Louis, Petra; Duncan, Sylvia H; McCrae, Sheila I; Millar, Jacqueline; Jackson, Michelle S; Flint, Harry J
The final steps in butyrate synthesis by anaerobic bacteria can occur via butyrate kinase and phosphotransbutyrylase or via butyryl-coenzyme A (CoA):acetate CoA-transferase. Degenerate PCR and enzymatic assays were used to assess the presence of butyrate kinase among 38 anaerobic butyrate-producing bacterial isolates from human feces that represent three different clostridial clusters (IV, XIVa, and XVI). Only four strains were found to possess detectable butyrate kinase activity. These were also the only strains to give PCR products (verifiable by sequencing) with degenerate primer pairs designed within the butyrate kinase gene or between the linked butyrate kinase/phosphotransbutyrylase genes. Further analysis of the butyrate kinase/phosphotransbutyrylase genes of one isolate, L2-50, revealed similar organization to that described previously from different groups of clostridia, along with differences in flanking sequences and phylogenetic relationships. Butyryl-CoA:acetate CoA-transferase activity was detected in all 38 strains examined, suggesting that it, rather than butyrate kinase, provides the dominant route for butyrate formation in the human colonic ecosystem that contains a constantly high concentration of acetate.
Ramsay, Alan G; Scott, Karen P; Martin, Jenny C; Rincon, Marco T; Flint, Harry J
Selected butyrate-producing bacteria from the human colon that are related to Roseburia spp. and Butyrivibrio fibrisolvens showed a good ability to utilize a variety of starches for growth when compared with the Gram-negative amylolytic anaerobe Bacteroides thetaiotaomicron. A major cell-associated amylase of high molecular mass (140-210 kDa) was detected in each strain by SDS-PAGE zymogram analysis, and genes corresponding to these enzymes were analysed for two representative strains. Amy13B from But. fibrisolvens 16/4 is a multi-domain enzyme of 144.6 kDa that includes a family 13 glycoside hydrolase domain, and duplicated family 26 carbohydrate-binding modules. Amy13A (182.4 kDa), from Roseburia inulinivorans A2-194, also includes a family 13 domain, which is preceded by two repeat units of approximately 116 aa rich in aromatic residues, an isoamylase N-terminal domain, a pullulanase-associated domain, and an additional unidentified domain. Both Amy13A and Amy13B have N-terminal signal peptides and C-terminal cell-wall sorting signals, including a modified LPXTG motif similar to that involved in interactions with the cell surface in other Gram-positive bacteria, a hydrophobic transmembrane segment, and a basic C terminus. The overexpressed family 13 domains showed an absolute requirement for Mg2+ or Ca2+ for activity, and functioned as 1,4-alpha-glucanohydrolases (alpha-amylases; EC 18.104.22.168). These major starch-degrading enzymes thus appear to be anchored to the cell wall in this important group of human gut bacteria.
Scott, Karen P; Martin, Jennifer C; Duncan, Sylvia H; Flint, Harry J
Dietary macronutrients affect the composition of the gut microbiota, and prebiotics are used to improve and maintain a healthy gut. The impact of prebiotics on dominant gut bacteria other than bifidobacteria, however, is under-researched. Here, we report carbohydrate utilisation patterns for representative butyrate-producing anaerobes, belonging to the Gram-positive Firmicutes families Lachnospiraceae and Ruminococcaceae, by comparison with selected Bacteroides and Bifidobacterium species. Growth assessments using anaerobic Hungate tubes and a new rapid microtitre plate assay were generally in good agreement. The Bacteroides strains tested showed some growth on basal medium with no added carbohydrates, utilising peptides in the growth medium. The butyrate-producing strains exhibited different growth profiles on the substrates, which included starch, inulin, fructooligosaccharides (FOS), galactooligosaccharides (GOS) and xylooligosaccharides (XOS). Eleven were able to grow on short-chain FOS, but this number decreased as the chain length of the fructan substrates increased. Long-chain inulin was utilised by Roseburia inulinivorans, but by none of the Bifidobacterium species examined here. XOS was a more selective growth substrate than FOS, with only six of the 11 Firmicutes strains able to use XOS for growth. These results illustrate the selectivity of different prebiotics and help to explain why some are butyrogenic.
Rivière, Audrey; Selak, Marija; Lantin, David; Leroy, Frédéric; De Vuyst, Luc
With the increasing amount of evidence linking certain disorders of the human body to a disturbed gut microbiota, there is a growing interest for compounds that positively influence its composition and activity through diet. Besides the consumption of probiotics to stimulate favorable bacterial communities in the human gastrointestinal tract, prebiotics such as inulin-type fructans (ITF) and arabinoxylan-oligosaccharides (AXOS) can be consumed to increase the number of bifidobacteria in the colon. Several functions have been attributed to bifidobacteria, encompassing degradation of non-digestible carbohydrates, protection against pathogens, production of vitamin B, antioxidants, and conjugated linoleic acids, and stimulation of the immune system. During life, the numbers of bifidobacteria decrease from up to 90% of the total colon microbiota in vaginally delivered breast-fed infants to <5% in the colon of adults and they decrease even more in that of elderly as well as in patients with certain disorders such as antibiotic-associated diarrhea, inflammatory bowel disease, irritable bowel syndrome, obesity, allergies, and regressive autism. It has been suggested that the bifidogenic effects of ITF and AXOS are the result of strain-specific yet complementary carbohydrate degradation mechanisms within cooperating bifidobacterial consortia. Except for a bifidogenic effect, ITF and AXOS also have shown to cause a butyrogenic effect in the human colon, i.e., an enhancement of colon butyrate production. Butyrate is an essential metabolite in the human colon, as it is the preferred energy source for the colon epithelial cells, contributes to the maintenance of the gut barrier functions, and has immunomodulatory and anti-inflammatory properties. It has been shown that the butyrogenic effects of ITF and AXOS are the result of cross-feeding interactions between bifidobacteria and butyrate-producing colon bacteria, such as Faecalibacterium prausnitzii (clostridial cluster IV
Louis, Petra; Young, Pauline; Holtrop, Grietje; Flint, Harry J
Butyrate-producing bacteria play an important role in the human colon, supplying energy to the gut epithelium and regulating host cell responses. In order to explore the diversity and culturability of this functional group, we designed degenerate primers to amplify butyryl-CoA:acetate CoA-transferase sequences from faecal samples provided by 10 healthy volunteers. Eighty-eight per cent of amplified sequences showed >98% DNA sequence identity to CoA-transferases from cultured butyrate-producing bacteria, and these fell into 12 operational taxonomic units (OTUs). The four most prevalent OTUs corresponded to Eubacterium rectale, Roseburia faecis, Eubacterium hallii and an unnamed cultured species SS2/1. The remaining 12% of sequences, however, belonged to 20 OTUs that are assumed to come from uncultured butyrate-producing strains. Samples taken after ingestion of inulin showed significant (P=0.019) increases in Faecalibacterium prausnitzii. Because several of the dominant butyrate producers differ in their DNA % G+C content, analysis of thermal melt curves obtained for PCR amplicons of the butyryl-CoA:acetate CoA-transferase gene provides a convenient and rapid qualitative assessment of the major butyrate producing groups present in a given sample. This type of analysis therefore provides an excellent source of information on functionally important groups within the colonic microbial community.
Tanaka, Sachi; Yamamoto, Kana; Yamada, Kazuki; Furuya, Kanon; Uyeno, Yutaka
This study was performed to determine the effects of feeding a fiber-rich fraction of Brassica vegetables on the immune response through changes in enteric bacteria and short-chain fatty acid (SCFA) production in normal mice. The boiled-water-insoluble fraction of Brassica rapa L. (nozawana), which consists mainly of dietary fiber, was chosen as a test material. A total of 31 male C57BL/6J mice were divided into two groups and housed in a specific-pathogen-free facility. The animals were fed either a control diet or the control diet plus the insoluble B. rapa L. fraction for 2 weeks and sacrificed to determine microbiological and SCFA profiles in lower-gut samples and immunological molecules. rRNA-based quantification indicated that the relative population of Bacteroidetes was markedly lower in the colon samples of the insoluble B. rapa L. fraction-fed group than that in the controls. Populations of the Eubacterium rectale group and Faecalibacterium prausnitzii, both of which are representative butyrate-producing bacteria, doubled after 2 weeks of fraction intake, accompanying a marginal increase in the proportion of colonic butyrate. In addition, feeding with the fraction significantly increased levels of the anti-inflammatory cytokine interleukin-10 (IL-10) and tended to increase splenic regulatory T cell numbers but significantly reduced the population of cells expressing activation markers. We demonstrated that inclusion of the boiled-water-insoluble fraction of B. rapa L. can alter the composition of the gut microbiota to decrease the numbers of Bacteroidetes and to increase the numbers of butyrate-producing bacteria, either of which may be involved in the observed shift in the production of splenic IL-10.
Falony, Gwen; Vlachou, Angeliki; Verbrugghe, Kristof; De Vuyst, Luc
In vitro coculture fermentations of Bifidobacterium longum BB536 and two acetate-converting, butyrate-producing colon bacteria, Anaerostipes caccae DSM 14662 and Roseburia intestinalis DSM 14610, with oligofructose as the sole energy source, were performed to study interspecies interactions. Two clearly distinct types of cross-feeding were identified. A. caccae DSM 14662 was not able to degrade oligofructose but could grow on the fructose released by B. longum BB536 during oligofructose breakdown. R. intestinalis DSM 14610 could degrade oligofructose, but only after acetate was added to the medium. Detailed kinetic analyses of oligofructose breakdown by the last strain revealed simultaneous degradation of the different chain length fractions, in contrast with the preferential degradation of shorter fractions by B. longum BB536. In a coculture of both strains, initial oligofructose degradation and acetate production by B. longum BB536 took place, which in turn also allowed oligofructose breakdown by R. intestinalis DSM 14610. These and similar cross-feeding mechanisms could play a role in the colon ecosystem and contribute to the combined bifidogenic/butyrogenic effect observed after addition of inulin-type fructans to the diet.
Mu, Chunlong; Zhang, Lingli; He, Xiangyu; Smidt, Hauke; Zhu, Weiyun
Dietary fibres have been shown to affect early-life microbiota colonization in the large intestine of suckling piglets, however, much less is known as to whether they also modulate the composition and activity of butyrate-producing bacteria. Here, we investigated the effect of dietary fibres on the abundance, composition, and activity of butyrate-producing bacteria in suckling piglets. Piglets were fed a control diet or creep feeds containing alfalfa, wheat bran, or pure cellulose, respectively, from postnatal day 7 to 22. Large intestinal digesta and mucosa samples were collected for quantitative analysis of bacterial group-specific 16S ribosomal RNA- and butyrate production-related genes, and digesta samples for quantification of short-chain fatty acids. The alfalfa diet increased (P < 0.05) Clostridium cluster XIVa abundance, copies of genes encoding proteins involved in butyrate production (butyryl-CoA:acetate CoA-transferase, butyrate kinase), and butyrate concentration compared to the wheat bran diet in the digesta of the proximal colon. In the distal colonic digesta, animals fed the alfalfa diet had the highest number of butyryl-CoA:acetate CoA-transferase gene copies (P < 0.05) and numerically the highest butyrate concentration, albeit not significant (P > 0.05), compared to other groups. In the distal colonic mucosa, the cellulose diet increased (P < 0.05) the abundance of Clostridium cluster XIVa and copies of the butyryl-CoA:acetate CoA-transferase gene compared to the alfalfa diet. These results indicated that dietary fibres modulate the abundance and activity of butyrate-producing bacteria in the large intestine of suckling piglets, and that a moderate supplementation of alfalfa and cellulose may benefit early-life gut health through the delivery of butyrate to the mucosa.
Nylund, L; Nermes, M; Isolauri, E; Salminen, S; de Vos, W M; Satokari, R
The reports on atopic diseases and microbiota in early childhood remain contradictory, and both decreased and increased microbiota diversity have been associated with atopic eczema. In this study, the intestinal microbiota signatures associated with the severity of eczema in 6-month-old infants were characterized. Further, the changes in intestinal microbiota composition related to the improvement of this disease 3 months later were assessed. The severity of eczema correlated inversely with microbiota diversity (r = -0.54, P = 0.002) and with the abundance of butyrate-producing bacteria (r = -0.52, P = 0.005). During the 3-month follow-up, microbiota diversity increased (P < 0.001) and scoring atopic dermatitis values decreased (P < 0.001) in all infants. This decrease coincided with the increase in bacteria related to butyrate-producing Coprococcus eutactus (r = -0.59, P = 0.02). In conclusion, the high diversity of microbiota and high abundance of butyrate-producing bacteria were associated with milder eczema, thus suggesting they have a role in alleviating symptoms of atopic eczema.
Perrin, P; Pierre, F; Patry, Y; Champ, M; Berreur, M; Pradal, G; Bornet, F; Meflah, K; Menanteau, J
BACKGROUND—Dietary fibres have been proposed as protective agents against colon cancer but results of both epidemiological and experimental studies are inconclusive. AIMS—Hypothesising that protection against colon cancer may be restricted to butyrate producing fibres, we investigated the factors needed for long term stable butyrate production and its relation to susceptibility to colon cancer. METHODS—A two part randomised blinded study in rats, mimicking a prospective study in humans, was performed using a low fibre control diet (CD) and three high fibre diets: starch free wheat bran (WB), type III resistant starch (RS), and short chain fructo-oligosaccharides (FOS). Using a randomised block design, 96 inbred rats were fed for two, 16, 30, or 44 days to determine the period of adaptation to the diets, fermentation profiles, and effects on the colon, including mucosal proliferation on day 44. Subsequently, 36 rats fed the same diets for 44 days were injected with azoxymethane and checked for aberrant crypt foci 30 days later. RESULTS—After fermentation had stabilised (44 days), only RS and FOS produced large amounts of butyrate, with a trophic effect in the large intestine. No difference in mucosal proliferation between the diets was noted at this time. In the subsequent experiment one month later, fewer aberrant crypt foci were present in rats fed high butyrate producing diets (RS, p=0.022; FOS, p=0.043). CONCLUSION—A stable butyrate producing colonic ecosystem related to selected fibres appears to be less conducive to colon carcinogenesis. Keywords: fibre; fermentation; butyrate; colon carcinogenesis; aberrant crypt foci; rat PMID:11115823
O. Sheridan, Paul; Martin, Jennifer C.; Lawley, Trevor D.; Browne, Hilary P.; Harris, Hugh M. B.; Bernalier-Donadille, Annick; Duncan, Sylvia H.; O'Toole, Paul W.; J. Flint, Harry
Firmicutes and Bacteroidetes are the predominant bacterial phyla colonizing the healthy human large intestine. Whilst both ferment dietary fibre, genes responsible for this important activity have been analysed only in the Bacteroidetes, with very little known about the Firmicutes. This work investigates the carbohydrate-active enzymes (CAZymes) in a group of Firmicutes, Roseburia spp. and Eubacterium rectale, which play an important role in producing butyrate from dietary carbohydrates and in health maintenance. Genome sequences of 11 strains representing E. rectale and four Roseburia spp. were analysed for carbohydrate-active genes. Following assembly into a pan-genome, core, variable and unique genes were identified. The 1840 CAZyme genes identified in the pan-genome were assigned to 538 orthologous groups, of which only 26 were present in all strains, indicating considerable inter-strain variability. This analysis was used to categorize the 11 strains into four carbohydrate utilization ecotypes (CUEs), which were shown to correspond to utilization of different carbohydrates for growth. Many glycoside hydrolase genes were found linked to genes encoding oligosaccharide transporters and regulatory elements in the genomes of Roseburia spp. and E. rectale, forming distinct polysaccharide utilization loci (PULs). Whilst PULs are also a common feature in Bacteroidetes, key differences were noted in these Firmicutes, including the absence of close homologues of Bacteroides polysaccharide utilization genes, hence we refer to Gram-positive PULs (gpPULs). Most CAZyme genes in the Roseburia/E. rectale group are organized into gpPULs. Variation in gpPULs can explain the high degree of nutritional specialization at the species level within this group. PMID:28348841
Geirnaert, Annelies; Steyaert, Alix; Eeckhaut, Venessa; Debruyne, Bo; Arends, Jan B A; Van Immerseel, Filip; Boon, Nico; Van de Wiele, Tom
Butyrate has several beneficial properties that are essential to maintain gastrointestinal health. Therefore butyrate-producing bacteria are seen as the next generation of probiotics. The butyrate-producing bacterium Butyricicoccus pullicaecorum (a clostridial cluster IV strain) is such a promising probiotic candidate for people suffering from inflammatory bowel disease. To exert its beneficial properties, it is crucial that B. pullicaecorum survives the harsh conditions of the upper gastrointestinal tract to arrive in the colon in a viable and metabolically active state. Before developing a stable formulation of B. pullicaecorum for oral administration, it is important to know its intrinsic acid and bile tolerance. We monitored the survival during and short chain fatty acid production after incubation in conditions simulating the stomach and small intestine using in vitro batch experiments. In case of acid conditions (pH 2 and pH 3), B. pullicaecorum was viable and active but not cultivable. Cultivability was restored during subsequent small intestine conditions. Importantly, bile and pancreatic juice had no lethal effect. Milk, as a suspension medium, only had a protective effect on the cultivability during the first hour at pH 2. B. pullicaecorum was still metabolically active after upper gastrointestinal conditions and produced short chain fatty acids, but a shift from butyrate to acetate production was observed. Although the butyrate-producing anaerobe B. pullicaecorum showed good intrinsic acid and bile tolerance in terms of viability and metabolic activity, colonization efficiency and butyrate production under colon conditions is needed to further evaluate its probiotic potential.
Moens, Frédéric; Verce, Marko; De Vuyst, Luc
Cross-feeding interactions were studied between selected strains of lactobacilli and/or bifidobacteria and butyrate-producing colon bacteria that consume lactate but are not able to degrade inulin-type fructans (ITF) in a medium for colon bacteria (supplemented with ITF as energy source and acetate when necessary). Degradation of oligofructose by Lactobacillus acidophilus IBB 801 and inulin by Lactobacillus paracasei 8700:2 and Bifidobacterium longum LMG 11047 resulted in the release of free fructose into the medium and the production of mainly lactate (lactobacilli) and acetate (B. longum LMG 11047). During bicultures of Lb. acidophilus IBB 801 and Anaerostipes caccae DSM 14662(T) on oligofructose, the latter strain converted lactate (produced by the former strain from oligofructose) into butyrate and gases, but only in the presence of acetate. During bicultures of Lb. paracasei 8700:2 and A. caccae DSM 14662(T) or Eubacterium hallii DSM 17630 on inulin, the butyrate-producing strains consumed low concentrations of lactate and acetate generated by inulin degradation by the Lactobacillus strain. As more acetate was produced during tricultures of Lb. paracasei 8700:2 and B. longum LMG 11047, which degraded inulin simultaneously, and A. caccae DSM 14662(T) or E. hallii DSM 17630, a complete conversion of lactate into butyrate and gases by these butyrate-producing strains occurred. Therefore, butyrate production by lactate-consuming, butyrate-producing colon bacterial strains incapable of ITF degradation, resulted from cross-feeding of monosaccharides and lactate by an ITF-degrading Lactobacillus strain and acetate produced by a Bifidobacterium strain.
Vital, Marius; Gao, Jiarong; Rizzo, Mike; Harrison, Tara; Tiedje, James M
Butyrate-producing bacteria have an important role in maintaining host health. They are well studied in human and medically associated animal models; however, much less is known for other Vertebrata. We investigated the butyrate-producing community in hindgut-fermenting Mammalia (n=38), Aves (n=8) and Reptilia (n=8) using a gene-targeted pyrosequencing approach of the terminal genes of the main butyrate-synthesis pathways, namely butyryl-CoA:acetate CoA-transferase (but) and butyrate kinase (buk). Most animals exhibit high gene abundances, and clear diet-specific signatures were detected with but genes significantly enriched in omnivores and herbivores compared with carnivores. But dominated the butyrate-producing community in these two groups, whereas buk was more abundant in many carnivorous animals. Clustering of protein sequences (5% cutoff) of the combined communities (but and buk) placed carnivores apart from other diet groups, except for noncarnivorous Carnivora, which clustered together with carnivores. The majority of clusters (but: 5141 and buk: 2924) did not show close relation to any reference sequences from public databases (identity <90%) demonstrating a large ‘unknown diversity'. Each diet group had abundant signature taxa, where buk genes linked to Clostridium perfringens dominated in carnivores and but genes associated with Ruminococcaceae bacterium D16 were specific for herbivores and omnivores. Whereas 16S rRNA gene analysis showed similar overall patterns, it was unable to reveal communities at the same depth and resolution as the functional gene-targeted approach. This study demonstrates that butyrate producers are abundant across vertebrates exhibiting great functional redundancy and that diet is the primary determinant governing the composition of the butyrate-producing guild. PMID:25343515
Vital, Marius; Gao, Jiarong; Rizzo, Mike; Harrison, Tara; Tiedje, James M
Butyrate-producing bacteria have an important role in maintaining host health. They are well studied in human and medically associated animal models; however, much less is known for other Vertebrata. We investigated the butyrate-producing community in hindgut-fermenting Mammalia (n = 38), Aves (n = 8) and Reptilia (n = 8) using a gene-targeted pyrosequencing approach of the terminal genes of the main butyrate-synthesis pathways, namely butyryl-CoA:acetate CoA-transferase (but) and butyrate kinase (buk). Most animals exhibit high gene abundances, and clear diet-specific signatures were detected with but genes significantly enriched in omnivores and herbivores compared with carnivores. But dominated the butyrate-producing community in these two groups, whereas buk was more abundant in many carnivorous animals. Clustering of protein sequences (5% cutoff) of the combined communities (but and buk) placed carnivores apart from other diet groups, except for noncarnivorous Carnivora, which clustered together with carnivores. The majority of clusters (but: 5141 and buk: 2924) did not show close relation to any reference sequences from public databases (identity <90%) demonstrating a large 'unknown diversity'. Each diet group had abundant signature taxa, where buk genes linked to Clostridium perfringens dominated in carnivores and but genes associated with Ruminococcaceae bacterium D16 were specific for herbivores and omnivores. Whereas 16S rRNA gene analysis showed similar overall patterns, it was unable to reveal communities at the same depth and resolution as the functional gene-targeted approach. This study demonstrates that butyrate producers are abundant across vertebrates exhibiting great functional redundancy and that diet is the primary determinant governing the composition of the butyrate-producing guild.
Weng, Huachun; Endo, Kosuke; Li, Jiawei; Kito, Naoko; Iwai, Naoharu
We previously found that peroxisomal biogenesis factor 11a (Pex11a) deficiency is associated with a reduction in peroxisome abundance and impaired fatty acid metabolism in hepatocytes, and results in steatosis. In the present study, we investigated whether butyrate induces Pex11a expression and peroxisome proliferation, and studied its effect on lipid metabolism. C57BL/6 mice fed standard chow or a high-fat diet (HFD) were treated with tributyrin, 4-phelybutyrate acid (4-PBA), or the butyrate-producing probiotics (Clostridium butyricum MIYAIRI 588 [CBM]) plus inulin (dietary fiber), and the body weight, white adipose tissue, serum triglycerides, mRNA expression, and peroxisome abundance were evaluated. Tributyrin or 4-PBA treatment significantly decreased body weight and increased hepatic mRNA expression of peroxisome proliferator-activated receptor-α (PPARα) and Pex11a. In addition, 4-PBA treatment increased peroxisome abundance and the expression of genes involved in peroxisomal fatty acid β-oxidation (acyl-coenzyme A oxidase 1 and hydroxysteroid [17-beta] dehydrogenase 4). CBM and inulin administration reduced adipose tissue mass and serum triglycerides, induced Pex11a, acyl-coenzyme A oxidase 1, and hydroxysteroid (17-beta) dehydrogenase 4 genes, and increased peroxisome abundance in mice fed standard chow or an HFD. In conclusion, elevation of butyrate availability (directly through administration of butyrate or indirectly via administration of butyrate-producing probiotics plus fiber) induces PPARα and Pex11a and the genes involved in peroxisomal fatty acid β-oxidation, increases peroxisome abundance, and improves lipid metabolism. These results may provide a new therapeutic strategy against hyperlipidemia and obesity.
Zhang, Qianpeng; Wu, Yanqiu; Wang, Jing; Wu, Guojun; Long, Wenmin; Xue, Zhengsheng; Wang, Linghua; Zhang, Xiaojun; Pang, Xiaoyan; Zhao, Yufeng; Zhao, Liping; Zhang, Chenhong
Butyrate-producing bacteria (BPB) are potential probiotic candidates for inflammatory bowel diseases as they are often depleted in the diseased gut microbiota. However, here we found that augmentation of a human-derived butyrate-producing strain, Anaerostipes hadrus BPB5, significantly aggravated colitis in dextran sulphate sodium (DSS)-treated mice while exerted no detrimental effect in healthy mice. We explored how the interaction between BPB5 and gut microbiota may contribute to this differential impact on the hosts. Butyrate production and severity of colitis were assessed in both healthy and DSS-treated mice, and gut microbiota structural changes were analysed using high-throughput sequencing. BPB5-inoculated healthy mice showed no signs of colitis, but increased butyrate content in the gut. In DSS-treated mice, BPB5 augmentation did not increase butyrate content, but induced significantly more severe disease activity index and much higher mortality. BPB5 didn’t induce significant changes of gut microbiota in healthy hosts, but expedited the structural shifts 3 days earlier toward the disease phase in BPB5-augmented than DSS-treated animals. The differential response of gut microbiota in healthy and DSS-treated mice to the same potentially beneficial bacterium with drastically different health consequences suggest that animals with dysbiotic gut microbiota should also be employed for the safety assessment of probiotic candidates. PMID:27264309
... https://medlineplus.gov/news/fullstory_163274.html Gut Bacteria May Link Diet, Colon Cancer, Study Says High- ... link appears to be a type of intestinal bacteria, the Boston research team said. Specifically, they looked ...
Kopecný, J; Hajer, J; Mrázek, J
The main representatives of bacteria in the human colon were investigated by specific PCR and denaturing gradient gel electrophoresis (DGGE). Prevalent in both cases were species of Bifidobacterium, Clostridium, Bacteroides, Faecalibacterium and Eubacterium. Simultaneously, cellulolytic bacteria were isolated from the human feces. The largest proportion was represented by ruminococcus-like isolates. Their presence was confirmed both by PCR and DGGE methods; the latter one was able to give more comprehensive data about the composition of bacterial population in the human colon chyme.
Ravn, I; Dige, I; Meyer, R L; Nyvad, B
The aim of this study was to investigate if three probiotic bacteria present in the milk product Cultura Dofilus® naturell could be detected in saliva and on oral mucosal surfaces, and if they colonized dental surfaces in situ in 8 caries-inactive individuals after 8 daily exposures to the milk product for up to 3 days. Bacteria were identified by fluorescence in situ hybridization and confocal laser scanning microscopy. While probiotic bacteria were present sporadically in the oral cavity on mucosal surfaces and in saliva after 3 days of frequent use of the probiotic milk, they were not detected on dental surfaces. Probiotic bacteria may thus contribute to general oral health, but their potential role in biofilm-induced dental diseases remains unclear.
Liu, Cui Hua; Lee, S Melanie; Vanlare, Jordan M; Kasper, Dennis L; Mazmanian, Sarkis K
Microbes occupy countless ecological niches in nature. Sometimes these environments may be on or within another organism, as is the case in both microbial infections and symbiosis of mammals. Unlike pathogens that establish opportunistic infections, hundreds of human commensal bacterial species establish a lifelong cohabitation with their hosts. Although many virulence factors of infectious bacteria have been described, the molecular mechanisms used during beneficial host-symbiont colonization remain almost entirely unknown. The novel identification of multiple surface polysaccharides in the important human symbiont Bacteroides fragilis raised the critical question of how these molecules contribute to commensalism. To understand the function of the bacterial capsule during symbiotic colonization of mammals, we generated B. fragilis strains deleted in the global regulator of polysaccharide expression and isolated mutants with defects in capsule expression. Surprisingly, attempts to completely eliminate capsule production are not tolerated by the microorganism, which displays growth deficits and subsequent reversion to express capsular polysaccharides. We identify an alternative pathway by which B. fragilis is able to reestablish capsule production and modulate expression of surface structures. Most importantly, mutants expressing single, defined surface polysaccharides are defective for intestinal colonization compared with bacteria expressing a complete polysaccharide repertoire. Restoring the expression of multiple capsular polysaccharides rescues the inability of mutants to compete for commensalism. These findings suggest a model whereby display of multiple capsular polysaccharides provides essential functions for bacterial colonization during host-symbiont mutualism.
Haas, Kelly Nicole; Blanchard, Jeffrey L
An anaerobic, saccharolytic, spore-forming, butyrate-producing bacterium, strain KNHs209T, was isolated from a switchgrass microcosm seeded with forest soil. Cells were highly motile rods, often forming long filamentous chains which were easily observed moving under the microscope. Its closest phylogenetic relative was Eisenbergiella tayi (16S rRNA gene sequence identity 94.2 %), although it was easily distinguishable based on its morphology and physiology. Whole-genome sequencing enabled development of a minimal medium, and also suggested that the organism is capable of fixing nitrogen. Its wide variety of growth substrates was mirrored by a high number of encoded chemotaxis receptors (45, the highest in the family Lachnospiraceae). Strain KNHs209T utilized a wide variety of carbohydrates, but not cellulose or xylan. Fermentation products included formate, acetate and butyrate; sulfur compounds and nitrate were not reduced. Strain KNHs209T grew optimally at 35-40 °C and pH 7. The genomic DNA G+C content was 42.74 mol%; the major membrane fatty acids were C14 : 0 and C16 : 0. Based on phenotypic, genomic, phylogenetic and chemotaxonomic analyses, this organism represents a novel genus and species within the family Lachnospiraceae for which the name Kineothrix alysoides, gen. nov., sp. nov. is proposed. The type strain is KNHs209T (=ATCC TSD-26T=DSM 100556T).
Hol, Felix J H; Hubert, Bert; Dekker, Cees; Keymer, Juan E
During antibiotic treatment, antibiotic concentration gradients develop. Little is know regarding the effects of antibiotic gradients on populations of nonresistant bacteria. Using a microfluidic device, we show that high-density motile Escherichia coli populations composed of nonresistant bacteria can, unexpectedly, colonize environments where a lethal concentration of the antibiotic kanamycin is present. Colonizing bacteria establish an adaptively resistant population, which remains viable for over 24 h while exposed to the antibiotic. Quantitative analysis of multiple colonization events shows that collectively swimming bacteria need to exceed a critical population density in order to successfully colonize the antibiotic landscape. After colonization, bacteria are not dormant but show both growth and swimming motility under antibiotic stress. Our results highlight the importance of motility and population density in facilitating adaptive resistance, and indicate that adaptive resistance may be a first step to the emergence of genetically encoded resistance in landscapes of antibiotic gradients.
Personne, J.-C.; Poty, F.; Mahler, B.J.; Drogue, C.
Experiments were carried out to investigate the potential for bacterial colonization of different substrates in karst aquifers and the nature of the colonizing bacteria. Laboratory batch experiments were performed using limestone and PVC as substrates, a natural bacterial isolate and a known laboratory strain (Escherichia coli [E. coli]) as inocula, and karst ground water and a synthetic formula as growth media. In parallel, fragments of limestone and granite were submerged in boreholes penetrating two karst aquifers for more than one year; the boreholes are periodically contaminated by enteric bacteria from waste water. Once a month, rock samples were removed and the colonizing bacteria quantified and identified. The batch experiments demonstrated that the natural isolate and E. coli both readily colonized limestone surfaces using karst ground water as the growth medium. In contrast, bacterial colonization of both the limestone and granite substrates, when submerged in the karst, was less intense. More than 300 bacterial strains were isolated over the period sampled, but no temporal pattern in colonization was seen as far as strain, and colonization by E. coli was notably absent, although strains of Salmonella and Citrobacter were each observed once. Samples suspended in boreholes penetrating highly fractured zones were less densely colonized than those in the borehole penetrating a less fractured zone. The results suggest that contamination of karst aquifers by enteric bacteria is unlikely to be persistent. We hypothesize that this may be a result of the high flow velocities found in karst conduits, and of predation of colonizing bacteria by autochthonous zooplankton.
Frenkel, Erica Shapiro
Understanding how the body's natural defenses function to protect the oral cavity from the myriad of bacteria that colonize its surfaces is an ongoing topic of research that can lead to breakthroughs in treatment and prevention. One key defense mechanism on all moist epithelial linings, such as the mouth, gastrointestinal tract, and lungs, is a layer of thick, well-hydrated mucus. The main gel-forming components of mucus are mucins, large glycoproteins that play a key role in host defense. This study focuses on elucidating the connection between MUC5B salivary mucins and dental caries, one of the most common oral diseases. Dental caries is predominantly caused by Streptococcus mutans attachment and biofilm formation on the tooth surface. Once S. mutans attaches to the tooth, it produces organic acids as metabolic by-products that dissolve tooth enamel, leading to cavity formation. We utilize CFU counts and fluorescence microscopy to quantitatively show that S. mutans attachment and biofilm formation are most robust in the presence of sucrose and that aqueous solutions of purified human MUC5B protect surfaces by acting as an antibiofouling agent in the presence of sucrose. In addition, we find that MUC5B does not alter S. mutans growth and decreases surface attachment and biofilm formation by maintaining S. mutans in the planktonic form. These insights point to the importance of salivary mucins in oral health and lead to a better understanding of how MUC5B could play a role in cavity prevention or diagnosis. PMID:25344244
Seedorf, Henning; Griffin, Nicholas W; Ridaura, Vanessa K; Reyes, Alejandro; Cheng, Jiye; Rey, Federico E; Smith, Michelle I; Simon, Gabriel M; Scheffrahn, Rudolf H; Woebken, Dagmar; Spormann, Alfred M; Van Treuren, William; Ursell, Luke K; Pirrung, Megan; Robbins-Pianka, Adam; Cantarel, Brandi L; Lombard, Vincent; Henrissat, Bernard; Knight, Rob; Gordon, Jeffrey I
To study how microbes establish themselves in a mammalian gut environment, we colonized germ-free mice with microbial communities from human, zebrafish, and termite guts, human skin and tongue, soil, and estuarine microbial mats. Bacteria from these foreign environments colonized and persisted in the mouse gut; their capacity to metabolize dietary and host carbohydrates and bile acids correlated with colonization success. Cohousing mice harboring these xenomicrobiota or a mouse cecal microbiota, along with germ-free "bystanders," revealed the success of particular bacterial taxa in invading guts with established communities and empty gut habitats. Unanticipated patterns of ecological succession were observed; for example, a soil-derived bacterium dominated even in the presence of bacteria from other gut communities (zebrafish and termite), and human-derived bacteria colonized germ-free bystander mice before mouse-derived organisms. This approach can be generalized to address a variety of mechanistic questions about succession, including succession in the context of microbiota-directed therapeutics.
Fan, Di; Coughlin, Laura A; Neubauer, Megan M; Kim, Jiwoong; Kim, Min Soo; Zhan, Xiaowei; Simms-Waldrip, Tiffany R; Xie, Yang; Hooper, Lora V; Koh, Andrew Y
Candida albicans colonization is required for invasive disease. Unlike humans, adult mice with mature intact gut microbiota are resistant to C. albicans gastrointestinal (GI) colonization, but the factors that promote C. albicans colonization resistance are unknown. Here we demonstrate that commensal anaerobic bacteria-specifically clostridial Firmicutes (clusters IV and XIVa) and Bacteroidetes-are critical for maintaining C. albicans colonization resistance in mice. Using Bacteroides thetaiotamicron as a model organism, we find that hypoxia-inducible factor-1α (HIF-1α), a transcription factor important for activating innate immune effectors, and the antimicrobial peptide LL-37 (CRAMP in mice) are key determinants of C. albicans colonization resistance. Although antibiotic treatment enables C. albicans colonization, pharmacologic activation of colonic Hif1a induces CRAMP expression and results in a significant reduction of C. albicans GI colonization and a 50% decrease in mortality from invasive disease. In the setting of antibiotics, Hif1a and Camp (which encodes CRAMP) are required for B. thetaiotamicron-induced protection against C. albicans colonization of the gut. Thus, modulating C. albicans GI colonization by activation of gut mucosal immune effectors may represent a novel therapeutic approach for preventing invasive fungal disease in humans.
James, Douglas W.; Suslow, Trevor V.; Steinback, Katherine E.
For rhizobacteria to exert physiological effects on plant growth, the bacteria must first effectively colonize the root surface. To examine the relationship between long-term colonization of root systems and adherence to roots in the short term, a binding assay was developed. Adherence was determined by incubating roots of intact radish seedlings with bacteria, washing and homogenizing the roots, and dilution plating the resulting homogenate. Irreversible binding of bacteria was rapid, reaching half-maximum by 5 min. All of the rhizosphere bacteria tested showed similar, concentration-dependent binding (ranging from 104 to 108 CFU/ml), as well as long-term colonization of radish roots under sterile conditions. Escherichia coli, which is not a root colonizer, showed about 10-fold less binding, but still demonstrated concentration-dependent binding and rapid kinetics of adherence at high concentrations (106 to 108 CFU/ml). The bacteria tested were very different with respect to source or habitat and plant response, yet they showed similar concentration-dependent binding. There was no correlation between the relative hydrophobicities of the cell surfaces of strains and the adherence of the strains to roots. Binding of Pseudomonas fluorescens E6-22 was promoted by divalent cations (Ca2+ and Mg2+) at concentrations of 5 to 10 mM, whereas monovalent cations (Na+ and K+) had little effect; electrostatic phenomena may partially explain adherence in the short term, an important prelude to long-term colonization of root surfaces. PMID:16346859
Tanaka, Yuriko; Ito, Sachiko; Isobe, Ken-ichi
Inflammatory bowel disease confers an increased risk of developing colitis-associated colon cancer (CAC). During the active colitis or developing tumor stage, commensal bacteria show dynamic translocation. However, whether alteration of the bacterial composition in the gut causes CAC is still unclear. To clarify the effect of commensal bacteria on CAC development, we employed an azoxymethane (AOM) and dextran sodium sulfate (DSS)-induced murine CAC model treated with or without antibiotics. In addition, we analyzed the effects of antibiotics on infiltration of myeloid cells, colonic inflammatory responses, and colorectal cancer formation. We found that vancomycin treatment dramatically suppressed tumor development. In addition, AOM/DSS treatment greatly induced the infiltration of Gr-1high/CD11bhigh neutrophils to the colon, which led to the production of tumor necrosis factor α and inducible nitric oxide synthase. Vancomycin treatment suppressed the infiltration of neutrophils induced by AOM/DSS. Moreover, vancomycin treatment greatly reduced the colon injury and DNA damage caused by AOM/DSS-induced NO radicals. Our results indicate that vancomycin-sensitive bacteria induced colon inflammation and DNA damage by attracting neutrophils into damaged colon tissue, thus promoting tumor formation. PMID:27050089
Tanaka, Yuriko; Ito, Sachiko; Isobe, Ken-ichi
Inflammatory bowel disease confers an increased risk of developing colitis-associated colon cancer (CAC). During the active colitis or developing tumor stage, commensal bacteria show dynamic translocation. However, whether alteration of the bacterial composition in the gut causes CAC is still unclear. To clarify the effect of commensal bacteria on CAC development, we employed an azoxymethane (AOM) and dextran sodium sulfate (DSS)-induced murine CAC model treated with or without antibiotics. In addition, we analyzed the effects of antibiotics on infiltration of myeloid cells, colonic inflammatory responses, and colorectal cancer formation. We found that vancomycin treatment dramatically suppressed tumor development. In addition, AOM/DSS treatment greatly induced the infiltration of Gr-1(high)/CD11b(high) neutrophils to the colon, which led to the production of tumor necrosis factor α and inducible nitric oxide synthase. Vancomycin treatment suppressed the infiltration of neutrophils induced by AOM/DSS. Moreover, vancomycin treatment greatly reduced the colon injury and DNA damage caused by AOM/DSS-induced NO radicals. Our results indicate that vancomycin-sensitive bacteria induced colon inflammation and DNA damage by attracting neutrophils into damaged colon tissue, thus promoting tumor formation.
Neumann, Philipp-Alexander; Koch, Stefan; Hilgarth, Roland S.; Perez-Chanona, Ernesto; Denning, Patricia; Jobin, Christian; Nusrat, Asma
Regional expression of Wingless/Int (Wnt) genes plays a central role in regulating intestinal development and homeostasis. However, our knowledge of such regional Wnt proteins in the colon remains limited. To understand further the effect of Wnt signaling components in controlling intestinal epithelial homeostasis, we investigated whether the physiological heterogeneity of the proximal and distal colon can be explained by differential Wnt signaling. With the use of a Wnt signaling-specific PCR array, expression of 84 Wnt-mediated signal transduction genes was analyzed, and a differential signature of Wnt-related genes in the proximal versus distal murine colon was identified. Several Wnt agonists (Wnt5a, Wnt8b, and Wnt11), the Wnt receptor frizzled family receptor 3, and the Wnt inhibitory factor 1 were differentially expressed along the colon length. These Wnt signatures were associated with differential epithelial cell proliferation and migration in the proximal versus distal colon. Furthermore, reduced Wnt/β-catenin activity and decreased Wnt5a and Wnt11 expression were observed in mice lacking commensal bacteria, an effect that was reversed by conventionalization of germ-free mice. Interestingly, myeloid differentiation primary response gene 88 knockout mice showed decreased Wnt5a levels, indicating a role for Toll-like receptor signaling in regulating Wnt5a expression. Our results suggest that the morphological and physiological heterogeneity within the colon is in part facilitated by the differential expression of Wnt signaling components and influenced by colonization with bacteria. PMID:24418259
Although clinical benefits of dietary fiber supplementation seem to depend in part on the extent of fiber degradation and fermentation by colonic bacteria, little is known about the effect of the type of supplemented fiber on bacterial metabolism. In an experiment using a non-adapted human bacterial...
Nosova, T; Jousimies-Somer, H; Kaihovaara, P; Jokelainen, K; Heine, R; Salaspuro, M
We have recently proposed the existence of a bacteriocolonic pathway for ethanol oxidation [i.e., ethanol is oxidized by alcohol dehydrogenases (ADHs) of intestinal bacteria resulting in high intracolonic levels of reactive and toxic acetaldehyde]. The aim of this in vitro study was to characterize further ADH activity of some aerobic bacteria, representing the normal human colonic flora. These bacteria were earlier shown to possess high cytosolic ADH activities (Escherichia coli IH 133369, Klebsiella pneumoniae IH 35385, Klebsiella oxytoca IH 35339, Pseudomonas aeruginosa IH 35342, and Hafnia alvei IH 53227). ADHs of the tested bacteria strongly preferred NAD as a cofactor. Marked ADH activities were found in all bacteria, even at low ethanol concentrations (1.5 mM) that may occur in the colon due to bacterial fermentation. The Km for ethanol varied from 29.9 mM for K. pneumoniae to 0.06 mM for Hafnia alvei. The inhibition of ADH by 4-methylpyrazole was found to be of the competitive type in 4 of 5 bacteria, and Ki varied from 18.26 +/- 3.3 mM for Escherichia coli to 0.47 +/- 0.13 mM for K. pneumoniae. At pH 7.4, ADH activity was significantly lower than at pH 9.6 in four bacterial strains. ADH of K. oxytoca, however, showed almost equal activities at neutral pH and at 9.6. In conclusion, NAD-linked alcohol dehydrogenases of aerobic colonic bacteria possess low apparent Km's for ethanol. Accordingly, they may oxidize moderate amounts of ethanol ingested during social drinking with nearly maximal velocity. This may result in the marked production of intracolonic acetaldehyde. Kinetic characteristics of the bacterial enzymes may enable some of them to produce acetaldehyde even from endogenous ethanol formed by other bacteria via alcoholic fermentation. The microbial ADHs were inhibited by 4-methylpyrazole by the same competitive inhibition as hepatic ADH, however, with nearly 1000 times lower susceptibility. Individual variations in human colonic flora may thus
Schoeni, J L; Wong, A C
Campylobacter enteritis in humans has been linked to consumption of chicken. Reducing Campylobacter jejuni colonization in chickens can potentially reduce Campylobacter infections in humans. In this study, the reduction of C. jejuni colonization in chicks by oral administration of defined competitive exclusion (CE) cultures, 2.5% dietary carbohydrates, or CE cultures and carbohydrates was examined. Prevention, elimination, or direct challenge of Campylobacter infection was simulated by administering treatments before, after, or at the same time as that of the Campylobacter inoculation. Additionally, the effect of maintaining high levels of protective bacteria was evaluated by administering CE cultures on days 1 and 4 (booster treatment). All treatments reduced C. jejuni colonization. Protection by aerobically grown CE cultures was not statistically different from that by anaerobically grown CE cultures. A combination of Citrobacter diversus 22, Klebsiella pneumoniae 23, and Escherichia coli 25 (CE 3) was the most effective CE treatment. Maintaining high numbers of CE isolates by administering CE boosters did not increase protection. The greatest reduction of Campylobacter colonization was observed in schemes to prevent or eliminate C. jejuni infection. C. jejuni was not detected in the ceca of birds receiving the prevention treatment, CE 3 with mannose, representing a 62% reduction in the colonization rate. The protection factor (PF), a value combining the colonization rate and the level of infection, for CE 3 with mannose was high (> 13.2). Fructo-oligosaccharides alone strongly prevented Campylobacter colonization. Only 8% of the chicks in this group were colonized, with a PF of > 14.3.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8017915
Wiles, Siouxsie; Robertson, Brian D; Frankel, Gad; Kerton, Angela
Bioluminescence is an excellent reporter system for analysing bacterial colonization and clearance dynamics in vivo. Many bacterial species have been rendered bioluminescent, allowing the sensitive detection of bacterial burden and metabolic activity in real-time and in situ in living animals. In this chapter we describe the protocols for characterizing in vivo infection models using bioluminescent bacteria: from real-time imaging in living animals by bioluminescence imaging (BLI) to ex vivo BLI of harvested organs and tissues and, finally, to quantification of bacterial numbers in organ and tissue homogenates by luminometry and viable counts. While the lux operon from Photorhabdus luminescens is ideally suited for use in such models, there may be times when alternative luciferases, such as those from the firefly (luc) or marine copepods (Gluc), may be more appropriate. Here we describe the protocols required to monitor colonization and clearance dynamics using bioluminescent bacteria that are lux-, luc-, or Gluc-positive.
Shim, Hojae; Chauhan, Sadhana; Ryoo, Doohyun; Bowers, Kally; Thomas, Stuart M.; Canada, Keith A.; Burken, Joel G.; Wood, Thomas K.
Indigenous bacteria from poplar tree (Populus canadensis var. eugenei ‘Imperial Carolina’) and southern California shrub rhizospheres, as well as two tree-colonizing Rhizobium strains (ATCC 10320 and ATCC 35645), were engineered to express constitutively and stably toluene o-monooxygenase (TOM) from Burkholderia cepacia G4 by integrating the tom locus into the chromosome. The poplar and Rhizobium recombinant bacteria degraded trichloroethylene at a rate of 0.8 to 2.1 nmol/min/mg of protein and were competitive against the unengineered hosts in wheat and barley rhizospheres for 1 month (colonization occurred at a level of 1.0 × 105 to 23 × 105 CFU/cm of root). In addition, six of these recombinants colonized poplar roots stably and competitively with populations as large as 79% ± 12% of all rhizosphere bacteria after 28 days (0.2 × 105 to 31 × 105 CFU/cm of root). Furthermore, five of the most competitive poplar recombinants (e.g., Pb3-1 and Pb5-1, which were identified as Pseudomonas sp. strain PsK recombinants) retained the ability to express TOM for 29 days as 100% ± 0% of the recombinants detected in the poplar rhizosphere expressed TOM constitutively. PMID:11055909
Huws, Sharon A; Edwards, Joan E; Creevey, Christopher J; Rees Stevens, Pauline; Lin, Wanchang; Girdwood, Susan E; Pachebat, Justin A; Kingston-Smith, Alison H
This study investigated successional colonization of fresh perennial ryegrass (PRG) by the rumen microbiota over time. Fresh PRG was incubated in sacco in the rumens of three Holstein × Friesian cows over a period of 8 h, with samples recovered at various times. The diversity of attached bacteria was assessed using 454 pyrosequencing of 16S rRNA (cDNA). Results showed that plant epiphytic communities either decreased to low relative abundances or disappeared following rumen incubation, and that temporal colonization of the PRG by the rumen bacteria was biphasic with primary (1 and 2 h) and secondary (4-8 h) events evident with the transition period being with 2-4 h. A decrease in sequence reads pertaining to Succinivibrio spp. and increases in Pseudobutyrivibrio, Roseburia and Ruminococcus spp. (the latter all order Clostridiales) were evident during secondary colonization. Irrespective of temporal changes, the continually high abundances of Butyrivibrio, Fibrobacter, Olsenella and Prevotella suggest that they play a major role in the degradation of the plant. It is clear that a temporal understanding of the functional roles of these microbiota within the rumen is now required to unravel the role of these bacteria in the ruminal degradation of fresh PRG.
Malmuthuge, Nilusha; Chen, Yanhong; Liang, Guanxiang; Goonewardene, Laksiri A; Guan, Le Luo
The present study investigated the effect of heat-treated colostrum feeding on the bacterial colonization in calf small intestine of neonatal calves within the first 12h of life. Newborn Holstein bull calves (n=32) were assigned to 3 treatment groups and fed with either fresh colostrum (FC, n=12) or heat-treated (60°C, 60 min) colostrum (HC, n=12) soon after birth, whereas the control (NC, n=8) group did not receive colostrum or water. Small intestinal tissues and contents were collected from proximal jejunum, distal jejunum, and ileum at 6 and 12h after birth, following euthanasia. Quantitative real time-PCR was used to explore the colonization of total bacteria, Lactobacillus, Bifidobacterium, and Escherichia coli. The feeding of colostrum soon after birth increased the colonization of total bacteria in calf gut within the first 12h compared with NC. In contrast, the prevalence of Lactobacillus was lower in HC and FC compared to NC. Remarkable changes in the prevalence of small intestinal tissue-attached Bifidobacterium were observed with the feeding of HC, but not that in small intestinal contents. The prevalence of Bifidobacterium was 3.2 and 5.2 fold higher in HC than FC and NC, respectively, at 6h. Although the feeding of FC did not enhance the prevalence of tissue-attached Bifidobacterium at 6h compared with NC, it displayed a gradual increase over the time that was higher than NC, but similar to that of HC at 12h. Moreover, the colonization of E. coli was drastically reduced in HC calves compared with FC and NC. Thus, the present study suggests that the feeding of HC enhances the colonization of Bifidobacterium but lessens E. coli in the calf small intestine immediately postpartum compared with that of FC and NC. The increased colonization of beneficial bacteria along with the decreased colonization of potential pathogens in calf gut may also diminish the neonatal calf diarrhea when calves are fed heat-treated colostrum soon after birth.
Yang, Liying; Poles, Michael A.; Fisch, Gene S; Ma, Yingfei; Nossa, Carlos; Phelan, Joan A; Pei, Zhiheng
Objectives To evaluate the impact of HIV infection on colonization resistance in the proximal gut. Design It was a case-control study. Methods We contrasted microbiota composition between 8 HIV-1-infected patients and 8 HIV-negative controls to characterize community alteration and detect exogenous bacteria in the esophagus, stomach, and duodenum as well as the mouth using a universal 16S rRNA gene survey and correlated the findings with HIV serostatus and peripheral blood T-cell counts. Results HIV infection was associated with an enrichment of Proteobacteria (p=0.020) and depletion of Firmicutes (p=0.005) in the proximal gut. In particular, environmental species Burkholderia fungorum and Bradyrhizobium pachyrhizi colonized the duodenum of HIV patients who had abnormal blood CD4+ T-cell counts but were absent in HIV-negative controls or HIV patients whose CD4 counts were normal. The two species coexisted and exhibited a decreasing trend proximally towards the stomach and esophagus and were virtually absent in the mouth. B. fungorum always outnumbered B. pachyrhizi in a ratio of approximately 15 to 1 regardless of the body sites (p<0.0001, r2=0.965). Their abundance was inversely correlated with CD4 counts (p=0.004) but not viral load. Overgrowth of potential opportunistic pathogens e.g. Prevotella, Fusobacterium, and Ralstonia and depletion of beneficial bacteria, e.g. Lactobacillus were also observed in HIV patients. Conclusions The colonization of the duodenum by environmental bacteria reflects loss of colonization resistance in HIV infection. Their correlation with CD4 counts suggests that compromised immunity could be responsible for the observed invasion by exogenous microbes. PMID:26731752
Liévin-Le Moal, Vanessa
SUMMARY Hosts are protected from attack by potentially harmful enteric microorganisms, viruses, and parasites by the polarized fully differentiated epithelial cells that make up the epithelium, providing a physical and functional barrier. Enterovirulent bacteria interact with the epithelial polarized cells lining the intestinal barrier, and some invade the cells. A better understanding of the cross talk between enterovirulent bacteria and the polarized intestinal cells has resulted in the identification of essential enterovirulent bacterial structures and virulence gene products playing pivotal roles in pathogenesis. Cultured animal cell lines and cultured human nonintestinal, undifferentiated epithelial cells have been extensively used for understanding the mechanisms by which some human enterovirulent bacteria induce intestinal disorders. Human colon carcinoma cell lines which are able to express in culture the functional and structural characteristics of mature enterocytes and goblet cells have been established, mimicking structurally and functionally an intestinal epithelial barrier. Moreover, Caco-2-derived M-like cells have been established, mimicking the bacterial capture property of M cells of Peyer's patches. This review intends to analyze the cellular and molecular mechanisms of pathogenesis of human enterovirulent bacteria observed in infected cultured human colon carcinoma enterocyte-like HT-29 subpopulations, enterocyte-like Caco-2 and clone cells, the colonic T84 cell line, HT-29 mucus-secreting cell subpopulations, and Caco-2-derived M-like cells, including cell association, cell entry, intracellular lifestyle, structural lesions at the brush border, functional lesions in enterocytes and goblet cells, functional and structural lesions at the junctional domain, and host cellular defense responses. PMID:24006470
Isoflavones are found in leguminous plants, especially soybeans. They have a structural similarity to natural estrogens, which enables them to bind to estrogen receptors and elicit biological activities similar to natural estrogens. They have been suggested to be beneficial for the prevention and therapy of hormone-dependent diseases. After soy products are consumed, the bacteria of the intestinal microflora metabolize isoflavones to metabolites with altered absorption, bioavailability, and estrogenic characteristics. Variations in the effect of soy products have been correlated with the isoflavone metabolites found in plasma and urine samples of the individuals consuming soy products. The beneficial effects of the soy isoflavone daidzin, the glycoside of daidzein, have been reported in individuals producing equol, a reduction product of daidzein produced by specific colonic bacteria in individuals called equol producers. These individuals comprise 30% and 60% of populations consuming Western and soy-rich Asian diets, respectively. Since the higher percentage of equol producers in populations consuming soy-rich diets is correlated with a lower incidence of hormone-dependent diseases, considerable efforts have been made to detect the specific colonic bacteria involved in the metabolism of daidzein to the more estrogenic compound, equol, which should facilitate the investigation of the metabolic activities related to this compound.
