolated Enterobacter indicated that the culturing water was polluted. We report here for the first time the microbial flora in the turbot cultured in deep well seawater of Liaodong Penisula, which provides a preliminary basis for the subsequent study on the specific spoilage organisms from chilled turbot fish.

Retraction

Environmental MicrobiologyVolume 14, Issue 12 p. 3289-3289 RetractionFree Access Retraction This article retracts the following: Retracted Geographical variation in cloacal microflora and bacterial antibiotic resistance in a threatened avian scavenger in relation to diet and livestock farming practices Guillermo Blanco, Jesús A. Lemus, Javier Grande, Laura Gangoso, Juan M. Grande, José A. Donázar, Bernardo Arroyo, Oscar Frías, Fernando Hiraldo, Volume 9Issue 7Environmental Microbiology pages: 1738-1749 First Published online: April 25, 2007 First published: 04 December 2012 https://doi.org/10.1111/1462-2920.12026AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL The following article from Environmental Microbiology, ‘Geographical variation in cloacal microflora and bacterial antibiotic resistance in a threatened avian scavenger in relation to diet and livestock farming practices’ by Guillermo Blanco, Jesús A. Lemus, Javier Grande, Laura Gangoso, Juan M. Grande, José A. Donázar, Bernardo Arroyo, Oscar Frías and Fernando Hiraldo published in Environmental Microbiology 9(7): 1738–1749, and online ahead of print on 25 April 2007, doi: 10.1111/j.1462-2920.2007.01291.x, has been retracted by agreement between Guillermo Blanco, José A. Donázar, Fernando Hiraldo, Óscar Frías, Laura Gangoso, Juan M. Grande, Felix Martínez, Bernardo Arroyo, the journal Editor-in-Chief Kenneth N. Timmis, and Blackwell Publishing Ltd. The retraction has been agreed because: There are doubts about the validity of the results on bacterial flora composition and antibiotic resistances (Table 1, Fig. 1–6), on which the main conclusions of the article were based. The authors were unable to repeat the analyses presented in the article with the same cloacal swab samples, given the likelihood of changes in the microbial compositions of the samples with time. Additionally, the authors were unable to identify Javier Grande. The authors hope to attempt determining the reliability of the results and hypotheses stated in the paper by using additional samples collected in the future. We sincerely apologize for any inconvenience to the readership of Environmental Microbiology. Reference Blanco, G., Lemus, J.A., Grande, J., Gangoso, L., Grande, J.M., Donázar, J.A., Arroyo, B., Frías, O. and Hiraldo, F. (2007) Geographical variation in cloacal microflora and bacterial antibiotic resistance in a threatened avian scavenger in relation to diet and livestock farming practices. Environ Microbiol, doi: 10.1111/j.1462-2920.2007.01291.x. Volume14, Issue12December 2012Pages 3289-3289 ReferencesRelatedInformation

Helicobacter pylori infection and colorectal carcinoma: pathologic aspects.

Helicobacter pylori infection and colorectal carcinoma: pathologic aspects.

What causes type 1 diabetes? Lessons from animal models

To study type 1 diabetes (T1D), excellent animal models exist, both spontaneously diabetic and virus-induced. Based on knowledge from these, this review focuses on the environmental factors leading to T1D, concentrated into four areas which are: (1) The thymus-dependent immune system: T1D is a T cell driven disease and the beta cells are destroyed in an inflammatory insulitis process. Autoimmunity is breakdown of self-tolerance and the balance between regulator T cells and aggressive effector T cells is disturbed. Inhibition of the T cells (by e.g. anti-CD3 antibody or cyclosporine) will stop the T1D process, even if initiated by virus. Theoretically, the risk from immunotherapy elicits a higher frequency of malignancy. (2) The activity of the beta cells: Resting beta cells display less antigenicity and are less sensitive to immune destruction. Beta-cell rest can be induced by giving insulin externally in metabolic doses or by administering potassium-channel openers. Both procedures prevent T1D in animal models, whereas no good human data exist due to the risk of hypoglycemia. (3) NKT cells: According to the hygiene hypothesis, stimulation of NKT cells by non-pathogen microbes gives rise to less T cell reaction and less autoimmunity. Glycolipids presented by CD1 molecules are central in this stimulation. (4) Importance of the intestine and gliadin intake: Gluten-free diet dramatically inhibits T1D in animal models, and epidemiological data are supportive of such an effect in humans. The mechanisms include less subclinical intestinal inflammation and permeability, and changed composition of bacterial flora, which can also be obtained by intake of probiotics. Gluten-free diet is difficult to implement, and short-term intake has no effect. Regarding the onset of the T1D disease process, slow-acting enterovirus and gliadin deposits are speculated to be etiological in genetically susceptible individuals, followed by the mentioned four pathogenetic factors acting in concert. Neutralization of any one of these factors is capable of stopping T1D development, as lessons are learned from the animal models.

Ribosomal RNA-based analysis of the bacterial flora from the conjunctivae of cattle with bovine keratoconjunctivitis (BKC)

Bovine keratoconjunctivitis (BKC), colloquially referred to as ‘pinkeye’, is a disease affecting cattle worldwide; it costs cattle producers millions of dollars in economic loss annually. While Moraxella spp. are the primary etiologic agent of pinkeye, surveys of flora from the conjunctivae of livestock from around the world have indicated that a variety of bacterial commensals occupy this niche. We used molecular biology-based methods to determine the composition of bacterial flora in the conjunctivae of normal dairy and beef cattle from Maryland ( n = 113), and beef cattle with clinical BKC from Louisiana ( n = 42). Three regimens were used: 16S rRNA PCR and DGGE analysis of amplicons; 16S rRNA PCR and cloning of amplicons into Escherichia coli followed by screening and sequencing of clones harboring inserts; and culture of bacteria on chromogenic agar followed by 16S rRNA PCR and sequencing. Most taxa were comprised of saprophytes found in the environment, such as Bacillus, Pantoea, E. coli, and Exiguobacterium. Moraxella spp. were infrequently observed. Some species, such as Propionibacterium acnes, represent taxa not previously associated with the conjunctivae. Bacillus pumilus and Bacillus licheniformis isolates from the conjunctivae of Maryland cattle were genetically distinct from isolates previously implicated in septic infections in cattle at the same location. We conclude that employing 16S rRNA-based methods for bacterial identification can be useful in defining the flora present in the conjunctivae of normal cattle, and those with BKC.

Novel Microarray Design Strategy To Study Complex Bacterial Communities

Assessing bacterial flora composition appears to be of increasing importance to fields as diverse as physiology, development, medicine, epidemiology, the environment, and the food industry. We report here the development and validation of an original microarray strategy that allows analysis of the phylogenic composition of complex bacterial mixtures. The microarray contains approximately 9,500 feature elements targeting 16S rRNA gene-specific regions. Probe design was performed by selecting oligonucleotide sequences specific to each node of the seven levels of the bacterial phylogenetic tree (domain, phylum, class, order, family, genus, and species). This approach, based on sequence information, allows analysis of the bacterial contents of complex bacterial mixtures to detect both known and unknown microorganisms. The presence of unknown organisms can be suspected and mapped on the phylogenetic tree, indicating where to refine analysis. Initial proof-of-concept experiments were performed on oral bacterial communities. Our results show that this hierarchical approach can reveal minor changes (<or=1%) in gingival flora content when samples collected in individuals from similar geographical origins are compared.

Effects of the In Vivo Supply of Butyrate on Histone Acetylation of Cecum in Piglets

In vitro, butyrate inhibits histone deacetylase and down-regulates expression of cyclin D1. We hypothesized that an increased entry rate of butyrate into the cecal lumen would have similar effects in vivo. We used frozen cecal tissue and data from previous studies, one showing that lactulose supplementation caused an increased rate of cecal synthesis of butyrate and decreased cecal cell proliferation and density of clostridia and the other showing that cecal cell proliferation was increased by an exogenous cecal butyrate infusion at a comparable rate. The ratio of acetylated to total histones (AH ratio) and cyclin D1 mRNA expression were measured in cecal tissue. Lactulose supplementation caused a 189% increase in the AH ratio (p = .004), which inversely correlated with cecal cell proliferation (r = -0.782; p = .008). With cecal butyrate infusion, we observed a significant decrease in histone acetylation (p = .02), which also inversely correlated with cecal cell proliferation (r = -0.797; p = .002). Cyclin D1 expression was increased 6.5-fold by lactulose feeding (p = .02) but decreased 50% with cecal butyrate infusion (p = .004). The effects on histone acetylation of increased "endogenous" butyrate production produced by lactulose feeding, but not exogenous cecal infusion of butyrate, mirror those in vitro. Thus, bacterial production and exogenous infusion of butyrate have opposite effects on histone acetylation and cyclin D1 expression, suggesting that the composition of bacterial flora may play a role in butyrate's in vivo effects on the cell cycle.