Isoflavones are found in leguminous plants, especially soybeans. They have a structural similarity to natural estrogens, which enables them to bind to estrogen receptors and elicit biological activities similar to natural estrogens. They have been suggested to be beneficial for the prevention and therapy of hormone-dependent diseases. After soy products are consumed, the bacteria of the intestinal microflora metabolize isoflavones to metabolites with altered absorption, bioavailability, and estrogenic characteristics. Variations in the effect of soy products have been correlated with the isoflavone metabolites found in plasma and urine samples of the individuals consuming soy products. The beneficial effects of the soy isoflavone daidzin, the glycoside of daidzein, have been reported in individuals producing equol, a reduction product of daidzein produced by specific colonic bacteria in individuals called equol producers. These individuals comprise 30% and 60% of populations consuming Western and soy-rich Asian diets, respectively. Since the higher percentage of equol producers in populations consuming soy-rich diets is correlated with a lower incidence of hormone-dependent diseases, considerable efforts have been made to detect the specific colonic bacteria involved in the metabolism of daidzein to the more estrogenic compound, equol, which should facilitate the investigation of the metabolic activities related to this compound. PMID:25594250
Suo, Xinkun; Abdoli, Leila; Liu, Yi; Xia, Peng; Yang, Guanjun; Li, Hua
Copper coatings were fabricated on stainless steel plates by cold spraying. Attachment and colonization of Bacillus sp. on their surfaces in artificial seawater were characterized, and their effects on anticorrosion performances of the coatings were examined. Attached bacteria were observed using field emission scanning electron microscopy. Electrochemical behaviors including potentiodynamic polarization and electrochemical impedance spectroscopy with/without bacterial attachment were evaluated using commercial electrochemical analysis station Modulab. Results show that Bacillus sp. opt to settle on low-lying spots of the coating surfaces in early stage, followed by recruitment and attachment of extracellular polymeric substances (EPS) secreted through metabolism of Bacillus sp. The bacteria survive with the protection of EPS. An attachment model is proposed to illustrate the bacterial behaviors on the surfaces of the coatings. Electrochemical data show that current density under Bacillus sp. environment decreases compared to that without the bacteria. Charge-transfer resistance increases markedly in bacteria-containing seawater, suggesting that corrosion resistance increases and corrosion rate decreases. The influencing mechanism of bacteria settlement on corrosion resistance of the cold-sprayed copper coatings was discussed and elucidated.
Castanheira, Nádia L; Dourado, Ana Catarina; Pais, Isabel; Semedo, José; Scotti-Campos, Paula; Borges, Nuno; Carvalho, Gilda; Barreto Crespo, Maria Teresa; Fareleira, Paula
Multi-strain inoculants have increased potential to accomplish a diversity of plant needs, mainly attributed to its multi-functionality. This work evaluated the ability of a mixture of three bacteria to colonize and induce a beneficial response on the pasture crop annual ryegrass. Pseudomonas G1Dc10 and Paenibacillus G3Ac9 were previously isolated from annual ryegrass and were selected for their ability to perform multiple functions related to plant growth promotion. Sphingomonas azotifigens DSMZ 18530(T) was included due to nitrogen fixing ability. The effects of the bacterial mixture were assessed in gnotobiotic plant inoculation assays and compared with single and dual inoculation treatments. Triple inoculation with 3×10(8) bacteria significantly increased plant dry weight and leaf pigments, indicating improved photosynthetic performance. Plant lipid biosynthesis was enhanced by 65%, mainly due to the rise of linolenic acid, an omega-3 fatty acid with high dietary value. Electrolyte leakage, an indicator of plant membrane stability under stress, was decreased pointing to a beneficial effect by inoculation. Plants physiological condition was more favoured by triple inoculation than by single, although benefits on biomass were only evident relative to non-inoculated plants. The colonization behaviour and coexistence in plant tissues were assessed using FISH and GFP-labelling, combined with confocal microscopy and a cultivation-based approach for quantification. The three strains occupied the same sites, localizing preferentially along root hairs and in stem epidermis. Endophytic colonization was observed as bacteria entered root and stem inner tissues. This study reveals the potential of this mixture of strains for biofertilization, contributing to improve crop productivity and nutritional value.
Santos, A S; Jerónimo, E; Ferreira, L M; Rodrigues, M A M; Bessa, R J B
The potential use of odd- and branched-chain fatty acids (OBCFA) and purine bases (PB) as microbial markers in the equine hindgut was studied. For this purpose, feed particles adherent bacteria [solid associated bacteria (SAB)] and planktonic bacteria [liquid associated bacteria (PAB)] were isolated from total cecum and colon contents of 8 healthy, crossbred horses (9 ± 3 yr). Horses were fasted for 12 to 15 h before slaughter, and the cecum and colon were identified and clamped in their extremities to avoid mixing of digesta contents. The total cecum or colon contents was collected into thermal containers previously filled with CO2, immediately transported to the laboratory, and subjected to separation of solid and liquid phases to obtain bacterial PAB and SAB pellets from each horse. Overall differences observed were mainly between site of bacterial collection (cecum vs. colon) rather than between type of bacterial population (PAB vs. SAB). Cecal bacteria fraction had greater (P < 0.05) OM, PB, and branched-chain fatty acids (BCFA):odd-chain fatty acids (OFA) ratio but less (P < 0.05) BCFA, OFA, BCFA:PB ratio, and adenine:guanine ratio than colon bacterial biomass. Results indicated that the composition of cecal and colon bacteria is very different from that of similar ecosystems (e.g., rumen). These differences can be a reflection of different growth stages or nutrition of particular populations as well as different bacterial metabolic activities. Results presented herein provide evidence that PB and fatty acids can be used as microbial markers in equine studies.
Schmitz, C; Goebel, I; Wagner, S; Vomberg, A; Klinner, U
An n-alkane-assimilating strain of Candida tropicalis was selected in sandy soil inoculated with microorganisms from contaminated sites. Competition experiments with n-alkane utilizers from different strain collections confirmed that yeasts overgrow bacteria in sandy soil. Acidification of the soil is one of the colonization factors useful for the yeasts. It can be counteracted by addition of bentonite, a clay mineral with high ion exchange capacity, but not, however, by kaolin. Strains of different yeast species showed different levels of competitiveness. Strains of Arxula adeninivorans, Candida maltosa, and Yarrowia lipolytica overgrew strains of C. tropicalis, C. shehatae or Pichia stipitis. Two strains of C. maltosa and Y. lipolytica coexisted during several serial transfers under microcosm conditions.
Bellenberg, Sören; Díaz, Mauricio; Noël, Nanni; Sand, Wolfgang; Poetsch, Ansgar; Guiliani, Nicolas; Vera, Mario
Bioleaching of metal sulfides is an interfacial process where biofilm formation is considered to be important in the initial steps of this process. Among the factors regulating biofilm formation, molecular cell-to-cell communication such as quorum sensing is involved. A functional LuxIR-type I quorum sensing system is present in Acidithiobacillus ferrooxidans. However, cell-to-cell communication among different species of acidophilic mineral-oxidizing bacteria has not been studied in detail. These aspects were the scope of this study with emphasis on the effects exerted by the external addition of mixtures of synthetic N-acyl-homoserine-lactones on pure and binary cultures. Results revealed that some mixtures had inhibitory effects on pyrite leaching. Some of them correlated with changes in biofilm formation patterns on pyrite coupons. We also provide evidence that A. thiooxidans and Acidiferrobacter spp. produce N-acyl-homoserine-lactones. In addition, the observation that A. thiooxidans cells attached more readily to pyrite pre-colonized by living iron-oxidizing acidophiles than to heat-inactivated or biofilm-free pyrite grains suggests that other interactions also occur. Our experiments show that pre-cultivation conditions influence A. ferrooxidans attachment to pre-colonized pyrite surfaces. The understanding of cell-to-cell communication may consequently be used to develop attempts to influence biomining/bioremediation processes.
Shimada, Yosuke; Kinoshita, Makoto; Harada, Kazuo; Mizutani, Masafumi; Masahata, Kazunori; Kayama, Hisako; Takeda, Kiyoshi
Microbiota have been shown to have a great influence on functions of intestinal epithelial cells (ECs). The role of indole as a quorum-sensing (QS) molecule mediating intercellular signals in bacteria has been well appreciated. However, it remains unknown whether indole has beneficial effects on maintaining intestinal barriers in vivo. In this study, we analyzed the effect of indole on ECs using a germ free (GF) mouse model. GF mice showed decreased expression of junctional complex molecules in colonic ECs. The feces of specific pathogen-free (SPF) mice contained a high amount of indole; however the amount was significantly decreased in the feces of GF mice by 27-fold. Oral administration of indole-containing capsules resulted in increased expression of both tight junction (TJ)- and adherens junction (AJ)-associated molecules in colonic ECs in GF mice. In accordance with the increased expression of these junctional complex molecules, GF mice given indole-containing capsules showed higher resistance to dextran sodium sulfate (DSS)-induced colitis. A similar protective effect of indole on DSS-induced epithelial damage was also observed in mice bred in SPF conditions. These findings highlight the beneficial role of indole in establishing an epithelial barrier in vivo. PMID:24278294
Toh, Michael C; Goodyear, Mara; Daigneault, Michelle; Allen-Vercoe, Emma; Van Raay, Terence J
The zebrafish has become increasingly popular for microbiological research. It has been used as an infection model for a variety of pathogens, and is also emerging as a tool for studying interactions between a host and its resident microbial communities. The mouse microbiota has been transplanted into the zebrafish gut, but to our knowledge, there has been no attempt to introduce a bacterial community derived from the human gut. We explored two methods for colonizing the developing gut of 5-day-old germ-free zebrafish larvae with a defined anaerobic microbial community derived from a single human fecal sample. Both environmental exposure (static immersion) and direct microinjection into the gut resulted in the establishment of two species-Lactobacillus paracasei and Eubacterium limosum-from a community of 30 strains consisting of 22 anaerobic species. Of particular interest is E. limosum, which, as a strict anaerobe, represents a group of bacteria which until now have not been shown to colonize the developing zebrafish gut. Our success here indicates that further investigation of zebrafish as a tool for studying human gut microbial communities is warranted.
Bae, Songmee; Yu, Jae-Yon; Lee, Kwangjun; Lee, Sunhwa; Park, Bohyun; Kang, Yeonho
A longitudinal analysis was carried out of the colonization by four potential respiratory pathogens - Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis and Staphylococcus aureus - in 165 healthy children (aged 3-7 years) attending three kindergartens and 417 healthy children (aged 7-10 years) attending an elementary school in Seoul, Korea, by four consecutive examinations over 1 year. The prevalence of nasal carriers of one or more of four bacteria was found to be higher in younger children (≤7 years) (mean 68.6%) than that in older children (mean 46.8%). The mean rates of nasal carriage of Strep. pneumoniae, H. influenzae, M. catarrhalis and Staph. aureus were 16.8, 18.9, 20.2 and 18.2%, respectively. Colonization by Strep. pneumoniae, H. influenzae and M. catarrhalis was higher in pre-school children (28.6, 32.4 and 35.0%, respectively) than in school children (12.2, 13.6 and 14.3%, respectively). Carriage trends differed with age, with Strep. pneumoniae, H. influenzae and M. catarrhalis colonization decreasing with age but Staph. aureus colonization increasing. Positive associations of co-occurrence between Strep. pneumoniae, H. influenzae and M. catarrhalis were evident, with a significant negative association evident between Staph. aureus and the other three bacteria. A better understanding of the colonization and interaction of potential respiratory pathogens may be important for predicting changes in bacterial ecology and for designing control strategies that target bacterial colonization in upper respiratory tract infections.
Chen, Chang-Qing; Li, Tong; Li, Xin-Lian; Jiang, Yun; Tian, Lei; Xu, Peng
To reveal the colonization characteristics in host of endophytic biocontrol bacteria NJ13 isolated from Panax ginseng, this study obtained the marked strain NJ13-R which was double antibiotic resistant to rifampicin and streptomycin through enhancing the method of inducing antibiotic. The colonization characteristics in ginseng and its biocontrol efficiency against Alternaria spot of ginseng in the field were studied. The results showed that the strain could colonize in root, stem and leaf of ginseng and the colonization amount was positive correlated with inoculation concentration. Meanwhile, the strain could infect and then transfer in different tissues of ginseng The colonization amount of strain in roots and leaves of ginseng increased first and then decreased. However, the tendency of colonization amount of strain in stems was ascend at first and then descend slowly, and was more than that in roots and leaves along with time, which had a preference to specific tissue of its host. In field experiment, the endophytic bacteria NJ13 was proved to be effective in controlling Alternaria leaf spot of ginseng. The biocontrol efficiency of fermentation broth at the concentration of 0.76 x 10(8) cfu x mL(-1) reached 75.62%, which was close to the controlling level (73.06%) of 0.67 mg x L(-1) 50% cyprodinil WG.
Franzetti, Andrea; Navarra, Federico; Tagliaferri, Ilario; Gandolfi, Isabella; Bestetti, Giuseppina; Minora, Umberto; Azzoni, Roberto Sergio; Diolaiuti, Guglielmina; Smiraglia, Claudio
We investigated the potential contribution of ice-marginal environments to the microbial communities of cryoconite holes, small depressions filled with meltwater that form on the surface of Forni Glacier (Italian Alps). Cryoconite holes are considered the most biologically active environments on glaciers. Bacteria can colonize these environments by short-range transport from ice-marginal environments or by long-range transport from distant areas. We used high throughput DNA sequencing to identify Operational Taxonomic Units (OTUs) present in cryoconite holes and three ice-marginal environments, the moraines, the glacier forefield, and a large (> 3 m high) ice-cored dirt cone occurring on the glacier surface. Bacterial communities of cryoconite holes were different from those of ice-marginal environments and hosted fewer OTUs. However, a network analysis revealed that the cryoconite holes shared more OTUs with the moraines and the dirt cone than with the glacier forefield. Ice-marginal environments may therefore act as sources of bacteria for cryoconite holes, but differences in environmental conditions limit the number of bacterial strains that may survive in them. At the same time, cryoconite holes host a few OTUs that were not found in any ice-marginal environment we sampled, thus suggesting that some bacterial populations are positively selected by the specific environmental conditions of the cryoconite holes. PMID:28358872
Franzetti, Andrea; Navarra, Federico; Tagliaferri, Ilario; Gandolfi, Isabella; Bestetti, Giuseppina; Minora, Umberto; Azzoni, Roberto Sergio; Diolaiuti, Guglielmina; Smiraglia, Claudio; Ambrosini, Roberto
We investigated the potential contribution of ice-marginal environments to the microbial communities of cryoconite holes, small depressions filled with meltwater that form on the surface of Forni Glacier (Italian Alps). Cryoconite holes are considered the most biologically active environments on glaciers. Bacteria can colonize these environments by short-range transport from ice-marginal environments or by long-range transport from distant areas. We used high throughput DNA sequencing to identify Operational Taxonomic Units (OTUs) present in cryoconite holes and three ice-marginal environments, the moraines, the glacier forefield, and a large (> 3 m high) ice-cored dirt cone occurring on the glacier surface. Bacterial communities of cryoconite holes were different from those of ice-marginal environments and hosted fewer OTUs. However, a network analysis revealed that the cryoconite holes shared more OTUs with the moraines and the dirt cone than with the glacier forefield. Ice-marginal environments may therefore act as sources of bacteria for cryoconite holes, but differences in environmental conditions limit the number of bacterial strains that may survive in them. At the same time, cryoconite holes host a few OTUs that were not found in any ice-marginal environment we sampled, thus suggesting that some bacterial populations are positively selected by the specific environmental conditions of the cryoconite holes.
Schreiner, Monika; Krumbein, Angelika; Ruppel, Silke
For determining interactive plant-bacterial effects between glucosinolates and phyllospheric colonization by a plant growth-promoting strain, Enterobacter radicincitans DSM 16656, in cruciferous vegetables, the extent of bacterial colonization was assessed in 5 cruciferous vegetables (Brassica juncea, Brassica campestris, Brassica oleracea var. capitata, Brassica rapa var. alboglabra, Nasturtium officinale) using a species-specific TaqMan probe and quantitative real-time PCR. Colonization ability of inoculated E. radicincitans in the phyllosphere of these species varied from inability to colonize B. rapa up to a very good colonization rate of B. campestris. In addition to morphological factors and other plant compounds, the colonization rate was affected by different individual aromatic and aliphatic glucosinolates and their concentration, revealing that both plant pathogens and plant growth-promoting bacteria were affected by glucosinolates in their colonization behavior. In contrast, after E. radicincitans inoculation neither the total nor the individual glucosinolate concentrations in the phyllosphere of the 5 cruciferous species were affected, indicating that the nonpathogenic E. radicincitans might cause only poor cell damage by metabolizing plant cell components and does not induce a plant defense response and thus subsequently an increased glucosinolate concentration in the phyllosphere. Moreover, E. radicincitans induced no stimulation of indole glucosinolate biosynthesis by additional bacterial auxin supply.
Kleinschmidt, Birgit; Kölsch, Gregor
The present paper reviews the biology of reed beetles (Donaciinae), presents experimental data on the role of specific symbiotic bacteria, and describes a molecular method for the detection of those bacteria. Reed beetles are herbivores living on wetland plants, each species being mono- or oligo-phagous. They lay their eggs on the host plant and the larvae live underwater in the sediment attached to its roots. The larvae pupate there in a water-tight cocoon, which they build using a secretion that is produced by symbiotic bacteria. The bacteria are located in four blind sacs at the foregut of the larvae; in (female) adults they colonize two out of the six Malpighian tubules. Tetracycline treatment of larvae reduced their pupation rate, although the bacteria could not be fully eliminated. When the small amount of bacterial mass attached to eggs was experimentally removed before hatching, symbiont free larvae resulted, showing the external transmission of the bacteria to the offspring. Specific primers were designed to detect the bacteria, and to confirm their absence in manipulated larvae. The pupation underwater enabled the reed beetles to permanently colonize the wetlands and to diversify in this habitat underexploited by herbivorous insects (adaptive radiation).
Kleinschmidt, Birgit; Kölsch, Gregor
The present paper reviews the biology of reed beetles (Donaciinae), presents experimental data on the role of specific symbiotic bacteria, and describes a molecular method for the detection of those bacteria. Reed beetles are herbivores living on wetland plants, each species being mono- or oligo-phagous. They lay their eggs on the host plant and the larvae live underwater in the sediment attached to its roots. The larvae pupate there in a water-tight cocoon, which they build using a secretion that is produced by symbiotic bacteria. The bacteria are located in four blind sacs at the foregut of the larvae; in (female) adults they colonize two out of the six Malpighian tubules. Tetracycline treatment of larvae reduced their pupation rate, although the bacteria could not be fully eliminated. When the small amount of bacterial mass attached to eggs was experimentally removed before hatching, symbiont free larvae resulted, showing the external transmission of the bacteria to the offspring. Specific primers were designed to detect the bacteria, and to confirm their absence in manipulated larvae. The pupation underwater enabled the reed beetles to permanently colonize the wetlands and to diversify in this habitat underexploited by herbivorous insects (adaptive radiation). PMID:26467833
Antibiotic treatment with ampicillin accelerates the healing of colonic damage impaired by aspirin and coxib in the experimental colitis. Importance of intestinal bacteria, colonic microcirculation and proinflammatory cytokines.
Zwolinska-Wcislo, M; Krzysiek-Maczka, G; Ptak-Belowska, A; Karczewska, E; Pajdo, R; Sliwowski, Z; Urbanczyk, K; Drozdowicz, D; Konturek, S J; Pawlik, W W; Brzozowski, T
-α levels, as well as an overexpression of mRNA for IL-1β and TNF-α, COX-2, VEGF and iNOS in the colonic tissue. ASA and coxib also resulted also in a significant increase of E. coli counts in the stool at day 3 and day 10 day of the observation compared with the intact rats. Moreover, E. coli translocation from the colon to the blood and extraintestinal organs such as liver and spleen in the group of rats treated without or with ASA and coxib. E. coli was the most common bacteria isolated from these organs. Treatment with ampicillin significantly attenuated the ASA- or celecoxib-induced increase in plasma levels of IL-1β and TNF-α and suppressed the mucosal mRNA expression for IL-1β and TNF-β, COX-2, iNOS and VEGF in the colonic mucosa. Ampicillin administration caused a significant fall in the number of E. coli in the faeces at day 3 and day 10 of observation in ASA- and coxib-treated rats with colitis. Antibiotic therapy markedly reduced bacterial translocation to the colonic tissue and the extraintestinal organs such as the liver and spleen. We conclude that administration of ASA and to lesser extent of celecoxib, delays the healing of experimental colitis and enhances the alterations in colonic blood flow, proinflammatory markers such as IL-1β, TNF-α, COX-2, iNOS and VEGF and increased intestinal mucosal permeability resulting in the intestinal bacterial translocation to the blood, spleen and liver. Antibiotic treatment with ampicillin is effective in the diminishing of the severity of colonic damage, counteracts both the NSAID-induced fall in colonic microcirculation and bacterial E.coli translocation to the extraintestinal organs.
Takada, Toshihiko; Watanabe, Koichi; Makino, Hiroshi; Kushiro, Akira
A Gram-positive-staining, coccoid-shaped, non-motile, asporogenous, obligately anaerobic and butyrate-producing bacterium was recovered from a healthy human's faeces. The organism was isolated by the enrichment culture technique using yeast extract-casein hydrolysate-fatty acids broth supplemented with 0.5 % mucin. Phylogenetic analysis of 16S rRNA gene sequences demonstrated that the novel strain should be classified as a member of the Eubacterium desmolans-related cluster in the family Ruminococcaceae. Furthermore, this analysis demonstrated that the type strains of Butyricicoccus pullicaecorum (95.6 %) and Eubacterium desmolans (94.7 %) were the closest phylogenetic neighbours to strain YIT 12789T. However, DNA‒DNA reassociation values with these closest strains were less than 20 %. On the basis of the phenotypic, genotypic and chemotaxonomic features, the novel coccoid-shaped bacterium should be designated as a representative of a novel species of the genus Butyricicoccus, for which the name Butyricicoccus faecihominis sp. nov. is proposed. The type strain is YIT 12789T (=JCM 31056T=DSM 100989T). It is also proposed that Eubacterium desmolans be reclassified in the genus Butyricicoccus as Butyricicoccus desmolans comb. nov.
Jeraldo, Patricio; Hernandez, Alvaro; Nielsen, Henrik B.; Chen, Xianfeng; White, Bryan A.; Goldenfeld, Nigel; Nelson, Heidi; Alhquist, David; Boardman, Lisa; Chia, Nicholas
The role of the microbiome in health and disease is attracting great attention, yet we still know little about some of the most prevalent microorganisms inside our bodies. Several years ago, Human Microbiome Project (HMP) researchers generated a list of “most wanted” taxa: bacteria both prevalent among healthy volunteers and distantly related to any sequenced organisms. Unfortunately, the challenge of assembling high-quality genomes from a tangle of metagenomic reads has slowed progress in learning about these uncultured bacteria. Here, we describe how recent advances in sequencing and analysis allowed us to assemble “most wanted” genomes from metagenomic data collected from four stool samples. Using a combination of both de novo and guided assembly methods, we assembled and binned over 100 genomes from an initial data set of over 1,300 Gbp. One of these genome bins, which met HMP’s criteria for a “most wanted” taxa, contained three essentially complete genomes belonging to a previously uncultivated species. This species is most closely related to Eubacterium desmolans and the clostridial cluster IV/Clostridium leptum subgroup species Butyricicoccus pullicaecorum (71–76% average nucleotide identity). Gene function analysis indicates that the species is an obligate anaerobe, forms spores, and produces the anti-inflammatory short-chain fatty acids acetate and butyrate. It also appears to take up metabolically costly molecules such as cobalamin, methionine, and branch-chained amino acids from the environment, and to lack virulence genes. Thus, the evidence is consistent with a secondary degrader that occupies a host-dependent, nutrient-scavenging niche within the gut; its ability to produce butyrate, which is thought to play an anti-inflammatory role, makes it intriguing for the study of diseases such as colon cancer and inflammatory bowel disease. In conclusion, we have assembled essentially complete genomes from stool metagenomic data, yielding
Endo, Hitoshi; Niioka, Maki; Kobayashi, Noriko; Tanaka, Mamoru; Watanabe, Tetsu
Nonalcoholic fatty liver disease (NAFLD) includes simple steatosis, nonalcoholic steatohepatitis (NASH), fibrosis, cirrhosis, and hepatocellular carcinoma. The gut-derived endotoxin plays an essential role in the pathophysiological development and progression of NAFLD. By using rat models of choline-deficient/L-amino acid-defined (CDAA)-diet-induced NAFLD, we examined whether MIYAIRI 588--a butyrate-producing probiotic--prevents the progression of pathophysiological changes from steatosis to hepatocarcinogenesis. In vivo experiments showed that treatment with MIYAIRI 588 reduced CDAA-diet-induced hepatic lipid deposition and significantly improved the triglyceride content, insulin resistance, serum endotoxin levels, and hepatic inflammatory indexes. We also found that MIYAIRI 588 substantially increased the activation of hepatic adenosine 5'-monophosphate-activated protein kinase (AMPK) and AKT and the expression of lipogenesis- or lipolysis-related proteins. MIYAIRI 588 also improved CDAA-diet-induced delocalization and substantially decreased the expression of the tight-junction proteins intestinal zonula occluden-1 and occludin in CDAA-diet-fed rats. Further, the MIYAIRI 588-treated rats also showed remarkable induction of nuclear factor erythoid 2-related factor 2 (Nrf2) and its targeted antioxidative enzymes, which suppressed hepatic oxidative stress. In vitro studies revealed that treatment with sodium butyrate (NaB) also activated AMPK and AKT and enhanced Nrf2 expression by precluding ubiquitination, thereby increasing the half-life of the Nrf2 protein. Pharmacological studies and siRNA knockdown experiments showed that NaB-mediated AMPK activation induced the phosphorylation and nuclear translocation of Sirtuin 1, leading to the increased assembly of mammalian TOR complex 2 and phosphorylation of AKT at Ser473 and subsequent induction of Nrf2 expression and activation. These favorable changes caused an obvious decrease in hepatic fibrous deposition, GST
Chagnot, Caroline; Zorgani, Mohamed A.; Astruc, Thierry; Desvaux, Mickaël
Bacterial colonization of biotic or abiotic surfaces results from two quite distinct physiological processes, namely bacterial adhesion and biofilm formation. Broadly speaking, a biofilm is defined as the sessile development of microbial cells. Biofilm formation arises following bacterial adhesion but not all single bacterial cells adhering reversibly or irreversibly engage inexorably into a sessile mode of growth. Among molecular determinants promoting bacterial colonization, surface proteins are the most functionally diverse active components. To be present on the bacterial cell surface, though, a protein must be secreted in the first place. Considering the close association of secreted proteins with their cognate secretion systems, the secretome (which refers both to the secretion systems and their protein substrates) is a key concept to apprehend the protein secretion and related physiological functions. The protein secretion systems are here considered in light of the differences in the cell-envelope architecture between diderm-LPS (archetypal Gram-negative), monoderm (archetypal Gram-positive) and diderm-mycolate (archetypal acid-fast) bacteria. Besides, their cognate secreted proteins engaged in the bacterial colonization process are regarded from single protein to supramolecular protein structure as well as the non-classical protein secretion. This state-of-the-art on the complement of the secretome (the secretion systems and their cognate effectors) involved in the surface colonization process in diderm-LPS and monoderm bacteria paves the way for future research directions in the field. PMID:24133488
Mularoni, A; Bertani, A; Vizzini, G; Gona, F; Campanella, M; Spada, M; Gruttadauria, S; Vitulo, P; Conaldi, P; Luca, A; Gridelli, B; Grossi, P
Donor-derived infections due to multidrug-resistant bacteria are a growing problem in solid organ transplantation, and optimal management options are not clear. In a 2-year period, 30/214 (14%) recipients received an organ from 18/170 (10.5%) deceased donors with infection or colonization caused by a carbapenem-resistant gram-negative bacteria that was unknown at the time of transplantation. Among them, 14/30 recipients (47%) received a transplant from a donor with bacteremia or with infection/colonization of the transplanted organ and were considered at high risk of donor-derived infection transmission. The remaining 16/30 (53%) recipients received an organ from a nonbacteremic donor with colonization of a nontransplanted organ and were considered at low risk of infection transmission. Proven transmission occurred in 4 of the 14 high-risk recipients because donor infection was either not recognized, underestimated, or not communicated. These recipients received late, short or inappropriate posttransplant antibiotic therapy. Transmission did not occur in high-risk recipients who received appropriate and prompt antibiotic therapy for at least 7 days. The safe use of organs from donors with multidrug-resistant bacteria requires intra- and inter-institutional communication to allow appropriate management and prompt treatment of recipients in order to avoid transmission of infection.
Broiler chickens are widely considered an important source for human exposure to Campylobacter jejuni because of the high numbers found colonizing the chicken gut and the consequent contamination of processed carcasses. We hoped to intervene in gut colonization by C. jejuni using a defined probioti...
Arena, Mattia Pia; Capozzi, Vittorio; Spano, Giuseppe; Fiocco, Daniela
Lactic acid bacteria (LAB) are a heterogeneous group of Gram-positive bacteria that comprise several species which have evolved in close association with humans (food and lifestyle). While their use to ferment food dates back to very ancient times, in the last decades, LAB have attracted much attention for their documented beneficial properties and for potential biomedical applications. Some LAB are commensal that colonize, stably or transiently, host mucosal surfaces, inlcuding the gut, where they may contribute to host health. In this review, we present and discuss the main factors enabling LAB adaptation to such lifestyle, including the gene reprogramming accompanying gut colonization, the specific bacterial components involved in adhesion and interaction with host, and how the gut niche has shaped the genome of intestine-adapted species. Moreover, the capacity of LAB to colonize abiotic surfaces by forming structured communities, i.e., biofilms, is briefly discussed, taking into account the main bacterial and environmental factors involved, particularly in relation to food-related environments. The vast spread of LAB surface-associated communities and the ability to control their occurrence hold great potentials for human health and food safety biotechnologies.
Shoemaker, N B; Wang, G R; Salyers, A A
Previously, we demonstrated conjugal transfer of a specially constructed shuttle vector, pRDB5, from the human colonic anaerobe Bacteroides uniformis to the ruminal anaerobe Prevotella (Bacteroides) ruminicola B(1)4. We have now shown that naturally occurring gene transfer elements in Bacteroides species and Prevotella ruminicola can also be transferred between these two genera. A self-transmissible chromosomal element originally found in a clinical isolate of Bacteroides fragilis (Tcr Emr 12256) was transferred from B. uniformis 0061 to P. ruminicola B(1)4 and from P. ruminicola B(1)4 back to B. uniformis or to another human colonic species, Bacteroides thetaiotaomicron. Similarly, a conjugative plasmid (pRRI4) originally found in P. ruminicola 223 was transferred from P. ruminicola B(1)4 to B. uniformis or B. thetaiotaomicron. pRRI4 could be transferred from the colonic Bacteroides species only if the donor strain contained the Tcr Emr 12256 element in its chromosome. These results show that transfer of naturally occurring elements can be demonstrated under laboratory conditions. Evidence that such transfers may actually have occurred in nature came from our finding that the tetracycline resistance (Tcr) gene on the P. ruminicola plasmid pRRI4 hybridized on high-stringency Southern blots with the Tcr gene found on the Bacteroides Tcr elements. The presence of the same gene in such distantly related genera of bacteria is most likely to have occurred as a result of horizontal transfer. Images PMID:1599250
Thomas, Pious; Sekhar, Aparna Chandra
It is generally believed that endophytic microorganisms are intercellular inhabitants present in either cultivable or non-cultivable form primarily as root colonizers. The objective of this study was to determine whether the actively mobile micro-particles observed in the intracellular matrix of fresh tissue sections of banana included endophytic bacteria. Tissue sections (50-100 µm) from apical leaf sheaths of surface-disinfected suckers (cv. Grand Naine) displayed 'Brownian motion'-reminiscent abundant motile micro-particles under bright-field and phase-contrast (×1000), which appeared similar in size and motility to the pure cultures of endophytes previously isolated from banana. Observations on callus, embryonic cells and protoplasts with intact cell wall/plasma membrane confirmed their cytoplasmic nature. The motility of these entities reduced or ceased upon tissue fixation or staining with safranin/crystal violet (0.5 % w/v), but continued uninterrupted following treatment with actin-disrupting drugs, ruling out the possibility of micro-organelles like peroxisomes. Staining with 2,3,5-triphenyl tetrazolium chloride (TTC) confirmed them to be live bacteria with similar observations after dilute safranin (0.005 %) treatment. Tissue staining with SYTO-9 coupled with epi-fluorescence or confocal laser scanning microscopy showed bacterial colonization along the peri-space between cell wall and plasma membrane initially. SYTO-9 counterstaining on TTC- or safranin-treated tissue and those subjected to enzymatic permeabilization revealed the cytoplasmic bacteria. These included organisms moving freely in the cytoplasm and those adhering to the nuclear envelope or vacuoles and the intravacuolar colonizers. The observations appeared ubiquitous to different genomes and genotypes of banana. Plating the tissue homogenate on nutrient media seldom yielded colony growth. This study, supported largely by live cell video-imaging, demonstrates enormous intracellular
Bergström, Joakim H.; Katona, Gergely; Schütte, André; Ermund, Anna; Hansson, Gunnar C.
The distal colon functions as a bioreactor and harbors an enormous amount of bacteria in a mutualistic relationship with the host. The microbiota have to be kept at a safe distance to prevent inflammation, something that is achieved by a dense inner mucus layer that lines the epithelial cells. The large polymeric nets made up by the heavily O-glycosylated MUC2 mucin forms this physical barrier. Proteomic analyses of mucus have identified the lectin-like protein ZG16 (zymogen granulae protein 16) as an abundant mucus component. To elucidate the function of ZG16, we generated recombinant ZG16 and studied Zg16−/− mice. ZG16 bound to and aggregated Gram-positive bacteria via binding to the bacterial cell wall peptidoglycan. Zg16−/− mice have a distal colon mucus layer with normal thickness, but with bacteria closer to the epithelium. Using distal colon explants mounted in a horizontal perfusion chamber we demonstrated that treatment of bacteria with recombinant ZG16 hindered bacterial penetration into the mucus. The inner colon mucus of Zg16−/− animals had a higher load of Gram-positive bacteria and showed bacteria with higher motility in the mucus close to the host epithelium compared with cohoused littermate Zg16+/+. The more penetrable Zg16−/− mucus allowed Gram-positive bacteria to translocate to systemic tissues. Viable bacteria were found in spleen and were associated with increased abdominal fat pad mass in Zg16−/− animals. The function of ZG16 reveals a mechanism for keeping bacteria further away from the host colon epithelium. PMID:27849619
The price of nitrogen continues to increase and is a major input in sugarcane production. Sugarcane grown in Egypt was screened for the presence of nitrogen-fixing bacteria. Nitrogen-free medium LGI-P was used to isolate bacteria from cane stalks. Among the 52 isolates subjected to acetylene redu...
Studying the host-associated butyrate-producing bacterial community is important because butyrate is essential for colonic homeostasis and gut health. Previous research has identified the butyryl-coA:acetate transferase (22.214.171.124) as a the main gene for butyrate production in intestinal ecosystems; h...
Broilers chickens are widely considered an important source for human exposure to Campylobacter jejuni. We sought to intervene in C. jejuni colonization by using a probiotic approach. Isolates from chicken intestine were screened for C. jejuni inhibition. These isolates were live-fed to treat chi...
Koole, K; Ellerbroek, P M; Lagendijk, R; Leenen, L P H; Ekkelenkamp, M B
In November 2011 51 Libyan war casualties were admitted to the Major Incident Hospital in Utrecht and from there were transferred to 26 other Dutch hospitals. Cultures and clinical data were collected to establish the prevalence of multidrug-resistant (MDR) bacteria in this patient group and to identify the associated risk factors. The prevalence of MDR bacteria was 59% (30/51 patients); extended spectrum β-lactamase-producing enterobacteriaceae were most common (26/51 patients: 51%). The major risk factor for carriage of MDR bacteria was the presence of open wounds at admission to the Major Incident Hospital.
Gibbs, Kathleen; Holzman, Ian R
The microbiology of the endotracheal tube culture plays a role in diagnosing a variety of diseases in the newborn intensive care unit, including subglottic stenosis, bronchopulmonary dysplasia, and ventilator-associated pneumonia. Bacterial production of a biofilm that coats the endotracheal tube acts as a reservoir for infection, prevents eradication, and may play a role in the development of subglottic stenosis. The diagnosis of ventilator-associated pneumonia is limited by the CDC definition as well as currently available diagnostic methods. Biomarkers could aid in differentiating colonization from infection, but are not available to most clinicians. The etiology of ventilator-associated pneumonia is often polymicrobial. Failure to differentiate colonization from infection results in unnecessary prescription of antibiotics, which could contribute to antimicrobial resistance. Measures to prevent ventilator-associated pneumonia have been described, primarily in the adult population.
Murphy, K M; Teakle, D S; Macrae, I C
The average total population of bacteria remained constant in the alimentary tracts of adult laboratory-raised Queensland fruit flies (Bactrocera tryoni) although the insects had ingested large numbers of live bacteria as part of their diet. The mean number of bacteria (about 13 million) present in the gut of the insects from 12 to 55 days after emergence was not significantly modified when, at 5 days after emergence, the flies were fed antibiotic-resistant bacteria belonging to two species commonly isolated from the gut of field-collected B. tryoni. Flies were fed one marked dinitrogen-fixing strain each of either Klebsiella oxytoca or Enterobacter cloacae, and the gastrointestinal tracts of fed flies were shown to be colonized within 7 days by antibiotic-resistant isolates of K. oxytoca but not E. cloacae. The composition of the microbial population also appeared to be stable in that the distribution and frequency of bacterial taxa among individual flies exhibited similar patterns whether or not the flies had been bacteria fed. Isolates of either E. cloacae or K. oxytoca, constituting 70% of the total numbers, were usually dominant, with oxidative species including pseudomonads forming the balance of the population. Antibiotic-resistant bacteria could be spread from one cage of flies to the adjacent surfaces of a second cage within a few days and had reached a control group several meters distant by 3 weeks. Restriction of marked bacteria to the population of one in five flies sampled from the control group over the next 30 days suggested that the bacterial population in the gut of the insect was susceptible to alteration in the first week after emergence but that thereafter it entered a steady state and was less likely to be perturbed by the introduction of newly encountered strains. All populations sampled, including controls, included at least one isolate of the dinitrogen-fixing family Enterobacteriaceae; many were distinct from the marked strains fed to the
Kepkay, P. E.; Schwinghamer, P.; Willar, T.; Bowen, A. J.
Short-term (65-h) bacterial colonization of 0.2-μm (pore size) filters submerged in water from Lake Charlotte, Nova Scotia, was characterized by a well-defined succession of cell types, in which small cocci gave way to larger, rod-shaped cells. This succession agrees with the concept of attachment as a strategy for survival, in which inactive cocci can attach to a surface and grow into larger, rod-shaped cells by using endogenous nutrients and the nutrients accumulated at the solid-liquid interface. Analyses of oxygen and CO2 microgradients above colonized surfaces indicated that a peak of respiration accompanied the succession of rods from cocci. CO2 fixation then became apparent as the rods began to bind manganese and iron to their surfaces. This means that survival by attachment may not be just the province of heterotrophs. It could also be a strategy adopted by metal-oxidizing chemoautotrophs. Long-term (34-day) colonization of similar filters indicated that, while a succession of attached cell types may indeed be a natural occurrence, other factors (such as the selective grazing of larger cells) tend to obscure the development of this succession. Images PMID:16346966
Nicoli, Jacques R; Oliveira, Adriana
Objective: To compare cutaneous and nasal population levels between patients colonized and infected by multidrug-resistant organisms in two intensive care units. Methods: A prospective cohort study was performed in adult intensive care units of two hospitals in Belo Horizonte, Brazil (April 2012 to February 2013). Clinical and demographic data were first collected by reviewing patients’ charts. Then, samples collected with nasal, groin, and perineum swabs were cultivated in selective media for 48 h at 37°C. After isolation, determination of antimicrobial susceptibility and biochemical identification were performed. Results: A total of 53 cases of colonization were observed by the following bacteria in decreasing frequencies: imipenem-resistant Acinetobacter baumannii (50.9%), vancomycin-resistant Enterococcus faecalis (43.4%), extended-spectrum beta-lactamase–producing Klebsiella pneumoniae (37.7%), imipenem-resistant Pseudomonas aeruginosa (32.1%), oxacillin-resistant Staphylococcus aureus (7.5%), and imipenem-resistant Klebsiella pneumoniae (5.7%). Among these colonization cases, 26 (49.0%) were followed by infection with bacteria phenotypically similar to those of the colonization. A relation between high population levels of colonization by most of the multidrug-resistant organisms at anatomical sites and a subsequent infection was observed. After colonization/infection, bacterial population levels decreased progressively and spontaneously until disappearance by day 45 in all the anatomical sites and for all the multidrug-resistant organisms. Conclusion: There was a correlation between high population levels of colonization by multidrug-resistant organisms at anatomical sites and a subsequent infection. Reduction in multidrug-resistant organism populations after colonization at anatomical sites could be a preventive measure to reduce evolution to infection as well as transmission of these bacteria between patients in intensive care unit. PMID:26770762
Kashama, Johnny; Prince, Véronique; Simao-Beaunoir, Anne-Marie; Beaulieu, Carole
Forty-one bacterial strains isolated from the headbox water of two machines in a Canadian paper mill were associated with the genera Asticcacaulis, Acidovorax, Bacillus, Exiguobacterium, Hydrogenophaga, Pseudomonas, Pseudoxanthomonas, Staphylococcus, Stenotrophomonas based on the sequence of their 16S rRNA genes. The metabolic profile of these strains were determined using Biolog EcoPlate, and the bacteria were divided into four metabolic groups. Metabolic profiles of the bacterial communities colonizing the headbox water of two paper machines was also determined weekly over a 1 year period. The only compound that was not reduced by the bacterial community was 2-hydroxybenzoic acid. Utilization frequency of the other carbon sources in the Biolog EcoPlate ranged from 3 to 100%. The metabolic profiles of the bacterial community did not vary considerably between the two paper machines. However, the metabolic profile varied among the sampling dates.
Gokul, Jarishma K; Hodson, Andrew J; Saetnan, Eli R; Irvine-Fynn, Tristram D L; Westall, Philippa J; Detheridge, Andrew P; Takeuchi, Nozomu; Bussell, Jennifer; Mur, Luis A J; Edwards, Arwyn
Microbial colonization of glacial ice surfaces incurs feedbacks which affect the melting rate of the ice surface. Ecosystems formed as microbe-mineral aggregates termed cryoconite locally reduce ice surface albedo and represent foci of biodiversity and biogeochemical cycling. Consequently, greater understanding the ecological processes in the formation of functional cryoconite ecosystems upon glacier surfaces is sought. Here, we present the first bacterial biogeography of an ice cap, evaluating the respective roles of dispersal, environmental and biotic filtration occurring at local scales in the assembly of cryoconite microbiota. 16S rRNA gene amplicon semiconductor sequencing of cryoconite colonizing a Svalbard ice cap coupled with digital elevation modelling of physical parameters reveals the bacterial community is dominated by a ubiquitous core of generalist taxa, with evidence for a moderate pairwise distance-decay relationship. While geographic position and melt season duration are prominent among environmental predictors of community structure, the core population of taxa appears highly influential in structuring the bacterial community. Taxon co-occurrence network analysis reveals a highly modular community structured by positive interactions with bottleneck taxa, predominantly Actinobacteria affiliated to isolates from soil humus. In contrast, the filamentous cyanobacterial taxon (assigned to Leptolyngbya/Phormidesmis pristleyi) which dominates the community and binds together granular cryoconite are poorly connected to other taxa. While our study targeted one ice cap, the prominent role of generalist core taxa with close environmental relatives across the global cryosphere indicate discrete roles for cosmopolitan Actinobacteria and Cyanobacteria as respective keystone taxa and ecosystem engineers of cryoconite ecosystems colonizing ice caps.
Ferreira, Anderson; Quecine, Maria Carolina; Lacava, Paulo Teixeira; Oda, Shinitiro; Azevedo, João Lúcio; Araújo, Welington Luiz
The diversity and beneficial characteristics of endophytic microorganisms have been studied in several host plants. However, information regarding naturally occurring seed-associated endophytes and vertical transmission among different life-history stages of hosts is limited. Endophytic bacteria were isolated from seeds and seedlings of 10 Eucalyptus species and two hybrids. The results showed that endophytic bacteria, such as Bacillus, Enterococcus, Paenibacillus and Methylobacterium, are vertically transferred from seeds to seedlings. In addition, the endophytic bacterium Pantoea agglomerans was tagged with the gfp gene, inoculated into seeds and further reisolated from seedlings. These results suggested a novel approach to change the profile of the plants, where the bacterium is a delivery vehicle for desired traits. This is the first report of an endophytic bacterial community residing in Eucalyptus seeds and the transmission of these bacteria from seeds to seedlings. The bacterial species reported in this work have been described as providing benefits to host plants. Therefore, we suggest that endophytic bacteria can be transmitted vertically from seeds to seedlings, assuring the support of the bacterial community in the host plant.
Zhang, Lihua; Dong, Danfeng; Jiang, Cen; Li, Zhen; Wang, Xuefeng; Peng, Yibing
Clostridium difficile is well recognized as the common pathogen of nosocomial diarrhea, meanwhile, asymptomatic colonization with C. difficile in part of the population has also drawn public attention. Although gut microbiota is known to play an important role in the pathogenesis of C. difficile infection (CDI), whether there is any alteration of gut microbial composition in asymptomatic C. difficile carriers hasn't been clearly described. The purpose of this study was to explore the differences in gut microbiome among CDI patients, asymptomatic C. difficile carriers and healthy individuals. We performed fecal microbiota analysis on the samples of eight CDI patients, eight asymptomatic C. difficile carriers and nine healthy subjects using 16S rRNA gene pyrosequencing. CDI patients and asymptomatic carriers showed reduced microbial richness and diversity compared with healthy subjects, accompanied with a paucity of phylum Bacteroidetes and Firmicutes as well as an overabundance of Proteobacteria. Some normally commensal bacteria, especially butyrate producers, were significantly depleted in CDI patients and asymptomatic carriers. Furthermore, the differences observed in microbial community structure between CDI patients and asymptomatic carriers suggested that the gut microbiota may be a potential factor of disease state for CDI. Our study demonstrates the characterization and diversity of gut microbiota in CDI and asymptomatic C. difficile colonization, which will provide new ideas for surveillance of the disease state and development of microbiota-targeted agents for CDI prevention and treatment.
Li, Min; Monaco, Marcia H; Wang, Mei; Comstock, Sarah S; Kuhlenschmidt, Theresa B; Fahey, George C; Miller, Michael J; Kuhlenschmidt, Mark S; Donovan, Sharon M
The impact of human milk oligosaccharides (HMO) on mucosal immunity, gut microbiota and response to rotavirus (RV) infection was investigated in the piglet model. Newborn piglets were fed with formula alone (FF) or formula supplemented with 4 g l(-1) HMO (HMO) or a prebiotic mixture of 9:1 short-chain galactooligosaccharides (3.6 g l(-1)) and long-chain fructooligosaccharides (0.4 g l(-1)) (PRE) (n=19-21 per group) for 15 days. Piglets (n=7-8) in each dietary group were orally infected with porcine rotavirus (RV) OSU strain on d10, and stool consistency was assessed daily. Blood, small intestine and colonic contents were collected at day 15. Serum RV-specific antibody concentrations, intestinal histomorphology, RV non-structural protein-4 (NSP4) and cytokine mRNA expression were assessed. Colonic content pH, dry matter (DM) and short-chain fatty acid concentrations were measured. Ascending colonic microbiota was analyzed by 16S rRNA gene v1-3 region pyrosequencing. HMO- and PRE-fed groups had shorter duration of diarrhea than FF piglets. Infection changed intestinal histomorphology, increased serum RV-specific antibody response and intestinal RV NSP4 expression, and modulated ileal cytokine expression. HMO enhanced T helper type 1 (interferon-gamma) and anti-inflammatory (interleukin-10) cytokines in the ileum, while prebiotics promoted RV-specific immunoglobulin M response to the infection. RV infection and HMO supplementation altered intraluminal environment and gut microbiota. HMO increased pH and lowered DM of colonic contents and enhanced the abundance of unclassified Lachnospiraceae, which contains numerous butyrate-producing bacteria. In conclusion, HMO and prebiotics did not prevent the onset of RV infection but reduced the duration of RV-induced diarrhea in piglets, in part, by modulating colonic microbiota and immune response to RV infection.
Li, Min; Monaco, Marcia H; Wang, Mei; Comstock, Sarah S; Kuhlenschmidt, Theresa B; Fahey Jr, George C; Miller, Michael J; Kuhlenschmidt, Mark S; Donovan, Sharon M
The impact of human milk oligosaccharides (HMO) on mucosal immunity, gut microbiota and response to rotavirus (RV) infection was investigated in the piglet model. Newborn piglets were fed with formula alone (FF) or formula supplemented with 4 g l−1 HMO (HMO) or a prebiotic mixture of 9:1 short-chain galactooligosaccharides (3.6 g l−1) and long-chain fructooligosaccharides (0.4 g l−1) (PRE) (n=19–21 per group) for 15 days. Piglets (n=7–8) in each dietary group were orally infected with porcine rotavirus (RV) OSU strain on d10, and stool consistency was assessed daily. Blood, small intestine and colonic contents were collected at day 15. Serum RV-specific antibody concentrations, intestinal histomorphology, RV non-structural protein-4 (NSP4) and cytokine mRNA expression were assessed. Colonic content pH, dry matter (DM) and short-chain fatty acid concentrations were measured. Ascending colonic microbiota was analyzed by 16S rRNA gene v1-3 region pyrosequencing. HMO- and PRE-fed groups had shorter duration of diarrhea than FF piglets. Infection changed intestinal histomorphology, increased serum RV-specific antibody response and intestinal RV NSP4 expression, and modulated ileal cytokine expression. HMO enhanced T helper type 1 (interferon-gamma) and anti-inflammatory (interleukin-10) cytokines in the ileum, while prebiotics promoted RV-specific immunoglobulin M response to the infection. RV infection and HMO supplementation altered intraluminal environment and gut microbiota. HMO increased pH and lowered DM of colonic contents and enhanced the abundance of unclassified Lachnospiraceae, which contains numerous butyrate-producing bacteria. In conclusion, HMO and prebiotics did not prevent the onset of RV infection but reduced the duration of RV-induced diarrhea in piglets, in part, by modulating colonic microbiota and immune response to RV infection. PMID:24522264
Hicks, Kristin A.; Nickelsen, Michael G.; Boyle, Susan L.; Baker, Jeffrey M.; Tornatore, Paul M.; Hristova, Krassimira R.; Scow, Kate M.
A field-scale fixed bed bioreactor was used to successfully treat an MTBE-contaminated aquifer in North Hollywood, CA without requiring inoculation with introduced bacteria. Native bacteria from the MTBE-impacted aquifer rapidly colonized the bioreactor, entering the bioreactor in the contaminated groundwater pumped from the site, and biodegraded MTBE with greater than 99 % removal efficiency. DNA sequencing of the 16S rRNA gene identified MTBE-degrading bacteria Methylibium petroleiphilum in the bioreactor. Quantitative PCR showed M. petroleiphilum enriched by three orders of magnitude in the bioreactor above densities pre-existing in the groundwater. Because treatment was carried out by indigenous rather than introduced organisms, regulatory approval was obtained for implementation of a full-scale bioreactor to continue treatment of the aquifer. In addition, after confirmation of MTBE removal in the bioreactor to below maximum contaminant limit levels (MCL; MTBE = 5 μg L−1), treated water was approved for reinjection back into the aquifer rather than requiring discharge to a water treatment system. This is the first treatment system in California to be approved for reinjection of biologically treated effluent into a drinking water aquifer. This study demonstrated the potential for using native microbial communities already present in the aquifer as an inoculum for ex-situ bioreactors, circumventing the need to establish non-native, non-acclimated and potentially costly inoculants. Understanding and harnessing the metabolic potential of native organisms circumvents some of the issues associated with introducing non-native organisms into drinking water aquifers, and can provide a low-cost and efficient remediation technology that can streamline future bioremediation approval processes. PMID:23613160
Duncan, Sylvia H; Louis, Petra; Flint, Harry J
The microbial community of the human colon contains many bacteria that produce lactic acid, but lactate is normally detected only at low concentrations (<5 mM) in feces from healthy individuals. It is not clear, however, which bacteria are mainly responsible for lactate utilization in the human colon. Here, bacteria able to utilize lactate and produce butyrate were identified among isolates obtained from 10(-8) dilutions of fecal samples from five different subjects. Out of nine such strains identified, four were found to be related to Eubacterium hallii and two to Anaerostipes caccae, while the remaining three represent a new species within clostridial cluster XIVa based on their 16S rRNA sequences. Significant ability to utilize lactate was not detected in the butyrate-producing species Roseburia intestinalis, Eubacterium rectale, or Faecalibacterium prausnitzii. Whereas E. hallii and A. caccae strains used both D- and L-lactate, the remaining strains used only the d form. Addition of glucose to batch cultures prevented lactate utilization until the glucose became exhausted. However, when two E. hallii strains and one A. caccae strain were grown in separate cocultures with a starch-utilizing Bifidobacterium adolescentis isolate, with starch as the carbohydrate energy source, the L-lactate produced by B. adolescentis became undetectable and butyrate was formed. Such cross-feeding may help to explain the reported butyrogenic effect of certain dietary substrates, including resistant starch. The abundance of E. hallii in particular in the colonic ecosystem suggests that these bacteria play important roles in preventing lactate accumulation.