Retracted Geographical variation in cloacal microflora and bacterial antibiotic resistance in a threatened avian scavenger in relation to diet and livestock farming practices

The impact on wildlife health of the increase in the use of antimicrobial agents with the intensification of livestock production remains unknown. The composition, richness and prevalence of cloacal microflora as well as bacterial resistance to antibiotics in nestlings and full-grown Egyptian vultures Neophron percnopterus were assessed in four areas of Spain in which the degree of farming intensification differs. Differences in diet composition, especially the role of stabled livestock carrion, appear to govern the similarities of bacterial flora composition among continental populations, while the insular vulture population (Fuerteventura, Canary Islands) showed differences attributed to isolation. Evidence of a positive relationship between the consumption of stabled livestock carrion and bacterial resistance to multiple antibiotics was found. Bacterial resistance was high for semisynthetic penicillins and enrofloxacin, especially in the area with the most intensive stabled livestock production. The pattern of antibiotic resistance was similar for the different bacterial species within each area. Bacterial resistance to antibiotics may be determined by resistance of bacteria present in the livestock meat remains that constituted the food of this species, as indicated by the fact that resistance to each antibiotic was correlated in Escherichia coli isolated from swine carrion and Egyptian vulture nestlings. In addition, resistance in normal faecal bacteria (present in the microflora of both livestock and vultures) was higher than in Staphylococcus epidermidis, a species indicator of the transient flora acquired presumably through the consumption of wild rabbits. Potential negative effects of the use of antimicrobials in livestock farming included the direct ingestion of these drug residues and the effects of bacterial antibiotic resistance on the health of scavengers.

Differences between Tissue-Associated Intestinal Microfloras of Patients with Crohn's Disease and Ulcerative Colitis

A leading hypothesis for the role of bacteria in inflammatory bowel diseases is that an imbalance in normal gut flora is a prerequisite for inflammation. Testing this hypothesis requires comparisons between the microbiota compositions of ulcerative colitis and Crohn's disease patients and those of healthy individuals. In this study, we obtained biopsy samples from patients with Crohn's disease and ulcerative colitis and from healthy controls. Bacterial DNA was extracted from the tissue samples, amplified using universal bacterial 16S rRNA gene primers, and cloned into a plasmid vector. Insert-containing colonies were picked for high-throughput sequencing, and sequence data were analyzed, yielding species-level phylogenetic data. The clone libraries yielded 3,305 sequenced clones, representing 151 operational taxonomical units. There was no significant difference between floras from inflamed and healthy tissues from within the same individual. Proteobacteria were significantly (P = 0.0007) increased in Crohn's disease patients, as were Bacteroidetes (P < 0.0001), while Clostridia were decreased in that group (P < 0.0001) in comparison with the healthy and ulcerative colitis groups, which displayed no significant differences. Thus, the bacterial flora composition of Crohn's patients appears to be significantly altered from that of healthy controls, unlike that of ulcerative colitis patients. Imbalance in flora in Crohn's disease is probably not sufficient to cause inflammation, since microbiotas from inflamed and noninflamed tissues were of similar compositions within the same individual.

Retracted: Faecal bacteria associated with different diets of wintering red kites: influence of livestock carcass dumps in microflora alteration and pathogen acquisition