Divya, K R; Isamma, A; Ramasubramanian, V; Sureshkumar, S; Arunjith, T S
The present study was conducted to assess the establishment and effect of probiotic bacteria such as Bacillus coagulans, Bacillus mesentericus, and Bifidobacterium infantis in the gut of freshwater ornamental fish Puntius conchonius. Postlarvae of 60 days old Puntius conchonius divided in four experimental groups each with three replicates. T1, T2 and T3 groups were fed with Bacillus coagulans, Bacillus mesentericus and Bifidobacterium infantis enriched copepod Thermocyclops decipiens respectively. T0 was the control group (without probiotic treated T. decipiens). The experiment was conducted for 45 days. The initial gut analysis of fish showed significant level of pathogenic bacteria in the gut of fish (p < 0.05). Total plate count of initial gut analysis of fish larvae were enumerated as 1.2 x 10(4)CFU ml(-1). The bacteriological study indicated thatfinal gut microflora of post-larvae have decreased level of pathogens. Total plate count of T1, T2 T3 and T0 were reported to be as 1.0 8 x 10(4), 1.06 x 10(4), 1.27 x 10(4) and 2.1 x 10(5) CFU ml(-1), respectively. Three experimental groups (T1, T2 and T3) were significantly different from control group (T0) (p < 0.05). At the end of the experiment, establishment of probiotics were examined. One week after probiotics administration, gut analysis of fish larvae showed, poor spore formation of Bacillus coagulans (2.3 x 10(3) CFU mL(-1)), when compared to B. mesentericus (3.2 +/- 0.03 x10(3) CFU ml(-1)) and Bifidobacterium infantis(3.1 x 10(3) CFU ml(-1)). The results from the study suggest that the probiotic bacteria significantly established in gut of P. conchonius and significant effects on the pathogenic gut inhabitants of the fish.
León-Barúa, Raúl; Alvarez De Roig, Maritza; Roig-Arosemena, Javier; Berendson-Seminario, Roberto; Torres-Zevallos, Hernando
Using a previously described technique, "in vitro" determinations were carried out for faecal fermentation (FF): basal faecal fermentation (BFF), i.e, only with faeces, with faeces and lactulose (LFF) and with faeces, lactulose and bismuth subsalicylate (BiLFF) in 34 patients with flatulence. The media+d.s. of the difference between the LFFand BFF levels (LFF-BFF) in patients with flatulence was significant and markedly higher than the respective media +d.s. in 30 normal control patients previously studied (9.1+4.7 vs. 3.9+3.2 ml gas/24 hrs; p<0.000001 respectively). And, although FF was reduced by adding bismuth salicylate in only 24% (70.6%) of the patients with flatulence but not in the remaining 10 (29.4%), in total the media+d.s. of the differences between the levels BiLFF and BFF (BiLFFBFF) was significantly lower that the media+d.s. of the differences between the LFF and BFF levels (LFF-BFF) (6.0+4.2 vs 9.1+4.7 ml gas/24 hrs; p<0.01 respectively). These results confirm that: 1) The fermentative capacity of the colonic bacteriae is most likely to be abnormally intense in peoples with flatulence and 2) Bismuth subsalicylate can be useful in the control of excessive colonic fermentation and flatulence; they raise, furthermore, the interesting possibility that we may have found the way to predict when the use of bismuth subsalicylate could be effective in the treatment of a patient with flatulence.
Farrell, John J; Hicks, Jennifer L; Wallace, Stephanie E; Seftel, Allen D
With the universal adoption of antibiotic prophylaxis prior to prostate biopsy, the current risk of post-biopsy infection (including sepsis) is <2%. Preoperative prophylactic antibiotic regimens can vary, and although fluoroquinolones have emerged as the standard of care, there is no universally agreed upon preoperative antibiotic regimen. Recently, an increase in the proportion of postoperative infections caused by fluoroquinolone-resistant Escherichia coli (as well as other Enterobacteriaceae) has led to the exploration of simple, practical, and cost-effective methods to minimize this postoperative infection risk. We performed a prospective, nonrandomized, controlled study of preoperative rectal cultures to screen for rectal colonization with fluoroquinolone-resistant bacteria using ciprofloxacin-supplemented MacConkey agar culture media. To evaluate the feasibility and practicality of this test, one provider used the results of rectal swab cultures collected during the preoperative outpatient evaluation to adjust each patient’s preoperative antibiotic prophylaxis when fluoroquinolone-resistant enteric bacteria were detected, whereas two other providers continued usual preoperative care and empiric antimicrobial prophylaxis. Rectal colonization with fluoroquinolone-resistant bacteria was detected in 19/152 (12.5%) of patients. In our intention-to-treat analysis (N=268), the rate of post-biopsy sepsis was 3.6% lower in the group that was screened for rectal colonization with fluoroquinolone-resistant bacteria prior to transrectal prostate biopsy. The observed risk reduction in the rectal screening group trended toward, but did not achieve, statistical significance. We suggest that preoperative screening for rectal colonization with fluoroquinolone-resistant enteric bacteria may be a useful step toward mitigating post-prostate biopsy sepsis. PMID:28280717
Li, Qiang; Zhang, Bingjian; He, Zhang; Yang, Xiaoru
The historical and cultural heritage of Qingxing palace and Lingyin and Kaihua temple, located in Hangzhou of China, include a large number of exquisite Buddhist statues and ancient stone sculptures which date back to the Northern Song (960–1219 A.D.) and Qing dynasties (1636–1912 A.D.) and are considered to be some of the best examples of ancient stone sculpting techniques. They were added to the World Heritage List in 2011 because of their unique craftsmanship and importance to the study of ancient Chinese Buddhist culture. However, biodeterioration of the surface of the ancient Buddhist statues and white marble pillars not only severely impairs their aesthetic value but also alters their material structure and thermo-hygric properties. In this study, high-throughput sequencing was utilized to identify the microbial communities colonizing the stone monuments. The diversity and distribution of the microbial communities in six samples collected from three different environmental conditions with signs of deterioration were analyzed by means of bioinformatics software and diversity indices. In addition, the impact of environmental factors, including temperature, light intensity, air humidity, and the concentration of NO2 and SO2, on the microbial communities’ diversity and distribution was evaluated. The results indicate that the presence of predominantly phototrophic microorganisms was correlated with light and humidity, while nitrifying bacteria and Thiobacillus were associated with NO2 and SO2 from air pollution. PMID:27658256
Li, Qiang; Zhang, Bingjian; He, Zhang; Yang, Xiaoru
The historical and cultural heritage of Qingxing palace and Lingyin and Kaihua temple, located in Hangzhou of China, include a large number of exquisite Buddhist statues and ancient stone sculptures which date back to the Northern Song (960-1219 A.D.) and Qing dynasties (1636-1912 A.D.) and are considered to be some of the best examples of ancient stone sculpting techniques. They were added to the World Heritage List in 2011 because of their unique craftsmanship and importance to the study of ancient Chinese Buddhist culture. However, biodeterioration of the surface of the ancient Buddhist statues and white marble pillars not only severely impairs their aesthetic value but also alters their material structure and thermo-hygric properties. In this study, high-throughput sequencing was utilized to identify the microbial communities colonizing the stone monuments. The diversity and distribution of the microbial communities in six samples collected from three different environmental conditions with signs of deterioration were analyzed by means of bioinformatics software and diversity indices. In addition, the impact of environmental factors, including temperature, light intensity, air humidity, and the concentration of NO2 and SO2, on the microbial communities' diversity and distribution was evaluated. The results indicate that the presence of predominantly phototrophic microorganisms was correlated with light and humidity, while nitrifying bacteria and Thiobacillus were associated with NO2 and SO2 from air pollution.
Background Drug resistant organisms pose an increasing threat to the successful treatment of common infections. Understanding colonization patterns of these bacteria is important for effective antibiotic treatment and infection control guidelines. Methods A prospective observational study was performed to determine the prevalence of colonization with extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E), methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-resistant Enterococcus (VRE) among patients admitted via the emergency department to a public tertiary hospital in Singapore. Anterior nares, groin, axillary and rectal swabs were collected at admission and cultured using standard bacteriological techniques. Clinical data including healthcare contact within the past 12 months and recent antibiotic use was collected and analyzed using a logistic regression model. Results 1006 patients were screened. 124 (12.4%) were colonized by ESBL-E, 18 (1.8%) by MRSA while no VRE was detected. Antibiotic use within the past month was the only significant predictor for ESBL-E colonization in the regression model, with an adjusted odds ratio (AOR) of 2.58 (1.04 to 6.42). In participants recently prescribed antibiotics and hospitalized in the previous 3 months, 29.4% were colonized by ESBL-E. This represented 20.2% of the total ESBL-E burden, and ESBL-E was also detected in 6.3% of participants with no healthcare contact. Hospitalization and outpatient hospital visits predicted MRSA colonization in the univariate analysis. Neither was statistically significant in the logistic regression model, with AORs for MRSA colonization following hospitalization in the past 3 and 12 months of 3.81 [95% CI 0.84-17.28] and 3.48 [0.64-18.92] respectively. Conclusion A high prevalence of colonization with ESBL-E was evident among patients at admission, even in the absence of recent antibiotic use or contact with healthcare. PMID:24889720
Strus, M; Gosiewski, T; Fyderek, K; Wedrychowicz, A; Kowalska-Duplaga, K; Kochan, P; Adamski, P; Heczko, P B
Bacteria in the gut play a central role in the initiation and progress of inflammatory bowel disease (IBD). This study was prepared to elucidate the role in the inflammatory process of the bacterial species which are able to produce hydrogen peroxide, present in samples taken from colon lesions in adolescents with inflammatory bowel disease. Fifty eight adolescents were enrolled into the study from January 2004 to October 2006 in Cracow, Poland. Biopsies and stool samples were collected. Bacteriological examinations and measurements of hydrogen peroxide production by enterococci, streptococci and lactobacilli were performed. For the first time it has been shown here that HP producing bacteria may contribute to increased amounts of hydrogen peroxide in the inflamed mucosa of Crohn's disease and ulcerative colitis patients. Moreover, we have been able to demonstrate an increase of total populations of aerobic bacteria but not anaerobes in the studied samples of mucosa of adolescents with inflammatory bowel disease which is an indirect evidence of higher oxygen tension present in inflamed tissues in IBD. We have also been able to demonstrate the direct relationship between presence of blood in stools of IBD adolescents and increased populations of Enterobacteriaceae but not streptococci in samples of colon mucosa. It is, therefore, possible that different products of Enterobacteriaceae and especially their lipopolysaccharides may also contribute to perpetuation of the chronic colon inflammation.
Mori, J. F.; Neu, T. R.; Lu, S.; Händel, M.; Totsche, K. U.; Küsel, K.
Filamentous macroscopic algae were observed in slightly acidic to circumneutral (pH 5.9-6.5), metal-rich stream water that leaked out from a former uranium mining district (Ronneburg, Germany). These algae differed in color and morphology and were encrusted with Fe-deposits. To elucidate their potential interaction with Fe(II)-oxidizing bacteria (FeOB), we collected algal samples at three time points during summer 2013 and studied the algae-bacteria-mineral compositions via confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectra, and a 16S and 18S rRNA gene-based bacterial and algae community analysis. Surprisingly, sequencing analysis of 18S rRNA gene regions of green and brown algae revealed high homologies with the freshwater algae Tribonema (99.9-100 %). CLSM imaging indicated a loss of active chloroplasts in the algae cells, which may be responsible for the change in color in
Wang, X; Conway, P L; Brown, I L; Evans, A J
It has been well established that a certain amount of ingested starch can escape digestion in the human small intestine and consequently enters the large intestine, where it may serve as a carbon source for bacterial fermentation. Thirty-eight types of human colonic bacteria were screened for their capacity to utilize soluble starch, gelatinized amylopectin maize starch, and high-amylose maize starch granules by measuring the clear zones on starch agar plates. The six cultures which produced clear zones on amylopectin maize starch- containing plates were selected for further studies for utilization of amylopectin maize starch and high-amylose maize starch granules A (amylose; Sigma) and B (Culture Pro 958N). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was used to detect bacterial starch-degrading enzymes. It was demonstrated that Bifidobacterium spp., Bacteroides spp., Fusobacterium spp., and strains of Eubacterium, Clostridium, Streptococcus, and Propionibacterium could hydrolyze the gelatinized amylopectin maize starch, while only Bifidobacterium spp. and Clostridium butyricum could efficiently utilize high-amylose maize starch granules. In fact, C. butyricum and Bifidobacterium spp. had higher specific growth rates in the autoclaved medium containing high-amylose maize starch granules and hydrolyzed 80 and 40% of the amylose, respectively. Starch-degrading enzymes were cell bound on Bifidobacterium and Bacteroides cells and were extracellular for C. butyricum. Active staining for starch-degrading enzymes on SDS-PAGE gels showed that the Bifidobacterium cells produced several starch-degrading enzymes with high relative molecular (M(r)) weights (>160,000), medium-sized relative molecular weights (>66,000), and low relative molecular weights (<66,000). It was concluded that Bifidobacterium spp. and C. butyricum degraded and utilized granules of amylomaize starch.
Thomas, Pious; Reddy, Krishna M.
This study was aimed at generating microscopic evidence of intra-tissue colonization in banana in support of the previous findings on widespread association of endophytic bacteria with the shoot tips of field-grown plants and micropropagated cultures, and to understand the extent of tissue colonization. Leaf-sheath tissue sections (∼50–100 µm) from aseptically gathered shoot tips of cv. Grand Naine were treated with Live/Dead bacterial viability kit components SYTO 9 (S9) and propidium iodide (PI) followed by epifluorescence or confocal laser scanning microscopy (CLSM). The S9, which targets live bacteria, showed abundant green-fluorescing particles along the host cell periphery in CLSM, apparently in between the plasma membrane and the cell wall. These included non-motile and occasional actively motile single bacterial cells seen in different x–y planes and z-stacks over several cell layers, with the fluorescence signal similar to that of pure cultures of banana endophytes. Propidium iodide, which stains dead bacteria, did not detect any, but post-ethanol treatment, both PI and 4′,6-diamidino-2-phenylindole detected abundant bacteria. Propidium iodide showed clear nuclear staining, as did S9 to some extent, and the fluorophores appeared to detect bacteria at the exclusion of DNA-containing plant organelles as gathered from bright-field and phase-contrast microscopy. The S9–PI staining did not work satisfactorily with formalin- or paraformaldehyde-fixed tissue. The extensive bacterial colonization in fresh tissue was further confirmed with the suckers of different cultivars, and was supported by transmission electron microscopy. This study thus provides clear microscopic evidence of the extensive endophytic bacterial inhabitation in the confined cell wall–plasma membrane peri-space in shoot tissue of banana with the organisms sharing an integral association with the host. The abundant tissue colonization suggests a possible involvement of endophytes in
Smith, E A; Macfarlane, G T
Concentrations of phenolic compounds in human gut contents were more than fourfold higher in the distal colon (6.2 mmol kg-1) compared to the proximal bowel (1.4 mmol kg-1). Tryptophan metabolites were never found in more than trace amounts in large intestinal contents and phenol substituted fatty acids were the major products of aromatic amino acid fermentation that accumulated in the proximal colon, whereas phenol and p-cresol were more important in the distal gut, accounting for 70% of all products of dissimilatory aromatic amino acid metabolism. In vitro incubations of colonic material showed that phenol was produced most rapidly (1.0 mumol g-1 h-1), whereas indole was formed comparatively slowly (0.06 mumol g-1 h-1). Most probable number (MPN) estimations demonstrated that large populations of phenol and indole producing bacteria occur in the large intestine (range log10 9.8-11.5 (g dry wt faeces)-1, mean 10.6, N = 7). With respect to phenolic compounds, phenylacetate and phenylpropionate producers predominated, while indoleacetate-forming bacteria were the major tryptophan-utilizing organisms. Quantitation of products of dissimilatory aromatic amino acid metabolism in MPN tubes showed that phenol and phenylpropionate mainly accumulated at low sample dilutions, whereas phenylacetate, p-cresol, indoleacetate and indolepropionate were formed in greatest amounts at high sample dilutions. The significance of pH and carbohydrate availability with respect to aromatic amino acid metabolism was shown in batch culture fermentation studies, where net production of phenolic compounds by mixed populations of intestinal bacteria was reduced by approximately 33% during growth at pH 5.5 compared to pH 6.8, and by 60% in the presence of a fermentable carbohydrate. Experiments with 16 species of intestinal bacteria belonging to six different genera showed that environmental factors such as low pH and high carbohydrate availability markedly reduced dissimilatory aromatic amino
Altonsy, Mohammed O; Andrews, Simon C; Tuohy, Kieran M
The induction of apoptosis in mammalian cells by bacteria is well reported. This process may assist infection by pathogens whereas for non-pathogens apoptosis induction within carcinoma cells protects against colon cancer. Here, apoptosis induction by a major new gut bacterium, Atopobium minutum, was compared with induction by commensal (Escherichia coli K-12 strains), probiotic (Lactobacillus rhamnosus, Bifidobacterium latis) and pathogenic (E. coli: EPEC and VTEC) gut bacteria within the colon cancer cell line, Caco-2. The results show a major apoptotic effect for the pathogens, mild effects for the probiotic strains and A. minutum, but no effect for commensal E. coli. The mild apoptotic effects observed are consistent with the beneficial roles of probotics in protection against colon cancer and suggest, for the first time, that A. minutum possesses similar advantageous, anti-cancerous activity. Although bacterial infection increased Caco-2 membrane FAS levels, caspase-8 was not activated indicating that apoptosis is FAS independent. Instead, in all cases, apoptosis was induced through the mitochondrial pathway as indicated by BAX translocation, cytochrome c release, and caspase-9 and -3 cleavage. This suggests that an intracellular stimulus initiates the observed apoptosis responses.
Gonzalez-Gil, Francisco; Diaz-Sanchez, Sandra; Pendleton, Sean; Andino, Ana; Zhang, Nan; Yard, Carrie; Crilly, Nate; Harte, Federico; Hanning, Irene
Yerba mate (Ilex paraguariensis) is a tea known to have beneficial effects on human health and antimicrobial activity against some foodborne pathogens. Thus, the application of yerba mate as a feed additive for broiler chickens to reduce Salmonella colonization was evaluated. The first in vitro evaluation was conducted by suspending Salmonella Enteritidis and lactic acid bacteria (LAB) in yerba mate extract. The in vivo evaluations were conducted using preventative and horizontal transmission experiments. In all experiments, day-of-hatch chicks were treated with one of the following 1) no treatment (control); 2) ground yerba mate in feed; 3) probiotic treatment (Lactobacillus acidophilus and Pediococcus; 9:1 administered once on day of hatch by gavage); or 4) both yerba mate and probiotic treatments. At d 3, all chicks were challenged with Salmonella Enteritidis (preventative experiment) or 5 of 20 chicks (horizontal transmission experiment). At d 10, all birds were euthanized, weighed, and cecal contents enumerated for Salmonella. For the in vitro evaluation, antimicrobial activity was observed against Salmonella and the same treatment enhanced growth of LAB. For in vivo evaluations, none of the yerba mate treatments significantly reduced Salmonella Enteritidis colonization, whereas the probiotic treatment significantly reduced Salmonella colonization in the horizontal transmission experiment. Yerba mate decreased chicken BW and decreased the performance of the probiotic treatment when used in combination. In conclusion, yerba mate had antimicrobial activity against foodborne pathogens and enhanced the growth of LAB in vitro, but in vivo yerba mate did not decrease Salmonella Enteritidis colonization.
Haverkate, Manon R.; Weiner, Shayna; Lolans, Karen; Moore, Nicholas M.; Weinstein, Robert A.; Bonten, Marc J. M.; Hayden, Mary K.; Bootsma, Martin C. J.
Background. High prevalence of Klebsiella pneumoniae carbapenemase (KPC)-producing Enterobacteriaceae has been reported in long-term acute care hospitals (LTACHs), in part because of frequent readmissions of colonized patients. Knowledge of the duration of colonization with KPC is essential to identify patients at risk of KPC colonization upon readmission and to make predictions on the effects of transmission control measures. Methods. We analyzed data on surveillance isolates that were collected at 4 LTACHs in the Chicago region during a period of bundled interventions, to simultaneously estimate the duration of colonization during an LTACH admission and between LTACH (re)admissions. A maximum-likelihood method was used, taking interval-censoring into account. Results. Eighty-three percent of patients remained colonized for at least 4 weeks, which was the median duration of LTACH stay. Between LTACH admissions, the median duration of colonization was 270 days (95% confidence interval, 91–∞). Conclusions. Only 17% of LTACH patients lost colonization with KPC within 4 weeks. Approximately half of the KPC-positive patients were still carriers when readmitted after 9 months. Infection control practices should take prolonged carriage into account to limit transmission of KPCs in LTACHs. PMID:27747253
Bindelle, J; Buldgen, A; Wavreille, J; Agneessens, R; Destain, J P; Wathelet, B; Leterme, P
Two in vitro experiments were carried out to quantify the incorporation of nitrogen (N) by pig colonic bacteria during the fermentation of dietary fibre, including non-starch polysaccharides and resistant starch. In the first experiment, five purified carbohydrates were used: starch (S), cellulose (C), inulin (I), pectin (P) and xylan (X). In the second experiment, three pepsin-pancreatin hydrolysed ingredients were investigated: potato, sugar-beet pulp and wheat bran. The substrates were incubated in an inoculum, prepared from fresh faeces of sows and a buffer solution providing 15N-labelled NH4Cl. Gas production was monitored. Bacterial N incorporation (BNI) was estimated by measuring the incorporation of 15N in the solid residue at half-time to asymptotic gas production (T/2). The remaining substrate was analysed for sugar content. Short-chain fatty acids (SCFA) were determined in the liquid phase. In the first experiment, the fermentation kinetics differed between the substrates. P, S and I showed higher rates of degradation (P < 0.001), while X and C showed a longer lag time and T/2. The sugar disappearance reached 0.91, 0.90, 0.81, 0.56 and 0.46, respectively, for P, I, S, C and X. Among them, S and I fixed more N per gram substrate (P < 0.05) than C, X and P (22.9 and 23.2 mg fixed N per gram fermented substrate v. 11.3, 12.3 and 9.8, respectively). Production of SCFA was the highest for the substrates with low N fixation: 562 and 565 mg/g fermented substrate for X and C v. 290 to 451 for P, I and S (P < 0.01). In the second experiment, potato and sugar-beet pulp fermented more rapidly than wheat bran (P < 0.001). Substrate disappearance at T/2 varied from 0.17 to 0.50. BNI were 18.3, 17.0 and 10.2 fixed N per gram fermented substrate, for sugar-beet pulp, potato and wheat bran, respectively, but were not statistically different. SCFA productions were the highest with wheat bran (913 mg/g fermented substrate) followed by sugar-beet pulp (641) and potato (556
Allen-Vercoe, Emma; Daigneault, Michelle; White, Aaron; Panaccione, Remo; Duncan, Sylvia H; Flint, Harry J; O'Neal, Lindsey; Lawson, Paul A
Recent molecular analyses suggest that bacteria related to strains SS2/1 and SSC/2, previously reported to be distantly related to Anaerostipes caccae NCIMB 13811(T), represent one of the ten most abundant phylotypes detected in adult human faecal samples. These two strains were isolated as d-lactate-utilizing bacteria from faecal samples of a healthy individual. We show here that they share >99.9% similarity in 16S rRNA gene sequence with a new butyrate-producing isolate recovered from a colonic biopsy of a Crohn's disease patient, and also with the sequence reported recently for Eubacterium hadrum ATCC 29173(T). Biochemical profiling using API Rapid ID 32A and API ZYM test systems confirmed a close phenotypic similarity to E. hadrum ATCC 29173(T), but also indicated that the description of this species should be expanded to include the ability to produce butyrate from d-lactate and acetate. Phylogenetic analysis confirmed an affinity between E. hadrum and members of the genus Anaerostipes (92.3-94.2% sequence similarity) belonging to the family Lachnospiraceae (formerly Clostridium cluster XIVa). Based on phylogenetic, phenotypic and chemotaxonomic evidence it is proposed that E. hadrum be transferred to the genus Anaerostipes with the name Anaerostipes hadrus comb. nov. The type strain of A. hadrus comb. nov. is =ATCC 29173(T) (=DSM 3319(T) = VP 82-52(T)).
Köck, R.; Werner, P.; Friedrich, A.W.; Fegeler, C.; Becker, K.; Bindewald, O.; Bui, T.T.; Eckhoff, C.; Epping, R.; Kähmann, L.; Meurer, M.; Steger, J.; von Auenmüller, L.
The nares represent an important bacterial reservoir for endogenous infections. This study aimed to assess the prevalence of nasal colonization by different important pathogens, the associated antimicrobial susceptibility and risk factors. We performed a prospective cohort study among 1878 nonhospitalized volunteers recruited from the general population in Germany. Participants provided nasal swabs at three time points (each separated by 4–6 months). Staphylococcus aureus, Enterobacteriaceae and important nonfermenters were cultured and subjected to susceptibility testing. Factors potentially influencing bacterial colonization patterns were assessed. The overall prevalence of S. aureus, Enterobacteriaceae and nonfermenters was 41.0, 33.4 and 3.7%, respectively. Thirteen participants (0.7%) were colonized with methicillin-resistant S. aureus. Enterobacteriaceae were mostly (>99%) susceptible against ciprofloxacin and carbapenems (100%). Extended-spectrum β-lactamase–producing isolates were not detected among Klebsiella oxytoca, Klebsiella pneumoniae and Escherichia coli. Several lifestyle- and health-related factors (e.g. household size, travel, livestock density of the residential area or occupational livestock contact, atopic dermatitis, antidepressant or anti-infective drugs) were associated with colonization by different microorganisms. This study unexpectedly demonstrated high nasal colonization rates with Enterobacteriaceae in the German general population, but rates of antibiotic resistance were low. Methicillin-resistant S. aureus carriage was rare but highly associated with occupational livestock contact. PMID:26862431
Rendueles, Olaya; Ferrières, Lionel; Frétaud, Maxence; Bégaud, Evelyne; Herbomel, Philippe; Levraud, Jean-Pierre; Ghigo, Jean-Marc
The beneficial contribution of commensal bacteria to host health and homeostasis led to the concept that exogenous non-pathogenic bacteria called probiotics could be used to limit disease caused by pathogens. However, despite recent progress using gnotobiotic mammal and invertebrate models, mechanisms underlying protection afforded by commensal and probiotic bacteria against pathogens remain poorly understood. Here we developed a zebrafish model of controlled co-infection in which germ-free zebrafish raised on axenic living protozoa enabled the study of interactions between host and commensal and pathogenic bacteria. We screened enteric fish pathogens and identified Edwardsiella ictaluri as a virulent strain inducing a strong inflammatory response and rapid mortality in zebrafish larvae infected by the natural oro-intestinal route. Using mortality induced by infection as a phenotypic read-out, we pre-colonized zebrafish larvae with 37 potential probiotic bacterial strains and screened for survival upon E. ictaluri infection. We identified 3 robustly protective strains, including Vibrio parahaemolyticus and 2 Escherichia coli strains. We showed that the observed protective effect of E. coli was not correlated with a reduced host inflammatory response, nor with the release of biocidal molecules by protective bacteria, but rather with the presence of specific adhesion factors such as F pili that promote the emergence of probiotic bacteria in zebrafish larvae. Our study therefore provides new insights into the molecular events underlying the probiotic effect and constitutes a potentially high-throughput in vivo approach to the study of the molecular basis of pathogen exclusion in a relevant model of vertebrate oro-intestinal infection.
Fürnkranz, Michael; Wanek, Wolfgang; Richter, Andreas; Abell, Guy; Rasche, Frank; Sessitsch, Angela
Leaf surfaces (phyllospheres) have been shown to provide appropriate conditions for colonization by microorganisms including diazotrophic bacteria that are able to fix atmospheric nitrogen (N(2)). In this study, we determined leaf-associated N(2) fixation of a range of rainforest plants in Costa Rica, under different environmental conditions, by tracing biomass N incorporation from (15)N(2). N(2)-fixing bacterial communities of the plant species Carludovica drudei, Grias cauliflora and Costus laevis were investigated in more detail by analysis of the nifH gene and leaf-associated bacteria were identified by 16S rRNA gene analysis. N(2) fixation rates varied among plant species, their growth sites (different microclimatic conditions) and light exposure. Leaf-associated diazotrophic bacterial communities detected on C. drudei and C. laevis were mainly composed of cyanobacteria (Nostoc spp.), whereas on the leaves of G. cauliflora gamma-proteobacteria were dominant in addition to cyanobacteria. The complexity of diazotrophic communities on leaves was not correlated with N(2) fixation activity. 16S rRNA gene sequence analysis suggested the presence of complex microbial communities in association with leaves, however, cyanobacteria showed only low abundance. Our findings suggest that cyanobacteria as well as gamma-proteobacteria associated with leaf-colonizing epiphytes may provide significant nitrogen input into this rainforest ecosystem.
Sarrabayrouse, Guillaume; Bossard, Céline; Chauvin, Joe-Marc; Jarry, Anne; Meurette, Guillaume; Quévrain, Elodie; Bridonneau, Chantal; Preisser, Laurence; Asehnoune, Karim; Labarrière, Nathalie; Altare, Frédéric; Sokol, Harry; Jotereau, Francine
How the microbiota affects health and disease is a crucial question. In mice, gut Clostridium bacteria are potent inducers of colonic interleukin (IL)-10-producing Foxp3 regulatory T cells (Treg), which play key roles in the prevention of colitis and in systemic immunity. In humans, although gut microbiota dysbiosis is associated with immune disorders, the underlying mechanism remains unknown. In contrast with mice, the contribution of Foxp3 Treg in colitis prevention has been questioned, suggesting that other compensatory regulatory cells or mechanisms may exist. Here we addressed the regulatory role of the CD4CD8 T cells whose presence had been reported in the intestinal mucosa and blood. Using colonic lamina propria lymphocytes (LPL) and peripheral blood lymphocytes (PBL) from healthy individuals, and those with colon cancer and irritable bowel disease (IBD), we demonstrated that CD4CD8αα (DP8α) T lymphocytes expressed most of the regulatory markers and functions of Foxp3 Treg and secreted IL-10. Strikingly, DP8α LPL and PBL exhibited a highly skewed repertoire toward the recognition of Faecalibacterium prausnitzii, a major Clostridium species of the human gut microbiota, which is decreased in patients with IBD. Furthermore, the frequencies of DP8α PBL and colonic LPL were lower in patients with IBD than in healthy donors and in the healthy mucosa of patients with colon cancer, respectively. Moreover, PBL and LPL from most patients with active IBD failed to respond to F. prausnitzii in contrast to PBL and LPL from patients in remission and/or healthy donors. These data (i) uncover a Clostridium-specific IL-10-secreting Treg subset present in the human colonic LP and blood, (ii) identify F. prausnitzii as a major inducer of these Treg, (iii) argue that these cells contribute to the control or prevention of colitis, opening new diagnostic and therapeutic strategies for IBD, and (iv) provide new tools to address the systemic impact of both these Treg and the
Coutinho, Carla P.; dos Santos, Sandra C.; Madeira, Andreia; Mira, Nuno P.; Moreira, Ana S.; Sá-Correia, Isabel
Long-term respiratory infections with Burkholderia cepacia complex (Bcc) bacteria in cystic fibrosis (CF) patients generally lead to a more rapid decline in lung function and, in some cases, to a fatal necrotizing pneumonia known as the “cepacia syndrome.” Bcc bacteria are ubiquitous in the environment and are recognized as serious opportunistic pathogens that are virtually impossible to eradicate from the CF lung, posing a serious clinical threat. The epidemiological survey of Bcc bacteria involved in respiratory infections at the major Portuguese CF Treatment Center at Santa Maria Hospital, in Lisbon, has been carried out by our research group for the past 16 years, covering over 500 clinical isolates where B. cepacia and B. cenocepacia are the predominant species, with B. stabilis, B. contaminans, B. dolosa, and B. multivorans also represented. The systematic and longitudinal study of this CF population during such an extended period of time represents a unique case–study, comprehending 41 Bcc-infected patients (29 pediatric and 12 adult) of whom around 70% have been persistently colonized between 7 months and 9 years. During chronic infection, the CF airways represent an evolving ecosystem, with multiple phenotypic variants emerging from the clonal population and becoming established in the patients’ airways as the result of genetic adaptation. Understanding the evolutionary mechanisms involved is crucial for an improved therapeutic outcome of chronic infections in CF. This review focuses on our contribution to the understanding of these adaptive mechanisms based on extensive phenotypic, genotypic, and genome-wide expression approaches of selected Bcc clonal variants obtained during long-term colonization of the CF airways. PMID:22919578
Walker, Alan W; Duncan, Sylvia H; McWilliam Leitch, E Carol; Child, Matthew W; Flint, Harry J
The effects of changes in the gut environment upon the human colonic microbiota are poorly understood. The response of human fecal microbial communities from two donors to alterations in pH (5.5 or 6.5) and peptides (0.6 or 0.1%) was studied here in anaerobic continuous cultures supplied with a mixed carbohydrate source. Final butyrate concentrations were markedly higher at pH 5.5 (0.6% peptide mean, 24.9 mM; 0.1% peptide mean, 13.8 mM) than at pH 6.5 (0.6% peptide mean, 5.3 mM; 0.1% peptide mean, 7.6 mM). At pH 5.5 and 0.6% peptide input, a high butyrate production coincided with decreasing acetate concentrations. The highest propionate concentrations (mean, 20.6 mM) occurred at pH 6.5 and 0.6% peptide input. In parallel, major bacterial groups were monitored by using fluorescence in situ hybridization with a panel of specific 16S rRNA probes. Bacteroides levels increased from ca. 20 to 75% of total eubacteria after a shift from pH 5.5 to 6.5, at 0.6% peptide, coinciding with high propionate formation. Conversely, populations of the butyrate-producing Roseburia group were highest (11 to 19%) at pH 5.5 but fell at pH 6.5, a finding that correlates with butyrate formation. When tested in batch culture, three Bacteroides species grew well at pH 6.7 but poorly at pH 5.5, which is consistent with the behavior observed for the mixed community. Two Roseburia isolates grew equally well at pH 6.7 and 5.5. These findings suggest that a lowering of pH resulting from substrate fermentation in the colon may boost butyrate production and populations of butyrate-producing bacteria, while at the same time curtailing the growth of Bacteroides spp.
subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. 1. REPORT DATE 05...30 days of specimen collection, and Afghanistan-based personnel were receiving doxycycline for malaria chemoprophylaxis at time of specimen...antimicrobial resistance and increased rates of MDR E. coli colonization needs further evaluation. Keywords Deployment, Malaria chemoprophylaxis
March, A; Aschbacher, R; Dhanji, H; Livermore, D M; Böttcher, A; Sleghel, F; Maggi, S; Noale, M; Larcher, C; Woodford, N
Long-term-care facilities (LTCFs) are reservoirs of resistant bacteria. We undertook a point-prevalence survey and risk factor analysis for specific resistance types among residents and staff of a Bolzano LTCF and among geriatric unit patients in the associated acute-care hospital. Urine samples and rectal, inguinal, oropharyngeal and nasal swabs were plated on chromogenic agar; isolates were typed by pulsed-field gel electrophoresis; resistance genes and links to insertion sequences were sought by PCR; plasmids were analysed by PCR, restriction fragment length polymorphism and incompatibility grouping. Demographic data were collected. Of the LTCF residents, 74.8% were colonized with ≥1 resistant organism, 64% with extended-spectrum β-lactamase (ESBL) producers, 38.7% with methicillin-resistant Staphylococcus aureus (MRSA), 6.3% with metallo-β-lactamase (MBL) producers, and 2.7% with vancomycin-resistant enterococci. Corresponding rates for LTCF staff were 27.5%, 14.5%, 14.5%, 1.5% and 0%, respectively. Colonization frequencies for geriatric unit patients were lower than for those in the LTCF. Both clonal spread and plasmid transfer were implicated in the dissemination of MBL producers that harboured IncN plasmids bearing bla(VIM-1), qnrS, and bla(SHV-12). Most (44/45) ESBL-producing Escherichia coli isolates had bla(CTX-M) genes of group 1; a few had bla(CTX-M) genes of group 9 or bla(SHV-5); those with bla(CTX-M-15) or bla(SHV-5) were clonal. Risk factors for colonization of LTCF residents with resistant bacteria included age ≥86 years, antibiotic treatment in the previous 3 months, indwelling devices, chronic obstructive pulmonary disease, physical disability, and the particular LTCF unit; those for geriatric unit patients were age and dementia. In conclusion, ESBL-producing and MBL-producing Enterobacteriaceae and MRSA were prevalent among the LTCF residents and staff, but less so in the hospital geriatric unit. Education of LTCF employees and better
Cocking, Edward C; Stone, Philip J; Davey, Michael R
It has been forecast that the challenge of meeting increased food demand and protecting environmental quality will be won or lost in maize, rice and wheat cropping systems, and that the problem of environmental nitrogen enrichment is most likely to be solved by substituting synthetic nitrogen fertilizers by the creation of cereal crops that are able to fix nitrogen symbiotically as legumes do. In legumes, rhizobia present intracellularly in membrane-bound vesicular compartments in the cytoplasm of nodule cells fix nitrogen endosymbiotically. Within these symbiosomes, membrane-bound vesicular compartments, rhizobia are supplied with energy derived from plant photosynthates and in return supply the plant with biologically fixed nitrogen, usually as ammonia. This minimizes or eliminates the need for inputs of synthetic nitrogen fertilizers. Recently we have demonstrated, using novel inoculation conditions with very low numbers of bacteria, that cells of root meristems of maize, rice, wheat and other major non-legume crops, such as oilseed rape and tomato, can be intracellularly colonized by the non-rhizobial, non-nodulating, nitrogen fixing bacterium, Gluconacetobacter diazotrophicus that naturally occurs in sugarcane. G. diazotrophicus expressing nitrogen fixing (nifH) genes is present in symbiosome-like compartments in the cytoplasm of cells of the root meristems of the target cereals and non-legume crop species, somewhat similar to the intracellular symbiosome colonization of legume nodule cells by rhizobia. To obtain an indication of the likelihood of adequate growth and yield, of maize for example, with reduced inputs of synthetic nitrogen fertilizers, we are currently determining the extent to which nitrogen fixation, as assessed using various methods, is correlated with the extent of systemic intracellular colonization by G. diazotrophicus, with minimal or zero inputs.
Cocking, Edward C; Stone, Philip J; Davey, Michael R
It has been forecast that the challenge of meeting increased food demand and protecting environmental quality will be won or lost in maize, rice and wheat cropping systems, and that the problem of environmental nitrogen enrichment is most likely to be solved by substituting synthetic nitrogen fertilizers by the creation of cereal crops that are able to fix nitrogen symbiotically as legumes do. In legumes, rhizobia present intracellularly in membrane-bound vesicular compartments in the cytoplasm of nodule cells fix nitrogen endosymbiotically. Within these symbiosomes, membrane-bound vesicular compartments, rhizobia are supplied with energy derived from plant photosynthates and in return supply the plant with biologically fixed nitrogen, usually as ammonia. This minimizes or eliminates the need for inputs of synthetic nitrogen fertilizers. Recently we have demonstrated, using novel inoculation conditions with very low numbers of bacteria, that cells of root meristems of maize, rice, wheat and other major non-legume crops, such as oilseed rape and tomato, can be intracellularly colonized by the non-rhizobial, non-nodulating, nitrogen fixing bacterium,Gluconacetobacter diazotrophicus that naturally occurs in sugarcane.G. diazotrophicus expressing nitrogen fixing (nifH) genes is present in symbiosome-like compartments in the cytoplasm of cells of the root meristems of the target cereals and non-legume crop species, somewhat similar to the intracellular symbiosome colonization of legume nodule cells by rhizobia. To obtain an indication of the likelihood of adequate growth and yield, of maize for example, with reduced inputs of synthetic nitrogen fertilizers, we are currently determining the extent to which nitrogen fixation, as assessed using various methods, is correlated with the extent of systemic intracellular colonization byG. diazotrophicus, with minimal or zero inputs.
Fan, Wei; Wu, Daming; Tay, Franklin R; Ma, Tengjiao; Wu, Yujie; Fan, Bing
Mesoporous calcium-silicate nanoparticles (MCSNs) are advanced biomaterials for controlled drug delivery and mineralization induction. Nanosilver-incorporated MCSNs (Ag-MCSNs) were prepared in the present study using both the adsorption and template methods. Both versions of Ag-MCSNs showed characteristic morphology of mesoporous materials and exhibited sustained release of ions over time. In antibacterial testing against planktonic Enterococcus faecalis, Ag-MCSNs showed significantly better antibacterial effects when compared with MCSNs (P<0.05). The Ag-MCSNs aggregated on the dentin surface of root canal walls and infiltrated into dentinal tubules after ultrasound activation, significantly inhibiting the adherence and colonization of E. faecalis on dentin (P<0.05). Despite this, Ag-MCSNs with templated nanosilver showed much lower cytotoxicity than Ag-MCSNs with adsorbed nanosilver (P<0.05). The results of the present study indicated that nanosilver could be incorporated into MCSNs using the template method. The templated nanosilver could release silver ions and inhibit the growth and colonization of E. faecalis both in the planktonic form and as biofilms on dentin surfaces as absorbed nanosilver. Templated Ag-MCSNs may be developed into a new intracanal disinfectant for root canal disinfection due to their antibacterial ability and low cytotoxicity, and as controlled release devices for other bioactive molecules to produce multifunctional biomaterials.
Rukayadi, Yaya; Kim, Kyu-Hoi; Hwang, Jae-Kwan
In early dental plaque formation, oral primary colonizers such as Streptococcus mutans, Streptococcus sanguis and Actinomyces viscosus are initially attached to the pellicle-coated tooth surface to form a biofilm. The study aimed to determine the efficacy of macelignan, isolated from nutmeg (Myristica fragrans Houtt.), in removing each single oral primary biofilm in vitro on a polystyrene 96-well microtiter plate. Four biofilm growth phases (4, 12, 20 and 24 h) were evaluated in this study after treatment with macelignan at various concentrations (0.2, 2 and 10 microg/mL) and exposure times (5, 10 and 30 min). Anti-biofilm activity of macelignan was measured as the percentage of the remaining biofilm absorbance after macelignan treatment in comparison with the untreated control. At 24 h of biofilm growth, S. mutans, A. viscosus and S. sanguis biofilms were reduced by up to 30%, 30% and 38%, respectively, after treatment with 10 microg/mL macelignan for 5 min. Increasing the treatment time to 30 min resulted in a reduction of more than 50% of each of the single primary biofilms. The results indicate that macelignan is a potent natural anti-biofilm agent against oral primary colonizers.
Corfield, A P; Wagner, S A; Clamp, J R; Kriaris, M S; Hoskins, L C
Oligosaccharide side chains of human colonic mucins contain O-acetylated sialic acids and glycosulfate esters. Although these substituents are considered to protect the chains against degradation by bacterial glycosidases, sialate O-acetylesterase, N-acetylneuraminate lyase, and glycosulfatase activities have been found in fecal extracts. To better define the source of these activities, we measured extracellular and cell-bound sialidase, sialate O-acetylesterase, N-acetylneuraminate lyase, arylesterase, and glycosulfatase activities produced by 23 isolates of human fecal bacteria grown anaerobically in a hog gastric mucin culture medium; these represented dominant populations of fecal anaerobes, facultative anaerobes, and the subset of mucin oligosaccharide-degrading bacteria. Every strain produced sialidase and high levels of arylesterase, and all but five facultative anaerobes produced sialate O-acetylesterase. Sialic acids containing 2 mol or more of O-acetyl ester per mol of sialic acid were cleaved from mucin glycoproteins more slowly by sialidases of mucin oligosaccharide-degrading stains than were sialic acids containing 1 or 0 mol, and only N-acetyl- and mono-O-acetylated sialic acids were recovered from enzyme digests of a mucin containing di-O-acetylated sialic acids. No detectable N-acetylneuraminate lyase activity was produced by any strain, but low activity was induced by increasing the glycoprotein-bound sialic acid concentration in the culture medium of six Escherichia coli strains. Using lactitol-6-sulfate as a substrate, we found weak glycosulfatase activity in the partially purified, concentrated enzyme mixture in the culture supernatants of four mucin oligosaccharide-degrading strains but in none of the unconcentrated culture fractions. We conclude that the presence of two or more O-acetyl groups on sialic acids inhibits enteric bacterial sialidases but that production of sialate O-acetylesterases by several populations of enteric bacteria
Elo; Maunuksela; Salkinoja-Salonen; Smolander; Haahtela
We studied the potential of the humus layer of the Norway spruce stands to supply beneficial rhizobacteria to birch (Betula pendula), alder (Alnus incana) and fescue grass (Festuca rubra), representatives of pioneer vegetation after clear-cutting of the coniferous forest. Axenically grown seedlings of these species were inoculated with the acid spruce humus, pH 3.7-5.3. Actinorhizal propagules, capable of nodulating alder, were present in high density (10(3) g(-1)) in humus of long-term limed plots, whereas plots with nitrogen fertilization contained almost none (=10 g(-1)). The genera most frequently found in the humus were Bacillus, Paenibacillus, Arthrobacter, Nocardia, Rhodococcus and Pseudomonas, independently of prior liming or fertilization of the plots. The taxa found in the seedling roots differed from that in humus by the prevalence of the Gram-negative genera Pseudomonas, Alcaligenes and Comamonas. Enrichment cultures of the roots on nitrogen-free media yielded Paenibacillus and Rhodococcus species. Nitrogen-fixing R. erythropolis and a novel Paenibacillus, closest by full sequence of 16S rDNA to P. durus, represented new classes of nitrogen-fixing rhizosphere bacteria. In addition, nitrogen-fixing R. fascians was found in the humus. The rhizoflora and humus contained high proportions of bacteria antagonistic towards plant pathogenic Rhizoctonia sp., Botrytis cinerea and Fusarium culmorum. The antagonistic isolates also commonly produced siderophores and/or cell wall degrading enzymes.
Barrow, P. A.; Tucker, J. F.; Simpson, J. M.
Oral administration of strains of food poisoning salmonellas to day-old chickens produced a profound inhibition in the subsequent colonization of the caeca by a strain of Salmonella typhimurium given one day later. Closely related genera were unable to produce a similar inhibition. The inhibition was not the result of bacteriophages produced by the first strain. Neither was it the result of an immunological response by the host induced by the first strain. In additional experiments in day-old chickens, inhibition of an Escherichia coli Nalr strain and of a Citrobacter sp. Nalr strain was produced by the antibiotic-sensitive forms of the homologous strains while strains from other genera did not produce any inhibition. When an avirulent mutant of S. typhimurium was used for pre-treatment a statistically significant reduction in the excretion of the super-infecting S. typhimurium Nalr strain over several weeks was produced. A genus specific inhibition was reproduced in vitro by mixed culture experiments. Live cultures were necessary for in vitro inhibition. Killed cells or a culture supernatant produced no inhibition. PMID:2954839
Prado-Rebolledo, Omar F; Delgado-Machuca, Jaime de Jesus; Macedo-Barragan, Rafael J; Garcia-Márquez, Luis J; Morales-Barrera, Jesus E; Latorre, Juan D; Hernandez-Velasco, Xochitl; Tellez, Guillermo
Two experiments were conducted to evaluate the effect of a lactic acid bacteria-based probiotic (FloraMax-B11(®)) against Salmonella enterica serovar Enteritidis intestinal colonization and intestinal permeability in broiler chickens. Experiment 1 consisted of two independent trials. In each trial, day-old broiler chicks were assigned to one of two groups: control + S. Enteritidis or probiotic + S. Enteritidis. At 72 h post-S. Enteritidis challenge, haematology and caecal content were evaluated for S. Enteritidis colonization. In Experiment 2, day-old broiler chicks were assigned to one of four groups: negative control; probiotic; control + S. Enteritidis; or probiotic + S. Enteritidis. At 72 h post-S. Enteritidis challenge, chickens in all groups were given an oral gavage dose of fluorescein isothiocyanate dextran (FITC-d). In both trials of Experiment 1, a significant reduction (P < 0.05) in colony-forming units/gram of S. Enteritidis in caecal content and a reduction in the incidence of S. Enteritidis enriched caecal samples were observed in probiotic + S. Enteritidis chickens. In addition, significant heterophilia and lymphopaenia were observed in control + S. Enteritidis chickens. In Experiment 2, a decrease in numbers of S. Enteritidis in caeca were observed in probiotic + S. Enteritidis chickens when compared to control + S. Enteritidis. Also, an increase in serum FITC-d concentration was detected in control + S. Enteritidis. These results suggest that early infection with S. Enteritidis can increase intestinal permeability, but the adverse effects can be prevented by the administration of the probiotic tested.
Tobias, Joshua; Holmgren, Jan; Hellman, Maria; Nygren, Erik; Lebens, Michael; Svennerholm, Ann-Mari
Enterotoxigenic Escherichia coli (ETEC) is an important cause of diarrheal disease and deaths among children in developing countries and the major cause of traveller's diarrhea. Since surface protein colonization factors (CFs) of ETEC are important for pathogenicity and immune protection is mainly mediated by locally produced IgA antibodies in the gut, much effort has focused on the development of an oral CF-based vaccine. We have recently described the development of recombinant strains over-expressing CFA/I; the most prevalent CF among human clinical ETEC isolates. Here, non-toxigenic recombinant E. coli strains over-expressing Coli surface antigen 2 (CS2), CS4, CS5, and CS6, either alone, or each in combination with CFA/I were constructed by cloning the genes required for expression and assembly of each CF into expression vectors harboring a strong promoter. Immunological assays showed that recombinant strains expressing single CFs produced those in significantly larger amounts than did corresponding naturally high producing reference strains. Recombinant strains co-expressing CFA/I together with another CF also expressed significantly larger amounts of both CFs compared with the corresponding references strains. Further, when tested in mice, oral immunization with formalin-killed recombinant bacteria co-expressing one such double-expression CF pair, CFA/I+CS2, induced specific serum IgG+IgM and fecal IgA antibody responses against both CFs exceeding the responses induced by immunizations with natural reference strains expressing CFA/I and CS2, respectively. We conclude that the described type of recombinant bacteria over-expressing major CFs of ETEC, alone or in combination, may be useful as candidate strains for use in an oral whole-cell CF-ETEC vaccine.
Delgado, Susana; Suárez, Adolfo; Mayo, Baltasar
The aim of this work was to examine by culturing the changes in the total and indicator populations of the feces of two individuals over 1 year and to identify the dominant microbial components of a single sample of feces from each donor. Populations and dominant bacteria from a sample of colonic mucosa from a further individual were also assessed. The culture results were then compared to those obtained with the same samples by 16S rDNA cloning and sequencing. High interindividual variation in representative microbial populations of the gastrointestinal tract (GIT) was revealed by both the culture and the culture-independent techniques. Species belonging to Clostridium clusters (XIVa, IV, and XVIII) predominated in both the fecal and the mucosal samples (except in the mucose cultured isolates), members of Clostridium coccoides cluster XIVa being the most numerous microorganisms. Species of gamma-proteobacteria (Escherichia coli and Shigella spp.), bifidobacteria, and actinobacteria appeared in lower numbers than those of clostridia. From the mucosal cultured sample, only facultative anaerobes and bifidobacteria were recovered, suggesting destruction of the anaerobe population during processing. In accordance with this, the microbial diversity revealed by 16S rDNA sequence analysis was greater than that revealed by culturing. Despite large interindividual differences, distinct human communities may have group-associated GIT microbiota characteristics, such as the low number of Bacteroides seen in the subjects in this study.
Gokul Raj, K.; Manikandan, R.; Arulvasu, C.; Pandi, M.
Cladosporium oxysporum a new taxol producing endophytic fungus was identified and production of taxol were characterized using UV-visible spectroscopy (UV-vis), high-performance liquid chromatography (HPLC), infrared (IR) nuclear magnetic resonance spectroscopy (NMR (13C and 1H)) and liquid chromatography-mass spectrometry (LC-MS). The taxol biosynthetic gene (dbat) was evaluated for new taxol producing fungus. Antibacterial activity against six different human pathogenic bacteria was done by agar well diffusion method. The anticancer efficacy of isolated fungal taxol were also evaluated in human colon cancer cell HCT 15 by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), cytotoxicity and nuclear morphology analysis. The isolated fungal taxol showed positive towards biosynthetic gene (dbat) and effective against both Gram positive as well as Gram negative. The fungal taxol suppress growth of cancer cell line HCT 15 with an IC50 value of 3.5 μM concentration by 24 h treatment. Thus, the result reveals that C. oxysporum could be a potential alternative source for production of taxol and have antibacterial as well as anticancer properties with possible clinical applications.
Louis, Petra; Flint, Harry J
The human gut microbiota ferments dietary non-digestible carbohydrates into short-chain fatty acids (SCFA). These microbial products are utilized by the host and propionate and butyrate in particular exert a range of health-promoting functions. Here an overview of the metabolic pathways utilized by gut microbes to produce these two SCFA from dietary carbohydrates and from amino acids resulting from protein breakdown is provided. This overview emphasizes the important role played by cross-feeding of intermediary metabolites (in particular lactate, succinate and 1,2-propanediol) between different gut bacteria. The ecophysiology, including growth requirements and responses to environmental factors, of major propionate and butyrate producing bacteria are discussed in relation to dietary modulation of these metabolites. A detailed understanding of SCFA metabolism by the gut microbiota is necessary to underpin effective strategies to optimize SCFA supply to the host.
Habil, N; Abate, W; Beal, J; Foey, A D
The inducible antimicrobial peptide human β-defensin-2 (hBD-2) stimulated by pro-inflammatory cytokines and bacterial products is essential to antipathogen responses of gut epithelial cells. Commensal and probiotic bacteria can augment such mucosal defences. Probiotic use in the treatment of inflammatory bowel disease, however, may have adverse effects, boosting inflammatory responses. The aim of this investigation was to determine the effect of selected probiotic strains on hBD-2 production by epithelial cells induced by pathologically relevant pro-inflammatory cytokines and the role of cytokine modulators in controlling hBD-2. Caco-2 colonic intestinal epithelial cells were pre-incubated with heat-killed probiotics, i.e. Lactobacillus casei strain Shirota (LcS) or Lactobacillus fermentum strain MS15 (LF), followed by stimulation of hBD-2 by interleukin (IL)-1β and tumour necrosis factor alpha (TNF-α) in the absence or presence of exogenous IL-10 or anti-IL-10 neutralising antibody. Cytokines and hBD-2 mRNA and protein were analysed by real-time quantitative polymerase chain reaction and enzyme-linked immunosorbent assay. LcS augmented IL-1β-induced hBD-2, whereas LF enhanced TNF-α- and suppressed IL-1β-induced hBD-2. LF enhanced TNF-α-induced TNF-α and suppressed IL-10, whereas augmented IL-1β-induced IL-10. LcS upregulated IL-1β-induced TNF-α mRNA and suppressed IL-10. Endogenous IL-10 differentially regulated hBD-2; neutralisation of IL-10 augmented TNF-α- and suppressed IL-1β-induced hBD-2. Exogenous IL-10, however, suppressed both TNF-α- and IL-1β-induced hBD-2; LcS partially rescued suppression in TNF-α- and IL-1β-stimulation, whereas LF further suppressed IL-1β-induced hBD-2. It can be concluded that probiotic strains differentially regulate hBD-2 mRNA expression and protein secretion, modulation being dictated by inflammatory stimulus and resulting cytokine environment.
Colorectal cancer; Cancer - colon; Rectal cancer; Cancer - rectum; Adenocarcinoma - colon; Colon - adenocarcinoma ... In the United States, colorectal cancer is one of the leading causes of deaths due to cancer. Early diagnosis can often lead to a complete cure. Almost ...
Szafranski, Kamil M; Deschamps, Philippe; Cunha, Marina R; Gaudron, Sylvie M; Duperron, Sébastien
Reducing conditions with elevated sulfide and methane concentrations in ecosystems such as hydrothermal vents, cold seeps or organic falls, are suitable for chemosynthetic primary production. Understanding processes driving bacterial diversity, colonization and dispersal is of prime importance for deep-sea microbial ecology. This study provides a detailed characterization of bacterial assemblages colonizing plant-derived substrates using a standardized approach over a geographic area spanning the North-East Atlantic and Mediterranean. Wood and alfalfa substrates in colonization devices were deployed for different periods at 8 deep-sea chemosynthesis-based sites in four distinct geographic areas. Pyrosequencing of a fragment of the 16S rRNA-encoding gene was used to describe bacterial communities. Colonization occurred within the first 14 days. The diversity was higher in samples deployed for more than 289 days. After 289 days, no relation was observed between community richness and deployment duration, suggesting that diversity may have reached saturation sometime in between. Communities in long-term deployments were different, and their composition was mainly influenced by the geographical location where devices were deployed. Numerous sequences related to horizontally-transmitted chemosynthetic symbionts of metazoans were identified. Their potential status as free-living forms of these symbionts was evaluated based on sequence similarity with demonstrated symbionts. Results suggest that some free-living forms of metazoan symbionts or their close relatives, such as Epsilonproteobacteria associated with the shrimp Rimicaris exoculata, are efficient colonizers of plant substrates at vents and seeps.
Szafranski, Kamil M.; Deschamps, Philippe; Cunha, Marina R.; Gaudron, Sylvie M.; Duperron, Sébastien
Reducing conditions with elevated sulfide and methane concentrations in ecosystems such as hydrothermal vents, cold seeps or organic falls, are suitable for chemosynthetic primary production. Understanding processes driving bacterial diversity, colonization and dispersal is of prime importance for deep-sea microbial ecology. This study provides a detailed characterization of bacterial assemblages colonizing plant-derived substrates using a standardized approach over a geographic area spanning the North-East Atlantic and Mediterranean. Wood and alfalfa substrates in colonization devices were deployed for different periods at 8 deep-sea chemosynthesis-based sites in four distinct geographic areas. Pyrosequencing of a fragment of the 16S rRNA-encoding gene was used to describe bacterial communities. Colonization occurred within the first 14 days. The diversity was higher in samples deployed for more than 289 days. After 289 days, no relation was observed between community richness and deployment duration, suggesting that diversity may have reached saturation sometime in between. Communities in long-term deployments were different, and their composition was mainly influenced by the geographical location where devices were deployed. Numerous sequences related to horizontally-transmitted chemosynthetic symbionts of metazoans were identified. Their potential status as free-living forms of these symbionts was evaluated based on sequence similarity with demonstrated symbionts. Results suggest that some free-living forms of metazoan symbionts or their close relatives, such as Epsilonproteobacteria associated with the shrimp Rimicaris exoculata, are efficient colonizers of plant substrates at vents and seeps. PMID:25774156
Aminov, Rustam I; Walker, Alan W; Duncan, Sylvia H; Harmsen, Hermie J M; Welling, Gjalt W; Flint, Harry J
Phylogenetic analysis was used to compare 16S rRNA sequences from 19 cultured human gut strains of Roseburia and Eubacterium rectale with 356 related sequences derived from clone libraries. The cultured strains were found to represent five of the six phylotypes identified. A new oligonucleotide probe, Rrec584, and the previous group probe Rint623, when used in conjunction with a new helper oligonucleotide, each recognized an average of 7% of bacteria detected by the eubacterial probe Eub338 in feces from 10 healthy volunteers. Most of the diversity within this important group of butyrate-producing gut bacteria can apparently be retrieved through cultivation.
Bible, Amber N.; Fletcher, Sarah J.; Pelletier, Dale A.; Schadt, Christopher W.; Jawdy, Sara S.; Weston, David J.; Engle, Nancy L.; Tschaplinski, Timothy; Masyuko, Rachel; Polisetti, Sneha; Bohn, Paul W.; Coutinho, Teresa A.; Doktycz, Mitchel J.; Morrell-Falvey, Jennifer L.
The complex interactions between plants and their microbiome can have a profound effect on the health and productivity of the plant host. A better understanding of the microbial mechanisms that promote plant health and stress tolerance will enable strategies for improving the productivity of economically important plants. Pantoea sp. YR343 is a motile, rod-shaped bacterium isolated from the roots of Populus deltoides that possesses the ability to solubilize phosphate and produce the phytohormone indole-3-acetic acid (IAA). Pantoea sp. YR343 readily colonizes plant roots and does not appear to be pathogenic when applied to the leaves or roots of selected plant hosts. To better understand the molecular mechanisms involved in plant association and rhizosphere survival by Pantoea sp. YR343, we constructed a mutant in which the crtB gene encoding phytoene synthase was deleted. Phytoene synthase is responsible for converting geranylgeranyl pyrophosphate to phytoene, an important precursor to the production of carotenoids. As predicted, the ΔcrtB mutant is defective in carotenoid production, and shows increased sensitivity to oxidative stress. Moreover, we find that the ΔcrtB mutant is impaired in biofilm formation and production of IAA. Finally we demonstrate that the ΔcrtB mutant shows reduced colonization of plant roots. Taken together, these data suggest that carotenoids are important for plant association and/or rhizosphere survival in Pantoea sp. YR343. PMID:27148182
Bible, Amber; Fletcher, Sarah J; Pelletier, Dale A; ...
The complex interactions between plants and their microbiome can have a profound effect on the health and productivity of the plant host. A better understanding of the microbial mechanisms that promote plant health and stress tolerance will enable strategies for improving the productivity of economically-important plants. Pantoea sp. YR343 is a motile, rod-shaped bacterium isolated from the roots of Populus deltoides that possesses the ability to solubilize phosphate and produce the phytohormone indole-3-acetic acid. Pantoea sp. YR343 readily colonizes plant roots and does not appear to be pathogenic when applied to the leaves or roots of selected plant hosts. Tomore » better understand the molecular mechanisms involved in plant association and rhizosphere survival by Pantoea sp. YR343, we constructed a mutant in which the crtB gene encoding phytoene synthase was deleted. Phytoene synthase is responsible for converting geranylgeranyl pyrophosphate to phytoene, an important precursor to the production of carotenoids. As predicted, the ΔcrtB mutant is defective in carotenoid production, and shows increased sensitivity to oxidative stress. Moreover, we find that the ΔcrtB mutant is impaired in biofilm formation and production of indole-3-acetic acid. Finally we demonstrate that the ΔcrtB mutant shows reduced colonization of plant roots. Taken together, these data suggest that carotenoids are important for plant association and/or rhizosphere survival in Pantoea sp. YR343.« less
Bible, Amber; Fletcher, Sarah J; Pelletier, Dale A; Schadt, Christopher Warren; Jawdy, Sara; Weston, David; Engle, Nancy L.; Tschaplinski, Timothy J.; Masyuko, Rachel; Polisetti, Sneha; Bohn, Paul W.; Coutinho, Teresa; Doktycz, Mitchel John; Morrell-Falvey, Jennifer L.
The complex interactions between plants and their microbiome can have a profound effect on the health and productivity of the plant host. A better understanding of the microbial mechanisms that promote plant health and stress tolerance will enable strategies for improving the productivity of economically-important plants. Pantoea sp. YR343 is a motile, rod-shaped bacterium isolated from the roots of Populus deltoides that possesses the ability to solubilize phosphate and produce the phytohormone indole-3-acetic acid. Pantoea sp. YR343 readily colonizes plant roots and does not appear to be pathogenic when applied to the leaves or roots of selected plant hosts. To better understand the molecular mechanisms involved in plant association and rhizosphere survival by Pantoea sp. YR343, we constructed a mutant in which the crtB gene encoding phytoene synthase was deleted. Phytoene synthase is responsible for converting geranylgeranyl pyrophosphate to phytoene, an important precursor to the production of carotenoids. As predicted, the ΔcrtB mutant is defective in carotenoid production, and shows increased sensitivity to oxidative stress. Moreover, we find that the ΔcrtB mutant is impaired in biofilm formation and production of indole-3-acetic acid. Finally we demonstrate that the ΔcrtB mutant shows reduced colonization of plant roots. Taken together, these data suggest that carotenoids are important for plant association and/or rhizosphere survival in Pantoea sp. YR343.
Mora-Cristancho, Jennyfer A; Arévalo-Ferro, Catalina; Ramos, Freddy A; Tello, Edisson; Duque, Carmenza; Lhullier, Cintia; Falkenberg, Miriam; Schenkel, Eloir Paulo
The growth inhibition of 12 native marine bacteria isolated from Aplysina sponge surfaces, the shell of a bivalve, and Phytagel immersed for 48 h in sea water were used as indicator of the antifouling activity of the extracts of 39 marine organisms (octocorals, sponges, algae, and zoanthid) collected in the Colombian Caribbean Sea and on the Brazilian coast (Santa Catarina). Gram-negative bacteria represented 75% of the isolates; identified strains belonged to Oceanobacillus iheyensis, Ochrobactrum pseudogrignonense, Vibrio campbellii, Vibrio harveyi, and Bacillus megaterium species and seven strains were classified at genus level by the 16S rRNA sequencing method. The extracts of the octocorals Pseudopterogorgia elisabethae, four Eunicea octocorals, and the sponges Topsentia ophiraphidites, Agelas citrina, Neopetrosia carbonaria, Monanchora arbuscula, Cliona tenuis, Iotrochota imminuta, and Ptilocaulis walpersii were the most active, thus suggesting those species as antifoulant producers. This is the first study of natural antifoulants from marine organisms collected on the Colombian and Brazilian coasts.
Bacterial surface colonizers are subject to a variety of physical stresses. During the colonization of human epithelia such as on the skin or the intestinal mucosa, bacteria mainly have to withstand the mechanical stress of being removed by fluid flow, scraping, or epithelial turnover. To that end, they express a series of molecules to establish firm attachment to the epithelial surface, such as fibrillar protrusions (pili) and surface-anchored proteins that bind to human matrix proteins. In addition, some bacteria – in particular gut and urinary tract pathogens – use internalization by epithelial cells and other methods such as directed inhibition of epithelial turnover to ascertain continued association with the epithelial layer. Furthermore, many bacteria produce multi-layered agglomerations called biofilms with a sticky extracellular matrix, providing additional protection from removal. This review will give an overview over the mechanisms human bacterial colonizers have to withstand physical stresses with a focus on bacterial adhesion. PMID:25212723
Seagrass (Zostera marina) Colonization Promotes the Accumulation of Diazotrophic Bacteria and Alters the Relative Abundances of Specific Bacterial Lineages Involved in Benthic Carbon and Sulfur Cycling
Sun, Feifei; Zhang, Xiaoli; Zhang, Qianqian; Liu, Fanghua
Seagrass colonization changes the chemistry and biogeochemical cycles mediated by microbes in coastal sediments. In this study, we molecularly characterized the diazotrophic assemblages and entire bacterial community in surface sediments of a Zostera marina-colonized coastal lagoon in northern China. Higher nitrogenase gene (nifH) copy numbers were detected in the sediments from the vegetated region than in the sediments from the unvegetated region nearby. The nifH phylotypes detected were mostly affiliated with the Geobacteraceae, Desulfobulbus, Desulfocapsa, and Pseudomonas. Redundancy analysis based on terminal restriction fragment length polymorphism analysis showed that the distribution of nifH genotypes was mostly shaped by the ratio of total organic carbon to total organic nitrogen, the concentration of cadmium in the sediments, and the pH of the overlying water. High-throughput sequencing and phylogenetic analyses of bacterial 16S rRNA genes also indicated the presence of Geobacteraceae and Desulfobulbaceae phylotypes in these samples. A comparison of these results with those of previous studies suggests the prevalence and predominance of iron(III)-reducing Geobacteraceae and sulfate-reducing Desulfobulbaceae diazotrophs in coastal sedimentary environments. Although the entire bacterial community structure was not significantly different between these two niches, Desulfococcus (Deltaproteobacteria) and Anaerolineae (Chloroflexi) presented with much higher proportions in the vegetated sediments, and Flavobacteriaceae (Bacteroidetes) occurred more frequently in the bare sediments. These data suggest that the high bioavailability of organic matter (indicated by relatively lower carbon-to-nitrogen ratios) and the less-reducing anaerobic condition in vegetated sediments may favor Desulfococcus and Anaerolineae lineages, which are potentially important populations in benthic carbon and sulfur cycling in the highly productive seagrass ecosystem. PMID:26209674
Seagrass (Zostera marina) Colonization Promotes the Accumulation of Diazotrophic Bacteria and Alters the Relative Abundances of Specific Bacterial Lineages Involved in Benthic Carbon and Sulfur Cycling.
Sun, Feifei; Zhang, Xiaoli; Zhang, Qianqian; Liu, Fanghua; Zhang, Jianping; Gong, Jun
Seagrass colonization changes the chemistry and biogeochemical cycles mediated by microbes in coastal sediments. In this study, we molecularly characterized the diazotrophic assemblages and entire bacterial community in surface sediments of a Zostera marina-colonized coastal lagoon in northern China. Higher nitrogenase gene (nifH) copy numbers were detected in the sediments from the vegetated region than in the sediments from the unvegetated region nearby. The nifH phylotypes detected were mostly affiliated with the Geobacteraceae, Desulfobulbus, Desulfocapsa, and Pseudomonas. Redundancy analysis based on terminal restriction fragment length polymorphism analysis showed that the distribution of nifH genotypes was mostly shaped by the ratio of total organic carbon to total organic nitrogen, the concentration of cadmium in the sediments, and the pH of the overlying water. High-throughput sequencing and phylogenetic analyses of bacterial 16S rRNA genes also indicated the presence of Geobacteraceae and Desulfobulbaceae phylotypes in these samples. A comparison of these results with those of previous studies suggests the prevalence and predominance of iron(III)-reducing Geobacteraceae and sulfate-reducing Desulfobulbaceae diazotrophs in coastal sedimentary environments. Although the entire bacterial community structure was not significantly different between these two niches, Desulfococcus (Deltaproteobacteria) and Anaerolineae (Chloroflexi) presented with much higher proportions in the vegetated sediments, and Flavobacteriaceae (Bacteroidetes) occurred more frequently in the bare sediments. These data suggest that the high bioavailability of organic matter (indicated by relatively lower carbon-to-nitrogen ratios) and the less-reducing anaerobic condition in vegetated sediments may favor Desulfococcus and Anaerolineae lineages, which are potentially important populations in benthic carbon and sulfur cycling in the highly productive seagrass ecosystem.
This research has focused on the attachment of bacteria to solid surfaces and the significance of their adhesion properties in their transport through porous media. Our work has focused on strains of Pseudomonas and a related species Burkholderia cepacia. Most of our experimental strains were isolated from subsurface environments at USDOE experimental field sites. The first portion of this project was conducted at the University of Maryland during 1994-1996, during which two graduates and one graduate student were supported by the award. The project was then continued under contract number DE-FG02-96ER62302 at the University of South Carolina, where one postdoctoral associate has been supported by the award.
Massagué, Joan; Obenauf, Anna C.
Metastasis is the main cause of death from cancer. To colonize distant organs, circulating cancer cells must overcome many obstacles through mechanisms that we are starting to understand. Infiltrating distant tissue, evading immune defences, adapting to supportive niches, surviving as latent tumour-initiating seeds, and eventually breaking out to replace the host tissue, are key steps for metastatic colonization. These obstacles make metastasis a highly inefficient process, but once metastases are established current treatments frequently fail to provide durable responses. A better understanding of the mechanistic determinants of metastatic colonization is needed to better prevent and treat metastatic cancer. PMID:26791720
... polyps important? Rochester, Minn.: Mayo Foundation for Medical Education and Research; 2012. Elmunzer BJ. Endoscopic resection of sessile colon polyps. Gastroenterology. 2013;144:30. Baron TH, et al. Recommended intervals between screening and surveillance colonoscopies. Mayo Clinic Proceedings. ...
Sinha, V R; Kumria, R
Natural polysaccharides are now extensively used for the development of solid dosage forms for delivery of drug to the colon. The rationale for the development of a polysaccharide based delivery system for colon is the presence of large amounts of polysaccharidases in the human colon as the colon is inhabited by a large number and variety of bacteria which secrete many enzymes e.g. beta-D-glucosidase, beta-D-galactosidase, amylase, pectinase, xylanase, beta-D-xylosidase, dextranase, etc. Various major approaches utilizing polysaccharides for colon-specific delivery are fermentable coating of the drug core, embedding of the drug in biodegradable matrix, formulation of drug-saccharide conjugate (prodrugs). A large number of polysaccharides have already been studied for their potential as colon-specific drug carrier systems, such as chitosan, pectin, chondroitin sulphate, cyclodextrin, dextrans, guar gum, inulin, amylose and locust bean gum. Recent efforts and approaches exploiting these polysaccharides in colon-specific drug delivery are discussed.
Chi Fru, E
The aerobic methane-oxidizing bacteria (MOB) are suggested to be important for the removal of oxygen from subterranean aquifers that become oxygenated by natural and engineering processes. This is primarily because MOB are ubiquitous in the environment and in addition reduce oxygen efficiently. The biogeochemical factors that will control the success of the aerobic MOB in these kinds of underground aquifers remain unknown. In this study, viable and cultivable MOB occurring at natural and engineered deep granitic aquifers targeted for the disposal of spent nuclear fuel (SNF) in the Fennoscandian Shield (approximately 3-1000 m) were enumerated. The numbers were correlated with in situ salinity, methane concentrations, conductivity, pH, and depth. A mixed population habiting freshwater aquifers (approximately 3-20 m), a potential source for the inoculation of MOB into the deeper aquifers was tested for tolerance to NaCl, temperature, pH, and an ability to produce cysts and exospores. Extrapolations show that due to changing in situ parameters (salinity, conductivity, and pH), the numbers of MOB in the aquifers dropped quickly with depth. A positive correlation between the most probable numbers of MOB and methane concentrations was observed. Furthermore, the tolerance-based tests of cultured strains indicated that the MOB in the shallow aquifers thrived best in mesophilic and neutrophilic conditions as opposed to the hyperthermophilic and alkaliphilic conditions expected to develop in an engineered subterranean SNF repository. Overall, the survival of the MOB both quantitatively and physiologically in the granitic aquifers was under the strong influence of biogeochemical factors that are strongly depth-dependent.
Hofmanová, Jiřina; Straková, Nicol; Vaculová, Alena Hyršlová; Tylichová, Zuzana; Safaříková, Barbora; Skender, Belma; Kozubík, Alois
Intestinal homeostasis is precisely regulated by a number of endogenous regulatory molecules but significantly influenced by dietary compounds. Malfunction of this system may result in chronic inflammation and cancer. Dietary essential n-3 polyunsaturated fatty acids (PUFAs) and short-chain fatty acid butyrate produced from fibre display anti-inflammatory and anticancer activities. Both compounds were shown to modulate the production and activities of TNF family cytokines. Cytokines from the TNF family (TNF- α, TRAIL, and FasL) have potent inflammatory activities and can also regulate apoptosis, which plays an important role in cancer development. The results of our own research showed enhancement of apoptosis in colon cancer cells by a combination of either docosahexaenoic acid (DHA) or butyrate with TNF family cytokines, especially by promotion of the mitochondrial apoptotic pathway and modulation of NF κ B activity. This review is focused mainly on the interaction of dietary PUFAs and butyrate with these cytokines during colon inflammation and cancer development. We summarised recent knowledge about the cellular and molecular mechanisms involved in such effects and outcomes for intestinal cell behaviour and pathologies. Finally, the possible application for the prevention and therapy of colon inflammation and cancer is also outlined.
Straková, Nicol; Vaculová, Alena Hyršlová; Tylichová, Zuzana; Šafaříková, Barbora; Kozubík, Alois
Intestinal homeostasis is precisely regulated by a number of endogenous regulatory molecules but significantly influenced by dietary compounds. Malfunction of this system may result in chronic inflammation and cancer. Dietary essential n-3 polyunsaturated fatty acids (PUFAs) and short-chain fatty acid butyrate produced from fibre display anti-inflammatory and anticancer activities. Both compounds were shown to modulate the production and activities of TNF family cytokines. Cytokines from the TNF family (TNF-α, TRAIL, and FasL) have potent inflammatory activities and can also regulate apoptosis, which plays an important role in cancer development. The results of our own research showed enhancement of apoptosis in colon cancer cells by a combination of either docosahexaenoic acid (DHA) or butyrate with TNF family cytokines, especially by promotion of the mitochondrial apoptotic pathway and modulation of NFκB activity. This review is focused mainly on the interaction of dietary PUFAs and butyrate with these cytokines during colon inflammation and cancer development. We summarised recent knowledge about the cellular and molecular mechanisms involved in such effects and outcomes for intestinal cell behaviour and pathologies. Finally, the possible application for the prevention and therapy of colon inflammation and cancer is also outlined. PMID:24876678
NASA interest in colonization encompasses space tourism; space exploration; space bases in orbit, at L1, on the Moon, or on Mars; in-situ resource utilization; and planetary terraforming. Activities progressed during 2002 in areas such as Mars colonies, hoppers, and biomass; space elevators and construction; and in-situ consumables.
Serrato, Rodrigo V
Biological nitrogen fixation (BNF) is a process in which the atmospheric nitrogen (N2) is transformed into ammonia (NH3) by a select group of nitrogen-fixing organisms, or diazotrophic bacteria. In order to furnish the biologically useful nitrogen to plants, these bacteria must be in constant molecular communication with their host plants. Some of these molecular plant-microbe interactions are very specific, resulting in a symbiotic relationship between the diazotroph and the host. Others are found between associative diazotrophs and plants, resulting in plant infection and colonization of internal tissues. Independent of the type of ecological interaction, glycans, and glycoconjugates produced by these bacteria play an important role in the molecular communication prior and during colonization. Even though exopolysaccharides (EPS) and lipochitooligosaccharides (LCO) produced by diazotrophic bacteria and released onto the environment have their importance in the microbe-plant interaction, it is the lipopolysaccharides (LPS), anchored on the external membrane of these bacteria, that mediates the direct contact of the diazotroph with the host cells. These molecules are extremely variable among the several species of nitrogen fixing-bacteria, and there are evidences of the mechanisms of infection being closely related to their structure.
Anaerobic bacteria are bacteria that do not live or grow when oxygen is present. In humans, these bacteria ... Goldstein EJ. Diseases caused by non-spore forming anaerobic bacteria. In: Goldman L, Schafer AI, eds. Goldman's Cecil ...
Mariani-Kurkdjian, P; Bingen, E
Since the CF gene identification in 1989 and despite the improvement of our knowledge in the physiopathology of the disease, bronchopulmonary infection determines the vital prognosis. Following Staphylococcus aureus infection, patients are colonized or colonized by Pseudomonas aeruginosa, greatly involved in the pulmonary deterioration. Other bacteria may be involved Burkholderia cepacia, Stenotrophomonas maltophilia, Alcaligenes sp. Intensive antibiotic treatment of primocolonisation helps to prevent or delay chronic colonisation. Chronic colonization needs a rational long term antibiotic strategy to prevent the occurrence of multiresistant germs; antibiotic cures are performed every 3 or 4 months before pulmonary exacerbation symptoms.
Pandak, Nenad; Pajić-Penavić, Ivana; Sekelj, Alen; Tomić-Paradžik, Maja; Cabraja, Ivica; Miklaušić, Božana
The aim of this study was the determination of bacteria present in maxillary and ethmoid cavities in patients with chronic sinusitis and to correlate these findings with bacteria simultaneously present in their nasopharynx. The purpose of this correlation was to establish the role of bacteria found in chronically inflamed sinuses and to evaluate if the bacteria present colonized or infected sinus mucosa. Nasopharyngeal and sinus swabs of 65 patients that underwent functional endoscopic sinus surgery were cultivated and at the same time the presence of leukocytes were determined in each swab. The most frequently found bacteria in nasopharynx were Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus spp., Streptococcus viridans and Streptococcus pneumoniae. Maxillary or ethmoidal sinus swabs yielded bacterial growth in 47 (72.31%) patients. The most frequently found bacteria in sinuses were Staphylococcus epidermidis, Staphylococcus aureus, Klebsiella spp. and Streptococci (pneumoniae, viridans and spp.). The insignificant number of leukocytes was present in each sinus and nasopharyngeal swab. Every published microbiology study of chronic sinusitis proved that sinus mucosa were colonized with bacteria and not infected, yet antibiotic therapy was discussed making no difference between infection and colonization. Chronic sinusitis should be considered a chronic inflammatory condition rather than bacterial infection, so routine antibiotic therapy should be avoided. Empiric antibiotic therapy should be prescribed only in cases when the acute exacerbation of chronic sinusitis occurs and the antibiotics prescribed should aim the usual bacteria causing acute sinusitis. In case of therapy failure, antibiotics should be changed having in mind that under certain circumstances any bacteria colonizing sinus mucosa can cause acute exacerbation of chronic sinusitis.
Resources - colon cancer ... The following organizations are good resources for information on colon cancer : American Cancer Society -- www.cancer.org/cancer/colonandrectumcancer/index Colon Cancer Alliance -- www.ccalliance.org National ...
Obesity is associated with a cluster of metabolic disorders and systemic low-grade inflammation involving multiple organs. Recent findings have suggested that intestine is a key organ altered in response to high fat diet (HFD) feeding. Probiotics mainly lactobacillus strains have earlier been implicated in alleviating metabolic disorders. Here we aimed to examine the effects of a naturally occurring butyrate-producing probiotic clostridium butyricum CGMCC0313.1 (CB0313.1) in limiting the development of HFD-induced obesity. Mice treated with CB0313.1 exhibited reduced lipid accumulation in liver and serum, lower circulating insulin levels and improved glucose tolerance and insulin sensitivity. Furthermore, CB0313.1 administration reversed the HFD-induced colonic inflammation as evidenced by reduced tumor necrosis factor (TNF)-α level and increases the interleukin (IL)-10 and IL-22 levels in colon tissue. Additionally to colonic inflammation, CB0313.1 also reduced the colon permeability by upregulating the tight junction (TJ) proteins (claudin-1 and occludin) and contributed to a decreased circulating endotoxin level. In colon content, CB0313.1 administration restored the reduced production of butyrate and other short chain fatty acids (SCFAs) caused by HFD feeding. In adipose tissue, lower transcriptional levels of pro-inflammatory TNF-α, IL-6, IL-1β and monocyte chemotactic protein (MCP)-1 in adipose tissue were observed in CB0313.1-treated mice. Collectively, our data demonstrated that CB0313.1, targeting colon inflammation and permeability, ameliorated HFD-induced obesity, insulin resistance as well as adipose inflammation. PMID:27123997
Ofek, Maya; Hadar, Yitzhak; Minz, Dror
Background Ecologically meaningful classification of bacterial populations is essential for understanding the structure and function of bacterial communities. As in soils, the ecological strategy of the majority of root-colonizing bacteria is mostly unknown. Among those are Massilia (Oxalobacteraceae), a major group of rhizosphere and root colonizing bacteria of many plant species. Methodology/Principal Findings The ecology of Massilia was explored in cucumber root and seed, and compared to that of Agrobacterium population, using culture-independent tools, including DNA-based pyrosequencing, fluorescence in situ hybridization and quantitative real-time PCR. Seed- and root-colonizing Massilia were primarily affiliated with other members of the genus described in soil and rhizosphere. Massilia colonized and proliferated on the seed coat, radicle, roots, and also on hyphae of phytopathogenic Pythium aphanidermatum infecting seeds. High variation in Massilia abundance was found in relation to plant developmental stage, along with sensitivity to plant growth medium modification (amendment with organic matter) and potential competitors. Massilia absolute abundance and relative abundance (dominance) were positively related, and peaked (up to 85%) at early stages of succession of the root microbiome. In comparison, variation in abundance of Agrobacterium was moderate and their dominance increased at later stages of succession. Conclusions In accordance with contemporary models for microbial ecology classification, copiotrophic and competition-sensitive root colonization by Massilia is suggested. These bacteria exploit, in a transient way, a window of opportunity within the succession of communities within this niche. PMID:22808103
Abt, Michael C.; Pamer, Eric G.
Commensal bacterial communities residing within the intestinal lumen of mammals have evolved to flourish in this microenvironment. To preserve this niche, commensal bacteria act with the host to prevent colonization by invasive pathogens that induce inflammation and disrupt the intestinal niche commensal bacteria rely upon. Thus, it is mutually beneficial to the host and commensal bacteria to inhibit a pathogen's ability to establish an infection. Commensal bacteria express factors that support colonization, maximize nutrient uptake, and produce metabolites that confer a survival advantage over pathogens. Further, commensal bacteria stimulate the host's immune defenses and drive tonic expression of anti-microbial factors. In combination, these mechanisms preserve the niche for commensal bacteria and assist the host in preventing infection. PMID:24727150
... for information about colorectal cancer in children. Health history affects the risk of developing colon cancer. Anything ... colorectal cancer include the following: Having a family history of colon or rectal cancer in a first- ...
DATES COVERED (From - To) 01/01/2008-31/03/2015 4. TITLE AND SUBTITLE Role of Fe-oxidizing bacteria in metal bio-corrosion in the marine...source, and that steel coupons incubated in natural seawater are rapidly colonized by these bacteria . This is the first demonstration these bacteria ...exist outside of marine hydrothermal vents. These bacteria are early colonizers of steel surfaces and through th&ir fomiatiori of a thick tiufilir
Wang, Jie; Yadav, Vipul; Smart, Alice L; Tajiri, Shinichiro; Basit, Abdul W
This study was the first to investigate the colonic stability of 17 peptide molecules (insulin, calcitonin, glucagon, secretin, somatostatin, desmopressin, oxytocin, Arg-vasopressin, octreotide, ciclosporin, leuprolide, nafarelin, buserelin, histrelin, [D-Ser(4)]-gonadorelin, deslorelin, and goserelin) in a model of the large intestine using mixed human faecal bacteria. Of these, the larger peptides - insulin, calcitonin, somatostatin, glucagon and secretin - were metabolized rapidly, with complete degradation observed within 5 min. In contrast, a number of the smaller peptides - Arg-vasopressin, desmopressin, oxytocin, gonadorelin, goserelin, buserelin, leuprolide, nafarelin and deslorelin - degraded more slowly, while octreotide, histrelin and ciclosporin were seen to be more stable as compared to the other small peptides under the same conditions. Peptide degradation rate was directly correlated to peptide lipophilicity (logP); those peptides with a higher logP were more stable in the colonic model (R(2)=0.94). In the absence of human faecal bacteria, all peptides were stable. This study highlights the impact of the colonic environment - in particular, the gut microbiota - on the metabolism of peptide drugs, and identifies potential peptide candidates for drug delivery to the colon.
Adult horses depend on the microbial community in the hindgut to produce VFAs that are utilized for energy. Microbial colonization in the gastrointestinal tract of foals is essential to develop a healthy symbiotic relationship and prevent proliferation of pathogenic bacteria. However, colonization i...
Screening for colon cancer; Colonoscopy - screening; Sigmoidoscopy - screening; Virtual colonoscopy - screening; Fecal immunochemical test; Stool DNA test; sDNA test; Colorectal cancer - screening; Rectal ...
Berni Canani, Roberto; Sangwan, Naseer; Stefka, Andrew T; Nocerino, Rita; Paparo, Lorella; Aitoro, Rosita; Calignano, Antonio; Khan, Aly A; Gilbert, Jack A; Nagler, Cathryn R
Dietary intervention with extensively hydrolyzed casein formula supplemented with Lactobacillus rhamnosus GG (EHCF+LGG) accelerates tolerance acquisition in infants with cow's milk allergy (CMA). We examined whether this effect is attributable, at least in part, to an influence on the gut microbiota. Fecal samples from healthy controls (n=20) and from CMA infants (n=19) before and after treatment with EHCF with (n=12) and without (n=7) supplementation with LGG were compared by 16S rRNA-based operational taxonomic unit clustering and oligotyping. Differential feature selection and generalized linear model fitting revealed that the CMA infants have a diverse gut microbial community structure dominated by Lachnospiraceae (20.5±9.7%) and Ruminococcaceae (16.2±9.1%). Blautia, Roseburia and Coprococcus were significantly enriched following treatment with EHCF and LGG, but only one genus, Oscillospira, was significantly different between infants that became tolerant and those that remained allergic. However, most tolerant infants showed a significant increase in fecal butyrate levels, and those taxa that were significantly enriched in these samples, Blautia and Roseburia, exhibited specific strain-level demarcations between tolerant and allergic infants. Our data suggest that EHCF+LGG promotes tolerance in infants with CMA, in part, by influencing the strain-level bacterial community structure of the infant gut. PMID:26394008
Kläring, Karoline; Hanske, Laura; Bui, Nam; Charrier, Cédric; Blaut, Michael; Haller, Dirk; Plugge, Caroline M; Clavel, Thomas
A Gram-positive, spore-forming, non-motile, strictly anaerobic rod-shaped bacterium was isolated from the caecal content of a TNF(deltaARE) mouse. The isolate, referred to as strain SRB-521-5-I(T), was originally cultured on a reduced agar medium containing yeast extract, rumen fluid and lactic acid as main energy and carbon sources. Phylogenetic analysis of partial 16S rRNA genes revealed that the species most closely related to strain SRB-521-5-I(T) were Flavonifractor plautii and Pseudoflavonifractor capillosus (<95 % sequence similarity; 1436 bp). In contrast to F. plautii and P. capillosus, strain SRB-521-5-I(T) contained a substantial amount of C18 : 0 dimethylacetal. Additional major fatty acids were C14 : 0 methyl ester, C16 : 0 dimethylacetal and C18 : 0 aldehyde. Strain SRB-521-5-I(T) differed in its enzyme profile from F. plautii and P. capillosus by being positive for dextrin, maltotriose, turanose, dl-lactic acid and d-lactic acid methyl ester but negative for d-fructose. In reduced Wilkins-Chalgren-Anaerobe broth, strain SRB-521-5-I(T) produced approximately 8 mM butyrate and 4 mM acetate. In contrast to F. plautii, the strain did not metabolize flavonoids. It showed intermediate resistance towards the antibiotics ciprofloxacin, colistin and tetracycline. Based on genotypic and phenotypic characteristics, we propose the name Intestinimonas butyriciproducens gen. nov., sp. nov. to accommodate strain SRB-521-5-I(T) ( = DSM 26588(T) = CCUG 63529(T)) as the type strain.
Kant, Ravi; Rasinkangas, Pia; Satokari, Reetta; Pietilä, Taija E; Palva, Airi
Anaerostipes hadrus PEL 85, which was isolated from human feces, is a Gram-positive rod-shaped bacterium. The species may play an important role in gut health, as it was previously reported to produce butyric acid. Here, we present the genome assembly of PEL 85, a novel strain of A. hadrus.
Berni Canani, Roberto; Sangwan, Naseer; Stefka, Andrew T.; ...
Dietary intervention with extensively hydrolyzed casein formula supplemented with Lactobacillus rhamnosus GG (EHCF+LGG) accelerates tolerance acquisition in infants with cow’s milk allergy (CMA). We examined whether this effect is attributable, at least in part, to an influence on the gut microbiota. Fecal samples from healthy controls (n=20) and from CMA infants (n=19) before and after treatment with EHCF with (n=12) and without (n=7) supplementation with LGG were compared by 16S rRNA-based operational taxonomic unit clustering and oligotyping. Differential feature selection and generalized linear model fitting revealed that the CMA infants have a diverse gut microbial community structure dominated by Lachnospiraceaemore » (20.5±9.7%) and Ruminococcaceae (16.2±9.1%). Blautia, Roseburia and Coprococcus were significantly enriched following treatment with EHCF and LGG, but only one genus, Oscillospira, was significantly different between infants that became tolerant and those that remained allergic. However, most tolerant infants showed a significant increase in fecal butyrate levels, and those taxa that were significantly enriched in these samples, Blautia and Roseburia, exhibited specific strain-level demarcations between tolerant and allergic infants. As a result, our data suggest that EHCF+LGG promotes tolerance in infants with CMA, in part, by influencing the strain-level bacterial community structure of the infant gut.« less
Vermeiren, Joan; Van den Abbeele, Pieter; Laukens, Debby; Vigsnaes, Louise Kristine; De Vos, Martine; Boon, Nico; Van de Wiele, Tom
The mucus layer in the colon, acting as a barrier to prevent invasion of pathogens, is thinner and discontinuous in patients with ulcerative colitis (UC). A recent developed in vitro dynamic gut model, the M-SHIME, was used to compare long-term colonization of the mucin layer by the microbiota from six healthy volunteers (HV) and six UC patients and thus distinguish the mucin adhered from the luminal microbiota. Although under the same nutritional conditions, short-chain fatty acid production by the luminal communities from UC patients showed a tendency toward a lower butyrate production. A more in-depth community analysis of those microbial groups known to produce butyrate revealed that the diversity of the Clostridium coccoides/Eubacterium rectale and Clostridium leptum group, and counts of Faecalibacterium prausnitzii were lower in the luminal fractions of the UC samples. Counts of Roseburia spp. were lower in the mucosal fractions of the UC samples. qPCR analysis for butyryl-CoA:acetate CoA transferase, responsible for butyrate production, displayed a lower abundance in both the luminal and mucosal fractions of the UC samples. The M-SHIME model revealed depletion in butyrate producing microbial communities not restricted to the luminal but also in the mucosal samples from UC patients compared to HV.
Sears, Cynthia L; Garrett, Wendy S
Colorectal cancer (CRC) presents a considerable disease burden worldwide. The human colon is also an anatomical location with the largest number of microbes. It is natural, therefore, to anticipate a role for microbes, particularly bacteria, in colorectal carcinogenesis. The increasing accessibility of microbial meta'omics is fueling a surge in our understanding of the role that microbes and the microbiota play in CRC. In this review, we will discuss recent insights into contributions of the microbiota to CRC and explore conceptual frameworks for evaluating the role of microbes in cancer causation. We also highlight new findings on candidate CRC-potentiating species and current knowledge gaps. Finally, we explore the roles of microbial metabolism as it relates to bile acids, xenobiotics, and diet in the etiology and therapeutics of CRC.
Sears, Cynthia L.; Garrett, Wendy S.
Summary Colorectal cancer (CRC) presents a considerable disease burden worldwide. The human colon is also an anatomical location with the largest number of microbes. It is natural therefore to anticipate a role for microbes, particularly bacteria, in colorectal carcinogenesis. The increasing accessibility of microbial meta’omics is fueling a surge in our understanding of the role that microbes and the microbiota play in CRC. In this review, we will discuss recent insights into contributions of the microbiota to CRC and explore conceptual frameworks for evaluating the role of microbes in cancer causation. We also highlight new findings on candidate CRC-potentiating species and current knowledge gaps. Finally, we explore the roles of microbial metabolism as it relates to bile acids, xenobiotics, and diet in the etiology and therapeutics of CRC. PMID:24629338
Kim, Sang Won; Shin, Hyeong Cheol; Kim, Il Young; Kim, Young Tong; Kim, Chang-Jin
A broad spectrum of colonic complications can occur in patients with colon cancer. Clinically, some of these complications can obscure the presence of underlying malignancies in the colon and these complications may require emergency surgical management. The complications of the colon that can be associated with colon cancer include obstruction, perforation, abscess formation, acute appendicitis, ischemic colitis and intussusception. Although the majority of these complications only rarely occur, familiarity with the various manifestations of colon cancer complications will facilitate making an accurate diagnosis and administering prompt management in these situations. The purpose of this pictorial essay is to review the CT appearance of the colonic complications associated with colon cancer.
Tuncer, Oğuz; Melek, Mehmet; Kaba, Sultan; Bulan, Keziban; Peker, Erdal
Though the perforation of the colon in neonates is rare, it is associated with more than 50% mortality in high-risk patients. We report a case of idiopathic neonatal perforation of the sigmoid colon in an 8-day-old, healthy, male neonate without any demonstrable cause. PMID:26023477
Freeman, Hugh James
Evidence has now accumulated that colonoscopy and removal of polyps, especially during screening and surveillance programs, is effective in overall risk reduction for colon cancer. After resection of malignant pedunculated colon polyps or early stage colon cancers, long-term repeated surveillance programs can also lead to detection and removal of asymptomatic high risk advanced adenomas and new early stage metachronous cancers. Early stage colon cancer can be defined as disease that appears to have been completely resected with no subsequent evidence of involvement of adjacent organs, lymph nodes or distant sites. This differs from the clinical setting of an apparent "curative" resection later pathologically upstaged following detection of malignant cells extending into adjacent organs, peritoneum, lymph nodes or other distant sites, including liver. This highly selected early stage colon cancer group remains at high risk for subsequent colon polyps and metachronous colon cancer. Precise staging is important, not only for assessing the need for adjuvant chemotherapy, but also for patient selection for continued surveillance. With advanced stages of colon cancer and a more guarded outlook, repeated surveillance should be limited. In future, novel imaging technologies (e.g., confocal endomicroscopy), coupled with increased pathological recognition of high risk markers for lymph node involvement (e.g., "tumor budding") should lead to improved staging and clinical care.
Colon cancer - prevention; Colon cancer - screening ... We do not know what causes colon cancer, but we do know some of the things that may increase the risk of getting it, such as: Age. Your risk increases after ...
Wild, D C; Mehta, D; Conboy, P J
Infections with organisms resistant to conventional antibiotics are of increasing concern. This observational study investigates the bacterial colonization of the peristomal area of laryngectomy patients. Thirty-two consecutive patients who had previously undergone laryngectomy were recruited from the Head and Neck Clinic of a teaching hospital. Swabs were taken from the laryngectomy stoma site, the mouth and both nasal cavities. Microbiological culture and isolation were performed following standard procedures. Despite no clinical sign of infection, 27 patients were found to be carriers of one or more organism (84.4 per cent). Staphylococcus aureus was detected in the peristomal area of 15 patients (46.9 per cent). Methicillin-resistant Staphylococcus aureus (MRSA) was isolated in seven (21.9 per cent) cases. In this series the authors found a high incidence of colonization with potentially pathogenic bacteria in laryngectomy stomas with no clinical signs of infection. In a significant number of patients, Gram positive organisms were identified that could potentially cause cellulitis or wound infections.
Nelson, Jane Bray; Nelson, Jim
Describes the history of Richard Blakemore's discovery of magnetotaxic organisms. Discusses possible reasons why the magnetic response in bacteria developed. Proposes research experiments integrating biology and physics in which students investigate problems using cultures of magnetotaxic organisms. (MDH)
Kumar, Manish; Tomar, Rajesh Singh; Lade, Harshad; Paul, Diby
Excessive use of chemical fertilizers to increase production from available land has resulted in deterioration of soil quality. To prevent further soil deterioration, the use of methylotrophic bacteria that have the ability to colonize different habitats, including soil, sediment, water, and both epiphytes and endophytes as host plants, has been suggested for sustainable agriculture. Methylotrophic bacteria are known to play a significant role in the biogeochemical cycle in soil ecosystems, ultimately fortifying plants and sustaining agriculture. Methylotrophs also improve air quality by using volatile organic compounds such as dichloromethane, formaldehyde, methanol, and formic acid. Additionally, methylotrophs are involved in phosphorous, nitrogen, and carbon cycling and can help reduce global warming. In this review, different aspects of the interaction between methylotrophs and host plants are discussed, including the role of methylotrophs in phosphorus acquisition, nitrogen fixation, phytohormone production, iron chelation, and plant growth promotion, and co-inoculation of these bacteria as biofertilizers for viable agriculture practices.
Mantas, D; Damaskos, C; Bamias, G; Dimitroulis, D
Introduction Extensive colonic ischaemia can result in passage of a colonic 'cast' (CC) through the rectum. Case Study We report a 69-year-old male who initially underwent surgery to remove a sessile polyp. On postoperative day (POD)15, he was febrile, suffering from diarrhoea, and was treated conservatively. On POD18, the patient returned to our hospital with a CC that presented after defaecation. Computed tomography of the abdomen revealed a CC extending from the descending colon to the anal orifice with presentation of air between the affected colonic wall and the CC. The patient was treated conservatively and discharged on POD20 without complications having passed the CC (≈80cm) completely and becoming afebrile. Conclusions In most cases, the cause of CC passage is surgery for colorectal cancer or repair of an abdominal aortic aneurysm. A mild-to-severe presentation is dependent upon the bowel-wall layers affected by ischaemia and which therefore are included in the CC.
Bifidobacterium ssp. constitute up to 90% of microbial gut flora in the infant colon, but considerably less in adults. Carbohydrate metabolism in these bacteria is highly unusual. Data from four Bifidobacterium genomes indicates genes missing from glycolysis, gluconeogenesis, and the TCA cycle, in...
Katayama, Yuki; Baba, Tadashi; Sekine, Miwa; Fukuda, Minoru; Hiramatsu, Keiichi
Colonization by Staphylococcus aureus is a characteristic feature of several inflammatory skin diseases and is often followed by epidermal damage and invasive infection. In this study, we investigated the mechanism of skin colonization by a virulent community-acquired methicillin-resistant S. aureus (CA-MRSA) strain, MW2, using a murine ear colonization model. MW2 does not produce a hemolytic toxin, beta-hemolysin (Hlb), due to integration of a prophage, Sa3mw, inside the toxin gene (hlb). However, we found that strain MW2 bacteria that had successfully colonized murine ears included derivatives that produced Hlb. Genome sequencing of the Hlb-producing colonies revealed that precise excision of prophage Sa3mw occurred, leading to reconstruction of the intact hlb gene in their chromosomes. To address the question of whether Hlb is involved in skin colonization, we constructed MW2-derivative strains with and without the Hlb gene and then subjected them to colonization tests. The colonization efficiency of the Hlb-producing mutant on murine ears was more than 50-fold greater than that of the mutant without hlb. Furthermore, we also showed that Hlb toxin had elevated cytotoxicity for human primary keratinocytes. Our results indicate that S. aureus Hlb plays an important role in skin colonization by damaging keratinocytes, in addition to its well-known hemolytic activity for erythrocytes.
Katayama, Yuki; Sekine, Miwa; Fukuda, Minoru; Hiramatsu, Keiichi
Colonization by Staphylococcus aureus is a characteristic feature of several inflammatory skin diseases and is often followed by epidermal damage and invasive infection. In this study, we investigated the mechanism of skin colonization by a virulent community-acquired methicillin-resistant S. aureus (CA-MRSA) strain, MW2, using a murine ear colonization model. MW2 does not produce a hemolytic toxin, beta-hemolysin (Hlb), due to integration of a prophage, ϕSa3mw, inside the toxin gene (hlb). However, we found that strain MW2 bacteria that had successfully colonized murine ears included derivatives that produced Hlb. Genome sequencing of the Hlb-producing colonies revealed that precise excision of prophage ϕSa3mw occurred, leading to reconstruction of the intact hlb gene in their chromosomes. To address the question of whether Hlb is involved in skin colonization, we constructed MW2-derivative strains with and without the Hlb gene and then subjected them to colonization tests. The colonization efficiency of the Hlb-producing mutant on murine ears was more than 50-fold greater than that of the mutant without hlb. Furthermore, we also showed that Hlb toxin had elevated cytotoxicity for human primary keratinocytes. Our results indicate that S. aureus Hlb plays an important role in skin colonization by damaging keratinocytes, in addition to its well-known hemolytic activity for erythrocytes. PMID:23292775
McDermott, Frank D.; Folan, David M. A.; Winter, Des C.; Folan, Michael A.; Baird, Alan W.
Background A novel emulsion with efficacy as an agent for eliminating biofilms was selected. The aim of this study was to examine efficacy and effect of a formulation of ML:8 against commensal bacteria harvested from ex vivo human colonic tissues. Methods Mucosal sheets, obtained at the time of surgery, were exposed for 2 minutes to one of four solutions: Krebs-Hensleit (KH) solution, saline (NaCl; 0.9%), povidone iodine (1%), or ML:8 (2%); n = 4. Lumenal surfaces were swabbed for culture under aerobic or anaerobic conditions. Following treatment, each sheet was mounted in Ussing chambers and voltage clamped. Tissues were challenged with carbachol. Permeability coefficient (Papp) was determined using mannitol fluxes. At the end of each experiment, tissues were examined histologically. Results Similar colony forming units grew in aerobic and anaerobic conditions in both control and NaCl treated tissues. Iodine reduced and ML:8 virtually abolished viable bacteria. Basal electrophysiological parameters were not different between treatments. Transepithelial electrical resistance values did not differ between groups. All tissues responded to carbachol, although this was attenuated in iodine treated tissue. Papp values were slightly elevated in all treated tissues but this did not reach significance. Histopathological assessment revealed no overt damage to tissues. Conclusion Brief exposure to ML:8 reduced culturable bacterial burden from human intestinal tissues harvested at the time of surgical resection. Such gnotobiotic tissues retain structural and functional integrity. This is a novel approach to reduce bacterial burden. PMID:27785304
Kelly, Orlaith B; Mroz, Magdalena S; Ward, Joseph B J; Colliva, Carolina; Scharl, Michael; Pellicciari, Roberto; Gilmer, John F; Fallon, Padraic G; Hofmann, Alan F; Roda, Aldo; Murray, Frank E; Keely, Stephen J
Dihydroxy bile acids, such as chenodeoxycholic acid (CDCA), are well known to promote colonic fluid and electrolyte secretion, thereby causing diarrhoea associated with bile acid malabsorption. However, CDCA is rapidly metabolised by colonic bacteria to ursodeoxycholic acid (UDCA), the effects of which on epithelial transport are poorly characterised. Here, we investigated the role of UDCA in the regulation of colonic epithelial secretion. Cl− secretion was measured across voltage-clamped monolayers of T84 cells and muscle-stripped sections of mouse or human colon. Cell surface biotinylation was used to assess abundance/surface expression of transport proteins. Acute (15 min) treatment of T84 cells with bilateral UDCA attenuated Cl− secretory responses to the Ca2+ and cAMP-dependent secretagogues carbachol (CCh) and forskolin (FSK) to 14.0 ± 3.8 and 40.2 ± 7.4% of controls, respectively (n= 18, P < 0.001). Investigation of the molecular targets involved revealed that UDCA acts by inhibiting Na+/K+-ATPase activity and basolateral K+ channel currents, without altering their cell surface expression. In contrast, intraperitoneal administration of UDCA (25 mg kg−1) to mice enhanced agonist-induced colonic secretory responses, an effect we hypothesised to be due to bacterial metabolism of UDCA to lithocholic acid (LCA). Accordingly, LCA (50–200 μm) enhanced agonist-induced secretory responses in vitro and a metabolically stable UDCA analogue, 6α-methyl-UDCA, exerted anti-secretory actions in vitro and in vivo. In conclusion, UDCA exerts direct anti-secretory actions on colonic epithelial cells and metabolically stable derivatives of the bile acid may offer a new approach for treating intestinal diseases associated with diarrhoea. PMID:23507881
Hanson, R S; Hanson, T E
Methane-utilizing bacteria (methanotrophs) are a diverse group of gram-negative bacteria that are related to other members of the Proteobacteria. These bacteria are classified into three groups based on the pathways used for assimilation of formaldehyde, the major source of cell carbon, and other physiological and morphological features. The type I and type X methanotrophs are found within the gamma subdivision of the Proteobacteria and employ the ribulose monophosphate pathway for formaldehyde assimilation, whereas type II methanotrophs, which employ the serine pathway for formaldehyde assimilation, form a coherent cluster within the beta subdivision of the Proteobacteria. Methanotrophic bacteria are ubiquitous. The growth of type II bacteria appears to be favored in environments that contain relatively high levels of methane, low levels of dissolved oxygen, and limiting concentrations of combined nitrogen and/or copper. Type I methanotrophs appear to be dominant in environments in which methane is limiting and combined nitrogen and copper levels are relatively high. These bacteria serve as biofilters for the oxidation of methane produced in anaerobic environments, and when oxygen is present in soils, atmospheric methane is oxidized. Their activities in nature are greatly influenced by agricultural practices and other human activities. Recent evidence indicates that naturally occurring, uncultured methanotrophs represent new genera. Methanotrophs that are capable of oxidizing methane at atmospheric levels exhibit methane oxidation kinetics different from those of methanotrophs available in pure cultures. A limited number of methanotrophs have the genetic capacity to synthesize a soluble methane monooxygenase which catalyzes the rapid oxidation of environmental pollutants including trichloroethylene. PMID:8801441
... inches to complete the procedure. What are the Advantages of Laparoscopic Colon Resection? Results may vary depending ... type of procedure and patient’s overall condition. Common advantages are: Less postoperative pain May shorten hospital stay ...