Summary Despite the important role of refuse dumps for the conservation of threatened avian scavengers, there is no information about the direct effects on scavenger health from feeding on meat remains found at these places, including the potential for exposure to infections agents and harmful chemical residues. We assessed the composition, species richness and prevalence of faecal microflora of wintering red kites Milvus milvus in two areas of central Spain where kites fed primarily on carrion from stabled livestock reared in intensive conditions (Segovia) versus those that fed on wild rabbits Oryctolagus cuniculus (Madrid). Faecal bacterial flora composition, species richness and prevalence differed between areas. These differences were attributed to diet and the environmental conditions found at the sites where the kites obtained most of their food. The intestinal microflora of kites feeding on carrion from stabled livestock (mostly fattening pigs) differed from the flora considered to be normal for a healthy raptor. Salmonella sp. was found in a relatively high proportion of samples from Segovia (25%), 6% of those samples yielded in pure culture (serotypes enteritidis and gallinarum). If these serotypes cause disease in kites and other raptors, as they do for poultry and some other birds, there may be cause for concern regarding the health of an important sector of the red kite wintering population. Synthesis and applications. Conservation of wintering red kites in Spain should involve management to promote the recovery of populations of wild prey, especially wild rabbits, and measures to allow free‐range livestock carcasses to be placed in the countryside for scavenger elimination without posing a risk from the spread and transfer of disease, especially bovine spongiform encephalopathy (BSE). Periodic inspections by management agencies should ensure that meat originating from stabled livestock and disposed of in refuse dumps does not pose major hazards for avian scavengers. The risk to scavengers from ingestion of residues of veterinary drugs, pathogen acquisition and gut flora alteration, arising from disposal and accumulation of infected carcasses and rotten meat in refuse dumps, must be carefully monitored and managed.

Influence of Preoperative Oxytetracycline Administration on Community Composition and Antimicrobial Susceptibility of Cloacal Bacterial Flora of Loggerhead Sea Turtle, Caretta caretta, Post-Hatchlings

ABSTRACT Cloacal cultures from loggerhead sea turtle, Caretta caretta, post-hatchlings were obtained and evaluated for bacterial flora composition and antimicrobial susceptibility before and after laparoscopic surgery with or without preoperative oxytetracycline. Eight of 16 turtles received 25 mg/kg oxytetracycline IM. An equivalent volume of saline was administered to eight control turtles. Cultures were performed in all turtles immediately prior to treatment, at one week, and at one month following treatment. Minimum inhibitory concentration of tetracycline testing was performed. Cloacal bacterial diversity was also evaluated prior to and after administration of oxytetracycline in each group. There was an apparent shift in the community composition and diversity of cloacal bacterial flora in both groups between treatment times. In the saline treated hatchlings, the cloacal bacterial species diversity was unchanged or increased following treatment, whereas the bacterial flora diversity in the oxytetracy...

Developmental changes in stomach, intestine, and skin glycoconjugates in summer flounder ( Paralichthys dentatus): A lectin histochemical study

This study asked whether the glycoconjugates of stomach, intestine, and skin epithelia and their mucous secretions change during metamorphosis in summer flounder. Larvae and juveniles were assayed histochemically with biotinylated lectins, and scored for differences in staining intensity and specificity between the two developmental stages. In the stomach epithelium, the number of positive lectins changed little from larvae to juveniles; however, the secreted mucus increased in staining with DBA, ECL, GSA II, PNA, and SBA lectins. In the intestine, a developmental decrease in the binding intensity of the intestinal brush border was noted for DSL, RCA 120, VVA, SNA, and UEA I lectins, while intestinal goblet cells underwent a large increase in binding for GSA II. The skin mucous cells of the larvae were negative for DBA, DSL, ECL, PNA, RCA 120, and SNA, but became positive in the juveniles. In conclusion, this study showed that changes in glycoconjugate expression occur during metamorphosis in the stomach, intestine, and skin of summer flounder. The changes in the gut glycoconjugates correlate developmentally with shifts in bacterial flora composition found by other studies, and therefore might be relevant to the study of bacteria–host relationships in summer flounder.

Optimizing Gas Mixtures for Modified Atmosphere Packaging of Fresh King Salmon (Oncorhynchus tshawytscha)