... ency/presentations/100157.htm Colon cancer - Series—Normal anatomy To use the sharing features on this page, ... Bethesda, MD 20894 U.S. Department of Health and Human Services National Institutes of Health Page last updated: ...
Millichap, J J; McKendrick, A I; Drelichman, V S
Certain species of bacteria are known to be associated with colorectal cancer. We report a case of adenocarcinoma of the colon with bacteraemia and liver abscesses due to Streptococcus intermedius. The isolation of this organism should prompt investigation for colorectal neoplasm, which may be present but asymptomatic, without metastases, and therefore at a curative stage.
Paniagua Estévez, M; González Calleja, I; González Lazo, N; Jimenéz Mesa, G; Hernández Miranda, W
Recent international publications remark the association about carcinoma of the colon and cholelithiasis. These two entities with similar geographical distribution can be seen frequently in the modern western societies, being the cause as aetiological factors the low content in dietetics fiber. Different studies about the carcinoma of the colon and cholelithiasis pathogenesis had lead the possibility that the abnormal degradation of bile acids for the colonic bacterias, could be responsible of each one of these illness. The exposition of colonic mucosa to products of degradation of bile acids, specially secondary bile acids, may play a role in the etiopathogenic of colon carcinoma. It was analysed 135 patients with colon carcinoma or adenomatosis polyps, 42 with cholelithiasis or cholecystectomized for the same cause (31.1%), although in the control group, only 2(5%) had cholelithiasis. The female predominated the group of colon carcinoma and cholelithiasis, as well as cholecystectomized for that cause. The most frequent associated pathology was the diverticulosis.
Stephens, W. Zac; Wiles, Travis J.; Martinez, Emily S.; Jemielita, Matthew; Burns, Adam R.; Parthasarathy, Raghuveer; Bohannan, Brendan J. M.
ABSTRACT The zebrafish, Danio rerio, is a powerful model for studying bacterial colonization of the vertebrate intestine, but the genes required by commensal bacteria to colonize the zebrafish gut have not yet been interrogated on a genome-wide level. Here we apply a high-throughput transposon mutagenesis screen to Aeromonas veronii Hm21 and Vibrio sp. strain ZWU0020 during their colonization of the zebrafish intestine alone and in competition with each other, as well as in different colonization orders. We use these transposon-tagged libraries to track bacterial population sizes in different colonization regimes and to identify gene functions required during these processes. We show that intraspecific, but not interspecific, competition with a previously established bacterial population greatly reduces the ability of these two bacterial species to colonize. Further, using a simple binomial sampling model, we show that under conditions of interspecific competition, genes required for colonization cannot be identified because of the population bottleneck experienced by the second colonizer. When bacteria colonize the intestine alone or at the same time as the other species, we find shared suites of functional requirements for colonization by the two species, including a prominent role for chemotaxis and motility, regardless of the presence of another species. PMID:26507229
Beneficial bacteria in probiotics produce and utilize several organic acids that may play a role in the ability of these bacteria to inhibit colonization of poultry by enteropathogens. Since cecal contents of adult poultry contain many of these beneficial bacteria, 3 experiments were conducted to ex...
Science Applications, Inc.'s ATP Photometer makes a rapid and accurate count of the bacteria in a body fluid sample. Instrument provides information on the presence and quantity of bacteria by measuring the amount of light emitted by the reaction between two substances. Substances are ATP adenosine triphosphate and luciferase. The reactants are applied to a human body sample and the ATP Photometer observes the intensity of the light emitted displaying its findings in a numerical output. Total time lapse is usually less than 10 minutes, which represents a significant time savings in comparison of other techniques. Other applications are measuring organisms in fresh and ocean waters, determining bacterial contamination of foodstuffs, biological process control in the beverage industry, and in assay of activated sewage sludge.
Development and preclinical evaluation of safety and immunogenicity of an oral ETEC vaccine containing inactivated E. coli bacteria overexpressing colonization factors CFA/I, CS3, CS5 and CS6 combined with a hybrid LT/CT B subunit antigen, administered alone and together with dmLT adjuvant.
Holmgren, J; Bourgeois, L; Carlin, N; Clements, J; Gustafsson, B; Lundgren, A; Nygren, E; Tobias, J; Walker, R; Svennerholm, A-M
A first-generation oral inactivated whole-cell enterotoxigenic Escherichia coli (ETEC) vaccine, comprising formalin-killed ETEC bacteria expressing different colonization factor (CF) antigens combined with cholera toxin B subunit (CTB), when tested in phase III studies did not significantly reduce overall (generally mild) ETEC diarrhea in travelers or children although it reduced more severe ETEC diarrhea in travelers by almost 80%. We have now developed a novel more immunogenic ETEC vaccine based on recombinant non-toxigenic E. coli strains engineered to express increased amounts of CF antigens, including CS6 as well as an ETEC-based B subunit protein (LCTBA), and the optional combination with a nontoxic double-mutant heat-labile toxin (LT) molecule (dmLT) as an adjuvant. Two test vaccines were prepared under GMP: (1) A prototype E. coli CFA/I-only formalin-killed whole-cell+LCTBA vaccine, and (2) A "complete" inactivated multivalent ETEC-CF (CFA/I, CS3, CS5 and CS6 antigens) whole-cell+LCTBA vaccine. These vaccines, when given intragastrically alone or together with dmLT in mice, were well tolerated and induced strong intestinal-mucosal IgA antibody responses as well as serum IgG and IgA responses to each of the vaccine CF antigens as well as to LT B subunit (LTB). Both mucosal and serum responses were further enhanced (adjuvanted) when the vaccines were co-administered with dmLT. We conclude that the new multivalent oral ETEC vaccine, both alone and especially in combination with the dmLT adjuvant, shows great promise for further testing in humans.
Canganella, F; Zirletta, G; Gualterio, L; Massa, S; Trovatelli, L D
Anaerobic facultative bacteria colonizing the intestinal tract of conventional rabbits fed three different diets (standard pellet, hay and pellet/hay mixture) were enumerated in brain heart infusion agar. Colony counts recovered from homogenized samples of small intestine, caecum and rectum differed with reference to the diet given. Among anaerobic groups, identified from rabbit fed pellet/hay mixture, Enterococci (E. faecalis, E. avium, E. faecium and E. durans) represented the predominant flora. Enterobacters (E. cloacae and E. aerogenes) accounted for about 10 to 25% of the bacteria in the rectum and colon respectively, whereas Staphylococci (S. intermedius, S. epidermidis and S. lentus) represented 11% of the bacteria isolated from colon.
Cornelis, K; Ritsema, T; Nijsse, J; Holsters, M; Goethals, K; Jaziri, M
Rhodococcus fascians is a plant-pathogenic bacterium that causes malformations on aerial plant parts, whereby leafy galls occur at axillary meristems. The colonization behavior on Nicotiana tabacum and Arabidopsis thaliana plants was examined. Independent of the infection methods, R. fascians extensively colonized the plant surface where the bacteria were surrounded by a slime layer. R. fascians caused the collapse of epidermal cells and penetrated intercellularly into the plant tissues. The onset of symptom development preceded the extensive colonization of the interior. The meristematic regions induced by pathogenic strain D188 were surrounded by bacteria. The nonpathogenic strain, D188-5, colonized the exterior of the plant equally well, but the linear plasmid (pFiD188) seemed to be involved in the penetration efficiency and colonization of tobacco tissues.
Terzić, Janos; Grivennikov, Sergei; Karin, Eliad; Karin, Michael
The connection between inflammation and tumorigenesis is well-established and in the last decade has received a great deal of supporting evidence from genetic, pharmacological, and epidemiological data. Inflammatory bowel disease is an important risk factor for the development of colon cancer. Inflammation is also likely to be involved with other forms of sporadic as well as heritable colon cancer. The molecular mechanisms by which inflammation promotes cancer development are still being uncovered and could differ between colitis-associated and other forms of colorectal cancer. Recent work has elucidated the role of distinct immune cells, cytokines, and other immune mediators in virtually all steps of colon tumorigenesis, including initiation, promotion, progression, and metastasis. These mechanisms, as well as new approaches to prevention and therapy, are discussed in this review.
Ugoji, E O; Laing, M D; Hunter, C H
Seed coating, dipping and Scanning Electron Microscopy (SEM) were employed to study bacterial and fungal colonization of the seeds and rhizoplane of maize (Zea mays L.) during the early stages of growth. Isolation of Bacillus spp. entailed screening soil bacteria with potential growth stimulation and plant pathogen suppressive abilities isolated from the rhizospheres and rhizoplanes of vegetable crops. The bacterial colonization of the spermosphere was 90%. When the coated seeds were fully germinated, bacteria moved to the emerging radicle. Virtually no bacteria occurred on the root tip both for the treated and untreated. However, colonization was 20% in the basal portion of the roots close to the seed-root junction. SEM observations showed that the bacterial cells were arranged linearly and laterally on the growing root axis. This phenomenon was more noticeable in the seedlings dipped in the bacterial culture on the 3rd day after germination. The results indicate that attachment to the seed coat and the rhizoplane by the plant growth-promoting rhizobacterium (PGPR) is an important factor in the successful colonization of the rhizoplane. The significance of the work is to ascertain that the inoculated Bacillus spp. adhered to and established in the rhizoplane of maize. It can therefore be used as a PGPR and as a biocontrol agent.
Spagnuolo, Anna Maria; Dirita, Victor; Kirschner, Denise
Vibrio cholerae is a strict human pathogen that causes the disease cholera. It is an old-world pathogen that has re-emerged as a new threat since the early 1990s. V. cholerae colonizes the upper, small intestine where it produces a toxin that leads to watery diarrhea, characterizing the disease (Kahn et al., 1988). The dynamics of colonization by the bacteria of the intestines are largely unknown. Although a large initial infectious dose is required for infection, data suggests that only a smaller sub-population colonizes a portion of the small bowel leading to disease. There are many barriers to colonization in the intestines including peristalsis, fluid wash-out, viscosity of the mucus layer, and pH. We are interested in identifying the mechanisms that allow this sub-population of bacteria to survive and colonize the intestines when faced with these barriers. To elaborate the dynamics of V. cholerae infection, we have developed a mathematical model based on a convection-diffusion-reaction-swimming equation capturing bacterial dynamics coupled with Stokes equations governing fluid velocity where we developed a novel non-local boundary condition. Our results indicate that both host and bacterial factors contribute to bacterial density in the gut. Host factors include intestinal diffusion and convection rates while bacterial factors include adherence, motility and growth rates. This model can ultimately be used to test therapeutic strategies against V. cholerae.
Zeiger, Diana N; Stafford, Christopher M; Cheng, Yajun; Leigh, Stefan D; Lin-Gibson, Sheng; Lin, Nancy J
Characterization of materials developed for medical usage frequently includes studies in which the materials are inoculated with bacteria in order to assess bacterial colonization and biofilm formation. Observed differences in bacterial growth are typically considered to be due to the material or the incubation conditions. To our knowledge, the method used to prepare the materials has generally not been considered with regard to its influence on bacterial colonization. The objective of this study was to determine the effects that various preparation methods exert on bacterial colonization of polymer disks. Polymer disks of the same dimethacrylate composition were photopolymerized: (1) between untreated glass slides, (2) between polyester release film, (3) between glass slides treated with an alkyl silane, (4) between glass slides treated with a perfluorinated silane, or (5) with one free surface in an argon-purged chamber. Surface chemistry was quantified using X-ray photoelectron spectroscopy, hydrophobicity was assessed by water contact angle, and topography was characterized using atomic force microscopy. The disks were inoculated with Streptococcus mutans for 4 h, fixed, and visualized using confocal laser scanning microscopy. Differences among all groups were found with regard to surface chemistry, hydrophobicity, topography, and bacteria morphology, density, and coverage, indicating that the method of sample preparation strongly affects both the surface properties and the initial bacterial colonization. Polymerization on untreated slides was selected as the preferred method of preparation due to minimal material transfer to the polymer and consistent, reproducible bacterial colonization.
Vuono, David C; Munakata-Marr, Junko; Spear, John R; Drewes, Jörg E
Little is known about the role of immigration in shaping bacterial communities or the factors that may dictate success or failure of colonization by bacteria from regional species pools. To address these knowledge gaps, the influence of bacterial colonization into an ecosystem (activated sludge bioreactor) was measured through a disturbance gradient (successive decreases in the parameter solids retention time) relative to stable operational conditions. Through a DNA sequencing approach, we show that the most abundant bacteria within the immigrant community have a greater probability of colonizing the receiving ecosystem, but mostly as low abundance community members. Only during the disturbance do some of these bacterial populations significantly increase in abundance beyond background levels and in few cases become dominant community members post-disturbance. Two mechanisms facilitate the enhanced enrichment of immigrant populations during disturbance: (i) the availability of resources left unconsumed by established species and (ii) the increased availability of niche space for colonizers to establish and displace resident populations. Thus, as a disturbance decreases local diversity, recruitment sites become available to promote colonization. This work advances our understanding of microbial resource management and diversity maintenance in complex ecosystems.
Cassmann, Eric; White, Robin; Atherly, Todd; Wang, Chong; Sun, Yaxuan; Khoda, Samir; Mosher, Curtis; Ackermann, Mark; Jergens, Albert
Background The intestinal microbiota is increasingly linked to the pathogenesis of chronic enteropathies (CE) in dogs. While imbalances in duodenal and fecal microbial communities have been associated with mucosal inflammation, relatively little is known about alterations in mucosal bacteria seen with CE involving the ileum and colon. Aim To investigate the composition and spatial organization of mucosal microbiota in dogs with CE and controls. Methods Tissue sections from endoscopic biopsies of the ileum and colon from 19 dogs with inflammatory bowel disease (IBD), 6 dogs with granulomatous colitis (GC), 12 dogs with intestinal neoplasia, and 15 controls were studied by fluorescence in situ hybridization (FISH) on a quantifiable basis. Results The ileal and colonic mucosa of healthy dogs and dogs with CE is predominantly colonized by bacteria localized to free and adherent mucus compartments. CE dogs harbored more (P < 0.05) mucosal bacteria belonging to the Clostridium-coccoides/Eubacterium rectale group, Bacteroides, Enterobacteriaceae, and Escherichia coli versus controls. Within the CE group, IBD dogs had increased (P < 0.05) Enterobacteriaceae and E. coli bacteria attached onto surface epithelia or invading within the intestinal mucosa. Bacterial invasion with E. coli was observed in the ileal and colonic mucosa of dogs with GC (P < 0.05). Dogs with intestinal neoplasia had increased (P < 0.05) adherent (total bacteria, Enterobacteriaceae, E. coli) and invasive (Enterobacteriaceae, E. coli, and Bacteroides) bacteria in biopsy specimens. Increased numbers of total bacteria adherent to the colonic mucosa were associated with clinical disease severity in IBD dogs (P < 0.05). Conclusion Pathogenic events in canine CE are associated with different populations of the ileal and colonic mucosal microbiota. PMID:26840462
... https://medlineplus.gov/news/fullstory_164231.html Keep Colon Cancer at Bay Colonoscopy best way to detect disease ... 22, 2017 WEDNESDAY, March 22, 2017 (HealthDay News) -- Colon cancer can be treated and cured if it's diagnosed ...
Brooks, John F; Gyllborg, Mattias C; Cronin, David C; Quillin, Sarah J; Mallama, Celeste A; Foxall, Randi; Whistler, Cheryl; Goodman, Andrew L; Mandel, Mark J
Animal epithelial tissue becomes reproducibly colonized by specific environmental bacteria. The bacteria (microbiota) perform critical functions for the host's tissue development, immune system development, and nutrition; yet the processes by which bacterial diversity in the environment is selected to assemble the correct communities in the host are unclear. To understand the molecular determinants of microbiota selection, we examined colonization of a simplified model in which the light organ of Euprymna scolopes squid is colonized exclusively by Vibrio fischeri bacteria. We applied high-throughput insertion sequencing to identify which bacterial genes are required during host colonization. A library of over 41,000 unique transposon insertions was analyzed before and after colonization of 1,500 squid hatchlings. Mutants that were reproducibly depleted following squid colonization represented 380 genes, including 37 that encode known colonization factors. Validation of select mutants in defined competitions against the wild-type strain identified nine mutants that exhibited a reproducible colonization defect. Some of the colonization factors identified included genes predicted to influence copper regulation and secretion. Other mutants exhibited defects in biofilm development, which is required for aggregation in host mucus and initiation of colonization. Biofilm formation in culture and in vivo was abolished in a strain lacking the cytoplasmic chaperone DnaJ, suggesting an important role for protein quality control during the elaboration of bacterial biofilm in the context of an intact host immune system. Overall these data suggest that cellular stress responses and biofilm regulation are critical processes underlying the reproducible colonization of animal hosts by specific microbial symbionts.
Sana, Landolsi; Ali, Gassara; Kallel, Helmi; Amine, Baklouti; Ahmed, Saadaoui; Mohamed Ali, Elouer; Wajdi, Chaeib; Saber, Mannaï
We report a case of spontaneous transverse colon volvulus in a young healthy woman. It constitutes an unusual case since it occurred in a young healthy woman with a subacute onset and no aetiological factor has been found. Its diagnosis is still challenging. Prompt recognition with emergency intervention constitutes the key to successful outcome. PMID:23785565
Sana, Landolsi; Ali, Gassara; Kallel, Helmi; Amine, Baklouti; Ahmed, Saadaoui; Ali, Elouer Mohamed; Wajdi, Chaeib; Saber, Mannaï
We report a case of spontaneous transverse colon volvulus in a young healthy woman. It constitutes an unusual case since it occurred in a young healthy woman with a subacute onset and no aetiological factor has been found. Its diagnosis is still challenging. Prompt recognition with emergency intervention constitutes the key to successful outcome.
... collection below explain colon cancer risk factors, screening tests, and treatments. There are also personal stories from ... Colon Cancer Risk Play Play Colon Cancer: Screening Tests Play Play Colon Cancer Screening Tests: Colonoscopy Play ...
The contribution of seagrasses to the stability and fertility of estuarine ecosystems is well established. Loss of seagrasses in recent years to disease and coastal development underscores the importance of understanding the microbial ecology of seagrasses, and the possible roles...
Nobbs, Angela H.; Lamont, Richard J.; Jenkinson, Howard F.
Summary: Streptococci readily colonize mucosal tissues in the nasopharynx; the respiratory, gastrointestinal, and genitourinary tracts; and the skin. Each ecological niche presents a series of challenges to successful colonization with which streptococci have to contend. Some species exist in equilibrium with their host, neither stimulating nor submitting to immune defenses mounted against them. Most are either opportunistic or true pathogens responsible for diseases such as pharyngitis, tooth decay, necrotizing fasciitis, infective endocarditis, and meningitis. Part of the success of streptococci as colonizers is attributable to the spectrum of proteins expressed on their surfaces. Adhesins enable interactions with salivary, serum, and extracellular matrix components; host cells; and other microbes. This is the essential first step to colonization, the development of complex communities, and possible invasion of host tissues. The majority of streptococcal adhesins are anchored to the cell wall via a C-terminal LPxTz motif. Other proteins may be surface anchored through N-terminal lipid modifications, while the mechanism of cell wall associations for others remains unclear. Collectively, these surface-bound proteins provide Streptococcus species with a “coat of many colors,” enabling multiple intimate contacts and interplays between the bacterial cell and the host. In vitro and in vivo studies have demonstrated direct roles for many streptococcal adhesins as colonization or virulence factors, making them attractive targets for therapeutic and preventive strategies against streptococcal infections. There is, therefore, much focus on applying increasingly advanced molecular techniques to determine the precise structures and functions of these proteins, and their regulatory pathways, so that more targeted approaches can be developed. PMID:19721085
Ngwa, Taiwo; Peng, Jennifer L.; Choi, Euna; Tayarachakul, Sucharat; Liangpunsakul, Suthat
Spirochetes, a genetically and morphologically distinct group of bacteria, are thin, spiral-shaped, and highly motile. They are known causes of several human diseases such as syphilis, Lyme disease, relapsing fever, and leptospirosis. We report a case of colonic spirochetosis in a healthy patient presenting for surveillance colonoscopy. The diagnosis of intestinal spirochetosis was made accidentally during the histological examination of colonic polyps, which were removed during colonoscopy. We also performed an extensive review on intestinal spirochetosis with a focus on clinical presentation and outcomes of reported cases from the past two decades. PMID:27570780
Chao, Yashuan; Marks, Laura R.; Pettigrew, Melinda M.; Hakansson, Anders P.
Streptococcus pneumoniae (the pneumococcus) is a common colonizer of the human nasopharynx. Despite a low rate of invasive disease, the high prevalence of colonization results in millions of infections and over one million deaths per year, mostly in individuals under the age of 5 and the elderly. Colonizing pneumococci form well-organized biofilm communities in the nasopharyngeal environment, but the specific role of biofilms and their interaction with the host during colonization and disease is not yet clear. Pneumococci in biofilms are highly resistant to antimicrobial agents and this phenotype can be recapitulated when pneumococci are grown on respiratory epithelial cells under conditions found in the nasopharyngeal environment. Pneumococcal biofilms display lower levels of virulence in vivo and provide an optimal environment for increased genetic exchange both in vitro and in vivo, with increased natural transformation seen during co-colonization with multiple strains. Biofilms have also been detected on mucosal surfaces during pneumonia and middle ear infection, although the role of these biofilms in the disease process is debated. Recent studies have shown that changes in the nasopharyngeal environment caused by concomitant virus infection, changes in the microflora, inflammation, or other host assaults trigger active release of pneumococci from biofilms. These dispersed bacteria have distinct phenotypic properties and transcriptional profiles different from both biofilm and broth-grown, planktonic bacteria, resulting in a significantly increased virulence in vivo. In this review we discuss the properties of pneumococcal biofilms, the role of biofilm formation during pneumococcal colonization, including their propensity for increased ability to exchange genetic material, as well as mechanisms involved in transition from asymptomatic biofilm colonization to dissemination and disease of otherwise sterile sites. Greater understanding of pneumococcal biofilm
Zigangirova, N A; Tokarskaia, E A; Narodnitskiĭ, B S; Gintsburg, A L; Tugel'ian, V A
The wide use of antibiotics in livestock raising has contributed to the selection and accumulation of representatives of commensal microflora, as well as pathogenic bacteria, colonizing livestock and poultry. For this reason the problem of the possible transfer of antibiotic-resistance genes along the chain from bacteria, autochthonous for agricultural animals, to bacteria used for the production of foodstuffs, which are incorporated into normal microflora and may thus participate in the exchange of these genes with bacteria, enteropathogenic for humans, is a highly important task of medical microbiology. The article deals with the review of experimental data, indicative the possibility of the appearance of antibiotic-resistant pathogenic bacteria due to the transfer of antibiotic-resistance genes via alimentary chains.
Masood, Muhammad Irfan; Qadir, Muhammad Imran; Shirazi, Jafir Hussain; Khan, Ikram Ullah
Lactic acid bacteria are a diverse group of bacteria that produce lactic acid as their major fermented product. Most of them are normal flora of human being and animals and produce myriad beneficial effects for human beings include, alleviation of lactose intolerance, diarrhea, peptic ulcer, stimulation of immune system, antiallergic effects, antifungal actions, preservation of food, and prevention of colon cancer. This review highlights the potential species of Lactic acid bacteria responsible for producing these effects. It has been concluded that lactic acid bacteria are highly beneficial microorganisms for human beings and are present abundantly in dairy products so their use should be promoted for good human health.
Kim, Byung Kwon; Chung, Joon-hui; Kim, Seon-Young; Jeong, Haeyoung; Kang, Sung Gyun; Kwon, Soon-Kyeong; Lee, Choong Hoon; Song, Ju Yeon; Yu, Dong Su; Ryu, Choong-Min; Kim, Jihyun F
Plant growth-promoting bacteria colonize various habitats, including the phyllosphere. Here, we present the high-quality draft genome sequence of Bacillus sp. strain 5B6, which was isolated from the leaf of a cherry tree. The 3.9-Mb genome uncovers its potential for understanding the nature of leaf colonization as well as antibiosis against plant pathogens.
Allard-Massicotte, Rosalie; Tessier, Laurence; Lécuyer, Frédéric; Lakshmanan, Venkatachalam; Lucier, Jean-François; Garneau, Daniel; Caudwell, Larissa; Vlamakis, Hera; Bais, Harsh P.
ABSTRACT Colonization of plant roots by Bacillus subtilis is mutually beneficial to plants and bacteria. Plants can secrete up to 30% of their fixed carbon via root exudates, thereby feeding the bacteria, and in return the associated B. subtilis bacteria provide the plant with many growth-promoting traits. Formation of a biofilm on the root by matrix-producing B. subtilis is a well-established requirement for long-term colonization. However, we observed that cells start forming a biofilm only several hours after motile cells first settle on the plant. We also found that intact chemotaxis machinery is required for early root colonization by B. subtilis and for plant protection. Arabidopsis thaliana root exudates attract B. subtilis in vitro, an activity mediated by the two characterized chemoreceptors, McpB and McpC, as well as by the orphan receptor TlpC. Nonetheless, bacteria lacking these chemoreceptors are still able to colonize the root, suggesting that other chemoreceptors might also play a role in this process. These observations suggest that A. thaliana actively recruits B. subtilis through root-secreted molecules, and our results stress the important roles of B. subtilis chemoreceptors for efficient colonization of plants in natural environments. These results demonstrate a remarkable strategy adapted by beneficial rhizobacteria to utilize carbon-rich root exudates, which may facilitate rhizobacterial colonization and a mutualistic association with the host. PMID:27899502
Tamar, Einat; Koler, Moriah; Vaknin, Ady
Internal epithelial surfaces in humans are both oxygenated and physically protected by a few hundred microns thick hydrogel mucosal layer, conditions that might support bacterial aerotaxis. However, the potential role of aerotaxis in crossing such a thin hydrogel layer is not clear. Here, we used a new setup to study the potential role of motility and chemotaxis in the bacterial colonization of surfaces covered by a thin hydrogel layer and subjected to a vertical oxygen gradient. Using the bacterium Escherichia coli, we show that both non-motile and motile-but-non-chemotactic bacteria could barely reach the surface. However, an acquired mutation in the non-chemotactic bacteria that altered their inherent swimming behavior led to a critical enhancement of surface colonization. Most chemotactic strains accumulated within the bulk of the hydrogel layer, except for the MG1655 strain, which showed a unique tendency to accumulate directly at the oxygenated surface and thus exhibited distinctly enhanced colonization. Even after a long period of bacterial growth, non-motile bacteria could not colonize the hydrogel. Thus, switching motility, which can be spontaneously acquired or altered in vivo, is critical for the colonization of such protected surfaces, whereas aerotaxis capacity clearly expedites surface colonization, and can lead to diverse colonization patterns. PMID:26792493
Scharf, Birgit E; Hynes, Michael F; Alexandre, Gladys M
Beneficial plant-microbe associations play critical roles in plant health. Bacterial chemotaxis provides a competitive advantage to motile flagellated bacteria in colonization of plant root surfaces, which is a prerequisite for the establishment of beneficial associations. Chemotaxis signaling enables motile soil bacteria to sense and respond to gradients of chemical compounds released by plant roots. This process allows bacteria to actively swim towards plant roots and is thus critical for competitive root surface colonization. The complete genome sequences of several plant-associated bacterial species indicate the presence of multiple chemotaxis systems and a large number of chemoreceptors. Further, most soil bacteria are motile and capable of chemotaxis, and chemotaxis-encoding genes are enriched in the bacteria found in the rhizosphere compared to the bulk soil. This review compares the architecture and diversity of chemotaxis signaling systems in model beneficial plant-associated bacteria and discusses their relevance to the rhizosphere lifestyle. While it is unclear how controlling chemotaxis via multiple parallel chemotaxis systems provides a competitive advantage to certain bacterial species, the presence of a larger number of chemoreceptors is likely to contribute to the ability of motile bacteria to survive in the soil and to compete for root surface colonization.
Bagherzadeh Saba, Reza; Sadeghi, Amir; Rad, Neda; Safari, Mohammad Taghi; Barzegar, Farnoush
Lipomas of the colon are relatively rare benign soft tissue tumors derived from mature adipocytes of mesenchymatic origin. During colonoscopy, surgery or autopsy they are generally discovered incidentally. Most cases are asymptomatic, with a small tumor size, and do not need any special treatment. However, in the cases with larger in size of tumor some symptoms such as anemia, abdominal pain, constipation, diarrhea, bleeding, or intussusception may be presented. We reported a 47-year-old woman with colonic intussusception in the descending colon caused by colonic lipoma and diagnosed after surgical exploration for obstructive colonic mass. PMID:28224035
Vormbrock, Klaus; Mönkemüller, Klaus
Colorectal cancer (CRC) is one of the leading causes of death from cancer in the world. We now know that 90% of CRC develop from adenomatous polyps. Polypectomy of colon adenomas leads to a significant reduction in the incidence of CRC. At present most of the polyps are removed endoscopically. The vast majority of colorectal polyps identified at colonoscopy are small and do not pose a significant challenge for resection to an appropriately trained and skilled endoscopist. Advanced polypectomy techniques are intended for the removal of difficult colon polyps. We have defined a “difficult polyp” as any lesion that due to its size, shape or location represents a challenge for the colonoscopist to remove. Although many “difficult polyps” will be an easy target for the advanced endoscopist, polyps that are larger than 15 mm, have a large pedicle, are flat and extended, are difficult to see or are located in the cecum or any angulated portion of the colon should be always considered difficult. Although very successful, advanced resection techniques can potentially cause serious, even life-threatening complications. Moreover, post polypectomy complications are more common in the presence of difficult polyps. Therefore, any endoscopist attempting advanced polypectomy techniques should be adequately supervised by an expert or have an excellent training in interventional endoscopy. This review describes several useful tips and tricks to deal with difficult polyps. PMID:22816006
Da Re, Sandra; Valle, Jaione; Charbonnel, Nicolas; Beloin, Christophe; Latour-Lambert, Patricia; Faure, Philippe; Turlin, Evelyne; Le Bouguénec, Chantal; Renauld-Mongénie, Geneviève; Forestier, Christiane; Ghigo, Jean-Marc
Protection provided by host bacterial microbiota against microbial pathogens is a well known but ill-understood property referred to as the barrier effect, or colonization resistance. Despite recent genome-wide analyses of host microbiota and increasing therapeutic interest, molecular analysis of colonization resistance is hampered by the complexity of direct in vivo experiments. Here we developed an in vitro-to-in vivo approach to identification of genes involved in resistance of commensal bacteria to exogenous pathogens. We analyzed genetic responses induced in commensal Escherichia coli upon entry of a diarrheagenic enteroaggregative E. coli or an unrelated Klebsiella pneumoniae pathogen into a biofilm community. We showed that pathogens trigger specific responses in commensal bacteria and we identified genes involved in limiting colonization of incoming pathogens within commensal biofilm. We tested the in vivo relevance of our findings by comparing the extent of intestinal colonization by enteroaggregative E. coli and K. pneumoniae pathogens in mice pre-colonized with E. coli wild type commensal strain, or mutants corresponding to identified colonization resistance genes. We demonstrated that the absence of yiaF and bssS (yceP) differentially alters pathogen colonization in the mouse gut. This study therefore identifies previously uncharacterized colonization resistance genes and provides new approaches to unravelling molecular aspects of commensal/pathogen competitive interactions. PMID:23667443
Wysocki, Annette B
Open skin wounds are colonized with bacteria, and optimal wound care is required to prevent progression to infection. Intact skin normally provides protection from external environmental assaults. Disruption of the skin or tissue creating an open skin wound can result in infection, dehydration, hypothermia, scarring, compromised immunity, and changes in body image. Biofilms and bacterial genomics are areas of intense scientific investigation in the face of the emerging threat of bacterial resistance. Optimal wound care to prevent progression from colonization to infection remains the foundation of good clinical practice. On the basis of wound conditions, cleansing, debridement, measures to increase oxygenation and perfusion, adequate nutrition, and appropriate use of topical agents and antibiotics, when indicated, are the keys to managing open skin wounds. This article provides a targeted review of normal skin flora, wound healing, prevention of skin infection, colonization versus infection, biofilms, genomics and infectious disease, and management of open skin wounds.
O'Brien Andersen, L; Karim, A B; Roager, H M; Vigsnæs, L K; Krogfelt, K A; Licht, T R; Stensvold, C R
Several studies have shown associations between groups of intestinal bacterial or specific ratios between bacterial groups and various disease traits. Meanwhile, little is known about interactions and associations between eukaryotic and prokaryotic microorganisms in the human gut. In this work, we set out to investigate potential associations between common single-celled parasites such as Blastocystis spp. and Dientamoeba fragilis and intestinal bacteria. Stool DNA from patients with intestinal symptoms were selected based on being Blastocystis spp.-positive (B+)/negative (B-) and D. fragilis-positive (D+)/negative (D-), and split into four groups of 21 samples (B+ D+, B+ D-, B- D+, and B- D-). Quantitative PCR targeting the six bacterial taxa Bacteroides, Prevotella, the butyrate-producing clostridial clusters IV and XIVa, the mucin-degrading Akkermansia muciniphila, and the indigenous group of Bifidobacterium was subsequently performed, and the relative abundance of these bacteria across the four groups was compared. The relative abundance of Bacteroides in B- D- samples was significantly higher compared with B+ D- and B+ D+ samples (P < 0.05 and P < 0.01, respectively), and this association was even more significant when comparing all parasite-positive samples with parasite-negative samples (P < 0.001). Additionally, our data revealed that a low abundance of Prevotella and a higher abundance of Clostridial cluster XIVa was associated with parasite-negative samples (P < 0.05 and P < 0.01, respectively). Our data support the theory that Blastocystis alone or combined with D. fragilis is associated with gut microbiota characterized by low relative abundances of Bacteroides and Clostridial cluster XIVa and high levels of Prevotella.
Bacterial cultures of crop and cecal contents of adult poultry contain beneficial bacteria that reduce colonization of young poultry by Salmonella. Since endospore-forming bacteria may play a role in competitive exclusion of Salmonella in poultry, 3 trials were conducted to isolate these bacteria fr...
Baldotto, Lílian Estrela Borges; Olivares, Fábio Lopes
Plant surfaces are a favourable niche for bacterial establishment, and hypothetically, plant species differ in their capacity to harbour epiphytic bacterial communities. This study was conducted to evaluate and describe the structural relationship of a bacterial community at the phyllosphere level with different plant species in a tropical ecosystem. Leaf blades of 47 plant species distributed in 27 botanical families were collected on a typical small Brazilian farm and prepared for observation under light and scanning electron microscopy. Naturally occurring bacteria were the most abundant settlers of the phylloplane, followed by fungal spore or hyphae. All plant species studied were colonized by phylloepiphytic bacteria, which were observed as solitary cells, microcolonies, and biofilms. However, independent of the family, the plant species differed in the pattern of phyllosphere colonization, as reflected in bacteria frequency and presence or absence of anatomical features that would favour the association. The phylloepiphytic bacteria were preferentially established on the following sites: epidermal cell wall junctions, glandular and nonglandular trichomes, veins, stomata, and epidermal cell wall surface. Profuse bacteria and fungi colonization was observed, at a level that was at least comparable with temperate regions. Interestingly, fungi seemed to alter the bacteria colonization pattern, most probably by microenvironmental modifications. The trichome type and density as well as the presence of epicuticular wax on the leaf blade surface seemed to be the most determinant anatomical features for the pattern of phyllosphere colonization. The presence of trichomes has a favourable, and epicuticular wax an unfavourable influence on the plant-bacteria interaction.
Fungi are pathogens that commonly infect immunocompromised patients and can affect any organs of the body, including the colon. However, the literature provides limited details on colonic infections caused by fungi. This article is an intensive review of information available on the fungi that can cause colon infections. It uses a comparative style so that its conclusions may be accessible for clinical application. PMID:25364269
From May 29 to June 5, 2003, the American Society of Clinical Oncology held its 39th Annual Meeting in Chicago, Illinois, U.S.A. The meeting was devoted to the presentation of advances in clinical sciences, diagnosis, prevention and management of malignant disorders, and brings together investigators, clinicians, policy makers and other professionals interested in the science and impact of cancer worldwide. This report will be presented in two parts, the first focusing of colon cancer, and the second on breast cancer will be published in the next issue of Drug News & Perspectives.
Flannery, Maura C.
Explores new research about bacteria. Discusses bacterial genomes, archaea, unusual environments, evolution, pathogens, bacterial movement, biofilms, bacteria in the body, and a bacterial obsession. Contains 29 references. (JRH)
Beltran-Garcia, Miguel J.; White, Jr., James F.; Prado, Fernanda M.; Prieto, Katia R.; Yamaguchi, Lydia F.; Torres, Monica S.; Kato, Massuo J.; Medeiros, Marisa H. G.; Di Mascio, Paolo
Plants form symbiotic associations with endophytic bacteria within tissues of leaves, stems, and roots. It is unclear whether or how plants obtain nitrogen from these endophytic bacteria. Here we present evidence showing nitrogen flow from endophytic bacteria to plants in a process that appears to involve oxidative degradation of bacteria. In our experiments we employed Agave tequilana and its seed-transmitted endophyte Bacillus tequilensis to elucidate organic nitrogen transfer from 15N-labeled bacteria to plants. Bacillus tequilensis cells grown in a minimal medium with 15NH4Cl as the nitrogen source were watered onto plants growing in sand. We traced incorporation of 15N into tryptophan, deoxynucleosides and pheophytin derived from chlorophyll a. Probes for hydrogen peroxide show its presence during degradation of bacteria in plant tissues, supporting involvement of reactive oxygen in the degradation process. In another experiment to assess nitrogen absorbed as a result of endophytic colonization of plants we demonstrated that endophytic bacteria potentially transfer more nitrogen to plants and stimulate greater biomass in plants than heat-killed bacteria that do not colonize plants but instead degrade in the soil. Findings presented here support the hypothesis that some plants under nutrient limitation may degrade and obtain nitrogen from endophytic microbes. PMID:25374146
Beltran-Garcia, Miguel J; White, James F; Prado, Fernanda M; Prieto, Katia R; Yamaguchi, Lydia F; Torres, Monica S; Kato, Massuo J; Medeiros, Marisa H G; Di Mascio, Paolo
Plants form symbiotic associations with endophytic bacteria within tissues of leaves, stems, and roots. It is unclear whether or how plants obtain nitrogen from these endophytic bacteria. Here we present evidence showing nitrogen flow from endophytic bacteria to plants in a process that appears to involve oxidative degradation of bacteria. In our experiments we employed Agave tequilana and its seed-transmitted endophyte Bacillus tequilensis to elucidate organic nitrogen transfer from (15)N-labeled bacteria to plants. Bacillus tequilensis cells grown in a minimal medium with (15)NH4Cl as the nitrogen source were watered onto plants growing in sand. We traced incorporation of (15)N into tryptophan, deoxynucleosides and pheophytin derived from chlorophyll a. Probes for hydrogen peroxide show its presence during degradation of bacteria in plant tissues, supporting involvement of reactive oxygen in the degradation process. In another experiment to assess nitrogen absorbed as a result of endophytic colonization of plants we demonstrated that endophytic bacteria potentially transfer more nitrogen to plants and stimulate greater biomass in plants than heat-killed bacteria that do not colonize plants but instead degrade in the soil. Findings presented here support the hypothesis that some plants under nutrient limitation may degrade and obtain nitrogen from endophytic microbes.
Korkmaz, Mukadder; Çetinkol, Yeliz; Korkmaz, Hakan; Batmaz, Timur
Background: Epistaxis is a common problem in childhood. It has been shown that children with recurrent epistaxis are more likely to have nasal colonization with Staphylococcus aureus. It has been suggested that low-grade inflammation, crusting and increased vascularity due to bacterial colonization contributes to the development of epistaxis in children. Aims: This study aimed to investigate the nasal colonization and treatment outcome in pediatric epistaxis patients. Study Design: Retrospective cross-sectional study. Methods: Charts of the pediatric patients referred to our university hospital otolaryngology outpatient clinics for the evaluation of epistaxis were reviewed. The patients whose nasal cultures had been taken at the first clinical visit comprised the study group. Results: Staphylococcus aureus was the most common bacteria grown. The presence of crusting and hypervascularity was not dependent on the type of bacterial growth and there was no relation between hypervascularity and crusting of the nasal mucosa. Thirty-six patients were evaluated for the outcome analysis. Resolution of bleeding was not dependent on nasal colonization; in patients with colonization, there was no difference between topical antibacterial and non-antibacterial treatments. Conclusion: Despite the high colonization rates, topical antibacterial treatment was not found superior to non-antibacterial treatment. Our study does not support the belief that bacterial colonization results in hypervascularity of the septal mucosa causing epistaxis since no relation was found between nasal colonization, hypervascularity and crusting. The role of bacterial colonization in pediatric epistaxis need to be further investigated and treatment protocols must be determined accordingly. PMID:27403392
López-Molina, Dorotea; Chazarra, Soledad; How, Chee Wun; Pruidze, Nikolov; Navarro-Perán, Enma; García-Cánovas, Francisco; García-Ruiz, Pedro Antonio; Rojas-Melgarejo, Francisco; Rodríguez-López, José Neptuno
Colon diseases are difficult to treat because oral administrated drugs are absorbed at the stomach and intestine levels and they do not reach colon; in addition, intravenous administrated drugs are eliminated from the body before reaching colon. Inulin is a naturally occurring polysaccharide found in many plants. It consists of β 2-1 linked D-fructose molecules having a glucosyl unit at the reducing end. Various inulin and dextran hydrogels have been developed that serve as potential carrier for introduction of drugs into the colon. Because inulin is not absorbed in the stomach or in the small intestine, and inulin is degraded by colonic bacteria, drugs encapsulated in inulin-coated vesicles could be specifically liberated in the colon. Therefore, the use of inulin-coated vesicles could represent an advance for the treatment of colon diseases. Here, we study the use of a cinnamoylated derivative of chicory inulin as a vehicle for the controlled delivery of colonic drugs. The encapsulation of methotrexate in inulin vesicles and its release and activity was studied in colon cancer cells in cultures.
Carbonero, Franck; Benefiel, Ann C.; Alizadeh-Ghamsari, Amir H.; Gaskins, H. Rex
Sulfur is both crucial to life and a potential threat to health. While colonic sulfur metabolism mediated by eukaryotic cells is relatively well studied, much less is known about sulfur metabolism within gastrointestinal microbes. Sulfated compounds in the colon are either of inorganic (e.g., sulfates, sulfites) or organic (e.g., dietary amino acids and host mucins) origin. The most extensively studied of the microbes involved in colonic sulfur metabolism are the sulfate-reducing bacteria (SRB), which are common colonic inhabitants. Many other microbial pathways are likely to shape colonic sulfur metabolism as well as the composition and availability of sulfated compounds, and these interactions need to be examined in more detail. Hydrogen sulfide is the sulfur derivative that has attracted the most attention in the context of colonic health, and the extent to which it is detrimental or beneficial remains in debate. Several lines of evidence point to SRB or exogenous hydrogen sulfide as potential players in the etiology of intestinal disorders, inflammatory bowel diseases (IBDs) and colorectal cancer in particular. Generation of hydrogen sulfide via pathways other than dissimilatory sulfate reduction may be as, or more, important than those involving the SRB. We suggest here that a novel axis of research is to assess the effects of hydrogen sulfide in shaping colonic microbiome structure. Clearly, in-depth characterization of the microbial pathways involved in colonic sulfur metabolism is necessary for a better understanding of its contribution to colonic disorders and development of therapeutic strategies. PMID:23226130
Esser, Daniel S.; Leveau, Johan H.J.; Meyer, Katrin M.; Wiegand, Kerstin
Microbial life on plant leaves is characterized by a multitude of interactions between leaf colonizers and their environment. While the existence of many of these interactions has been confirmed, their spatial scale or reach often remained unknown. In this study, we applied spatial point pattern analysis to 244 distribution patterns of Pantoea agglomerans and Pseudomonas syringae on bean leaves. The results showed that bacterial colonizers of leaves interact with their environment at different spatial scales. Interactions among bacteria were often confined to small spatial scales up to 5–20 μm, compared to interactions between bacteria and leaf surface structures such as trichomes which could be observed in excess of 100 μm. Spatial point-pattern analyses prove a comprehensive tool to determine the different spatial scales of bacterial interactions on plant leaves and will help microbiologists to better understand the interplay between these interactions. PMID:25764562
Moore, Michael F
Chronic non-healing venous ulcers are by their very nature colonized with bacteria. The amount and make up will vary based on many variables. The transition from colonization to contamination, critical colonization, and infection complicates the treatment of these ulcers. Silver has been shown to be an effective antimicrobial agent with a diverse antimicrobial footprint, minimal allergic reactions, and has been employed for over twenty-five years with little resistance being encountered. Based on these factors, this study was initiated to evaluate the impact of silver containing absorbent dressings on critically colonized venous leg ulcers.
Moore, Michael F.
Chronic non-healing venous ulcers are by their very nature colonized with bacteria. The amount and make up will vary based on many variables. The transition from colonization to contamination, critical colonization, and infection complicates the treatment of these ulcers. Silver has been shown to be an effective antimicrobial agent with a diverse antimicrobial footprint, minimal allergic reactions, and has been employed for over twenty-five years with little resistance being encountered. Based on these factors, this study was initiated to evaluate the impact of silver containing absorbent dressings on critically colonized venous leg ulcers. PMID:26199888
Baldwin, David N; Shepherd, Benjamin; Kraemer, Petra; Hall, Michael K; Sycuro, Laura K; Pinto-Santini, Delia M; Salama, Nina R
Chronic infection of the human stomach by Helicobacter pylori leads to a variety of pathological sequelae, including peptic ulcer and gastric cancer, resulting in significant human morbidity and mortality. Several genes have been implicated in disease related to H. pylori infection, including the vacuolating cytotoxin and the cag pathogenicity island. Other factors important for the establishment and maintenance of infection include urease enzyme production, motility, iron uptake, and stress response. We utilized a C57BL/6 mouse infection model to query a collection of 2,400 transposon mutants in two different bacterial strain backgrounds for H. pylori genetic loci contributing to colonization of the stomach. Microarray-based tracking of transposon mutants allowed us to monitor the behavior of transposon insertions in 758 different gene loci. Of the loci measured, 223 (29%) had a predicted colonization defect. These included previously described H. pylori virulence genes, genes implicated in virulence in other pathogenic bacteria, and 81 hypothetical proteins. We have retested 10 previously uncharacterized candidate colonization gene loci by making independent null alleles and have confirmed their colonization phenotypes by using competition experiments and by determining the dose required for 50% infection. Of the genetic loci retested, 60% have strain-specific colonization defects, while 40% have phenotypes in both strain backgrounds for infection, highlighting the profound effect of H. pylori strain variation on the pathogenic potential of this organism.
Kasendra, Magdalena; Barrile, Riccardo; Leuzzi, Rosanna; Soriani, Marco
The contribution of Clostridium difficile toxin A and B (TcdA and TcdB) to cellular intoxication has been studied extensively, but their impact on bacterial colonization remains unclear. By setting up 2- and 3-dimensional in vitro models of polarized gut epithelium, we investigated how C. difficile infection is affected by host cell polarity and whether TcdA and TcdB contribute to such events. Indeed, we observed that C. difficile adhesion and penetration of the mucosal barrier are substantially enhanced in poorly polarized or ethylene glycol tetraacetic acid-treated cells, indicating that bacteria bind preferentially to the basolateral (BL) cell surface. In this context, we demonstrated that sub-lethal concentrations of C. difficile TcdA are able to alter cell polarity by causing redistribution of plasma membrane components between distinct surface domains. Taken together, the data suggest that toxin-mediated modulation of host cell organization may account for the capacity of this opportunistic pathogen to gain access to BL receptors, leading to a successful colonization of the colonic mucosa.
Oka, Yoshinobu; Kim, Wook-Cheol; Yoshida, Takashi; Hirashima, Toshiko; Mouri, Hisashi; Urade, Hidenori; Itoh, Yoshihisa; Kubo, Toshikazu
The purpose of this study was to evaluate the efficacy of titanium dioxide photocatalyst in inhibition of bacterial colonization on percutaneous implants. Titanium dioxide photocatalyst was prepared by direct oxidization of pure titanium substrate, and a comparative study with pure titanium was performed. The bactericidal ability of the photocatalyst was examined using methicillin-resistant Staphylococcus aureus (MRSA) suspensions in a colony-forming assay according to the Japanese Industrial Standards committee standard. After exposing the MRSA suspension on sample plates to ultraviolet A (UVA) light, the number of surviving bacteria was estimated. Next, an animal model for inhibition of colonization was examined in vivo. Pins were inserted into the femurs of rabbits, were infected with 10(8) colony-forming units of MRSA suspension, and were illuminated with UVA light for 60 min daily; the number of colonizing bacteria was estimated after 7 days. The bactericidal ability of the photocatalyst was apparent after 60 min, when the bacteria had almost disappeared. The number of colonizing bacteria on photocatalytic pins was decreased significantly in vivo. The photocatalyst was effective even against resistant bacterial colonization. Clinically, the incidence of percutaneous implant infection such as pin tract infection in external fixation could be reduced using the titanium photocatalyst.
Prieto, Pilar; Mercado-Blanco, Jesús
Confocal microscopy combined with three-dimensional olive root tissue sectioning was used to provide evidence of the endophytic behaviour of Pseudomonas fluorescens PICF7, an effective biocontrol strain against Verticillium wilt of olive. Two derivatives of the green fluorescent protein (GFP), the enhanced green and the red fluorescent proteins, have been used to visualize simultaneously two differently fluorescently tagged populations of P. fluorescens PICF7 within olive root tissues at the single cell level. The time-course of colonization events of olive roots cv. Arbequina by strain PICF7 and the localization of tagged bacteria within olive root tissues are described. First, bacteria rapidly colonized root surfaces and were predominantly found in the differentiation zone. Thereafter, microscopy observations showed that PICF7-tagged populations eventually disappeared from the root surface, and increasingly colonized inner root tissues. Localized and limited endophytic colonization by the introduced bacteria was observed over time. Fluorescent-tagged bacteria were always visualized in the intercellular spaces of the cortex region, and no colonization of the root xylem vessels was detected at any time. To the best of our knowledge, this is the first time this approach has been used to demonstrate endophytism of a biocontrol Pseudomonas spp. strain in a woody host such as olive using a nongnotobiotic system.
Smitherman, David V., Jr.
The steps required for space colonization are many to grow from our current 3-person International Space Station, now under construction, to an infrastructure that can support hundreds and eventually thousands of people in space. This paper will summarize the author's findings from numerous studies and workshops on related subjects and identify some of the critical next steps toward space colonization. Findings will be drawn from the author s previous work on space colony design, space infrastructure workshops, and various studies that addressed space policy. In conclusion, this paper will note that significant progress has been made on space facility construction through the International Space Station program, and that significant efforts are needed in the development of new reusable Earth to Orbit transportation systems. The next key steps will include reusable in space transportation systems supported by in space propellant depots, the continued development of inflatable habitat and space elevator technologies, and the resolution of policy issues that will establish a future vision for space development.
Sankaridurg, Padmaja R.; Sharma, Savitri; Willcox, Mark; Naduvilath, Thomas J.; Sweeney, Deborah F.; Holden, Brien A.; Rao, Gullapalli N.
Microorganisms, especially gram-negative bacteria, are considered to play a role in the etiology of certain corneal infiltrative events (CIEs) observed during soft contact lens wear. This study explored the possibility of microbial colonization of soft contact lenses as a risk factor leading to CIEs. In a clinical trial conducted from March 1993 to January 1996, 330 subjects wore disposable soft contact lenses on a 6-night extended-wear and disposal schedule. During this period, 4,321 lenses (118 during CIEs; 4,203 during asymptomatic lens wear) were recovered aseptically and analyzed for microbial colonization. A greater percentage of lenses were free from microbial colonization during asymptomatic wear than during CIEs (42 versus 23%; P < 0.0001). The incidence of gram-positive bacteria, gram-negative bacteria and fungi was greater during CIEs than during asymptomatic lens wear (P < 0.05). During asymptomatic lens wear, gram-positive bacteria were isolated most frequently and were usually normal external ocular microbiota. Of the gram-positive bacteria, the incidence of Streptococcus pneumoniae was greater during CIE than during asymptomatic wear (7.6 versus 0.6%; P < 0.0001). While gram-negative bacteria were seen in few cases during asymptomatic wear, their incidence during CIE in comparison to asymptomatic wear was substantial and significant (23.7 versus 3.8%; P < 0.0001). Also, the level of colonization was high. Of CIEs, events of microbial keratitis, contact lens acute red eye, and asymptomatic infiltrative keratitis were associated with lens colonization with gram-negative bacteria or S. pneumoniae. Colonization of soft contact lenses with pathogenic bacteria, especially gram-negative bacteria and S. pneumoniae, appears to be a significant risk factor leading to CIE. PMID:11101574
Chahales, Peter; Thanassi, David G.
Bacteria assemble a wide range of adhesive proteins, termed adhesins, to mediate binding to receptors and colonization of surfaces. For pathogenic bacteria, adhesins are critical for early stages of infection, allowing the bacteria to initiate contact with host cells, colonize different tissues, and establish a foothold within the host. The adhesins expressed by a pathogen are also critical for bacterial-bacterial interactions and the formation of bacterial communities such as biofilms. The ability to adhere to host tissues is particularly important for bacteria that colonize sites such as the urinary tract, where the flow of urine functions to maintain sterility by washing away non-adherent pathogens. Adhesins vary from monomeric proteins that are directly anchored to the bacterial surface to polymeric, hairlike fibers that extend out from the cell surface. These latter fibers are termed pili or fimbriae, and were among the first identified virulence factors of uropathogenic Escherichia coli. Studies since then have identified a range of both pilus and non-pilus adhesins that contribute to bacterial colonization of the urinary tract, and have revealed molecular details of the structures, assembly pathways, and functions of these adhesive organelles. In this review, we describe the different types of adhesins expressed by both Gram-negative and Gram-positive uropathogens, what is known about their structures, how they are assembled on the bacterial surface, and the functions of specific adhesins in the pathogenesis of urinary tract infections. PMID:26542038
Gonzalez, Quintín H; Heslin, Martin J; Dávila-Cervantes, Andrea; Alvarez-Tostado, Javier; de los Monteros, Antonio Espinosa; Shore, Gregg; Vickers, Selwyn M
Surgical resection of primary colonic lymphoma can be an important therapeutic tool. We performed a nonrandomized retrospective descriptive study at the University hospital tertiary care center. From January 1990 to June 2002, a total of 15 patients with primary colonic lymphoma were identified from the tumor registry at University of Alabama at Birmingham and retrospectively reviewed under Institutional Review Board approved protocol. Demographic data, clinical features, treatment method (surgery and/or chemotherapy), recurrence rate, and survival were analyzed. The results are presented as mean +/- standard deviation or median and range. Differences in survival were evaluated by the log-rank test and the interval of disease-free survival was calculated using the Kaplan-Meier method. A P value of <0.05 was considered statistically significant. Main outcome measures included surgical results, morbidity, mortality, and recurrence rate. Mean age was 51.5 years (standard deviation 16.4), 33 per cent were male and 67 per cent were female. Presenting symptoms were diarrhea (53.5%), lower gastrointestinal bleeding (13.3%), and nausea and vomiting (46.7%) secondary to low-grade obstruction. Concomitant colorectal disease was present in one patient with ulcerative colitis. Preoperative diagnosis of lymphoma was made in 13 patients (87%) with colonoscopy and biopsy. CT scan was performed in all patients; and none had radiographic evidence of systemic extension. Only one patient had a history of lymphoproliferative disease and exposure to radiation. The most common disease location was the cecum (60%), followed by the right colon (27%), and the sigmoid colon (13%). The mean lactic dehydrogenase (LDH) value was 214.9 u/L (range 129-309). Thirty-three per cent of the patients had an LDH value that was above the upper normal limit. LDH returned to normal after treatment in all patients. Operations performed consisted of right hemicolectomy (13), total proctocolectomy with ileal
Ritchie, J A
The mean distance of travel and hourly incidence of propulsive and retropulsive movements of colonic contents have been assessed by means of time-lapse cinefluorography and compared in 98 patients with the irritable colon syndrome and in 90 control subjects.Net propulsion in patients with the irritable colon syndrome was less than in the controls at rest, similar to the controls after feeding, and greater than in the controls after an injection of carbachol. In both clinical groups, food and carbachol increased the incidence of propulsive and retropulsive movements but did not alter the average distance over which they travelled.The figures suggest that at least two-thirds of all net propulsion of colonic contents in the irritable colon syndrome takes place under circumstances not reproduced in the present study.
Venditti, Carolina; Villa, Laura; Capone, Alessandro; Fortini, Daniela; D'Arezzo, Silvia; Nisii, Carla; Bordi, Eugenio; Puro, Vincenzo; Antonini, Mario; Carattoli, Alessandra; Cataldo, Maria Adriana; Petrosillo, Nicola; Di Caro, Antonino
We describe the interspecies transmission of the plasmid-mediated blaKPC-3 gene, which confers carbapenem resistance, between clinically relevant gram-negative bacteria in a single patient. A KPC-3 producing Enterobacter aerogenes was isolated from a hospitalized patient previously colonized and then infected by a Klebsiella pneumoniae ST101 carrying the blaKPC-3 gene. The strains showed identical plasmids. Since intense horizontal exchanges among bacteria can occur in the gut, clinicians should be aware that patients colonized by carbapenem-resistant K. pneumoniae could become carriers of other carbapenem-resistant Enterobacteriaceae.
Koivisto, T; Salaspuro, M
Intracolonic bacteria have previously been shown to produce substantial amounts of acetaldehyde during ethanol oxidation, and it has been suggested that this acetaldehyde might be associated with alcohol-related colonic disorders, as well as other alcohol-induced organ injuries. The capacity of colonic mucosa to remove this bacterial acetaldehyde by aldehyde dehydrogenase (ALDH) is, however, poorly known. We therefore measured ALDH activities and determined ALDH isoenzyme profiles from different subcellular fractions of rat colonic mucosa. For comparison, hepatic, gastric, and small intestinal samples were studied similarly. Alcohol dehydrogenase (ADH) activities were also measured from all of these tissues. Rat colonic mucosa was found to possess detectable amounts of ALDH activity with both micromolar and millimolar acetaldehyde concentrations and in all subcellular fractions. The ALDH activities of colonic mucosa were, however, generally low when compared with the liver and stomach, and they also tended to be lower than in small intestine. Mitochondrial low K(m) ALDH2 and cytosolic ALDH with low K(m) for acetaldehyde were expressed in the colonic mucosa, whereas some cytosolic high K(m) isoenzymes found in the small intestine and stomach were not detectable in colonic samples. Cytosolic ADH activity corresponded well to ALDH activity in different tissues: in colonic mucosa, it was approximately 6 times lower than in the liver and about one-half of gastric ADH activity. ALDH activity of the colonic mucosa should, thus, be sufficient for the removal of acetaldehyde produced by colonic mucosal ADH during ethanol oxidation. It may, however, be insufficient for the removal of the acetaldehyde produced by intracolonic bacteria. This may lead to the accumulation of acetaldehyde in the colon and colonic mucosa after ingestion of ethanol that might, at least after chronic heavy alcohol consumption, contribute to the development of alcohol-related colonic morbidity
Wentrup, Cecilia; Wendeberg, Annelie; Schimak, Mario; Borowski, Christian; Dubilier, Nicole
Symbiotic bivalves at hydrothermal vents and cold seeps host chemosynthetic bacteria intracellularly in gill cells. In bivalves, the gills grow continuously throughout their lifetime by forming new filaments. We examined how newly developed gill tissues are colonized in bivalves with horizontal and vertical symbiont transmission (Bathymodiolus mussels versus a vesicoymid clam) using fluorescence in situ hybridization and transmission electron microscopy. Symbiont colonization was similar in mussels and clams and was independent of the transmission modes. Symbionts were absent in the growth zones of the gills, indicating that symbionts colonize newly formed gill filaments de novo after they are formed and that gill colonization is a continuous process throughout the host's lifetime. Symbiont abundance and distribution suggested that colonization is shaped by the developmental stage of host cells. Self-infection, in which new gill cells are colonized by symbionts from ontogenetically older gill tissues, may also play a role. In mussels, symbiont infection led to changes in gill cell structure similar to those described from other epithelial cells infected by intracellular pathogens, such as the loss of microvilli. A better understanding of the factors that affect symbiont colonization of bivalve gills could provide new insights into interactions between intracellular bacteria and epithelial tissues.
Raveh-Sadka, Tali; Thomas, Brian C; Singh, Andrea; Firek, Brian; Brooks, Brandon; Castelle, Cindy J; Sharon, Itai; Baker, Robyn; Good, Misty; Morowitz, Michael J; Banfield, Jillian F
Premature infants are highly vulnerable to aberrant gastrointestinal tract colonization, a process that may lead to diseases like necrotizing enterocolitis. Thus, spread of potential pathogens among hospitalized infants is of great concern. Here, we reconstructed hundreds of high-quality genomes of microorganisms that colonized co-hospitalized premature infants, assessed their metabolic potential, and tracked them over time to evaluate bacterial strain dispersal among infants. We compared microbial communities in infants who did and did not develop necrotizing enterocolitis. Surprisingly, while potentially pathogenic bacteria of the same species colonized many infants, our genome-resolved analysis revealed that strains colonizing each baby were typically distinct. In particular, no strain was common to all infants who developed necrotizing enterocolitis. The paucity of shared gut colonizers suggests the existence of significant barriers to the spread of bacteria among infants. Importantly, we demonstrate that strain-resolved comprehensive community analysis can be accomplished on potentially medically relevant time scales.
Cultures of beneficial bacteria used in probiotics produce and utilize organic acids that may play a role in the ability of the cultures to inhibit colonization of poultry by enteropathogens. Cecal contents of adult poultry contain many of these beneficial bacteria, and earlier experiments showed th...
Agha, F.P.; Francis, I.R.; Simms, S.M.
Cystic lymphangioma is a rare benign lesion of the gastrointestinal tract, in which the colon is the least frequntly involved site. A case is reported displaying the characteristic radiographic features of an extramucosal intramural mass lesion in a patient with concurrent cystadenocarcinoma of the pancreas, in whom the possibility of a metastatic lesion to the colon could not be excluded except by surgical resection.
Pacheco, Alline R; Curtis, Meredith M; Ritchie, Jennifer M; Munera, Diana; Waldor, Matthew K; Moreira, Cristiano G; Sperandio, Vanessa
The mammalian gastrointestinal tract provides a complex and competitive environment for the microbiota. Successful colonization by pathogens requires scavenging nutrients, sensing chemical signals, competing with the resident bacteria and precisely regulating the expression of virulence genes. The gastrointestinal pathogen enterohaemorrhagic Escherichia coli (EHEC) relies on inter-kingdom chemical sensing systems to regulate virulence gene expression. Here we show that these systems control the expression of a novel two-component signal transduction system, named FusKR, where FusK is the histidine sensor kinase and FusR the response regulator. FusK senses fucose and controls expression of virulence and metabolic genes. This fucose-sensing system is required for robust EHEC colonization of the mammalian intestine. Fucose is highly abundant in the intestine. Bacteroides thetaiotaomicron produces multiple fucosidases that cleave fucose from host glycans, resulting in high fucose availability in the gut lumen. During growth in mucin, B. thetaiotaomicron contributes to EHEC virulence by cleaving fucose from mucin, thereby activating the FusKR signalling cascade, modulating the virulence gene expression of EHEC. Our findings suggest that EHEC uses fucose, a host-derived signal made available by the microbiota, to modulate EHEC pathogenicity and metabolism.
Carmichael, I; Harper, I S; Coventry, M J; Taylor, P W; Wan, J; Hickey, M W
Bacterial biofilms have been observed and reported on food and food-processing surfaces and can contribute to increased risks for product quality and food safety. The colonization of fruit and vegetables by pectynolitic bacteria like Pseudonomas fluorescens attributable to conditions such as soft rot, can also manifest as biofilms. A developed biofilm structure can provide a protective environment for pathogens such as Listeria monocytogenes reducing the effectiveness of sanitisers and other inhibitory agents. Understanding the colonization of bacteria on leaf surfaces is essential to the development of a better understanding of the leaf ecology of vegetable products. Studies of microbial colonization of leaf surfaces have been conducted using SEM and more recently using confocal microsocpy techniques. In the current study, a Leica TCS NT laser scanning confocal microscope was used to investigate biofilm formation using vital fluorescence staining on intact vegetable leaves. Reflection contrast and fluorescence three-dimensional imaging successfully delineated bacterial and biofilm morphology without disturbing the bacterial or leaf surface structure. The results demonstrate the presence and development of biofilm on the surface of lettuce. The biofilms appeared to originate on the cuticle in distinct micro-environments such as in the natural depression of the stomata, or in the intercellular junction. Bacteria also adhered to and developed biofilm colonies within an hour of contact and with clean stainless steel surfaces. Our study investigates the progression of biofilm formation from leaf colonization, and will assist in characterising the critical mechanisms of plant/host interaction and facilitate the development of improved preservation, sanitising and packaging strategies for minimally processed vegetable products.
Stones, Daniel Henry; Krachler, Anne Marie
Evolving under the constant exposure to an abundance of diverse microbial life, the human body has developed many ways of defining the boundaries between self and non-self. Many physical and immunological barriers to microbial invasion exist, and yet bacteria have found a multitude of ways to overcome these, initiate interactions with and colonize the human host. Adhesion to host cells and tissues is a key feature allowing bacteria to persist in an environment under constant flux and to initiate transient or permanent symbioses with the host. This review discusses reasons why adhesion is such a seemingly indispensable requirement for bacteria-host interactions, and whether bacteria can bypass the need to adhere and still persist. It further outlines open questions about the role of adhesion in bacterial colonization and persistence within the host.
Sikorszki, László; Horváth, Ors Péter; Papp, András; Cseke, László; Pavlovics, Gábor
The authors report the case of a colon adenocarcinoma developed on the neck at the anastomosis of the skin tube and colon 44 years following a corrosive oesophageal injury. This patient suffered a moderately severe oesophageal, stomach and laryngeal injuries due to drinking hydrochloric acid 44 years ago. He underwent serial laryngoplasties, then needed a tracheostomy, oesophagectomy, pyloroplasty and ileocolon transposition. An antethoracal oesophagus formation was performed with ileocolon and skin tube amendment. 44 years later an ulcerated adenocarcinoma developed in the transposed colon, which was resected and the ability to swallow was reinstated by the transplantation of an isolated jejunal segment using microvascular anastomosis.
Ryu, Seong Yeol; Baek, Won-Ki; Kim, Hyun Ah
Background/Aims The pathogen Acinetobacter baumannii is increasingly causing healthcare-associated infections worldwide, particularly in intensive care units. Biofilm formation, a factor contributing to the virulence of A. baumannii, is associated with long-term persistence in hospital environments. The present study investigates the clinical impact of biofilm production on colonization and acquisition after patient admission. Methods Forty-nine A. baumannii isolates were obtained between August and November 2013 from Keimyung University Dongsan Medical Center, Daegu, Korea. All isolates were obtained from sputum samples of new patients infected or colonized by A. baumannii. The microtiter plate assay was used to determine biofilm formation. Results Twenty-four A. baumannii isolates (48%) demonstrated enhanced biofilm formation capacity than that of the standard A. baumannii strain (ATCC 19606). All isolates were resistant to carbapenem, 38 isolates (77%) were collected from patients in an intensive care unit, and 47 isolates (95%) were from patients who had been exposed to antibiotics in the previous month. The median duration of colonization was longer for biofilm-producing isolates than that of the biofilm non-biofilm producing isolates (18 days vs. 12 days, p < 0.05). Simultaneous colonization with other bacteria was more common for biofilm-producing isolates than that for the non-biofilm producing isolates. The most prevalent co-colonizing bacteria was Staphylococcus aureus. Conclusions Biofilm-producing isolates seem to colonize the respiratory tract for longer durations than the non-biofilm producing isolates. During colonization, biofilm producers promote co-colonization by other bacteria, particularly S. aureus. Additional research is required to determine possible links between biofilm formation and nosocomial infection. PMID:27653617
Diseases affecting the colon are common worldwide and can cause a major health problem. Colorectal cancer (CRC) as well as Inflammatory bowel diseases represent a major cause of morbidity and mortality in western countries. PillCam colon capsule endoscopy (PCCE) is a novel and promising technology that can be useful for the screening and monitoring of colonic diseases. In the recent years many articles examined the use of various versions of PCCE—the 1st and 2nd generation versus various other endoscopic or radiologic modalities both for detection of colonic polyps or cancer and in both ulcerative colitis (UC) and Crohn’s disease. The aim of the current review is to provide up to date information regarding the use and usefulness of this method in these disease. PMID:27668227
Ljungh, Asa; Wadström, Torkel
A number of Lactobacillus species, Bifidobacterium sp, Saccharomyces boulardii, and some other microbes have been proposed as and are used as probiotic strains, i.e. live microorganisms as food supplement in order to benefit health. The health claims range from rather vague as regulation of bowel activity and increasing of well-being to more specific, such as exerting antagonistic effect on the gastroenteric pathogens Clostridium difficile, Campylobacter jejuni, Helicobacter pylori and rotavirus, neutralising food mutagens produced in colon, shifting the immune response towards a Th2 response, and thereby alleviating allergic reactions, and lowering serum cholesterol (Tannock, 2002). Unfortunately, most publications are case reports, uncontrolled studies in humans, or reports of animal or in vitro studies. Whether or not the probiotic strains employed shall be of human origin is a matter of debate but this is not a matter of concern, as long as the strains can be shown to survive the transport in the human gastrointestinal (GI) tract and to colonise the human large intestine. This includes survival in the stressful environment of the stomach - acidic pH and bile - with induction of new genes encoding a number of stress proteins. Since the availability of antioxidants decreases rostrally in the GI tract production of antioxidants by colonic bacteria provides a beneficial effect in scavenging free radicals. LAB strains commonly produce antimicrobial substance(s) with activity against the homologous strain, but LAB strains also often produce microbicidal substances with effect against gastric and intestinal pathogens and other microbes, or compete for cell surface and mucin binding sites. This could be the mechanism behind reports that some probiotic strains inhibit or decrease translocation of bacteria from the gut to the liver. A protective effect against cancer development can be ascribed to binding of mutagens by intestinal bacteria, reduction of the enzymes beta
New protozoan derived microbial consortia and method for their isolation are provided. Consortia and bacteria isolated therefrom are useful for treating wastes such as trichloroethylene and trinitrotoluene. Consortia, bacteria isolated therefrom, and dispersants isolated therefrom are useful for dispersing hydrocarbons such as oil, creosote, wax, and grease.
Tyndall, Richard L.
New protozoan derived microbial consortia and method for their isolation are provided. Consortia and bacteria isolated therefrom are useful for treating wastes such as trichloroethylene and trinitrotoluene. Consortia, bacteria isolated therefrom, and dispersants isolated therefrom are useful for dispersing hydrocarbons such as oil, creosote, wax, and grease.
Cilieborg, Malene S; Boye, Mette; Sangild, Per T
Necrotizing enterocolitis (NEC) develops in 5-10% of preterm infants in association with enteral feeding and bacterial colonization. It remains unclear how diet and bacteria interact to protect or provoke the immature gastrointestinal tract. Understanding the factors that control bacterial colonization may provide the clue to prevent NEC, and studies in infants must be combined with animal models to understand the mechanisms of the microbiota-epithelium interactions. Analyses of infant fecal samples show that the density and distribution of bacterial species are highly variable with no consistent effects of gestational age, delivery mode, diet or probiotic administration, while low bacterial diversity and bacterial overgrowth are commonly associated with NEC. A series of recent studies in preterm pigs show that the mucosa-associated microbiota is affected by delivery method, prematurity and NEC progression and that diet has limited effects. Overgrowth of specific groups (e.g. Clostridia) appears to be a consequence of NEC, rather than the cause of NEC. Administration of probiotics either decreases or increases NEC sensitivity in preterm pigs, while in preterm infants probiotics have generally decreased NEC incidence and overall mortality. The optimal nature and amount of probiotic bacteria are unknown and host defense factors appear more important for NEC sensitivity than the nature of the gut microbiota. Host defense is improved by feeding the optimal amount of enteral diets, such as mother's colostrum or milk, that help the immature intestinal immune system to respond appropriately to the highly variable bacterial colonization.
Berni Canani, Roberto; Sangwan, Naseer; Stefka, Andrew T.; Nocerino, Rita; Paparo, Lorella; Aitoro, Rosita; Calignano, Antonio; Khan, Aly A.; Gilbert, Jack A.; Nagler, Cathryn R.
Dietary intervention with extensively hydrolyzed casein formula supplemented with Lactobacillus rhamnosus GG (EHCF+LGG) accelerates tolerance acquisition in infants with cow’s milk allergy (CMA). We examined whether this effect is attributable, at least in part, to an influence on the gut microbiota. Fecal samples from healthy controls (n=20) and from CMA infants (n=19) before and after treatment with EHCF with (n=12) and without (n=7) supplementation with LGG were compared by 16S rRNA-based operational taxonomic unit clustering and oligotyping. Differential feature selection and generalized linear model fitting revealed that the CMA infants have a diverse gut microbial community structure dominated by Lachnospiraceae (20.5±9.7%) and Ruminococcaceae (16.2±9.1%). Blautia, Roseburia and Coprococcus were significantly enriched following treatment with EHCF and LGG, but only one genus, Oscillospira, was significantly different between infants that became tolerant and those that remained allergic. However, most tolerant infants showed a significant increase in fecal butyrate levels, and those taxa that were significantly enriched in these samples, Blautia and Roseburia, exhibited specific strain-level demarcations between tolerant and allergic infants. As a result, our data suggest that EHCF+LGG promotes tolerance in infants with CMA, in part, by influencing the strain-level bacterial community structure of the infant gut.
Doulberis, Michael; Angelopoulou, Katerina; Kaldrymidou, Eleni; Tsingotjidou, Anastasia; Abas, Zaphiris; Erdman, Suzan E; Poutahidis, Theofilos
Human studies and clues from animal models have provided important links between gastrointestinal (GI) tract bacteria and colon cancer. Gut microbiota antigenic stimuli play an important role in shaping the intestinal immune responses. Therefore, especially in the case of inflammation-associated colon cancer, gut bacteria antigens may affect tumorigenesis. The present study aimed to investigate the effects of the oral administration of a bacterial product with known immunomodulatory properties on inflammation-driven colorectal neoplasmatogenesis. For that, we used cholera-toxin and a well-established mouse model of colon cancer in which neoplasia is initiated by a single dose of the genotoxic agent azoxymethane (AOM) and subsequently promoted by inflammation caused by the colitogenic substance dextran sodium sulfate (DSS). We found that a single, low, non-pathogenic dose of CT, given orally at the beginning of each DSS treatment cycle downregulated neutrophils and upregulated regulatory T-cells and IL-10 in the colonic mucosa. The CT-induced disruption of the tumor-promoting character of DSS-induced inflammation led to the reduction of the AOM-initiated colonic polypoidogenesis. This result adds value to the emerging notion that certain GI tract bacteria or their products affect the immune system and render the microenvironment of preneoplastic lesions less favorable for promoting their evolution to cancer.
Broitman, S A; Cerda, S; Wilkinson, J
While epidemiologic and concordant experimental data indicate a direct relationship between dietary fat (and presumably caloric) intake and the development of colon cancer, the effect of dietary cholesterol on this disease is still not clear. However, there appears to be a developing literature concerning an inverse relationship between serum and plasma cholesterol levels, and the risk for colon cancer. Findings that low serum cholesterol levels are apparent as early as ten years prior to the detection of colon cancer implies that sub clinical disease is probably not involved initially in this process. The possibility of low serum cholesterol as a bio-marker was considered in epidemiologic studies which focused upon obese men with lower than normal serum cholesterol levels who were found to be at increased risk to colon cancer. While the relationship between low serum cholesterol and colonic or intestinal cholesterol metabolism is presently not understood, current genetic studies provide a promising though as yet unexplored potential association. Alterations which occur during the developmental progression of colonic cancer include changes in chromosome 5, which also carries two genes vital to the biosynthesis and regulation of systemic and cellular cholesterol metabolism, 3-hydroxy-3-methylglutaryl coenzyme A synthase, and 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCoA R). Regulation of cholesterol metabolism in intestinal cells in vivo and in vitro varies from that seen in normal fibroblasts or hepatocytes in terms of exogenous sources of cholesterol and how these sources regulate internal synthesis. Colonic cancer cells have been used to assess small bowel enterocyte cholesterol metabolism, which has been possible because of their ability to differentiate in culture, however information regarding true colonic enterocyte cholesterol metabolism is relatively scarce. Colonic cancer cells have been shown to possess a diminished or nonexistent ability to use
Brown, Carlos V R
For patients with small bowel and colonic perforations, a definitive diagnosis of the cause of perforation is not necessary before operation. Bowel obstruction and inflammatory bowel disease are the most common causes of nontraumatic intestinal perforations in industrialized countries, whereas infectious causes of intestinal perforations are more common in developing countries. Treatment of small bowel and colonic perforations generally includes intravenous antibiotics and fluid resuscitation, but the specific management of the bowel depends on the underlying cause of the perforation.
Amo Trillo, Víctor; Vera García, Pilar; Pinto, Isabel; Olmedo Martín, Raúl; Romero Blasco, Bartolomé
We report the case of a 68 year-old man in whom a tumour of the colon was identified by colonoscopy, during diagnostic studies for lower gastrointestinal bleeding as an outpatient. Histological examination showed clonal proliferation of plasma cells IgG-K. No other location was affected (including bone marrow). Diagnosis of plasmacytoma of the colon was made. We have carried out a review of the literature in relation to this unusual disorder.
Connelly-Frost, Alexandra; Poole, Charles; Satia, Jessie A.; Kupper, Lawrence L.; Millikan, Robert C.; Sandler, Robert S.
Background Selenium is an essential trace element which has been implicated in cancer risk; however, study results have been inconsistent with regard to colon cancer. Our objectives were to 1) investigate the association between selenium and colon cancer 2) evaluate possible effect measure modifiers and 3) evaluate potential biases associated with the use of post-diagnostic serum selenium measures Methods The North Carolina Colon Cancer Study is a large population-based, case-control study of colon cancer in North Carolina between 1996 and 2000 (n=1,691). Nurses interviewed patients about diet and lifestyle and drew blood specimens which were used to measure serum selenium. Results Individuals who had both high serum selenium (>140 mcg/L) and high reported folate (>354 mcg/day), had a reduced relative risk of colon cancer (OR=0.5, 95% CI=0.4,0.8). The risk of colon cancer for those with high selenium and low folate was approximately equal to the risk among those with low selenium and low folate (OR=1.1, 95% CI=0.7,1.5) as was the risk for those with low selenium and high folate (OR=0.9, 95% CI=0.7–1.2). We did not find evidence of bias due to weight loss, stage at diagnosis, or time from diagnosis to selenium measurement. Conclusion High levels of serum selenium and reported folate jointly were associated with a substantially reduced risk of colon cancer. Folate status should be taken into account when evaluating the relation between selenium and colon cancer in future studies. Importantly, weight loss, stage at diagnosis, or time from diagnosis to blood draw did not appear to produce strong bias in our study. PMID:19235033
Walker, W Allan
The paradigm of disease burden in the developed world has changed drastically in the last few decades from predominately infections to immune-mediated diseases (autoimmunity and allergy) because of alterations in the Western lifestyle (improved sanitation, immunizations, antibiotic usage and altered dietary intake). A diverse balanced microbiota is necessary for the development of an appropriate innate and adaptive immune response. There is strong evidence that disruption of the normal colonization process can lead to alterations in the important symbiotic relationship that is necessary for immune homeostasis. For example, infants born by cesarean section or receiving excessive perinatal antibiotics have inadequate initial colonization and aberrant mucosal immune function. As a result, later in childhood, they express an increased incidence in asthma and autoimmune diseases (e.g. celiac disease). An important component of initial colonization is the infant's diet. Breast milk contains a variety of nondigestible oligosaccharides which function as prebiotics preferentially stimulating proliferation of Bifidobacteria and Lactobacilli, important health-promoting bacteria, and cause fermentation of the oligosaccharides into short-chain fatty acids. In the absence of breastfeeding for the first 6 months of life, formula containing pre- and probiotics may overcome an initial inadequate colonization process and help establish a normal mucosal immune system.
Sanders, Mary Ellen
Although precise mechanisms responsible for all demonstrations of probiotic health benefits are not known, many lines of evidence suggest that probiotics function through direct or indirect impact on colonizing microbiota of the gut. Probiotics can directly influence colonizing microbes through multiple mechanisms, including the production of inhibitory compounds (bacteriocins, short chain fatty acids, and others), by producing substrates that might promote the growth of colonizing microbes (secreted exopolysaccharides, vitamins, fatty acids, sugars from undigested carbohydrates and others), and by promoting immune responses against specific microbes. Indirectly, probiotics can influence colonizing microbes by inhibiting attachment through stimulated mucin production, reinforcing gut barrier effects, and downregulation of gut inflammation, thereby promoting microbes that are associated with a healthier gut physiology. Although the value of targeted changes in populations of gut bacteria is a matter of debate, increased levels of Bifidobacterium and Lactobacillus in the gut correlate with numerous health endpoints. Microbiota changes due to probiotic intake include increased numbers of related phylotypes, decreasing pathogens and their toxins, altering bacterial community structure to enhance evenness, stabilizing bacterial communities when perturbed (eg, with antibiotics), or promoting a more rapid recovery from a perturbation. Further research will provide insight into the degree of permanence of probiotic-induced changes, although research to date suggests that continued probiotic consumption is needed for sustained impact.
del Sol Quintero, María; Mora, Ulises; Gutiérrez, Jorge; Mues, Enrique; Castaño, Eduardo; Fernández, Francisco; Loske, Achim M.
The influence of extracorporeal and intracorporeal lithotripsy on the viability of bacteria contained inside artificial kidney stones was investigated in vitro. Two different bacteria were exposed to the action of one extracorporeal shock wave generator and four intracorporeal lithotripters.
Wang, Shumei; Zhang, Lanwei; Shan, Yujuan
Epidemiological studies showed that incidence of colon carcinoma is increased in the world. There are many difficulties to inhibit colon carcinoma because the causes of inducing colon carcinoma were various and interactive each other. Previous evidence supported the balance of the colonic microflora was critical in inhibiting colon carcinoma and the protection by colonic microflora could be improved by ingesting lactobacilli. Therefore, the biological functions and anticancer effects of lactobacilli attract attention of researchers. In this review we discussed the causes of colon carcinoma; the anticancer mechanisms of lactobacilli on the basis of our own studies. Eventually, we summarized the effects of anticancer of different components and metabolic products extracted from lactobacilli.
de Moreno de LeBlanc, A; Perdigón, G
Yoghurt feeding inhibits induced colon cancer in mice. Several studies showed the immunomodulatory effect of yoghurt which can explain this inhibition. It is possible that yoghurt bacteria can also affect gut flora enzymes related to colon carcinogenesis as reported for other probiotics in different animal tumours. The aim of this work was to evaluate the role of yoghurt starter bacteria and their cell-free fermentation products on the reduction of procarcinogen enzyme activities (beta-glucuronidase and nitroreductase). Mice injected with 1,2-dimethylhydrazine (DMH) and fed with yoghurt were used for this study. Mice given milk or yoghurt supernatant (cell free extract) were used to evaluate if the yoghurt antitumour effect is due to the starter bacteria or other components released during fermentation, that could inhibit these enzymes. We determined that yoghurt by itself maintained enzymes activities similar or lower than non-treatment control group, and the enzyme activity was also lower than milk or yoghurt supernatant groups. DMH increased the activity of the enzymes. Mice injected with DMH and fed cyclically with yoghurt presented lower enzymes activities than the tumour control group. Feeding yoghurt decreased procarcinogenic enzyme levels in the large intestine contents of mice bearing colon tumour. The results of this study provide another mechanism by which yoghurt starter bacteria interact with the large intestine of the mice and prevent colon cancer.
Tuschewitzki, G J
Bacterial colonization developed within one month on the surface of a copper pipe used for the transport of drinking water. No severe signs of corrosion could be detected within six weeks. Dividing cells and the formation of microcolonies indicated active metabolism and multiplication of the bacteria and not only a more or less passive adsorption on the copper from the bulk phase.
Breynaert, Annelies; Bosscher, Douwina; Kahnt, Ariane; Claeys, Magda; Cos, Paul; Pieters, Luc; Hermans, Nina
The biological effects of polyphenols depend on their mechanism of action in the body. This is affected by bioconversion by colon microbiota and absorption of colonic metabolites. We developed and validated an in vitro continuous flow dialysis model with colon phase (GastroIntestinal dialysis model with colon phase) to study the gastrointestinal metabolism and absorption of phenolic food constituents. Chlorogenic acid was used as model compound. The physiological conditions during gastrointestinal digestion were mimicked. A continuous flow dialysis system simulated the one-way absorption by passive diffusion from lumen to mucosa. The colon phase was developed using pooled faecal suspensions. Several methodological aspects including implementation of an anaerobic environment, adapted Wilkins Chalgren broth medium, 1.10(8) CFU/mL bacteria suspension as inoculum, pH adaptation to 5.8 and implementation of the dialysis system were conducted. Validation of the GastroIntestinal dialysis model with colon phase system showed a good recovery and precision (CV < 16 %). Availability of chlorogenic acid in the small intestinal phase (37 ± 3 %) of the GastroIntestinal dialysis model with colon phase is comparable with in vivo studies on ileostomy patients. In the colon phase, the human faecal microbiota deconjugated chlorogenic acid to caffeic acid, 3,4-dihydroxyphenyl propionic acid, 4-hydroxybenzoic acid, 3- or 4-hydroxyphenyl acetic acid, 2-methoxy-4-methylphenol and 3-phenylpropionic acid. The GastroIntestinal dialysis model with colon phase is a new, reliable gastrointestinal simulation system. It permits a fast and easy way to predict the availability of complex secondary metabolites, and to detect metabolites in an early stage after digestion. Isolation and identification of these metabolites may be used as references for in vivo bioavailability experiments and for investigating their bioactivity in in vitro experiments.
Beeken, W; Northwood, I; Beliveau, C; Gump, D
Because little is known of the phagocytes of the human colon we enumerated these cells in mucosal suspensions and studied their phagocytic activity. Phagocyte rich suspensions were made by EDTA collagenase dissociation followed by elutriation centrifugation. Phagocytosis was evaluated by measuring cellular radioactivity after incubation of phagocytes with 3H-adenine labelled E coli ON2 and checked microscopically. Dissociation of normal mucosa from colorectal neoplasms yielded means of 1.9 X 10(6) eosinophils, 1.4 X 10(6) macrophages and 2 X 10(5) neutrophils per gram of mucosa. Visually normal mucosa of inflammatory states yielded 2.2 X 10(6) eosinophils, 2.3 X 10(6) macrophages and 7 X 10(5) neutrophils per gram of mucosa. Phagocyte rich suspensions of normal mucosa from tumour patients phagocytosed 21.8% of a pool of opsonised tritiated E coli ON2 and by microscopy 100% of mucosal neutrophils ingested bacteria, 83% of eosinophils were phagocytic, and 53% of macrophages contained bacteria. These results suggest that in the human colonic mucosa, the eosinophil is more abundant than the macrophage and the per cent of those cells exhibiting phagocytosis is intermediate between that of the macrophage and the neutrophil. Thus these three types of cells are actively phagocytic and share the potential for a major role in host defence against invasive enteric bacteria. PMID:3666566
Wu, Hao; Fang, Yongjun; Yu, Jun; Zhang, Zhang
Exploring molecular mechanisms underlying bacterial water-to-land transition represents a critical start toward a better understanding of the functioning and stability of the terrestrial ecosystems. Here, we perform comprehensive analyses based on a large variety of bacteria by integrating taxonomic, phylogenetic and metagenomic data, in the quest for a unified view that elucidates genomic, evolutionary and ecological dynamics of the marine progenitors in adapting to nonaquatic environments. We hypothesize that bacterial land colonization is dominated by a single-gene sweep, that is, the emergence of dnaE2 derived from an early duplication event of the primordial dnaE, followed by a series of niche-specific genomic adaptations, including GC content increase, intensive horizontal gene transfer and constant genome expansion. In addition, early bacterial radiation may be stimulated by an explosion of land-borne hosts (for example, plants and animals) after initial land colonization events. PMID:24451209
Mercier, J; Lindow, S E
The relationship between nutrients leached onto the leaf surface and the colonization of plants by bacteria was studied by measuring both the abundance of simple sugars and the growth of Pseudomonas fluorescens on individual bean leaves. Data obtained in this study indicate that the population size of epiphytic bacteria on plants under environmentally favorable conditions is limited by the abundance of carbon sources on the leaf surface. Sugars were depleted during the course of bacterial colonization of the leaf surface. However, about 20% of readily utilizable sugar, such as glucose, present initially remained on fully colonized leaves. The amounts of sugars on a population of apparently identical individual bean leaves before and after microbial colonization exhibited a similar right-hand-skewed distribution and varied by about 25-fold from leaf to leaf. Total bacterial population sizes on inoculated leaves under conditions favorable for bacterial growth also varied by about 29-fold and exhibited a right-hand-skewed distribution. The amounts of sugars on leaves of different plant species were directly correlated with the maximum bacterial population sizes that could be attained on those species. The capacity of bacteria to deplete leaf surface sugars varied greatly among plant species. Plants capable of supporting high bacterial population sizes were proportionally more depleted of leaf surface nutrients than plants with low epiphytic populations. Even in species with a high epiphytic bacterial population, a substantial amount of sugar remained after bacterial colonization. It is hypothesized that residual sugars on colonized leaves may not be physically accessible to the bacteria due to limitations in wettability and/or diffusion of nutrients across the leaf surface.
Whitman, T.; Neurath, R.; Zhang, P.; Yuan, T.; Weber, P. K.; Zhou, J.; Pett-Ridge, J.; Firestone, M. K.
Soil organic matter (SOM) stabilization by soil minerals is an important mechanism influencing soil C cycling. Microbes make up only a few percent of total SOM, but have a disproportionate impact on SOM cycling. Their direct interactions with soil minerals, however, are not well characterized. We studied colonization of fresh minerals by soil microbes in an Avena barbata (wild oat) California grassland soil microcosm. Examining quartz, ferrihydrite, kaolinite, and the heavy fraction of the native soil, we asked: (1) Do different minerals select for different communities, or do random processes drive the colonization of fresh minerals? (2) What factors influence which taxa colonize fresh minerals? After incubating mesh bags (<18 μm) of minerals buried next to actively growing plant roots for 2 months, we used high-throughput sequencing of 16S and ITS2 genes to characterize the microbial communities colonizing the minerals. We found significant differences between the microbial community composition of different minerals and soil for both bacteria and fungi. We found a higher relative abundance of arbuscular mycorrhial fungi with ferrihydrite and quartz, and nanoscale secondary ion mass spectrometry (NanoSIMS) imaging of these minerals suggests that some fungal hyphae are moving C directly from roots to mineral surfaces. The enriched presence of both nematode-associated fungi (Pochonia sp.) and bacteria (Candidatus Xiphinematobacter) in the minerals suggests that these minerals may be a habitat for nematodes. Bacteria of the family Chitinophagaceae and genus Janthinobacterium were significantly enriched on both ferrihydrite and quartz minerals, both of which may interact with colonizing fungi. These findings suggest that: (1) Microbial colonization of fresh minerals is not a fully passive or neutral process. (2) Mineral exploration by plant-associated fungi and soil fauna transport may be factors in determining the initial colonization of minerals and subsequent C
Maggio-Price, Lillian; Treuting, Piper; Zeng, Weiping; Tsang, Mark; Bielefeldt-Ohmann, Helle; Iritani, Brian M.
Accumulating evidence suggests that intestinal microbial organisms may play an important role in triggering and sustaining inflammation in individuals afflicted with inflammatory bowel disease (IBD). Moreover, individuals with IBD are at increased risk for developing colorectal cancer, suggesting that chronic inflammation may initiate genetic or epigenetic changes associated with cancer development. We tested the hypothesis that bacteria may contribute to the development of colon cancer by synergizing with defective transforming growth factor-β (TGF-β) signaling, a pathway commonly mutated in human colon cancer. Although others have reported that mice deficient in the TGF-β signaling molecule SMAD3 develop colon cancer, we found that SMAD3-deficient mice maintained free of the Gram-negative enterohepatic bacteria Helicobacter spp. for up to 9 months do not develop colon cancer. Furthermore, infection of SMAD3−/− mice with Helicobacter triggers colon cancer in 50% to 66% of the animals. Using real-time PCR, we found that Helicobacter organisms concentrate in the cecum, the preferred site of tumor development. Mucinous adenocarcinomas develop 5 to 30 weeks after infection and are preceded by an early inflammatory phase, consisting of increased proliferation of epithelial cells; increased numbers of cyclooxygenase-2–positive cells, CD4+ T cells, macrophages; and increased MHC class II expression. Colonic tissue revealed increased transcripts for the oncogene c-myc and the proinflammatory cytokines interleukin-1α (IL-1α), IL-1β, IL-6, IFN-γ, and tumor necrosis factor-α, some of which have been implicated in colon cancer. These results suggest that bacteria may be important in triggering colorectal cancer, notably in the context of gene mutations in the TGF-β signaling pathway, one of the most commonly affected cellular pathways in colorectal cancer in humans. PMID:16424015
Wirth, Stacy M; Bertuccio, Alex J; Cao, Feng; Lowry, Gregory V; Tilton, Robert D
Immobilization of antimicrobial silver nanoparticles (AgNPs) on surfaces has been proposed as a method to inhibit biofouling or as a possible route by which incidental releases of AgNPs may interfere with biofilms in the natural environment or in wastewater treatment. This study addresses the ability of planktonic Pseudomonas fluorescens bacteria to colonize surfaces with pre-adsorbed AgNPs. The ability of the AgNP-coated surfaces to inhibit colonization was controlled by the dissolved silver in the system, with a strong dependence on the initial planktonic cell concentration in the suspension, i.e., a strong inoculum effect. This dependence was attributed to a decrease in dissolved silver ion bioavailability and toxicity caused by its binding to cells and/or cell byproducts. Therefore, when the initial cell concentration was high (∼1×10(7)CFU/mL), an excess of silver binding capacity removed most of the free silver and allowed both planktonic growth and surface colonization directly on the AgNP-coated surface. When the initial cell concentration was low (∼1×10(5)CFU/mL), 100% killing of the planktonic cell inoculum occurred and prevented colonization. When an intermediate initial inoculum concentration (∼1×10(6)CFU/mL) was sufficiently large to prevent 100% killing of planktonic cells, even with 99.97% initial killing, the planktonic population recovered and bacteria colonized the AgNP-coated surface. In some conditions, colonization of AgNP-coated surfaces was enhanced relative to silver-free controls, and the bacteria demonstrated a preferential attachment to AgNP-coated, rather than bare, surface regions. The degree to which the bacterial concentration dictates whether or not surface-immobilized AgNPs can inhibit colonization has significant implications both for the design of antimicrobial surfaces and for the potential environmental impacts of AgNPs.
Wang, Yin; Rozen, Daniel E
Carrion beetles in the genus Nicrophorus rear their offspring on decomposing carcasses where larvae are exposed to a diverse community of decomposer bacteria. Parents coat the carcass with antimicrobial secretions prior to egg hatch (defined as Pre-Hatch care) and also feed regurgitated food, and potentially bacteria, to larvae throughout development (defined as Full care). Here we partition the roles of pre- and post-hatch parental care in the transmission and persistence of culturable symbiotic bacteria to larvae. Using three treatment groups (Full-Care, Pre-Hatch care only, and No Care), we found that larvae receiving Full-Care are predominantly colonized by bacteria resident in the maternal gut, while larvae receiving No Care are colonized with bacteria from the carcass. More importantly, larvae receiving only Pre-Hatch care were also predominantly colonized by maternal bacteria; this result indicates that parental treatment of the carcass, including application of bacteria to the carcass surface, is sufficient to ensure symbiont transfer even in the absence of direct larval feeding. Later in development, we found striking evidence that pupae undergo a aposymbiotic stage, after which they are recolonized at eclosion with bacteria similar to those found on the moulted larval cuticle and on the wall of the pupal chamber. Our results clarify the importance of pre-hatch parental care for symbiont transmission in Nicrophorus vespilloides, and suggest that these bacteria successfully outcompete decomposer bacteria during larval and pupal gut colonization.Importance Here we examine the origin and persistence of the culturable gut microbiota of larvae in the burying beetle Nicrophorus vespilloides This insect is particularly interesting for this study because larvae are reared on decomposing vertebrate carcasses where they are exposed to high-densities of carrion-decomposing microbes. Larvae also receive extensive parental care in the form of carcass preservation and
Huang, Julie Y.; Goers Sweeney, Emily; Guillemin, Karen
Helicobacter pylori’s ability to respond to environmental cues in the stomach is integral to its survival. By directly visualizing H. pylori swimming behavior when encountering a microscopic gradient consisting of the repellent acid and attractant urea, we found that H. pylori is able to simultaneously detect both signals, and its response depends on the magnitudes of the individual signals. By testing for the bacteria’s response to a pure acid gradient, we discovered that the chemoreceptors TlpA and TlpD are each independent acid sensors. They enable H. pylori to respond to and escape from increases in hydrogen ion concentration near 100 nanomolar. TlpD also mediates attraction to basic pH, a response dampened by another chemoreceptor TlpB. H. pylori mutants lacking both TlpA and TlpD (ΔtlpAD) are unable to sense acid and are defective in establishing colonization in the murine stomach. However, blocking acid production in the stomach with omeprazole rescues ΔtlpAD’s colonization defect. We used 3D confocal microscopy to determine how acid blockade affects the distribution of H. pylori in the stomach. We found that stomach acid controls not only the overall bacterial density, but also the microscopic distribution of bacteria that colonize the epithelium deep in the gastric glands. In omeprazole treated animals, bacterial abundance is increased in the antral glands, and gland colonization range is extended to the corpus. Our findings indicate that H. pylori has evolved at least two independent receptors capable of detecting acid gradients, allowing not only survival in the stomach, but also controlling the interaction of the bacteria with the epithelium. PMID:28103315
Nagy, B; Arp, L H; Moon, H W; Casey, T A
Intestinal colonization of 3-week-old weaned pigs by enterotoxigenic Escherichia coli (ETEC) strains that were originally isolated from weaned pigs with fatal diarrhea and that lacked K88, K99, F41, and 987P adhesins (4P- ETEC) was studied by histologic, immunofluorescent, and electron microscopic techniques. In the first experiment, 16 principal pigs were inoculated orogastrically with ETEC strain 2134 (serogroup O157: H19) or 2171 (serogroup 0141:H4), and eight control pigs were not inoculated. In the second experiment, 24 principals were inoculated with ETEC strain 2134, and 12 controls were inoculated with a nonenterotoxigenic strain of E. coli. Principal and control pigs were necropsied at intervals from 24 to 72 hours after inoculation of principals to provide the tissues used for this report. Results from the two experiments and with both ETEC strains were similar and therefore were combined. Adhesion by 4P- ETEC was demonstrated in ileum but not in cecum or colon in 22/40 principal pigs sampled at 24 to 72 hours after orogastric inoculation. Adherent bacteria were most apparent on the intestinal villi covering Peyer's patches. Only occasional adherent bacteria were detected in ileal sections from a few (4/20) of the control pigs. Adherence by 4P- ETEC was characterized by "patches" of bacteria closely associated with the lateral surfaces and less frequently with the tips and the bases of intact villi. In most cases, the adherent bacteria were separated from epithelial cell microvilli and other bacterial cells by a 50-400-nm space. Filamentous bacterial appendages bridged this space and formed a network among adjacent bacteria.(ABSTRACT TRUNCATED AT 250 WORDS)
Ranji, Peyman; Akbarzadeh, Abolfazl; Rahmati-Yamchi, Mohammad
Colorectal cancer (CRC) is one of most common causes of cancer-related death worldwide. Recent studies have suggested that microbial and environmental factors including diet and lifestyle can impact on colon cancer development. Vitamin D deficiency and dysfunction of vitamin D receptor (VDR) also correlate with colon cancer. Moreover, leptin, a 16-kDa polypeptide, participates in the regulation of food intake and is associated with other environmental factors affecting colon cancer through the leptin receptor. Altered levels of serum leptin and patterns of expression of its receptor (LPR) may be observed in human colon tumours. Furthermore, the collected data from in vitro and in vivo studies have indicated that consuming probiotic non-pathogenic lactic acid bacteria have beneficial effects on colon cancer. Probiotics, inflammation and vitamin D/VDR have been correlated with leptin and its receptor and are also with colon cancer. Thus, in this paper, we review recent progress on the roles of probiotic, vitamin D/VDR and leptin/LPR in inflammation and colon cancer.
Stones, Daniel Henry; Krachler, Anne Marie
Evolving under the constant exposure to an abundance of diverse microbial life, the human body has developed many ways of defining the boundaries between self and non-self. Many physical and immunological barriers to microbial invasion exist, and yet bacteria have found a multitude of ways to overcome these, initiate interactions with and colonize the human host. Adhesion to host cells and tissues is a key feature allowing bacteria to persist in an environment under constant flux and to initiate transient or permanent symbioses with the host. This review discusses reasons why adhesion is such a seemingly indispensable requirement for bacteria–host interactions, and whether bacteria can bypass the need to adhere and still persist. It further outlines open questions about the role of adhesion in bacterial colonization and persistence within the host. PMID:27913666
Weiss, G. Adrienne; Hennet, Thierry
Milk oligosaccharides influence the composition of intestinal microbiota and thereby mucosal inflammation. Some of the major milk oligosaccharides are α2,3-sialyllactose (3SL) and α2,6-sialyllactose, which are mainly produced by the sialyltransferases ST3GAL4 and ST6GAL1, respectively. Recently, we showed that mice fed milk deficient in 3SL were more resistant to dextran sulfate sodium-induced colitis. By contrast, the exposure to milk containing or deficient in 3SL had no impact on the development of mucosal leukocyte populations. Milk 3SL mainly affected the colonization of the intestine by clostridial cluster IV bacteria. PMID:22585928
Ye, Huimin; Liu, Junhua; Feng, Panfei; Zhu, Weiyun; Mao, Shengyong
Remarkably little information is available about the impact of high-grain (HG) feeding on colonic mucosa-associated bacteria and mucosal morphology. In the present study, 12 male goats were randomly assigned to either a hay diet (n = 6) or an HG diet (65% grain; n = 6) to characterise the changes in the composition of the bacterial community in colonic mucosa and the mucosal morphology of the colon. The results showed that HG feeding decreased the colonic pH and increased the concentrations of total short chain fatty acids and lipopolysaccharides in colonic digesta. The principal coordinate analysis results showed that the HG diet altered the colonic mucosal bacterial communities, with an increase in the abundance of genus Blautia and a decrease in the abundance of genera Bacillus, Enterococcus, and Lactococcus. The HG-fed goats showed sloughing of the surface layer epithelium, intercellular tight junction erosion, cell mitochondrial damage, and upregulation of the relative mRNA expression of IL-2 and IFN-γ in colonic mucosa. Collectively, our data indicate that HG feeding induced changes in colonic mucosal morphology and cytokines expression that might be caused by excessive fermentation and dramatic shifts in the bacterial populations in the colon. PMID:26841945
Pirttilä, Anna Maria; Laukkanen, Hanna; Pospiech, Helmut; Myllylä, Raili; Hohtola, Anja
Bacterial isolates were obtained from pine (Pinus sylvestris L.) tissue cultures and identified as Methylobacterium extorquens and Pseudomonas synxantha. The existence of bacteria in pine buds was investigated by 16S rRNA in situ hybridization. Bacteria inhabited the buds of every tree examined, primarily colonizing the cells of scale primordia and resin ducts. PMID:10877808
Dejea, Christine; Wick, Elizabeth; Sears, Cynthia L
The human colon plays host to a diverse and metabolically complex community of microorganisms. While the colonic microbiome has been suggested to contribute to the development of colorectal cancer (CRC), a definitive link has not been made. The role in which the colon microflora could contribute to the initiation and/or progression of CRC is explored in this review. Potential mechanisms of bacterial oncogenesis are presented, along with lines of evidence derived from animal models of microbially induced CRC. Particular focus is given to the oncogenic capabilities of enterotoxigenic Bacteroides fragilis. Recent progress in defining the microbiome of CRC in the human population is evaluated, and the future challenges of linking specific etiologic agents to CRC are emphasized. PMID:23534358
Simon, H M; Dodsworth, J A; Goodman, R M
Microorganisms that colonize plant roots are recruited from, and in turn contribute substantially to, the vast and virtually uncharacterized phylogenetic diversity of soil microbiota. The diverse, but poorly understood, microorganisms that colonize plant roots mediate mineral transformations and nutrient cycles that are central to biosphere functioning. Here, we report the results of epifluorescence microscopy and culture-independent recovery of small subunit (SSU) ribosomal RNA (rRNA) gene sequences showing that members of a previously reported clade of soil Crenarchaeota colonize both young and senescent plant roots at an unexpectedly high frequency, and are particularly abundant on the latter. Our results indicate that non-thermophilic members of the Archaea inhabit an important terrestrial niche on earth and direct attention to the need for studies that will determine their possible roles in mediating root biology.
Freeman, H J
Dietary plant fibre, or plantix, is thought to play a significant role in the pathogenesis of colon cancer in humans. It is a complex polymeric substance that has several distinct components resistant to hydrolysis by the digestive enzymes of humans. These components include cellulose, hemicelluloses, pectins, lignin, gums, mucilages and, in certain instances, algal polysaccharides. These polymers have different physicochemical properties, and recent evidence from experimental studies in animals treated with carcinogens suggests that some may exert protective effects in the intestine and others may enhance colon carcinogenesis. This review synthesizes information on the chemical composition, methods of analysis and physicochemical properties of dietary plant fibre and reviews available studies examining the role of fibre in colonic neoplasia in animals and humans. PMID:466603
Zhang, Yu-Jie; Li, Sha; Gan, Ren-You; Zhou, Tong; Xu, Dong-Ping; Li, Hua-Bin
Gut bacteria are an important component of the microbiota ecosystem in the human gut, which is colonized by 1014 microbes, ten times more than the human cells. Gut bacteria play an important role in human health, such as supplying essential nutrients, synthesizing vitamin K, aiding in the digestion of cellulose, and promoting angiogenesis and enteric nerve function. However, they can also be potentially harmful due to the change of their composition when the gut ecosystem undergoes abnormal changes in the light of the use of antibiotics, illness, stress, aging, bad dietary habits, and lifestyle. Dysbiosis of the gut bacteria communities can cause many chronic diseases, such as inflammatory bowel disease, obesity, cancer, and autism. This review summarizes and discusses the roles and potential mechanisms of gut bacteria in human health and diseases. PMID:25849657
Zhang, Yu-Jie; Li, Sha; Gan, Ren-You; Zhou, Tong; Xu, Dong-Ping; Li, Hua-Bin
Gut bacteria are an important component of the microbiota ecosystem in the human gut, which is colonized by 1014 microbes, ten times more than the human cells. Gut bacteria play an important role in human health, such as supplying essential nutrients, synthesizing vitamin K, aiding in the digestion of cellulose, and promoting angiogenesis and enteric nerve function. However, they can also be potentially harmful due to the change of their composition when the gut ecosystem undergoes abnormal changes in the light of the use of antibiotics, illness, stress, aging, bad dietary habits, and lifestyle. Dysbiosis of the gut bacteria communities can cause many chronic diseases, such as inflammatory bowel disease, obesity, cancer, and autism. This review summarizes and discusses the roles and potential mechanisms of gut bacteria in human health and diseases.
Gerard, Romain; Sendid, Boualem; Colombel, Jean-Frederic; Poulain, Daniel; Jouault, Thierry
The etiology of Crohn's disease (CD), an autoimmune, inflammatory bowel disease (IBD) which affects approximately one million people in Europe, is still unclear. Nevertheless, it is widely accepted that CD could result from an inappropriate inflammatory response to intestinal microorganisms in a genetically susceptible host. Most studies to date have concerned the involvement of bacteria in disease progression. In addition to bacteria, there appears to be a possible link between the commensal yeast Candida albicans and disease development. In this review, in an attempt to link the gut colonization process and the development of CD, we describe the different pathways that are involved in the progression of CD and in the host response to C. albicans, making the yeast a possible initiator of the inflammatory process observed in this IBD.