Researchers have evaluated the effect of modified atmosphere packaging (MAP) on the shelf life of fish products. However, there is little published basis for recommended gas mixtures. Most studies have examined the effects of empirical evidence of gas mixes on particular species, but they cannot be used to predict the effect of different gas mixes on shelf life. Further, while the fish:gas ratio has been shown to be a key determinant of bacterial growth under MAP, most studies did not control this parameter. The aim of our research was to optimize gas mixes and fish:gas ratios for the MAP storage of king salmon. Flesh portions from defined fillet positions were placed on drip pads and boxed, giving a standardized nominal volume of 27.4 cm3 and an exposed surface area of 14.4 cm2. Each sample was placed in a foil barrier bag containing an oxygen absorber. Controlled volumes (0-100 cm3) of CO2 or 100 cm3 of a 40:60 mixture of CO2:N2 were then hand-injected through a septa. Bags were stored in melting ice (0 ± 0.05°C) and analyzed after 0, 8, 22 and 90 days for headspace CO2 and O2, EH, fish freshness meter (Distell, West Lothian, Scotland) reading, drip loss, texture, raw and cooked sensory characteristics, microbial numbers, bacterial flora composition, total volatile base nitrogen (TVBN) and ATP derivatives. High CO2 levels reduced bacterial counts, but resulted in poor cooked sensory characteristics due to carbonated flavor. We calculated the threshold level of CO2 at which this could be detected by our trained panel. We also determined the solubility of CO2 in salmon flesh and calculated Henry's constant to resolve the relationship between gas mixes and the fish:gas ratio. We now have the basis of a simple mathematical model optimizing these to give maximum shelf life and sensory acceptability.

Childhood asthma hospitalization risk after cesarean delivery in former term and premature infants

Cesarean delivery modifies infant gut bacterial flora composition, which may result in hindered tolerance to allergenic substances, thereby increasing the risk of asthma in accordance with the hygiene hypothesis. Results of previous studies regarding an association between birth route and asthma are conflicting, and these studies have not evaluated some potential confounding effects, including prematurity and maternal asthma. To determine whether cesarean delivery in full-term and premature infants increases the risk of subsequent childhood asthma hospitalization. We conducted a case-control study using the Washington State Birth Events Record Database linked to statewide hospitalization data. The study included 2,028 children hospitalized for asthma (cases) and 8,292 age-matched controls. Cesarean delivery was modestly associated with an increased risk of asthma hospitalization (odds ratio [OR], 1.20; 95% confidence interval [CI], 1.04-1.39). However, when analyzed separately, there was an association between cesarean delivery and asthma hospitalization in premature infants (OR, 1.90; 95% CI, 1.09-3.02) but not in full-term infants (OR, 1.15; 95% CI, 0.97-1.34). Cesarean delivery was associated with subsequent asthma hospitalization only in premature infants. Because mothers with asthma are reported to have increased rates of cesarean delivery and premature delivery, other factors in addition to the hygiene hypothesis, including genetic and in utero influences associated with maternal asthma, may contribute to the increased risk of asthma in premature infants.

Prebiotics and lipid metabolism.

Prebiotics are defined as nondigestible food ingredients that beneficially affect the host by selectively stimulating the growth or the activity of one or a limited number of bacteria (bifidobacteria, lactobacilli) in the colon. Dietary fructans are nutritionally interesting oligosaccharides that strictly conform to the definition of prebiotics and (in view of experimental studies in animals and of less numerous studies in humans) exhibit interesting serum or hepatic lipid lowering properties. Other nondigestible/fermentable nutrients, which also modulate intestinal flora activity, exhibit cholesterol or triglyceride lowering effects. Are changes in intestinal bacterial flora composition or fermentation activity responsible for those effects? What is the future of prebiotics in the nutritional control of lipidaemia and cardiovascular disease risk in humans? Those questions only receive partial response in the present review because studies of the systemic effects of prebiotics are still in their infancy, and require fundamental research devoted to elucidating the biochemical and physiological events that allow prebiotics to exert systemic effects on lipid metabolism.

The question of whether gut microflora of the millipede Ommatoiulus sabulosus could function as a threshold to food infections

Summary The specific composition of bacterial flora in the intestines of O. sabulosus cannot be explained simply by antibiotic inhibition of contaminating microflora since the predominant types of bacteria present are unable to produce any bacteriolytic activity of lysozyme-like enzymes, bacteriocins or other antimicrobial molecules. The lack of microbial contaminators could rather result from the unfavourable biochemical niche in the midgut enzymes and little or no competition for the enteric bacteria group predominant in the millipede alimentary tract. In other words, the rapid colonization and overgrowth of the Ommatoiulus intestines eliminate adventitious bacteria, yeasts and moulds ingested with food.