Research has found that certain bacteria are associated with human cancers. Their role, however, is still unclear. Convincing evidence links some species to carcinogenesis while others appear promising in the diagnosis, prevention or treatment of cancers. The complex relationship between bacteria and humans is demonstrated by Helicobacter pylori and Salmonella typhi infections. Research has shown that H. pylori can cause gastric cancer or MALT lymphoma in some individuals. In contrast, exposure to H. pylori appears to reduce the risk of esophageal cancer in others. Salmonella typhi infection has been associated with the development of gallbladder cancer; however S. typhi is a promising carrier of therapeutic agents for melanoma, colon and bladder cancers. Thus bacterial species and their roles in particular cancers appear to differ among different individuals. Many species, however, share an important characteristic: highly site-specific colonization. This critical factor may lead to the development of non-invasive diagnostic tests, innovative treatments and cancer vaccines. PMID:16566840
Sulfur-oxidizing bacteria oxidize reduced inorganic compounds to sulfuric acid. Lithotrophic sulfur oxidizer use the energy obtained from oxidation for microbial growth. Heterotrophic sulfur oxidizers obtain energy from the oxidation of organic compounds. In sulfur-oxidizing mixotrophs energy are derived either from the oxidation of inorganic or organic compounds. Sulfur-oxidizing bacteria are usually located within the sulfide/oxygen interfaces of springs, sediments, soil microenvironments, and the hypolimnion. Colonization of the interface is necessary since sulfide auto-oxidizes and because both oxygen and sulfide are needed for growth. The environmental stresses associated with the colonization of these interfaces resulted in the evolution of morphologically diverse and unique aerobic sulfur oxidizers.
Medved, Mario; Truyen, Roel; Likar, Bostjan; Pernus, Franjo
Segmentation of colon CT images is the main factor that inhibits automation of virtual colonoscopy. There are two main reasons that make efficient colon segmentation difficult. First, besides the colon, the small bowel, lungs, and stomach are also gas-filled organs in the abdomen. Second, peristalsis or residual feces often obstruct the colon, so that it consists of multiple gas-filled segments. In virtual colonoscopy, it is very useful to automatically connect the centerlines of these segments into a single colon centerline. Unfortunately, in some cases this is a difficult task. In this study a novel method for automated colon segmentation and connection of colon segments' centerlines is proposed. The method successfully combines features of segments, such as centerline and thickness, with information on main colon segments. The results on twenty colon cases show that the method performs well in cases of small obstructions of the colon. Larger obstructions are mostly also resolved properly, especially if they do not appear in the sigmoid part of the colon. Obstructions in the sigmoid part of the colon sometimes cause improper classification of the small bowel segments. If a segment is too small, it is classified as the small bowel segment. However, such misclassifications have little impact on colon analysis.
Bukharin, O V; Usviatsov, B Ia; Doroshina, N B; Kushkinbaeva, D R; Khlopko, Iu A
Peculiarities of behavior reactions of bacteria-symbionts created conditions for the selection of translocators-strains. In microsymbiocenosis of parodontal pockets, from which translocation of bacteria into the blood was observed, the number of signals from intermicrobial communication, inhibiting the expression of the factors of colonization, virulence and persistence, was decreasing. Meanwhile, the number of signals on the increase of the expression of the factors given was increased. In 75% of cases strains-translocators were leaders; they gave more often signals on the inhibition of the growth of other strains-symbionts.
O'Flaherty, Sarah; Goh, Yong Jun; Klaenhammer, Todd R.
Probiotic bacteria from the Lactobacillus and Bifidobacterium species belong to the Firmicutes and the Actinobacteria phylum, respectively. Lactobacilli are members of the lactic acid bacteria (LAB) group, a broadly defined family of microorganisms that ferment various hexoses into primarily lactic acid. Lactobacilli are typically low G + C gram-positive species which are phylogenetically diverse, with over 100 species documented to date. Bifidobacteria are heterofermentative, high G + C content bacteria with about 30 species of bifidobacteria described to date.
Camacho, H.; Tuero, A. D.; Bacardí, D.; Palenzuela, D. O.; Aguilera, A.; Silva, J. A.; Estrada, R.; Gell, O.; Suárez, J.; Ancizar, J.; Brown, E.; Colarte, A. B.; Castro, J.; Novoa, L. I.
The study of the composition of the intestinal flora is important to the health of the host, playing a key role in maintaining intestinal homeostasis and the evolution of the immune system. For these studies, various universal primers of the 16S rDNA gene are used in microbial taxonomy. Here, we report an evaluation of 5 universal primers to explore the presence of microbial DNA in colon biopsies preserved in RNAlater solution. The DNA extracted was used for the amplification of PCR products containing the variable (V) regions of the microbial 16S rDNA gene. The PCR products were studied by restriction fragment length polymorphism (RFLP) analysis and DNA sequence, whose percent of homology with microbial sequences reported in GenBank was verified using bioinformatics tools. The presence of microbes in the colon of rats was quantified by the quantitative PCR (qPCR) technique. We obtained microbial DNA from rat, useful for PCR analysis with the universal primers for the bacteria 16S rDNA. The sequences of PCR products obtained from a colon biopsy of the animal showed homology with the classes bacilli (Lactobacillus spp) and proteobacteria, normally represented in the colon of rats. The proposed methodology allowed the attainment of DNA of bacteria with the quality and integrity for use in qPCR, sequencing, and PCR-RFLP analysis. The selected universal primers provided knowledge of the abundance of microorganisms and the formation of a preliminary test of bacterial diversity in rat colon biopsies. PMID:27382362
The Breast Cancer Family Registry and the Colon Cancer Family Registry were established by the National Cancer Institute as a resource for investigators to use in conducting studies on the genetics and molecular epidemiology of breast and colon cancer.
Huebner, Jay S.
Describes an undergraduate course, The Colonization of Space, which introduces nonscience majors at the University of North Florida to current topics in the exploration, industrialization, and colonization of space. References to the audiovisual resources and literature are also included. (HM)
Kim, Su Jin; Baek, Il Hyun
Colonic pseudolipomatosis is rare and its pathogenesis is still unclear. A number of mechanisms, including mechanical injury during an endoscopic procedure or chemical injury by disinfectant, seem to contribute to its pathogenesis. In our endoscopy unit, pseudolipomatosis occurred in an epidemic pattern after changing the endoscopic disinfectant from 2% glutaraldehyde to peracetic acid compound to decrease the length of endoscope reprocessing time. We assumed that pseudolipomatosis could be a type of chemical colitis produced by the residual disinfectant solution that remained on the surface or in a channel of the endoscope after reprocessing. The aim of this report was to highlight a series of 12 cases of colonic pseudolipomatosis in order to describe the endoscopic and pathological features and discuss the harmful effect of disinfectants as a possible cause of pseudolipomatosis. To identify the cause of the lesions, we systematically reviewed each patient history and the endoscopic and histological features. From March 2004 to February 2005, 1276 colonoscopies were performed and 12 cases (0.94%) of colonic pseudolipomatosis were diagnosed at the Kangnam Sacred Heart Hospital of Hallym University. The pathogenesis of colonic pseudolipomatosis is not well-known, but our experience indicates the endoscopic disinfectant as the probable cause of pseudolipomatosis rather than either mechanical traumatic injury or intraluminal air pressure-related injury.
Doğruöz, Nihal; Göksay, Duygu; Ilhan-Sungur, Esra; Cotuk, Ayşin
Some bacteria have a higher tendency to produce biofilm than others. Especially, Pseudomonas and Aeromonas strains are acknowledged to be pioneer colonizers and are predominant in biofilm formation. We examined biofilm formation and first attachment maintance of biofilms of Pseudomonas spp., Pseudomonas aeruginosa, Aeromonas spp, sulphate reducing bacteria and filamentous fungi. A simulated recirculating cooling-water system was used. Heterotrophic bacteria counts on galvanized steel and glass surfaces rose during the tidy period of 720 hours. In addition, we determined that although Pseudomonas spp., Pseudomonas aeruginosa and Aeromonas spp. were the pioneer colonizers, they surprisingly could not be determined in the biofilms on both types of surface after 456 hours. Sulphate reducing bacteria were observed in biofilms on both surfaces from the outset of the experiments. Filamentous fungi were seen on the galvanized steel and glass surfaces after 0.5 h.
Cicora, F; Petroni, J; Roberti, J
We present a case of a 59-year-old woman with Chagas disease who received a kidney transplant. At month 44 post-transplantation, the patient presented with diarrhea that had persisted for 2 months. Colonoscopy showed a colon ulcer and differential diagnoses included cytomegalovirus, bacteria, or parasite infection; drug-related diarrhea; Crohn's disease; celiac disease; and malignancy. The ulcer tissue was positive for Cryptococcus neoformans. Successful treatment consisted of amphotericin B for 8 days and oral fluconazole (800 mg daily) for 3 months. This case illustrates that a colonic ulcer, although rare, could be cryptococcosis.
... Inside Life Science > Bleach vs. Bacteria Inside Life Science View All Articles | Inside Life Science Home Page Bleach vs. Bacteria By Sharon Reynolds ... For Proteins, Form Shapes Function This Inside Life Science article also appears on LiveScience . Learn about related ...
McMahon, Peter B.
Most people would agree that bacteria usually spell trouble where the quality of drinking water is con cerned. However, recent studies conducted by the U.S. Geological Survey (USGS) under the National Water-Quality Assessment (NAWQA) program have shown that some bacteria can improve the quality of water.
Swarms of bacteria turn two 380-micron long gears, opening the possibility of building hybrid biological machines at the microscopic scale. Read more at Wired: http://www.wired.com/wiredscience/2009/12/bacterial-micro-machine/#more-15684 or Scientific American: http://www.scientificamerican.com/article.cfm?id=brownian-motion-bacteria
Lopes, Lucas D.; Pereira e Silva, Michele de Cássia; Andreote, Fernando D.
The rhizosphere harbors one of the most complex, diverse, and active plant-associated microbial communities. This community can be recruited by the plant host to either supply it with nutrients or to help in the survival under stressful conditions. Although selection for the rhizosphere community is evident, the specific bacterial traits that make them able to colonize this environment are still poorly understood. Thus, here we used a combination of community level physiological profile (CLPP) analysis and 16S rRNA gene quantification and sequencing (coupled with in silico analysis and metagenome prediction), to get insights on bacterial features and processes involved in rhizosphere colonization of sugarcane. CLPP revealed a higher metabolic activity in the rhizosphere compared to bulk soil, and suggested that D-galacturonic acid plays a role in bacterial selection by the plant roots (supported by results of metagenome prediction). Quantification of the 16S rRNA gene confirmed the higher abundance of bacteria in the rhizosphere. Sequence analysis showed that of the 252 classified families sampled, 24 were significantly more abundant in the bulk soil and 29 were more abundant in the rhizosphere. Furthermore, metagenomes predicted from the 16S rRNA gene sequences revealed a significant higher abundance of predicted genes associated with biofilm formation and with horizontal gene transfer (HGT) processes. In sum, this study identified major bacterial groups and their potential abilities to occupy the sugarcane rhizosphere, and indicated that polygalacturonase activity and HGT events may be important features for rhizosphere colonization. PMID:27610108
Pérez-Cobas, Ana Elena; Moya, Andrés; Gosalbes, María José; Latorre, Amparo
Antibiotics strongly disrupt the human gut microbiota, which in consequence loses its colonization resistance capacity, allowing infection by opportunistic pathogens such as Clostridium difficile. This bacterium is the main cause of antibiotic-associated diarrhea and a current problem in developed countries, since its incidence and severity have increased during the last years. Furthermore, the emergence of antibiotic resistance strains has reduced the efficiency of the standard treatment with antibiotics, leading to a higher rate of relapses. Here, we review recent efforts focused on the impact of antibiotics in the gut microbiome and their relationship with C. difficile colonization, as well as, in the identification of bacteria and mechanisms involved in the protection against C. difficile infection. Since a healthy gut microbiota is able to avoid pathogen colonization, restoration of the gut microbiota seems to be the most promising approach to face C. difficile infection, especially for recurrent cases. Therefore, it would be possible to design probiotics for patients undergoing antimicrobial therapies in order to prevent or fight the expansion of the pathogen in the gut ecosystem.
Fatima, K; Imran, A; Amin, I; Khan, Q M; Afzal, M
Plants coupled with endophytic bacteria hold great potential for the remediation of polluted environment. The colonization patterns and activity of inoculated endophytes in rhizosphere and endosphere of host plant are among the primary factors that may influence the phytoremediation process. However, these colonization patterns and metabolic activity of the inoculated endophytes are in turn controlled by none other than the host plant itself. The present study aims to determine such an interaction specifically for plant-endophyte systems remediating crude oil-contaminated soil. A consortium (AP) of two oil-degrading endophytic bacteria (Acinetobacter sp. strain BRSI56 and Pseudomonas aeruginosa strain BRRI54) was inoculated to two grasses, Brachiaria mutica and Leptochloa fusca, vegetated in crude oil-contaminated soil. Colonization patterns and metabolic activity of the endophytes were monitored in the rhizosphere and endosphere of the plants. Bacterial augmentation enhanced plant growth and crude oil degradation. Maximum crude oil degradation (78%) was achieved with B. mutica plants inoculated with AP consortium. This degradation was significantly higher than those treatments, where plants and bacteria were used individually or L. fusca and endophytes were used in combination. Moreover, colonization and metabolic activity of the endophytes were higher in the rhizosphere and endosphere of B. mutica than L. fusca. The plant species affected not only colonization pattern and biofilm formation of the inoculated bacteria in the rhizosphere and endosphere of the host plant but also affected the expression of alkane hydroxylase gene, alkB. Hence, the investigation revealed that plant species can affect colonization patterns and metabolic activity of inoculated endophytic bacteria and ultimately the phytoremediation process.
Piotrowska, Małgorzata; Śliżewska, Katarzyna; Nowak, Adriana; Zielonka, Łukasz; Żakowska, Zofia; Gajęcka, Magdalena; Gajęcki, Maciej
The objective of the study was to determine the effect of exposure of pigs to the Fusarium mycotoxins zearalenone (ZEN) and deoxynivalenol (DON), administered together and separately, on the colon microbiota. An experiment was conducted for 42 days on gilts, randomly assigned to four groups and administered either ZEN, DON, ZEN+DON, or a placebo. The number of aerobic mesophilic bacteria, yeasts, molds, anaerobic Clostridium perfringens, fecal streptococci, Enterobacteriaceae, Escherichia coli, and lactic acid bacteria (LAB) were determined in the contents of the ascending colon. The influence of mycotoxins on the functional diversity of the colonic microbiota was assessed using EcoPlate tests (Biolog). Analysis revealed the predominance of LAB in all groups of pigs. Zearalenone, administered separately and together with DON, was found to have an adverse effect on mesophilic aerobic bacteria, but only after long exposure to this mycotoxin. During the six weeks of the experiment, the concentration of C. perfringens, E. coli, and other bacteria in the family Enterobacteriaceae was most considerably reduced in the experimental groups exposed to zearalenone, both separately and together with DON. Mycotoxins also affected the functional biodiversity of microorganisms. Both Shannon’s diversity index and the number of catabolized substrates in Biolog plate (the R index) were much higher in the group subjected to mixed mycotoxicosis. PMID:25025709
Zheng, Longyu; Crippen, Tawni L.; Holmes, Leslie; Singh, Baneshwar; Pimsler, Meaghan L.; Benbow, M. Eric; Tarone, Aaron M.; Dowd, Scot; Yu, Ziniu; Vanlaerhoven, Sherah L.; Wood, Thomas K.; Tomberlin, Jeffery K.
There can be substantial negative consequences for insects colonizing a resource in the presence of competitors. We hypothesized that bacteria, associated with an oviposition resource and the insect eggs deposited on that resource, serve as a mechanism regulating subsequent insect attraction, colonization, and potentially succession of insect species. We isolated and identified bacterial species associated with insects associated with vertebrate carrion and used these bacteria to measure their influence on the oviposition preference of adult black soldier flies which utilizes animal carcasses and is an important species in waste management and forensics. We also ascertained that utilizing a mixture of bacteria, rather than a single species, differentially influenced behavioral responses of the flies, as did bacterial concentration and the species of fly from which the bacteria originated. These studies provide insight into interkingdom interactions commonly occurring during decomposition, but not commonly studied. PMID:23995019
Zheng, Longyu; Crippen, Tawni L; Holmes, Leslie; Singh, Baneshwar; Pimsler, Meaghan L; Benbow, M Eric; Tarone, Aaron M; Dowd, Scot; Yu, Ziniu; Vanlaerhoven, Sherah L; Wood, Thomas K; Tomberlin, Jeffery K
There can be substantial negative consequences for insects colonizing a resource in the presence of competitors. We hypothesized that bacteria, associated with an oviposition resource and the insect eggs deposited on that resource, serve as a mechanism regulating subsequent insect attraction, colonization, and potentially succession of insect species. We isolated and identified bacterial species associated with insects associated with vertebrate carrion and used these bacteria to measure their influence on the oviposition preference of adult black soldier flies which utilizes animal carcasses and is an important species in waste management and forensics. We also ascertained that utilizing a mixture of bacteria, rather than a single species, differentially influenced behavioral responses of the flies, as did bacterial concentration and the species of fly from which the bacteria originated. These studies provide insight into interkingdom interactions commonly occurring during decomposition, but not commonly studied.
Yu, D; Wei, L; Zhengxiu, L; Jian, L; Lijia, W; Wei, L; Xiqiang, Y; Xiaodong, Z; Zhou, F; Enmei, L
It is reported that bacterial colonization of the airway in neonates affects the likelihood and severity of subsequent wheezing in childhood. This study aimed to explore the impact of bacterial colonization on the severity of virus-induced wheezing, and accompanying airway inflammation. Nasopharyngeal aspirates (NPAs) from 68 hospitalized children with bronchiolitis and 85 children with recurrent wheezing were obtained. Eleven common respiratory viruses were sought by PCR and/or direct fluorescence assay. Bacteria were isolated from NPAs by routine culture methods. Cell numbers and concentrations of cytokines/chemokines in the NPAs were measured, and nucleated cells were characterized. The frequency of bacterial colonization in children with recurrent wheezing was significantly higher than in children with an initial attack of bronchiolitis. Bacterial colonization accompanying virus infection had no effect on clinical manifestations, duration of hospitalization, concentrations of cytokines/chemokines (except interleukin-10 (IL-10)) or cellularity in the children with bronchiolitis; however, among the children with recurrent wheezing, those who had coexistent non-invasive bacterial colonization and virus infection presented more frequent cyanosis, longer duration of hospitalization, a higher concentration of IL-10 and a higher percentage of neutrophils in NPAs than those with virus infection but without bacterial colonization. Bacterial colonization was common in children with virus-induced wheezing, particularly in the situation of recurrent wheezing. To some extent, bacterial colonization accompanying virus infection may contribute to the severity of the wheezing because of its impact on airway inflammation.
Iwase, Tadayuki; Uehara, Yoshio; Shinji, Hitomi; Tajima, Akiko; Seo, Hiromi; Takada, Koji; Agata, Toshihiko; Mizunoe, Yoshimitsu
Commensal bacteria are known to inhibit pathogen colonization; however, complex host-microbe and microbe-microbe interactions have made it difficult to gain a detailed understanding of the mechanisms involved in the inhibition of colonization. Here we show that the serine protease Esp secreted by a subset of Staphylococcus epidermidis, a commensal bacterium, inhibits biofilm formation and nasal colonization by Staphylococcus aureus, a human pathogen. Epidemiological studies have demonstrated that the presence of Esp-secreting S. epidermidis in the nasal cavities of human volunteers correlates with the absence of S. aureus. Purified Esp inhibits biofilm formation and destroys pre-existing S. aureus biofilms. Furthermore, Esp enhances the susceptibility of S. aureus in biofilms to immune system components. In vivo studies have shown that Esp-secreting S. epidermidis eliminates S. aureus nasal colonization. These findings indicate that Esp hinders S. aureus colonization in vivo through a novel mechanism of bacterial interference, which could lead to the development of novel therapeutics to prevent S. aureus colonization and infection.
Pearson, John; Aitchison, Alan; Dixon, Liane; Frizelle, Frank A.; Keenan, Jacqueline I.
Background Enterotoxigenic Bacteroides fragilis (ETBF) is a toxin-producing bacteria thought to possibly promote colorectal carcinogenesis by modulating the mucosal immune response and inducing epithelial cell changes. Here, we aim to examine the association of colonic mucosal colonization with ETBF and the presence of a range of lesions on the colonic neoplastic spectrum. Methods Mucosal tissue from up to four different colonic sites was obtained from a consecutive series of 150 patients referred for colonoscopy. The presence and relative abundance of the B. fragilis toxin gene (bft) in each tissue sample was determined using quantitative PCR, and associations with clinicopathological characteristics were analysed. Findings We found a high concordance of ETBF between different colonic sites (86%). Univariate analysis showed statistically significant associations between ETBF positivity and the presence of low-grade dysplasia (LGD), tubular adenomas (TA), and serrated polyps (P-values of 0.007, 0.027, and 0.007, respectively). A higher relative abundance of ETBF was significantly associated with LGD and TA (P-values of < 0.0001 and 0.025, respectively). Increased ETBF positivity and abundance was also associated with left-sided biopsies, compared to those from the right side of the colon. Conclusion Our results showing association of ETBF positivity and increased abundance with early-stage carcinogenic lesions underlines its importance in the development of colorectal cancer, and we suggest that detection of ETBF may be a potential marker of early colorectal carcinogenesis. PMID:28151975
Kirchberger, Stefanie; Royston, Daniel J; Boulard, Olivier; Thornton, Emily; Franchini, Fanny; Szabady, Rose L; Harrison, Oliver; Powrie, Fiona
Patients with inflammatory bowel disease (IBD) have an increased risk of colon cancer. However, the immune cells and cytokines that mediate the transition from intestinal inflammation to cancer are poorly understood. We show that bacteria-induced colon cancer is accompanied by differential accumulation of IL-17(+)IL-22(+) colonic innate lymphoid cells (cILCs), which are phenotypically distinct from LTi and NK-22 cells, and that their depletion in mice with dysplastic inflammation blocks the development of invasive colon cancer. Analysis of the functional role of distinct Type 17 cytokines shows that although blockade of IL-17 inhibits some parameters of intestinal inflammation, reduction in dysplasia and colorectal cancer (CRC) requires neutralization of IL-22 indicating a unique role for IL-22 in the maintenance of cancer in this model. Mechanistic analyses showed that IL-22 selectively acts on epithelial cells to induce Stat3 phosphorylation and proliferation. Importantly, we could detect IL-22(+)CD3(+) and IL-22(+)CD3(−) cells in human CRC. Our results describe a new activity of IL-22 in the colon as a nonredundant mediator of the inflammatory cascade required for perpetuation of CRC, highlighting the IL-22 axis as a novel therapeutic target in colon cancer.
Solak, Aynur; Solak, Ilhami; Genç, Berhan; Sahin, Neslin; Yalaz, Seyhan
Left colonic diverticula are common in Western populations, whereas right colonic diverticulosis primarily occurs in Oriental populations. Diverticulitis of the transverse colon is very rare, with very few cases reported in the literature. Herein, we report a case of transverse colon diverticulitis caused by a calcified stone in a 69-year-old female. This was a solitary diverticulum. The signs and symptoms of the disease are similar to acute pancreatitis. To the best of our knowledge, this is the first report describing the MRI findings of a patient with trans-verse colon diverticulitis caused by a calcified stone. PMID:25610254
Furne, J; Springfield, J; Koenig, T; DeMaster, E; Levitt, M D
Colonic bacteria release large quantities of the highly toxic thiols hydrogen sulfide (H(2)S) and methanethiol (CH(3)SH). These gases rapidly permeate the colonic mucosa, and tissue damage would be expected if the mucosa could not detoxify these compounds rapidly. We previously showed that rat cecal mucosa metabolizes these thiols via conversion to thiosulfate. The purpose of the present study in rats was to determine if this conversion of thiols to thiosulfate is (a) a generalized function of many tissues, or (b) a specialized function of the colonic mucosa. The tissues studied were mucosa from the cecum, right colon, mid-colon, ileum, and stomach; liver; muscle; erythrocytes; and plasma. The metabolic rate was determined by incubating homogenates of the various tissues with H(2)(35)S and CH(3)(35)SH and measuring the rate of incorporation of (35)S into thiosulfate and sulfate. The detoxification activity of H(2)S (expressed as nmol/mg per min) that resulted in thiosulfate production was at least eight times greater for cecal and right colonic mucosa than for the non-colonic tissues. Thiosulfate production from CH(3)SH was at least five times more rapid for cecal and right colonic mucosa than for the non-colonic tissues. We conclude that colonic mucosa possesses a specialized detoxification system that allows this tissue to rapidly metabolize H(2)S and CH(3)SH to thiosulfate. Presumably, this highly developed system protects the colon from what otherwise might be injurious concentrations of H(2)S and CH(3)SH. Defects in this detoxification pathway possibly could play a role in the pathogenesis of various forms of colitis.
Irvin, Thomas T.; Hunt, Thomas K.
It has been suggested that colonic healing is impaired in malnourished subjects, but there have been no biochemical studies of the effect of malnutrition on colonic healing. The effects of malnutrition on the colon and the healing of colonic anastomoses were studied in rats fed a protein-free diet. Test animals were compared with control animals of similar age, and control animals of similar weight. There was a significant reduction in the body weight, total serum proteins and serum albumin of animals starved of protein. Malnutrition resulted in a reduction in the weight of the uninjured colon, and an increase in the colonic collagen concentration. There was a significant reduction in the collagen content of the colon in animals starved of protein for seven weeks, and the collagen content of anastomoses in these animals was significantly lower than the value in control animals. Anastomotic edema occurred during colon healing in animals starved for seven weeks. Measurements of colonic bursting pressure were an inaccurate guide to colonic healing. It is concluded that severe malnutrition resulting in 34% loss of body weight had an adverse effect on colonic healing. PMID:4418508
LeChevallier, M W; Cawthon, C D; Lee, R G
The current project was developed to examine inactivation of biofilm bacteria and to characterize the interaction of biocides with pipe surfaces. Unattached bacteria were quite susceptible to the variety of disinfectants tested. Viable bacterial counts were reduced 99% by exposure to 0.08 mg of hypochlorous acid (pH 7.0) per liter (1 to 2 degrees C) for 1 min. For monochloramine, 94 mg/liter was required to kill 99% of the bacteria within 1 min. These results were consistent with those found by other investigators. Biofilm bacteria grown on the surfaces of granular activated carbon particles, metal coupons, or glass microscope slides were 150 to more than 3,000 times more resistant to hypochlorous acid (free chlorine, pH 7.0) than were unattached cells. In contrast, resistance of biofilm bacteria to monochloramine disinfection ranged from 2- to 100-fold more than that of unattached cells. The results suggested that, relative to inactivation of unattached bacteria, monochloramine was better able to penetrate and kill biofilm bacteria than free chlorine. For free chlorine, the data indicated that transport of the disinfectant into the biofilm was a major rate-limiting factor. Because of this phenomenon, increasing the level of free chlorine did not increase disinfection efficiency. Experiments where equal weights of disinfectants were used suggested that the greater penetrating power of monochloramine compensated for its limited disinfection activity. These studies showed that monochloramine was as effective as free chlorine for inactivation of biofilm bacteria. The research provides important insights into strategies for control of biofilm bacteria. Images PMID:2849380
Das, Rituparna; LaRose, Meredith I; Hergott, Christopher B; Leng, Lin; Bucala, Richard; Weiser, Jeffrey N
Human genetic polymorphisms associated with decreased expression of macrophage migration inhibitory factor (MIF) have been linked to the risk of community-acquired pneumonia. Because Streptococcus pneumoniae is the leading cause of community-acquired pneumonia and nasal carriage is a precursor to invasive disease, we explored the role of MIF in the clearance of pneumococcal colonization in a mouse model. MIF-deficient mice (Mif(-/-)) showed prolonged colonization with both avirulent (23F) and virulent (6A) pneumococcal serotypes compared with wild-type animals. Pneumococcal carriage led to both local upregulation of MIF expression and systemic increase of the cytokine. Delayed clearance in the Mif(-/-) mice was correlated with reduced numbers of macrophages in upper respiratory tract lavages as well as impaired upregulation of MCP-1/CCL2. We found that primary human monocyte-derived macrophages as well as THP-1 macrophages produced MIF upon pneumococcal infection in a pneumolysin-dependent manner. Pneumolysin-induced MIF production required its pore-forming activity and phosphorylation of p38-MAPK in macrophages, with sustained p38-MAPK phosphorylation abrogated in the setting of MIF deficiency. Challenge with pneumolysin-deficient bacteria demonstrated reduced MIF upregulation, decreased numbers of macrophages in the nasopharynx, and less effective clearance. Mif(-/-) mice also showed reduced Ab response to pneumococcal colonization and impaired ability to clear secondary carriage. Finally, local administration of MIF was able to restore bacterial clearance and macrophage accumulation in Mif(-/-) mice. Our work suggests that MIF is important for innate and adaptive immunity to pneumococcal colonization and could be a contributing factor in genetic differences in pneumococcal disease susceptibility.
Converse, Brandon J.; McKinley, James P.; Resch, Charles T.; Roden, Eric E.
Here our study employed 16S rRNA gene amplicon pyrosequencing to examine the hypothesis that chemolithotrophic Fe(II)-oxidizing bacteria (FeOB) would preferentially colonize the Fe(II)-bearing mineral biotite compared to quartz sand when the minerals were incubated in situ within a subsurface redox transition zone (RTZ) at the Hanford 300 Area site in Richland, WA, USA. The work was motivated by the recently documented presence of neutral-pH chemolithotrophic FeOB capable of oxidizing structural Fe(II) in primary silicate and secondary phyllosilicate minerals in 300 Area sediments and groundwater (Benzine et al., 2013). Sterilized portions of sand+biotite or sand alone were incubated in situ for 5 months within a multilevel sampling (MLS) apparatus that spanned a ca. 2-m interval across the RTZ in two separate groundwater wells. Parallel MLS measurements of aqueous geochemical species were performed prior to deployment of the minerals. Contrary to expectations, the 16S rRNA gene libraries showed no significant difference in microbial communities that colonized the sand+biotite vs. sand-only deployments. Both mineral-associated and groundwater communities were dominated by heterotrophic taxa, with organisms from the Pseudomonadaceae accounting for up to 70% of all reads from the colonized minerals. These results are consistent with previous results indicating the capacity for heterotrophic metabolism (including anaerobic metabolism below the RTZ) as well as the predominance of heterotrophic taxa within 300 Area sediments and groundwater. Although heterotrophic organisms clearly dominated the colonized minerals, several putative lithotrophic (NH4+, H2, Fe(II), and HS- oxidizing) taxa were detected in significant abundance above and within the RTZ. Such organisms may play a role in the coupling of anaerobic microbial metabolism to oxidative pathways with attendant impacts on elemental cycling and redox-sensitive contaminant
Converse, Brandon J.; McKinley, James P.; Resch, Charles T.; ...
Here our study employed 16S rRNA gene amplicon pyrosequencing to examine the hypothesis that chemolithotrophic Fe(II)-oxidizing bacteria (FeOB) would preferentially colonize the Fe(II)-bearing mineral biotite compared to quartz sand when the minerals were incubated in situ within a subsurface redox transition zone (RTZ) at the Hanford 300 Area site in Richland, WA, USA. The work was motivated by the recently documented presence of neutral-pH chemolithotrophic FeOB capable of oxidizing structural Fe(II) in primary silicate and secondary phyllosilicate minerals in 300 Area sediments and groundwater (Benzine et al., 2013). Sterilized portions of sand+biotite or sand alone were incubated in situ formore » 5 months within a multilevel sampling (MLS) apparatus that spanned a ca. 2-m interval across the RTZ in two separate groundwater wells. Parallel MLS measurements of aqueous geochemical species were performed prior to deployment of the minerals. Contrary to expectations, the 16S rRNA gene libraries showed no significant difference in microbial communities that colonized the sand+biotite vs. sand-only deployments. Both mineral-associated and groundwater communities were dominated by heterotrophic taxa, with organisms from the Pseudomonadaceae accounting for up to 70% of all reads from the colonized minerals. These results are consistent with previous results indicating the capacity for heterotrophic metabolism (including anaerobic metabolism below the RTZ) as well as the predominance of heterotrophic taxa within 300 Area sediments and groundwater. Although heterotrophic organisms clearly dominated the colonized minerals, several putative lithotrophic (NH4+, H2, Fe(II), and HS- oxidizing) taxa were detected in significant abundance above and within the RTZ. Such organisms may play a role in the coupling of anaerobic microbial metabolism to oxidative pathways with attendant impacts on elemental cycling and redox-sensitive contaminant behavior in the vicinity of the RTZ.« less
Converse, Brandon J.; McKinley, James P.; Resch, Charles T.; Roden, Eric E.
This study employed 16S rRNA gene amplicon pyrosequencing to examine the hypothesis that chemolithotrophic Fe(II)-oxidizing bacteria (FeOB) would preferentially colonize the Fe(II)-bearing mineral biotite compared to quartz sand when the minerals were incubated in situ within a subsurface redox transition zone (RTZ) at the Hanford 300 Area site in Richland, WA, USA. The work was motivated by the recently documented presence of neutral-pH chemolithotrophic FeOB capable of oxidizing structural Fe(II) in primary silicate and secondary phyllosilicate minerals in 300 Area sediments and groundwater (Benzine et al., 2013). Sterilized portions of sand+biotite or sand alone were incubated in situ for 5 months within a multilevel sampling (MLS) apparatus that spanned a ca. 2-m interval across the RTZ in two separate groundwater wells. Parallel MLS measurements of aqueous geochemical species were performed prior to deployment of the minerals. Contrary to expectations, the 16S rRNA gene libraries showed no significant difference in microbial communities that colonized the sand+biotite vs. sand-only deployments. Both mineral-associated and groundwater communities were dominated by heterotrophic taxa, with organisms from the Pseudomonadaceae accounting for up to 70% of all reads from the colonized minerals. These results are consistent with previous results indicating the capacity for heterotrophic metabolism (including anaerobic metabolism below the RTZ) as well as the predominance of heterotrophic taxa within 300 Area sediments and groundwater. Although heterotrophic organisms clearly dominated the colonized minerals, several putative lithotrophic (NH4+, H2, Fe(II), and HS- oxidizing) taxa were detected in significant abundance above and within the RTZ. Such organisms may play a role in the coupling of anaerobic microbial metabolism to oxidative pathways with attendant impacts on elemental cycling and redox-sensitive contaminant behavior in the vicinity of the RTZ. PMID
Septer, Alecia N; Wang, Yanling; Ruby, Edward G; Stabb, Eric V; Dunn, Anne K
Although it is accepted that bacteria-colonizing host tissues are commonly faced with iron-limiting conditions and that pathogenic bacteria often utilize iron from host-derived haem-based compounds, the mechanisms of iron acquisition by beneficial symbiotic bacteria are less clear. The bacterium Vibrio fischeri mutualistically colonizes the light organ of the squid Euprymna scolopes. Genome sequence analysis of V. fischeri revealed a putative haem-uptake gene cluster, and through mutant analysis we confirmed this cluster is important for haemin use by V. fischeri in culture. LacZ reporter assays demonstrated Fur-dependent transcriptional regulation of cluster promoter activity in culture. GFP-based reporter assays revealed that gene cluster promoter activity is induced in symbiotic V. fischeri as early as 14 h post inoculation, although colonization assays with the haem uptake mutant suggested an inability to uptake haem does not begin to limit colonization until later stages of the symbiosis. Our data indicate that the squid light organ is a low iron environment and that haem-based sources of iron are used by symbiotic V. fischeri cells. These findings provide important additional information on the availability of iron during symbiotic colonization of E. scolopes by V. fischeri, as well as the role of haem uptake in non-pathogenic host-microbe interactions.
Kannampalli, P; Shaker, R; Sengupta, J N
Irritable bowel syndrome (IBS) is a common health issue that is characterized by abdominal pain, abnormal bowel movements, and altered visceral perception. The complexity and variability in symptoms pose serious challenges in treating IBS. Current therapy for IBS is primarily focused on reducing the abdominal pain, thereby improving the quality of life to a significant extent. Although the use of fiber rich diet is widely recommended in treating IBS, some studies have questioned its use. Intra-colonic butyrate, a short-chain fatty acid, is primarily produced by the fermentation of dietary fibers in the colon. In the existing literature there are conflicting reports about the function of butyrate. In rats it is known to induce visceral hypersensitivity without altered pathology, whereas in humans it has been reported to reduce visceral pain. Understanding the molecular mechanisms responsible for this contrasting effect of butyrate is important before recommending fiber rich diet to IBS patients.
Fujita, K; Akiyama, N; Ishizaki, M; Tanaka, S; Ohsawa, K; Sugiyama, H; Kanoh, K; Toki, F; Asao, T; Kuwano, H
Dermoid cysts are benign cystic teratomas lined by skin and epidermal appendages. We report a dermoid cyst occurring in a 26-year-old female whose chief complaint was irregular vaginal bleeding. Abdominal magnetic resonance image demonstrated a space-occupying lesion in the right lower abdomen. The mass showed hyperintensity on the T2 image and the signal was homogeneous for the interior. During abdominal surgery we made the diagnosis of subserous tumor of the colon and resected the ileocecal portion of the colon. The tumor measured 5.4 x 4.8 x 3.5 cm and was soft and elastic. On cross section, a unilocular cyst filled with atheromatous material was found. Pathological examination revealed a dermoid cyst. In the view of this diagnosis, a simple excision would have been an adequate treatment.
Borner, M M
Colorectal cancer is the second leading cause of cancer death in Switzerland. The nihilism that dominated the treatment of these patients for decades has been replaced by a measure of enthusiasm, given recent therapeutic advances. New anticancer drugs such as irinotecan and oxaliplatin have changed the standard chemotherapy treatment of metastatic colorectal cancer. However, the real hype has come from molecular targeted therapy. Identification of cellular processes characteristic of colon cancer has permitted therapeutic targeting with favorable therapeutic index. Inhibition of the epidermal growth factor receptor in the clinic has provided proof of principle that interruption of signal transduction cascades in patients has therapeutic potential. Angiogenesis, especially the vascular endothelial growth factor pathway, has been proven to be another highly successful molecular target. In this article, we will review molecular targets, which are under active clinical investigation in colon cancer.
Meyer, Timothy W; Hostetter, Thomas H
There is renewed interest in identifying organic waste solutes that are normally excreted by the kidneys and must be removed by renal replacement therapy when the kidneys fail. A large number of these waste solutes are produced by colon microbes. Mass spectrometry is expanding our knowledge of their chemical identity, and DNA sequencing technologies are providing new knowledge of the microbes and metabolic pathways by which they are made. There is evidence that the most extensively studied of the colon-derived solutes, indoxyl sulfate and p-cresol sulfate, are toxic. Much more study is required to establish the toxicity of other solutes in this class. Because they are made in an isolated compartment by microbes, their production may prove simpler to suppress than the production of other waste solutes. To the extent that they are toxic, suppressing their production could improve the health of renal failure patients without the need for more intensive or prolonged dialysis.
Korp, Juliane; Vela Gurovic, María S
Summary Bacteria, which prey on other microorganisms, are commonly found in the environment. While some of these organisms act as solitary hunters, others band together in large consortia before they attack their prey. Anecdotal reports suggest that bacteria practicing such a wolfpack strategy utilize antibiotics as predatory weapons. Consistent with this hypothesis, genome sequencing revealed that these micropredators possess impressive capacities for natural product biosynthesis. Here, we will present the results from recent chemical investigations of this bacterial group, compare the biosynthetic potential with that of non-predatory bacteria and discuss the link between predation and secondary metabolism. PMID:27340451
Hunt, Terry L; Lipo, Carl P
Easter Island (Rapa Nui) provides a model of human-induced environmental degradation. A reliable chronology is central to understanding the cultural, ecological, and demographic processes involved. Radiocarbon dates for the earliest stratigraphic layers at Anakena, Easter Island, and analysis of previous radiocarbon dates imply that the island was colonized late, about 1200 A.D. Substantial ecological impacts and major cultural investments in monumental architecture and statuary thus began soon after initial settlement.
Broitman, S A
Populations consuming diets high in fat and cholesterol exhibit a greater incidence of colon cancer than those consuming less fat and cholesterol. Lowering elevated serum cholesterol levels experimentally or clinically is associated with increased large-bowel tumorigenesis. Thus, cholesterol lost to the gut, either dietary or endogenously synthesized, appears to have a role in large-bowel cancer. Whether the effect(s) is mediated by increases in fecal bile acid excretion or some other mechanism is not clear.
Avlund, Tue Højslev; Thomsen, Henrik
Gallstone is a rare cause of large bowel obstruction. The condition is mainly reported in elderly women with considerable comorbidity and hence with high morbidity and mortality. We describe a case of a 75 year-old woman, with known gallbladder stone, presenting with symptoms of large bowel obstruction. Computed tomography of the abdomen confirmed a large gallstone obstructing the colon. The gallstone was subsequent removed by cololithotomi and the patient made a full recovery.
Dowling, Catherine-M; Hill, Arnold-Dk; Malone, Carmel; Sheehan, John-J; Tormey, Shona; Sheahan, Kieran; McDermott, Enda; O'Higgins, Niall-J
A 17-year-old gentleman was admitted to our hospital for headache, the differential diagnosis of which included Behcet's syndrome (BS). He developed an acute abdomen and was found to have air under the diaphragm on erect chest X-ray. Subsequent laparotomy revealed multiple perforations throughout the colon. This report describes an unusual complication of Behcets syndrome occurring at the time of presentation and a review of the current literature of reported cases.
Botta, Anna Lucia; Santacecilia, Alessandra; Ercole, Claudia; Cacchio, Paola; Del Gallo, Maddalena
Four bacteria selected on the basis of their capability of fixing atmospheric nitrogen, stimulating plant-growth, and protecting the host plant from pathogens - Azospirillum brasilense, Gluconacetobacter diazotrophicus, Herbaspirillum seropedicae, Burkholderia ambifaria - were inoculated on tomato seeds either singularly, in couple and in a four bacteria mixer. Aim of this research was to evaluate: (1) effect of single and mixed cultures on the inoculated plant - plant growth, dry weight, root length and surface, number of leaves, among others; (2) colonization and interactions of the bacteria inside the host plant; (3) localization inside the host of single bacterial strains marked with the gusA reporter gene. The results obtained indicate that all selected microbial strains have colonized Lycopersicon esculentum but in a different way, depending on the single species. A. brasilense, G. diazotrophicus inoculated in vitro singularly and together were the best plant colonizers. In vivo essays, instead, B. ambifaria and the four-bacteria mixer gave the best results. It was possible to localize both A. brasilense and H. seropedicae inside the plant by the gusA reporter gene. The bacterial strains occur along the root axis from the apical zone until to the basal stem, on the shoot from the base up to the leaves. The four bacteria actively colonize tomato seeds and establish an endophytic community inside the plant. This review gives new information about colonization processes, in particular how bacteria interact with plants and whether they are likely to establish themselves in the plant environment after field application as biofertilizers or biocontrol agents.
Rio, Rute; Simões-Silva, Liliana; Garro, Sofia; Silva, Mário-Jorge; Azevedo, Álvaro
Background Recent studies suggest that placenta may harbour a unique microbiome that may have origin in maternal oral microbiome. Although the major physiological and hormonal adjustments observed in pregnant women lead to biochemical and microbiological modifications of the oral environment, very few studies evaluated the changes suffered by the oral microbiota throughout pregnancy. So, the aim of our study was to evaluate oral yeast colonization throughout pregnancy and to compare it with non-pregnant women. Material and Methods The oral yeast colonization was assessed in saliva of 30 pregnant and non-pregnant women longitudinally over a 6-months period. Demographic information was collected, a non-invasive intra-oral examination was performed and saliva flow and pH were determined. Results Pregnant and non-pregnant groups were similar regarding age and level of education. Saliva flow rate did not differ, but saliva pH was lower in pregnant than in non-pregnant women. Oral yeast prevalence was higher in pregnant than in non-pregnant women, either in the first or in the third trimester, but did not attain statistical significance. In individuals colonized with yeast, the total yeast quantification (Log10CFU/mL) increase from the 1st to the 3rd trimester in pregnant women, but not in non-pregnant women. Conclusions Pregnancy may favour oral yeast growth that may be associated with an acidic oral environment. Key words:Oral yeast, fungi, pregnancy, saliva pH. PMID:28160578
Liu, Junhua; Bian, Gaorui; Sun, Daming; Zhu, Weiyun; Mao, Shengyong
This study aims to investigate the effect of starter feeding supplementation on colonic mucosal bacterial communities and on mucosal immune homeostasis in pre-weaned lambs. We selected eight pairs of 10-day-old lamb twins. One twin was fed breast milk (M, n = 8), while the other was fed breast milk plus starter (M+S, n = 8). The lambs were sacrificed at 56 days age. Colonic content was collected to determine the pH and the concentrations of volatile fatty acids (VFA) and lactate. The colonic mucosa was harvested to characterize the bacterial communities using Illumina MiSeq sequencing and to determine mRNA expression levels of cytokines and toll-like receptors (TLR) using quantitative real-time PCR. The results show that starter feeding decreased luminal pH and increased the concentrations of acetate, propionate, butyrate, total VFA, and lactate in the colon. The principal coordinate analysis (PCA) and analysis of molecular variance show that starter feeding supplementation significantly affected the colonic mucosal bacterial communities with a higher relative abundance of the dominant taxa unclassified S24-7, Oscillibacter, Prevotella, Parabacteroides, Bifidobacterium, Ruminobacter, and Succinivibrio, and a lower proportion of unclassified Ruminococcaceae, RC9_gut_group, Blautia, Phocaeicola, Phascolarctobacterium, unclassified BS11_gut_group, unclassified family_XIII, and Campylobacter in lambs. Meanwhile, starter feeding decreased mRNA expression of TLR4 and cytokines TNF-α and IFN-γ in colonic tissue. Furthermore, the changes in the colonic mucosal mRNA expression of TLR and cytokines were associated with changes in mucosal bacterial composition. These findings may provide new insights into colonic mucosal bacteria and immune homeostasis in developing lambs. PMID:28382025
Bouakane, Amel; Benchaîeb, Ilhem; Rodolakis, Annie
Abortion, placental and fetal colonization, and levels of gamma interferon were analyzed for four Chlamydophila abortus strains presenting antigenic variations in a mouse model. Expression of virulence of these strains varied and indicated that abortion was not directly related to the number of bacteria in the placenta, and thus, other factors may have an important role in activating the abortion process. PMID:14638821
Characteristic protein extracted and detected. Natural protein marker found in Pseudomonas bacteria. Azurin, protein containing copper readily extracted, purified, and used to prepare antibodies. Possible to develop simple, fast, and accurate test for marker carried out in doctor's office.
Shatzkes, Kenneth; Tang, Chi; Singleton, Eric; Shukla, Sean; Zuena, Michael; Gupta, Shilpi; Dharani, Sonal; Rinaggio, Joseph; Connell, Nancy D.; Kadouri, Daniel E.
Bdellovibrio bacteriovorus and Micavibrio aeruginosavorus are Gram-negative proteobacteria that are obligate predators of other Gram-negative bacteria and are considered potential alternatives to antibiotics. Most studies focusing on predatory bacteria have been performed in vitro, thus the effect of predatory bacteria on a live host, including the impact on the ecology of the native microbiota, has yet to be fully examined. In this study, intrarectal inoculations of Sprague-Dawley rats with predatory bacteria were performed. Additionally, feces were collected for seven days post-inoculation to determine the effect on gut bacterial diversity. Rat colonic tissue exhibited no abnormal histopathological effects due to predatory bacteria. A modest increase in pro-inflammatory cytokines was measured in the colons of rats inoculated with predatory bacteria by 24 and 48 hours, with all but IL-13 returning to baseline by seven days. V4 16S rRNA gene sequencing of fecal DNA demonstrated minimal shifts in taxonomic representation over the week due to predatory bacteria. Changes in bacterial populations due to exposure to B. bacteriovorus are predicted to contribute to health, however, an overgrowth of Prevotella was observed due to exposure to M. aeruginosavorus. This study further addresses safety concerns associated with the potential use of predatory bacteria to treat infections. PMID:28262674
Shatzkes, Kenneth; Tang, Chi; Singleton, Eric; Shukla, Sean; Zuena, Michael; Gupta, Shilpi; Dharani, Sonal; Rinaggio, Joseph; Connell, Nancy D; Kadouri, Daniel E
Bdellovibrio bacteriovorus and Micavibrio aeruginosavorus are Gram-negative proteobacteria that are obligate predators of other Gram-negative bacteria and are considered potential alternatives to antibiotics. Most studies focusing on predatory bacteria have been performed in vitro, thus the effect of predatory bacteria on a live host, including the impact on the ecology of the native microbiota, has yet to be fully examined. In this study, intrarectal inoculations of Sprague-Dawley rats with predatory bacteria were performed. Additionally, feces were collected for seven days post-inoculation to determine the effect on gut bacterial diversity. Rat colonic tissue exhibited no abnormal histopathological effects due to predatory bacteria. A modest increase in pro-inflammatory cytokines was measured in the colons of rats inoculated with predatory bacteria by 24 and 48 hours, with all but IL-13 returning to baseline by seven days. V4 16S rRNA gene sequencing of fecal DNA demonstrated minimal shifts in taxonomic representation over the week due to predatory bacteria. Changes in bacterial populations due to exposure to B. bacteriovorus are predicted to contribute to health, however, an overgrowth of Prevotella was observed due to exposure to M. aeruginosavorus. This study further addresses safety concerns associated with the potential use of predatory bacteria to treat infections.
Kremer, Natacha; Philipp, Eva E R; Carpentier, Marie-Christine; Brennan, Caitlin A; Kraemer, Lars; Altura, Melissa A; Augustin, René; Häsler, Robert; Heath-Heckman, Elizabeth A C; Peyer, Suzanne M; Schwartzman, Julia; Rader, Bethany A; Ruby, Edward G; Rosenstiel, Philip; McFall-Ngai, Margaret J
Upon transit to colonization sites, bacteria often experience critical priming that prepares them for subsequent, specific interactions with the host; however, the underlying mechanisms are poorly described. During initiation of the symbiosis between the bacterium Vibrio fischeri and its squid host, which can be observed directly and in real time, approximately five V. fischeri cells aggregate along the mucociliary membranes of a superficial epithelium prior to entering host tissues. Here, we show that these few early host-associated symbionts specifically induce robust changes in host gene expression that are critical to subsequent colonization steps. This exquisitely sensitive response to the host's specific symbiotic partner includes the upregulation of a host endochitinase, whose activity hydrolyzes polymeric chitin in the mucus into chitobiose, thereby priming the symbiont and also producing a chemoattractant gradient that promotes V. fischeri migration into host tissues. Thus, the host responds transcriptionally upon initial symbiont contact, which facilitates subsequent colonization.
Desai, Mahesh S; Seekatz, Anna M; Koropatkin, Nicole M; Kamada, Nobuhiko; Hickey, Christina A; Wolter, Mathis; Pudlo, Nicholas A; Kitamoto, Sho; Terrapon, Nicolas; Muller, Arnaud; Young, Vincent B; Henrissat, Bernard; Wilmes, Paul; Stappenbeck, Thaddeus S; Núñez, Gabriel; Martens, Eric C
Despite the accepted health benefits of consuming dietary fiber, little is known about the mechanisms by which fiber deprivation impacts the gut microbiota and alters disease risk. Using a gnotobiotic mouse model, in which animals were colonized with a synthetic human gut microbiota composed of fully sequenced commensal bacteria, we elucidated the functional interactions between dietary fiber, the gut microbiota, and the colonic mucus barrier, which serves as a primary defense against enteric pathogens. We show that during chronic or intermittent dietary fiber deficiency, the gut microbiota resorts to host-secreted mucus glycoproteins as a nutrient source, leading to erosion of the colonic mucus barrier. Dietary fiber deprivation, together with a fiber-deprived, mucus-eroding microbiota, promotes greater epithelial access and lethal colitis by the mucosal pathogen, Citrobacter rodentium. Our work reveals intricate pathways linking diet, the gut microbiome, and intestinal barrier dysfunction, which could be exploited to improve health using dietary therapeutics.
Peretz, Avi; Koiefman, Anna; Dinisman, Eleonora; Brodsky, Diana; Labay, Kozitta
Transmission of nosocomial pathogens has been linked to transient colonization of health care workers, medical devices and other constituents of patients' environment. In this paper we present our findings concerning the presence of pathogenic bacteria on wheelchairs, and the possibility that wheelchairs constitute a reservoir of these bacteria and a means of spreading them. In this work we examined four wheelchairs, each from a different location: the internal medicine ward, the emergency department, the general surgery ward and wheelchair stockpile of the transportation unit of the hospital. The samples were collected and cultured on different media. Bacterial identification and antimicrobial sensitivity testing were carried out using accepted practices in the microbiology laboratory. We found that wheelchairs are contaminated with several pathogenic bacteria, among them antibiotic-resistant strains such as MRSA, Pseudomonas aeruginosa, Acinetobacter baumanni etc. Since there is no specific guideline protocol that deals with disinfection and cleaning frequency of wheelchairs in hospitals, we suggest each hospital to write one.
Juarez, Gabriel; Fernandez, Vicente; Stocker, Roman
Dispersants are used to break up marine oil slicks and increase the available surface area for bacteria to degrade oil hydrocarbons. However, this common view neglects key elements of the microscale interactions between bacteria and oil droplets, namely encounters and growth. Utilizing experimental observations of bacteria colonizing oil droplets, we model the interactions affecting hydrocarbon consumption between a collection of oil droplets with varying sizes and a single bacterial pool. The results show that degradation time is minimized for intermediate droplet sizes and that reducing droplet size too much can lead to years in increased degradation time. This mechanical model provides a baseline for understanding oil biodegradation and mitigation strategies in open marine systems.
Taktikos, Johannes; Zaburdaev, Vasily; Biais, Nicolas; Stark, Holger; Weitz, David A.
The first step of colonization of Neisseria gonorrhoeae bacteria, the etiological agent of gonorrhea, is the attachment to human epithelial cells. The attachment of N. gonorrhoeae bacteria to surfaces or other cells is primarily mediated by filamentous appendages, called type IV pili (Tfp). Cycles of elongation and retraction of Tfp are responsible for a common bacterial motility called twitching motility which allows the bacteria to crawl over surfaces. Experimentally, N. gonorrhoeae cells initially dispersed over a surface agglomerate into round microcolonies within hours. It is so far not known whether this clustering is driven entirely by the Tfp dynamics or if chemotactic interactions are needed. Thus, we investigate whether the agglomeration may stem solely from the pili-mediated attraction between cells. By developing a statistical model for pili-taxis, we try to explain the experimental measurements of the time evolution of the mean cluster size, number of clusters, and area fraction covered by the cells.
Yurkov, Vladimir V.; Beatty, J. Thomas
The aerobic anoxygenic phototrophic bacteria are a relatively recently discovered bacterial group. Although taxonomically and phylogenetically heterogeneous, these bacteria share the following distinguishing features: the presence of bacteriochlorophyll a incorporated into reaction center and light-harvesting complexes, low levels of the photosynthetic unit in cells, an abundance of carotenoids, a strong inhibition by light of bacteriochlorophyll synthesis, and the inability to grow photosynthetically under anaerobic conditions. Aerobic anoxygenic phototrophic bacteria are classified in two marine (Erythrobacter and Roseobacter) and six freshwater (Acidiphilium, Erythromicrobium, Erythromonas, Porphyrobacter, Roseococcus, and Sandaracinobacter) genera, which phylogenetically belong to the α-1, α-3, and α-4 subclasses of the class Proteobacteria. Despite this phylogenetic information, the evolution and ancestry of their photosynthetic properties are unclear. We discuss several current proposals for the evolutionary origin of aerobic phototrophic bacteria. The closest phylogenetic relatives of aerobic phototrophic bacteria include facultatively anaerobic purple nonsulfur phototrophic bacteria. Since these two bacterial groups share many properties, yet have significant differences, we compare and contrast their physiology, with an emphasis on morphology and photosynthetic and other metabolic processes. PMID:9729607
Gary, J M; Langohr, I M; Lim, A; Bolin, S; Bolin, C; Moore, I; Kiupel, M
Four, 1-to 4-week-old ferret kits were submitted to the Diagnostic Center for Population and Animal Health at Michigan State University for post-mortem examination. Grossly, multiple bowel loops in all ferret kits were distended by mucoid faecal material. Microscopically, there was no evidence of inflammation or notable alteration to the normal mucosal morphology. Gram-positive coccoid bacteria colonized variable segments of the small intestine. These bacteria were identified as Staphylococcus delphini by phenotypic and molecular analyses. Enzyme-linked immunosorbent assay for detection of Staphylococcus enterotoxins was positive and polymerase chain reaction detected the gene for Staphylococcus enterotoxin E in the isolates. The hypersecretory diarrhoea in these ferret kits may have been associated with colonization of the small intestine by S. delphini, cultures of which were shown in vitro to be potentially capable of producing enterotoxin E. The condition described in these ferrets is similar to 'sticky' kit syndrome in mink.
Marteinsson, V.; Klonowski, A.; Reynisson, E.; Vannier, P.; Sigurdsson, B. D.; Ólafsson, M.
Colonization of life on Surtsey has been observed systematically since the formation of the island 50 years ago. Although the first colonisers were prokaryotes, such as bacteria and blue-green algae, most studies have been focused on the settlement of plants and animals but less on microbial succession. To explore microbial colonization in diverse soils and the influence of associated vegetation and birds on numbers of environmental bacteria, we collected 45 samples from different soil types on the surface of the island. Total viable bacterial counts were performed with the plate count method at 22, 30 and 37 °C for all soil samples, and the amount of organic matter and nitrogen (N) was measured. Selected samples were also tested for coliforms, faecal coliforms and aerobic and anaerobic bacteria. The subsurface biosphere was investigated by collecting liquid subsurface samples from a 181 m borehole with a special sampler. Diversity analysis of uncultivated biota in samples was performed by 16S rRNA gene sequences analysis and cultivation. Correlation was observed between nutrient deficits and the number of microorganisms in surface soil samples. The lowest number of bacteria (1 × 104-1 × 105 cells g-1) was detected in almost pure pumice but the count was significantly higher (1 × 106-1 × 109 cells g-1) in vegetated soil or pumice with bird droppings. The number of faecal bacteria correlated also to the total number of bacteria and type of soil. Bacteria belonging to Enterobacteriaceae were only detected in vegetated samples and samples containing bird droppings. The human pathogens Salmonella, Campylobacter and Listeria were not in any sample. Both thermophilic bacteria and archaea 16S rDNA sequences were found in the subsurface samples collected at 145 and 172 m depth at 80 and 54 °C, respectively, but no growth was observed in enrichments. The microbiota sequences generally showed low affiliation to any known 16S rRNA gene sequences.
Naringenin is a plant polyphenol consumed in the diet. However, it is estimated that 90-95% of polyphenols are not absorbed in the small intestine and reach the colon intact where they interact with the gut microbiota. Previously, the effect of naringenin on the growth of the commensal gut bacteria...
Langbach, Odd; Kristoffersen, Anne Karin; Abesha-Belay, Emnet; Enersen, Morten; Røkke, Ola; Olsen, Ingar
Background In ventral hernia surgery, mesh implants are used to reduce recurrence. Infection after mesh implantation can be a problem and rates around 6–10% have been reported. Bacterial colonization of mesh implants in patients without clinical signs of infection has not been thoroughly investigated. Molecular techniques have proven effective in demonstrating bacterial diversity in various environments and are able to identify bacteria on a gene-specific level. Objective The purpose of this study was to detect bacterial biofilm in mesh implants, analyze its bacterial diversity, and look for possible resemblance with bacterial biofilm from the periodontal pocket. Methods Thirty patients referred to our hospital for recurrence after former ventral hernia mesh repair, were examined for periodontitis in advance of new surgical hernia repair. Oral examination included periapical radiographs, periodontal probing, and subgingival plaque collection. A piece of mesh (1×1 cm) from the abdominal wall was harvested during the new surgical hernia repair and analyzed for bacteria by PCR and 16S rRNA gene sequencing. From patients with positive PCR mesh samples, subgingival plaque samples were analyzed with the same techniques. Results A great variety of taxa were detected in 20 (66.7%) mesh samples, including typical oral commensals and periodontopathogens, enterics, and skin bacteria. Mesh and periodontal bacteria were further analyzed for similarity in 16S rRNA gene sequences. In 17 sequences, the level of resemblance between mesh and subgingival bacterial colonization was 98–100% suggesting, but not proving, a transfer of oral bacteria to the mesh. Conclusion The results show great bacterial diversity on mesh implants from the anterior abdominal wall including oral commensals and periodontopathogens. Mesh can be reached by bacteria in several ways including hematogenous spread from an oral site. However, other sites such as gut and skin may also serve as sources for the
Li, Ye; Zhai, He; Sanchez, Sandra; Kearns, Daniel; Wu, Yilin
Many bacteria swim by flagella motility which is essential for bacterial dispersal, chemotaxis, and pathogenesis. Here we combined single-cell tracking, theoretical analysis, and computational modeling to investigate two-dimensional swimming behavior of a well-characterized flagellated bacterium Bacillus subtilis at the single-cell level. We quantified the 2D motion pattern of B. subtilis in confined space and studied how cells interact with each other. Our findings shed light on bacterial colonization in confined environments, and will serve as the ground for building more accurate models to understand bacterial collective motion. Mailing address: Room 306 Science Centre North Block, The Chinese University of Hong Kong, Shatin, N.T. Hong Kong SAR. Phone: +852-3943-6354. Fax: +852-2603-5204. E-mail: firstname.lastname@example.org.
Rangjaroen, Chakrapong; Sungthong, Rungroch; Rerkasem, Benjavan; Teaumroong, Neung; Noisangiam, Rujirek; Lumyong, Saisamorn
With the aim of searching for potent diazotrophic bacteria that are free of public health concerns and optimize rice cultivation, the endophytic colonization and plant growth-promoting activities of some endophytic diazotrophic bacteria isolated from rice were evaluated. Among these bacteria, the emerging diazotrophic strains of the genus Novosphingobium effectively associated with rice plant interiors and consequently promoted the growth of rice, even with the lack of a nitrogen source. These results suggest that diazotrophic Novosphingobium is an alternative microbial resource for further development as a safe biological enhancer in the optimization of organic rice cultivation. PMID:28228608
Messad, Nourreddine; Prajsnar, Tomasz K.; Lina, Gerard; O’Callaghan, David; Foster, Simon J.; Renshaw, Steve A.; Skaar, Eric P.; Bes, Michèle; Dunyach-Remy, Catherine; Vandenesch, François; Sotto, Albert
Staphylococcus aureus is an opportunistic bacterium capable of causing a wide range of severe diseases when it gains access to underlying tissues. Paradoxically, S. aureus is a common inhabitant of the skin microflora and colonizes the nares and other human mucosa. The purpose of this study was to determine the genetic basis for the differences in the pathogenic versus colonizing potential of S. aureus isolated from diabetic foot ulcers (DFUs). By performing optical map comparisons of a collection of S. aureus strains isolated from DFUs, we brought to light a prophage present in noninfecting bacteria. The phage, namely ROSA-like, was localized in a hotspot region ΦNM2 near the locus isd, the iron surface determinant system. The integrated phage significantly reduces the virulence of the strain and increases the biofilm formation. DFUs seem to be a specific niche of this colonizing strain. The ROSA-like phage represents the first description of a mobile element present mainly in S. aureus isolated from DFUs, which modulates the relationship of the bacteria with its human host. This phage appears to attenuate bacterial virulence and promote colonization. PMID:25901094
Hydrophobicity is a very important surface property and there is a growing interest in the production and characterization of superhydrophobic surfaces. Accordingly, it was recently shown how to obtain a superhydrophobic surface using a simple and cost-effective method on a polymer named poly(L-lactic acid) (PLLA). To evaluate the ability of such material as a substrate for bacterial colonization, this work assessed the capability of different bacteria to colonize a biomimetic rough superhydrophobic (SH) PLLA surface and also a smooth hydrophobic (H) one. The interaction between these surfaces and bacteria with different morphologies and cell walls was studied using one strain of Staphylococcus aureus and one of Pseudomonas aeruginosa. Results showed that both bacterial strains colonized the surfaces tested, although significantly higher numbers of S. aureus cells were found on SH surfaces comparing to H ones. Moreover, scanning electron microscopy images showed an extracellular matrix produced by P. aeruginosa on SH PLLA surfaces, indicating that this bacterium is able to form a biofilm on such substratum. Bacterial removal through lotus leaf effect was also tested, being more efficient on H coupons than on SH PLLA ones. Overall, the results showed that SH PLLA surfaces can be used as a substrate for bacterial colonization and, thus, have an exceptional potential for biotechnology applications. PMID:22018163
Wu, Xian; Song, Mingyue; Wang, Minqi; Zheng, Jinkai; Gao, Zili; Xu, Fei; Zhang, Guodong; Xiao, Hang
Scope Nobiletin (NBT) is a major citrus flavonoid with various health benefits. Herein, we investigated the colon cancer chemopreventive effects of NBT and its colonic metabolites in a colitis-associated colon carcinogenesis mouse model as well as in human colon cancer cell models. Methods and results In azoxymethane (AOM)/dextran sulfate sodium (DSS)-treated mice, oral administration of NBT effectively decreased both incidence and multiplicity of colonic tumors. NBT showed significant anti-proliferative, pro-apoptotic and anti-inflammatory effects in the mouse colon. HPLC analysis revealed that oral administration of NBT resulted in high levels of metabolites, i.e. 3′-demethylnobiletin (M1), 4′-demethylnobiletin (M2), and 3′, 4′-didemethylnobiletin (M3) in the colonic mucosa. In contrast, the colonic level of NBT was about 20-fold lower than the total colonic level of three metabolites. Cell culture studies demonstrated that the colonic metabolites of NBT significantly inhibited the growth of human colon cancer cells, caused cell cycle arrest, induced apoptosis, and profoundly modulated signaling proteins related with cell proliferation and cell death. All of these effects were much stronger than those produced by NBT alone. Conclusions Our results demonstrated that oral administration of NBT significantly inhibited colitis-associated colon carcinogenesis in mice, and this chemopreventive effect was strongly associated with its colonic metabolites. PMID:26445322
Sadowsky, Michael J.; Whitman, Richard L.
The Fecal Bacteria offers a balanced, integrated discussion of fecal bacteria and their presence and ecology in the intestinal tract of mammals, in the environment, and in the food supply. This volume covers their use in examining and assessing water quality in order to offer protection from illnesses related to swimming in or ingesting contaminated water, in addition to discussing their use in engineering considerations of water quality, modeling, monitoring, and regulations. Fecal bacteria are additionally used as indicators of contamination of ready-to-eat foods and fresh produce. The intestinal environment, the microbial community structure of the gut microbiota, and the physiology and genomics of this broad group of microorganisms are explored in the book. With contributions from an internationally recognized group of experts, the book integrates medicine, public health, environmental, and microbiological topics in order to provide a unique, holistic understanding of fecal bacteria. Moreover, it shows how the latest basic science and applied research findings are helping to solve problems and develop effective management strategies. For example, readers will discover how the latest tools and molecular approaches have led to our current understanding of fecal bacteria and enabled us to improve human health and water quality. The Fecal Bacteria is recommended for microbiologists, clinicians, animal scientists, engineers, environmental scientists, food safety experts, water quality managers, and students. It will help them better understand fecal bacteria and use their knowledge to protect human and environmental health. They can also apply many of the techniques and molecular tools discussed in this book to the study of a broad range of microorganisms in a variety of habitats.
Mody, Lona; Gibson, Kristen E.; Horcher, Amanda; Prenovost, Katherine; McNamara, Sara E.; Foxman, Betsy; Kaye, Keith S.; Bradley, Suzanne
OBJECTIVE To characterize the epidemiology of multidrug-resistant (MDR) Acinetobacter baumannii colonization in high-risk nursing home (NH) residents. DESIGN Nested case-control study within a multicenter prospective intervention trial. SETTING Four NHs in Southeast Michigan. PARTICIPANTS Case patients and control subjects were NH residents with an indwelling device (urinary catheter and/or feeding tube) selected from the control arm of the Targeted Infection Prevention study. Cases were residents colonized with MDR (resistant to ≥3 classes of antibiotics) A. baumannii; controls were never colonized with MDR A. baumannii. METHODS For active surveillance cultures, specimens from the nares, oropharynx, groin, perianal area, wounds, and device insertion site(s) were collected upon study enrollment, day 14, and monthly thereafter. A. baumannii strains and their susceptibilities were identified using standard microbiologic methods. RESULTS Of 168 NH residents, 25 (15%) were colonized with MDR A. baumannii. Compared with the 143 controls, cases were more functionally disabled (Physical Self-Maintenance Score >24; odds ratio, 5.1 [95% CI, 1.8–14.9]; P < .004), colonized with Proteus mirabilis (5.8 [1.9–17.9]; P < .003), and diabetic (3.4 [1.2–9.9]; P < .03). Most cases (22 [88%]) were colonized with multiple antibiotic-resistant organisms and 16 (64%) exhibited co-colonization with at least one other resistant gram-negative bacteria. CONCLUSION Functional disability, P. mirabilis colonization, and diabetes mellitus are important risk factors for colonization with MDR A. baumannii in high-risk NH residents. A. baumannii exhibits widespread antibiotic resistance and a preference to colonize with other antibiotic-resistant organisms, meriting enhanced attention and improved infection control practices in these residents. PMID:26072936
Johnson, Caroline H.; Dejea, Christine M.; Edler, David; Hoang, Linh T.; Santidrian, Antonio F.; Felding, Brunhilde H.; Cho, Kevin; Wick, Elizabeth C.; Hechenbleikner, Elizabeth M.; Uritboonthai, Winnie; Goetz, Laura; Casero, Robert A.; Pardoll, Drew M.; White, James R.; Patti, Gary J.; Sears, Cynthia L.; Siuzdak, Gary
SUMMARY Bacterial biofilms in the colon alter the host tissue microenvironment. A role for biofilms in colon cancer metabolism has been suggested but to date has not been evaluated. Using metabolomics, we investigated the metabolic influence that microbial biofilms have on colon tissues and the related occurrence of cancer. Patient-matched colon cancers and histologically normal tissues, with or without biofilms, were examined. We show the upregulation of polyamine metabolites in tissues from cancer hosts with significant enhancement of N1, N12-diacetylspermine in both biofilm positive cancer and normal tissues. Antibiotic treatment, which cleared biofilms, decreased N1, N12-diacetylspermine levels to those seen in biofilm negative tissues, indicating that host cancer and bacterial biofilm structures contribute to the polyamine metabolite pool. These results show that colonic mucosal biofilms alter the cancer metabolome, to produce a regulator of cellular proliferation and colon cancer growth potentially affecting cancer development and progression. PMID:25959674
Johnson, Caroline H; Dejea, Christine M; Edler, David; Hoang, Linh T; Santidrian, Antonio F; Felding, Brunhilde H; Ivanisevic, Julijana; Cho, Kevin; Wick, Elizabeth C; Hechenbleikner, Elizabeth M; Uritboonthai, Winnie; Goetz, Laura; Casero, Robert A; Pardoll, Drew M; White, James R; Patti, Gary J; Sears, Cynthia L; Siuzdak, Gary
Bacterial biofilms in the colon alter the host tissue microenvironment. A role for biofilms in colon cancer metabolism has been suggested but to date has not been evaluated. Using metabolomics, we investigated the metabolic influence that microbial biofilms have on colon tissues and the related occurrence of cancer. Patient-matched colon cancers and histologically normal tissues, with or without biofilms, were examined. We show the upregulation of polyamine metabolites in tissues from cancer hosts with significant enhancement of N(1), N(12)-diacetylspermine in both biofilm-positive cancer and normal tissues. Antibiotic treatment, which cleared biofilms, decreased N(1), N(12)-diacetylspermine levels to those seen in biofilm-negative tissues, indicating that host cancer and bacterial biofilm structures contribute to the polyamine metabolite pool. These results show that colonic mucosal biofilms alter the cancer metabolome to produce a regulator of cellular proliferation and colon cancer growth potentially affecting cancer development and progression.
Causey, Marlin Wayne; Rivadeneira, David E.; Steele, Scott R.
The authors discuss the evolution of the evaluation and management of colonic trauma, as well as the debate regarding primary repair versus fecal diversion. Their evidence-based review covers diagnosis, management, surgical approaches, and perioperative care of patients with colon-related trauma. The management of traumatic colon injuries has evolved significantly over the past 50 years; here the authors describe a practical approach to the treatment and management of traumatic injuries to the colon based on the most current research. However, management of traumatic colon injuries remains a challenge and continues to be associated with significant morbidity. Familiarity with the different methods to the approach and management of colonic injuries will allow surgeons to minimize unnecessary complications and mortality. PMID:24294119
Karkera, Parag J; Bendre, Pradnya; D'souza, Flavia; Ramchandra, Mukunda; Nage, Amol; Palse, Nitin
Complete colonic duplication is a very rare congenital anomaly that may have different presentations according to its location and size. Complete colonic duplication can occur in about 15% of all gastrointestinal duplications. Double termination of tubular colonic duplication in the perineum is even more uncommon. We present a case of a Y-shaped tubular colonic duplication which presented with a rectovestibular fistula and a normal anus. Radiological evaluation and initial exploration for sigmoidostomy revealed duplicated colons with a common vascular supply. Endorectal mucosal resection of theduplicated distal segment till the colostomy site with division of the septum of the proximal segment and colostomy closure proved curative without compromise of the continence mechanism. Tubular colonic duplication should always be ruled out when a diagnosis of perineal canal is considered in cases of vestibular fistula alongwith a normal anus.
Bendre, Pradnya; D'souza, Flavia; Ramchandra, Mukunda; Nage, Amol; Palse, Nitin
Complete colonic duplication is a very rare congenital anomaly that may have different presentations according to its location and size. Complete colonic duplication can occur in about 15% of all gastrointestinal duplications. Double termination of tubular colonic duplication in the perineum is even more uncommon. We present a case of a Y-shaped tubular colonic duplication which presented with a rectovestibular fistula and a normal anus. Radiological evaluation and initial exploration for sigmoidostomy revealed duplicated colons with a common vascular supply. Endorectal mucosal resection of theduplicated distal segment till the colostomy site with division of the septum of the proximal segment and colostomy closure proved curative without compromise of the continence mechanism. Tubular colonic duplication should always be ruled out when a diagnosis of perineal canal is considered in cases of vestibular fistula alongwith a normal anus. PMID:26473141
Merckoll, Patricia; Jonassen, Tom Øystein; Vad, Marie Elisabeth; Jeansson, Stig L; Melby, Kjetil K
Chronically infected wounds are a costly source of suffering. An important factor in the failure of a sore to heal is the presence of multiple species of bacteria, living cooperatively in highly organized biofilms. The biofilm protects the bacteria from antibiotic therapy and the patient's immune response. Honey has been used as a wound treatment for millennia. The components responsible for its antibacterial properties are now being elucidated. The study aimed to determine the effects of different concentrations of 'Medihoney' therapeutic honey and Norwegian Forest Honey 1) on the real-time growth of typical chronic wound bacteria; 2) on biofilm formation; and 3) on the same bacteria already embedded in biofilm. Reference strains of MRSE, MRSA, ESBL Klebsiella pneumoniae and Pseudomonas aeruginosa were incubated with dilution series of the honeys in microtitre plates for 20 h. Growth of the bacteria was assessed by measuring optical density every 10 min. Growth curves, biofilm formation and minimum bactericidal concentrations are presented. Both honeys were bactericidal against all the strains of bacteria. Biofilm was penetrated by biocidal substances in honey. Reintroduction of honey as a conventional wound treatment may help improve individual wound care, prevent invasive infections, eliminate colonization, interrupt outbreaks and thereby preserve current antibiotic stocks.
Koga, Tetsufumi; Shimada, Yukio; Sato, Kiyoshi; Takahashi, Keigo; Kikuchi, Isamu; Okazaki, Yoko; Miura, Tomoko; Katsuta, Mitsuo; Iwata, Masayuki
Our previous study showed that the colonization levels of Helicobacter pylori were higher in the stomachs of 5-day-old miniature pigs than in 2-week-old ones. As dietary factors can cause these differences, we compared two diets, i.e., Weanymilk and a similar formula with a higher concentration of Fe(II), Weanylobulin. The colonization levels in the fundic mucosa were significantly higher in 2-week-old pigs fed Weanylobulin than in those fed Weanymilk. Supplementing Weanylobulin with an iron chelator, deferoxamine mesylate, significantly lowered the bacteria counts in the gastric mucosa. Normal diets supplemented with Fe(II) in 2-month-old pigs caused significantly more sites of bacteria in the antrum compared with normal diets alone. In addition, ranitidine, an inhibitor of gastric acid secretion that reduces Fe(III) to Fe(II) in the stomach, decreased the bacteria counts in 10-month-old pigs. These results suggested that Fe(II) maintained the colonization levels of H. pylori in the stomach of the miniature pigs.
Lachnit, Tim; Fischer, Matthias; Künzel, Sven; Baines, John F; Harder, Tilmann
The macroalga Fucus vesiculosus carries a specific community of surface bacteria. To identify chemical compounds that possibly mediate abundance and community composition of algae-associated bacteria, we tested the effect of surface-available algal compounds on bacterial settlement and community composition under field conditions. Compounds on algal thalli were separated from the surface by extraction with organic solvents and investigated on growth inhibition and settlement of bacterial isolates. Based on in vitro data, partially purified extract fractions were then exposed to bacterial colonizers in vivo followed by bacterial enumeration and community analysis. The polar fraction of the algal surface extract revealed a significant profouling effect for Vibrionales, whereas the nonpolar fraction - containing the xanthophyll pigment fucoxanthin and other unidentified nonpolar surface compounds - revealed a significant 80% reduction of surface colonizing bacteria. The analysis of bacterial surface communities by 454 pyrosequencing demonstrated that the antifouling activity of nonpolar algal surface compounds was targeting the abundance of natural bacterial colonizers rather than the relative composition of bacterial members within the community. Moreover, the bacterial community composition on F. vesiculosus was markedly different from artificial control substrates and chemically manipulated experimental treatments, suggesting that other, nonextractable surface features and/or physical properties render algal-specific epiphytic bacterial communities.
Talarico, Silvia T; Santos, Florenza E; Brandt, Katia Galeão; Martinez, Marina B; Taddei, Carla R
OBJECTIVE: Changes in the neonatal gut environment allow for the colonization of the mucin layer and lumen by anaerobic bacteria. The aim of the present study was to evaluate Bifidobacterium, Lactobacillus and Lactococcus colonization through the first year of life in a group of 12 Brazilian infants and to correlate these data with the levels of Escherichia coli. The presence of anaerobic members of the adult intestinal microbiota, including Eubacterium limosum and Faecalibacterium prausnitzii, was also evaluated. METHODS: Fecal samples were collected during the first year of life, and 16S rRNA from anaerobic and facultative bacteria was detected by real-time PCR. RESULTS: Bifidobacterium was present at the highest levels at all of the studied time points, followed by E. coli and Lactobacillus. E. limosum was rarely detected, and F. prausnitzii was detected only in the samples from the latest time points. CONCLUSION: These results are consistent with reports throughout the world on the community structure of the intestinal microbiota in infants fed a milk diet. Our findings also provide evidence for the influence of the environment on intestinal colonization due to the high abundance of E. coli. The presence of important anaerobic genera was observed in Brazilian infants living at a low socioeconomic level, a result that has already been well established for infants living in developed countries. PMID:28355361
Dylus, Ewa; Buda, Barbara; Górska-Frączek, Sabina; Brzozowska, Ewa; Gamian, Andrzej
Beneficial effects due to the presence of probiotic bacteria of the genus Bifidobacterium in the human intestinal tract are still an interesting object of study. So far activities have been confirmed of bifidobacteria in stimulation of the host immune system, stimulation of tumor cell apoptosis, improvement of bowel motility, alleviation of symptoms of lactose intolerance, cholesterol lowering capacity, prevention and treatment of diarrhea and irritable bowel syndrome, alleviation of allergy or atopic dermatitis, maintenance of homeostasis of the intestine, and stimulation of the development of normal intestinal microflora in infants. A multitude of therapeutic properties encourages researchers to investigate the possibility of using the potential of Bifidobacterium in the prevention and treatment of other conditions such as rheumatoid arthritis and depression. Although it is known that the beneficial effects are due to intestinal mucosal colonization by these bacteria, the cell components responsible for the colonization are still not determined. In addition to the beneficial effects of probiotic administration, there were also negative effects including sepsis. Therefore research has been directed to identify specific components of Bifidobacterium responsible for probiotic effects. Currently researchers are focused on identifying, isolating and evaluating the properties of surface proteins that are probably involved in the adhesion of bacterial cells to the intestinal epithelium, improving colonization. This paper is an overview of current knowledge on Bifidobacterium surface proteins. The ways of transport and anchoring proteins in Gram-positive bacterial cells, the assembly of cell wall, and a description of the genus Bifidobacterium are presented.
Bertrand, Fred E.; Angus, C. William; Partis, William J.; Sigounas, George
A hallmark of cancer is reactivation/alteration of pathways that control cellular differentiation during developmental processes. Evidence indicates that WNT, Notch, BMP and Hedgehog pathways have a role in normal epithelial cell differentiation, and that alterations in these pathways accompany establishment of the tumorigenic state. Interestingly, there is recent evidence that these pathways are intertwined at the molecular level, and these nodes of intersection may provide opportunities for effective targeted therapies. This review will highlight the role of the WNT, Notch, BMP and Hedgehog pathways in colon cancer. PMID:23032367
Colonic injury during percutaneous nephrolithotomy (PCNL) persists despite the advances in technical equipment and interventional radiology techniques. According to the Clavien-Dindo classification of surgical complications, colonic injury is regarded as a stage IVa complication. Currently, the rate of colonic injury ranges between 0.3% and 0.5%, with an unremarkable difference in incidence between supine and prone PCNL procedures. Colon injury is the most significant complication of PCNL. Colonic injury can result in more complicated open exploration of the abdomen, involving colostomy construction. The necessity of a second operation for the closure of the colostomy causes financial and emotional burden on the patients, patients’ relatives, and surgeons. Currently, the majority of colonic injuries occurring during PCNL are retroperitoneal. The primary treatment option is a conservative approach. It must be kept in mind that the time of diagnosis is as important as the diagnosis itself in colonic injury. Surgeons performing PCNL are advised to be conservative when considering exploratory laparotomy and colostomy construction during treatment of colonic injury. We present the case of a 49-year-old woman who underwent left prone PCNL that resulted in retroperitoneal colonic injury, along with a review of the current literature. PMID:26543436
Colonic injury during percutaneous nephrolithotomy (PCNL) persists despite the advances in technical equipment and interventional radiology techniques. According to the Clavien-Dindo classification of surgical complications, colonic injury is regarded as a stage IVa complication. Currently, the rate of colonic injury ranges between 0.3% and 0.5%, with an unremarkable difference in incidence between supine and prone PCNL procedures. Colon injury is the most significant complication of PCNL. Colonic injury can result in more complicated open exploration of the abdomen, involving colostomy construction. The necessity of a second operation for the closure of the colostomy causes financial and emotional burden on the patients, patients' relatives, and surgeons. Currently, the majority of colonic injuries occurring during PCNL are retroperitoneal. The primary treatment option is a conservative approach. It must be kept in mind that the time of diagnosis is as important as the diagnosis itself in colonic injury. Surgeons performing PCNL are advised to be conservative when considering exploratory laparotomy and colostomy construction during treatment of colonic injury. We present the case of a 49-year-old woman who underwent left prone PCNL that resulted in retroperitoneal colonic injury, along with a review of the current literature.
Cox, Clayton E.; Wright, Anita C.; McClelland, Michael
Although Salmonella has been isolated from 7.4 to 8.6% of domestic raw oysters, representing a significant risk for food-borne illness, little is known about the factors that influence their initial colonization by Salmonella. This study tested the hypothesis that specific regulatory changes enable a portion of the invading Salmonella population to colonize oysters. An in vivo promoter probe library screen identified 19 unique regions as regulated during colonization. The mutants in the nearest corresponding downstream genes were tested for colonization defects in oysters. Only one mutation, in ssrB, resulted in a significantly reduced ability to colonize oysters compared to that of wild-type Salmonella. Because ssrB regulates Salmonella pathogenicity island 2 (SPI-2)-dependent infections in vertebrate macrophages, the possibility that ssrB mediated colonization of oyster hemocytes in a similar manner was examined. However, no difference in hemocyte colonization was observed. The complementary hypothesis that signal exchange between Salmonella and the oyster's native microbial community aids colonization was also tested. Signals that triggered responses in quorum sensing (QS) reporters were shown to be produced by oyster-associated bacteria and present in oyster tissue. However, no evidence for signal exchange was observed in vivo. The sdiA reporter responded to salinity, suggesting that SdiA may also have a role in environmental sensing. Overall, this study suggests the initial colonization of live oysters by Salmonella is controlled by a limited number of regulators, including ssrB. PMID:26497459
Since the discovery of ice-nucleating bacteria in 1974 by Maki et al., a large number of studies on the biological characteristics, ice-nucleating substance, ice nucleation gene and frost damage etc. of the bacteria have been carried out. Ice-nucleating bacteria can cause the freezing of water at relatively warm temperature (-2.3°C). Tween 20 was good substrates for ice-nucleating activity of Pseudomonas fluorescens KUIN-1. Major fatty acids of Isolate (Pseudomonas fluorescens) W-11 grown at 30°C were palmitic, cis-9-hexadecenoic and cis-11-octadecenoic which amounted to 90% of the total fatty acids. Sequence analysis shows that an ice nucleation gene from Pseudomonas fluorescens is related to the gene of Pseudomonas syringae.
Otto, G; Hazell, S H; Fox, J G; Howlett, C R; Murphy, J C; O'Rourke, J L; Lee, A
The bacterial genus Helicobacter contains a number of species which colonize the gastric mucosa of mammals. Natural and/or experimental gastric pathology has been correlated with colonization in humans and a wide variety of animal species. Historical reports in the literature suggest that a high percentage of cats are colonized by large, spiral, gastric helicobacter-like organisms (GHLOs). One of these bacteria (Helicobacter felis) has been isolated on artificial media and has experimentally caused gastritis in gnotobiotic dogs. This study surveyed the prevalence of helicobacter colonization in random-source cats by using the urease assay. Histologic examination was performed to determine the degree of associated pathology present. GHLOs associated with chronic gastritis were present in 70% of the juvenile and 97% of the adult cats studied. Although further study is needed to determine specifically what role GHLOs play in feline gastrointestinal disease, these results indicate that helicobacter colonization should be considered in the pathogenesis of feline gastroenteropathy. Furthermore, the high prevalence of feline infection is interesting because cats have recently been implicated as a potential reservoir for human infection by helicobacter-like organisms. Images PMID:8027308
Aerssens, Jeroen; Camilleri, Michael; Talloen, Willem; Thielemans, Leen; Göhlmann, Hinrich W. H.; Wyngaert, Ilse Van den; Thielemans, Theo; de Hoogt, Ronald; Andrews, Christopher N.; Bharucha, Adil E.; Carlson, Paula J.; Busciglio, Irene; Burton, Duane D.; Smyrk, Thomas; Urrutia, Raul; Coulie, Bernard
BACKGROUND & AIMS Irritable bowel syndrome (IBS) has been associated with mucosal dysfunction,, mild inflammation, and altered colonic bacteria. We used microarray expression profiling of sigmoid colon mucosa to assess whether there are stably expressed sets of genes that suggest there are objective molecular biomarkers associated with IBS. METHODS Gene expression profiling was performed using Affymetrix GeneChips with RNA from sigmoid colon mucosal biopsies from 36 IBS patients and 25 healthy control subjects. RTQ-PCR was used to confirm the data in 12 genes of interest. Statistical methods for microarray data were applied to search for differentially expressed genes, and to assess the stability of molecular signatures in IBS patients. RESULTS Mucosal gene expression profiles were consistent across different sites within the sigmoid colon and were stable on repeat biopsy over ~3 months. Differentially expressed genes suggest functional alterations of several components of the host mucosal immune response to microbial pathogens. The most strikingly increased expression involved a yet uncharacterized gene, DKFZP564O0823. Identified specific genes suggest the hypothesis that molecular signatures may enable distinction of a subset of IBS patients from healthy controls. Using 75% of the biopsies as a validation set to develop a gene profile, the test set (25%) was correctly predicted with ~70% accuracy. CONCLUSIONS Mucosal gene expression analysis shows there are relatively stable alterations in colonic mucosal immunity in IBS. These molecular alterations provide the basis to test the hypothesis that objective biomarkers may be identified in IBS and enhance understanding of the disease. PMID:18237869
Chung, C; van Hoof, L; Policova, Z; Beharry, S; Sherman, P M; Neumann, A W; Durie, P
Patients with cystic fibrosis (CF) have abnormal concentrations and composition of electrolytes and macromolecules in gastrointestinal secretions. Such alterations could change intestinal surface properties, such as surface hydrophobicity, and may influence the adhesion of macromolecules, bacteria, or microbial toxins to the intestinal surface. The objective of this study was to compare the surface hydrophobicity of the gastrointestinal tract in wild type and CF mice. We used axisymmetric drop shape analysis-contact diameter to determine surface hydrophobicity by measuring contact angles of sessile water droplets placed onto epithelial surfaces. In wild type mice, there were no differences in contact angles between the duodenum, upper jejunum, lower jejunum, and ileum. The contact angle of the gastric mucosa was lower than the rest of the gastrointestinal tract. Contact angles of the proximal colon and distal colon were both higher than that of the gastric mucosa and those of the small intestinal sections. In CF mice, contact angles along the gastrointestinal tract followed the same pattern as in wild type mice. However, contact angles in the ileum and proximal colon of CF mice were greater than those from wild type mice. This study of the murine intestine showed regional differences in surface hydrophobicity comparable to those observed in other mammalian species. In addition, we showed that the ileum and proximal colon of CF mice were more hydrophobic than the corresponding segments in wild type mice. These observations are of potential clinical relevance because patients with CF exhibit clinical manifestations of gastrointestinal disease primarily in the ileum and proximal colon.
Caldwell, Denise; Kim, Bong-Suk; Iyer-Pascuzzi, Anjali S
Ralstonia solanacearum is the causal agent of bacterial wilt and infects over 200 plant species in 50 families. The soilborne bacterium is lethal to many solanaceous species, including tomato. Although resistant plants can carry high pathogen loads (between 10(5) and 10(8) CFU/g fresh weight), the disease is best controlled by the use of resistant cultivars, particularly resistant rootstocks. How these plants have latent infections yet maintain resistance is not clear. R. solanacearum first infects the plant through the root system and, thus, early root colonization events may be key to understanding resistance. We hypothesized that the distribution and timing of bacterial invasion differed in roots of resistant and susceptible tomato cultivars. Here, we use a combination of scanning electron microscopy and light microscopy to investigate R. solanacearum colonization in roots of soil-grown resistant and susceptible tomato cultivars at multiple time points after inoculation. Our results show that colonization of the root vascular cylinder is delayed in resistant 'Hawaii7996' and that, once bacteria enter the root vascular tissues, colonization in the vasculature is spatially restricted. Our data suggest that resistance is due, in part, to the ability of the resistant cultivar to restrict bacterial root colonization in space and time.
Kotla, Niranjan G; Singh, Sima; Maddiboyina, Balaji; Sunnapu, Omprakash; Webster, Thomas J
The aim of this study was to develop a novel microbially triggered and animal-sparing dissolution method for testing of nanorough polysaccharide-based micron granules for colonic drug delivery. In this method, probiotic cultures of bacteria present in the colonic region were prepared and added to the dissolution media and compared with the performance of conventional dissolution methodologies (such as media with rat cecal and human fecal media). In this study, the predominant species (such as Bacteroides, Bifidobacterium, Lactobacillus species, Eubacterium and Streptococcus) were cultured in 12% w/v skimmed milk powder and 5% w/v grade "A" honey. Approximately 10(10)-10(11) colony forming units m/L of probiotic culture was added to the dissolution media to test the drug release of polysaccharide-based formulations. A USP dissolution apparatus I/II using a gradient pH dissolution method was used to evaluate drug release from formulations meant for colonic drug delivery. Drug release of guar gum/Eudragit FS30D coated 5-fluorouracil granules was assessed under gastric and small intestine conditions within a simulated colonic environment involving fermentation testing with the probiotic culture. The results with the probiotic system were comparable to those obtained from the rat cecal and human fecal-based fermentation model, thereby suggesting that a probiotic dissolution method can be successfully applied for drug release testing of any polysaccharide-based oral formulation meant for colonic delivery. As such, this study significantly adds to the nanostructured biomaterials' community by elucidating an easier assay for colonic drug delivery.
Kotla, Niranjan G; Singh, Sima; Maddiboyina, Balaji; Sunnapu, Omprakash; Webster, Thomas J
The aim of this study was to develop a novel microbially triggered and animal-sparing dissolution method for testing of nanorough polysaccharide-based micron granules for colonic drug delivery. In this method, probiotic cultures of bacteria present in the colonic region were prepared and added to the dissolution media and compared with the performance of conventional dissolution methodologies (such as media with rat cecal and human fecal media). In this study, the predominant species (such as Bacteroides, Bifidobacterium, Lactobacillus species, Eubacterium and Streptococcus) were cultured in 12% w/v skimmed milk powder and 5% w/v grade “A” honey. Approximately 1010–1011 colony forming units m/L of probiotic culture was added to the dissolution media to test the drug release of polysaccharide-based formulations. A USP dissolution apparatus I/II using a gradient pH dissolution method was used to evaluate drug release from formulations meant for colonic drug delivery. Drug release of guar gum/Eudragit FS30D coated 5-fluorouracil granules was assessed under gastric and small intestine conditions within a simulated colonic environment involving fermentation testing with the probiotic culture. The results with the probiotic system were comparable to those obtained from the rat cecal and human fecal-based fermentation model, thereby suggesting that a probiotic dissolution method can be successfully applied for drug release testing of any polysaccharide-based oral formulation meant for colonic delivery. As such, this study significantly adds to the nanostructured biomaterials’ community by elucidating an easier assay for colonic drug delivery. PMID:27051284
Murray, Robert E.; Parsons, Laura L.; Smith, M. Scott
We examined the competitive relationship between two isolates of denitrifying bacteria, both of which grow well under aerobic conditions but differ in their ability to grow under denitrifying conditions. The growth and persistence of the two isolates, added to sterile soil or added to soil previously colonized by the other isolate, were monitored under aerobic and denitrifying (anaerobic) conditions. When isolates were added together to sterile soil, the isolate added at the higher density reduced the growth of the isolate added at the lower density. The magnitude of the growth reduction varied depending on the competitive abilities of the individual isolates and the aeration state of the soil. Prior colonization of soil with one of the isolates conferred a competitive advantage on the colonized isolate but did not lead to the disappearance of the challenging isolate. Fluctuations in aeration state caused large changes in the population density of one isolate and altered the competitive relationship between the two isolates. The competitive effectiveness of each isolate varied with cell density, the degree of prior colonization of the soil by the other isolate, and the aeration state of the soil. PMID:16348820
Grall, Sophie; Manceau, Charles
The dynamics of Xylophilus ampelinus were studied in Vitis vinifera cv. Ugni blanc using gfp-marked bacterial strains to evaluate the relative importance of epiphytic and endophytic phases of plant colonization in disease development. Currently, bacterial necrosis of grapevine is of economic importance in vineyards in three regions in France: the Cognac, Armagnac, and Die areas. This disease is responsible for progressive destruction of vine shoots, leading to their death. We constructed gfp-marked strains of the CFBP2098 strain of X. ampelinus for histological studies. We studied the colonization of young plants of V. vinifera cv. Ugni blanc by X. ampelinus after three types of artificial contamination in a growth chamber and in a greenhouse. (i) After wounding of the stem and inoculation, the bacteria progressed down to the crown through the xylem vessels, where they organized into biofilms. (ii) When the bacteria were forced into woody cuttings, they rarely colonized the emerging plantlets. Xylem vessels could play a key role in the multiplication and conservation of the bacteria, rather than being a route for plant colonization. (iii) When bacterial suspensions were sprayed onto the plants, bacteria progressed in two directions: both in emerging organs and down to the crown, thus displaying the importance of epiphytic colonization in disease development. PMID:12676663
Caprilli, R; Frieri, G; Marchetti, G; Giambartolomei, S
The large bowel daily absorbs passively 1500 ml of water down an osmotic gradient created by active electrolyte transports. The system is sustained by the enzyme Na(+)-K+ ATPase, the so called sodium-pump, present on the basolateral membrane of colonocytes. Some pathologic conditions may increase the amount of intraluminal water by inhibiting fluid absorbtion or enhancing fluid secretion. Diarrhoea represents the clinical counterpart of these alterations. Three forms of diarrhoea can be recognized on the basis of pathophysiological alterations. Diarrhoea is due to reduced ionic absorbtion, increased secretion or increased endoluminal osmolality. The drugs used to induce bowel actions or gut lavage increase also intraluminal water content by modifying transmural ionic transports. Laxatives or purges act by increasing either water secretion on endoluminal osmolality and therefore may produce systemic idro-electrolyte imbalance. To avoid this inconvenient an isosmotic electrolyte balanced polyethylene glicol solution (PEG-ELS) has been achieved. In addition orally administred PEG-ELS solution cleans the colon during its intestinal transit without producing relevant transmural water-ionic movements. Aim of this article was to describe the normal ionic transport, and its alterations in pathologic and pharmacologic conditions. Details on PEG-ELS were also given. This solution provides for an effective colon preparation for endoscopic or surgical procedures and resulted to be safe for patients with delicate fluid-electrolyte balance.
The overarching goal of this project is to understand the role of microbial colonists at newly formed vents as "mediators" in the transfer of energy from the geothermal source to the higher trophic levels, and their role in altering fluid chemistry and in "conditioning" the vent environment for metazoans to settle. Following the 2005-06 volcanic eruption along the East Pacific Rise (EPR) ridge crest between 9°N and 9°N, we had several opportunities to investigate the microbial colonization of the post-eruptive vents: in 2006 (about six months after the eruption), in January 2007 (one year after the eruption), and in December 2007/January 2008 (two years after the eruption). In order to investigate microbial colonization, we designed and deployed several experimental microbial colonizers on active diffuse flow vents characterized by different temperatures (approximate range 20-60°C) chemical (different redox conditions), and biological (e.g., presence or absence of metazoan colonists) regimes. Analyses of the 16S rRNA and fuctional gene transcripts from the colonizing communities indicated that Epsilonproteobacteria represented the dominant and active fraction of the chemosynthetic early microbial colonists, and that they expressed in-situ the genes involved in carbon dioxide fixation and nitrate respiration. However, data from our semi quantitative culture experiments indicated that Epsilonproteobacteria were not the only microorganisms that attached to basalts or to the experimental colonizers during the early phases of colonization. Sulfur dependent, chemosynthetic members of the Gamma- and Alphaproteobacteria were isolated from up to 10-5 dilutions of original samples along with heterotrophic Gammaproteobacteria capable of growth on n-alkanes as their sole carbon source. We propose a model that links the chemistry of hydrothermal fluids to the colonization of newly formed vents and suggests a role for chemosynthetic and heterotrophic bacteria in the
Schmidt, Hannes; Eickhorst, Thilo
The interface between soil and roots (i.e. the rhizosphere) represents a highly dynamic micro-environment for microbial populations. Root-derived compounds are released into the rhizosphere and may attract, stimulate, or inhibit native soil microorganisms. Microbes associated with the rhizosphere, in turn, may have deleterious, neutral, or promoting effects on the plant. Such influences of microbial populations on the plant and vice versa are likely to be greatest in close vicinity to the root surface. It is therefore essential to detect and visualize preferential micro-sites of microbial root colonization to identify potential areas of microbe-plant interaction. We present a single-cell based approach allowing for the localization, quantification, and visualization of native microbial populations in the rhizosphere and on the rhizoplane of soil-grown roots in situ. Catalyzed reporter deposition fluorescence in situ hybridization (CARD-FISH) in combination with confocal laser scanning microscopy was applied to observe colonization densities and patterns of microbial populations associated with wetland rice. Hybridizations with domain- and phylum-specific oligonucleotide probes showed that the growth stage of the rice plant as well as the distance to the root surface had a strong influence on microbial colonization patterns. Three-dimensional visualizations of root-associated microbes revealed micro-sites of preferential colonization. Highest cell numbers of archaea and bacteria were found at flowering stage of rice plant development. Irregular distribution patterns of microbiota observed at early growth stages shifted towards more uniform colonization with plant age. Accordingly, the highest colonization densities shifted from the tip to more mature regions of rice roots. Methanogenic archaea and methanotrophic bacteria were found to be co-localized at basal regions of lateral roots. Beneficial effects of a close association with root surfaces were indicated by
Onrust, Lonneke; Ducatelle, Richard; Van Driessche, Karolien; De Maesschalck, Celine; Vermeulen, Karen; Haesebrouck, Freddy; Eeckhaut, Venessa; Van Immerseel, Filip
The ban on antimicrobial growth promoters and efforts to reduce therapeutic antibiotic usage has led to major problems of gastrointestinal dysbiosis in livestock production in Europe. Control of dysbiosis without the use of antibiotics requires a thorough understanding of the interaction between the microbiota and the host mucosa. The gut microbiota of the healthy chicken is highly diverse, producing various metabolic end products, including gases and fermentation acids. The distal gut knows an abundance of bacteria from within the Firmicutes Clostridium clusters IV and XIVa that produce butyric acid, which is one of the metabolites that are sensed by the host as a signal. The host responds by strengthening the epithelial barrier, reducing inflammation, and increasing the production of mucins and antimicrobial peptides. Stimulating the colonization and growth of butyrate-producing bacteria thus may help optimizing gut health. Various strategies are available to stimulate butyrate production in the distal gut. These include delivery of prebiotic substrates that are broken down by bacteria into smaller molecules which are then used by butyrate producers, a concept called cross-feeding. Xylo-oligosaccharides (XOS) are such compounds as they can be converted to lactate, which is further metabolized to butyrate. Probiotic lactic acid producers can be supplied to support the cross-feeding reactions. Direct feeding of butyrate-producing Clostridium cluster IV and XIVa strains are a future tool provided that large scale production of strictly anaerobic bacteria can be optimized. Current results of strategies that promote butyrate production in the gut are promising. Nevertheless, our current understanding of the intestinal ecosystem is still insufficient, and further research efforts are needed to fully exploit the capacity of these strategies. PMID:26734618
Laurent, F; Grosgogeat, B; Reclaru, L; Dalard, F; Lissac, M
The aim of this study was to compare the resistance of the corrosion of dental alloys in a solution containing oral bacteria named Actinomyces viscosus (ATCC19246). In this paper, we explain the choice of this precise species of bacteria, then specify its culture in artificial saliva and the experimental precautions needed to avoid the pollution by other bacteria. The electrochemical behaviour of two dental alloys (Ni-Cr alloy and gold-based alloy) was investigated by electrochemical means in sterile Fusayama artificial saliva (AS), AS enriched with sterile yeast extract (YE) and YE modified by introducing bacteria (AV). Open-circuit potentials, potentiodynamic curves, polarization resistance and impedance spectroscopy are the electrochemical procedures selected for this work. It has thus been shown that the open-circuit potential of the non-precious alloy is always lower than that of the gold precious alloy, and the colonization of metal surface by bacteria caused a drop in open circuit potential. The electrochemical impedance spectroscopy results have shown that the electrolyte resistance decreased between the AS, YE and AV milieu, in the presence of bacteria a slight decrease in polarization resistance was observed with the precious alloy and an increase with the non-precious alloy. The drop in the electrolyte resistance cannot explain the change in polarization resistance. The influence of Actinomyces viscosus might be essentially due to the consumption of oxygen at the metal/electrolyte interface of the specimen. For the non-precious alloy, the absence of oxygen (instigator of corrosion) led to an increase in polarization resistance whereas the slight decrease for the precious alloys might be justified by the organic and inorganic metabolites released by bacteria in to the electrolyte. The scanning electron micrography after electrochemical analysis, confirmed the absence of contaminants. These preliminary results demonstrate the unquestionable influence of
Pilins or fimbrilins are a class of proteins found in bacterial surface pilus, a hair-like surface appendage. Both the Gram-negative and -positive bacteria produce pilins to assemble pili on their cell-surface for different purposes including adherence, twitching motility, conjugation, immunomodulation, biofilm formation, and electron transfer. Immunogenic properties of the pilins make them attractive vaccine candidates. The polymerized pilins play a key role in the initiation of host adhesion, which is a critical step for bacterial colonization and infection. Because of their key role in adhesion and exposure on the cell surface, targeting the pilins-mediated adhesion (anti-adhesion therapy) is also seen as a promising alternative approach for preventing and treating bacterial infections, one that may overcome their ever-increasing repertoires of resistance mechanisms. Individual pilins interact with each other non-covalently to assemble the pilus fiber with the help of associated proteins like chaperones and Usher in Gram-negative bacteria. In contrast, the pilins in Gram-positive bacteria often connect with each other covalently, with the help of sortases. Certain unique structural features present on the pilins distinguish them from one another across different bacterial strains, and these dictate their cellular targets and functions. While the structure of pilins has been extensively studied in Gram-negative pathogenic bacteria, the pilins in Gram-positive pathogenic bacteria have been in only during the last decade. Recently, the discovery of pilins in non-pathogenic bacteria, such as Lactobacillus rhamnosus GG, has received great attention, though traditionally the attention was on pathogenic bacteria. This review summarizes and discusses the current structural knowledge of pilins in Gram-positive bacteria with emphasis on those pilins which are sortase substrates.
Longenecker, Nevin E.; Oppenheimer, Dan
A study conducted by high school advanced bacteriology students appears to confirm the hypothesis that the incremental administration of antibiotics on several species of bacteria (Escherichia coli, Staphylococcus epidermis, Bacillus sublitus, Bacillus megaterium) will allow for the development of antibiotic-resistant strains. (PEB)
Tuson, Hannah H; Weibel, Douglas B
The interaction of bacteria with surfaces has important implications in a range of areas, including bioenergy, biofouling, biofilm formation, and the infection of plants and animals. Many of the interactions of bacteria with surfaces produce changes in the expression of genes that influence cell morphology and behavior, including genes essential for motility and surface attachment. Despite the attention that these phenotypes have garnered, the bacterial systems used for sensing and responding to surfaces are still not well understood. An understanding of these mechanisms will guide the development of new classes of materials that inhibit and promote cell growth, and complement studies of the physiology of bacteria in contact with surfaces. Recent studies from a range of fields in science and engineering are poised to guide future investigations in this area. This review summarizes recent studies on bacteria-surface interactions, discusses mechanisms of surface sensing and consequences of cell attachment, provides an overview of surfaces that have been used in bacterial studies, and highlights unanswered questions in this field.
There is a paucity of information concerning any link between the microorganisms commonly found in biofilms of drinking water systems and their impacts on human health. For bacteria, culture-based techniques detect only a limited number of the total microorganisms associated wit...
Macario, A J; Conway de Macario, E
Highlights are presented of most recent work in which monoclonal antibodies have been instrumental in the study of bacteria and their products. Topics summarized pertain to human and veterinary medicines, dentistry, phytopathology, ichthyology, and bacterial ecophysiology, differentiation, evolution and methanogenic biotechnology.
Scolozzi, Paolo; Lombardi, Tommaso; Edney, Timothy; Jaques, Bertrand
Osteomyelitis of the mandible is a relatively rare inflammatory disease that usually stems from the odontogenic polymicrobial flora of the oral cavity. We are reporting 2 unusual cases of mandibular osteomyelitis resulting from enteric bacteria infection. In one patient, abundant clinical evidence suggested a diagnosis of a chronic factitious disease, whereas in the second patient no obvious etiology was found.
Tuson, Hannah H.; Weibel, Douglas B.
The interaction of bacteria with surfaces has important implications in a range of areas, including bioenergy, biofouling, biofilm formation, and the infection of plants and animals. Many of the interactions of bacteria with surfaces produce changes in the expression of genes that influence cell morphology and behavior, including genes essential for motility and surface attachment. Despite the attention that these phenotypes have garnered, the bacterial systems used for sensing and responding to surfaces are still not well understood. An understanding of these mechanisms will guide the development of new classes of materials that inhibit and promote cell growth, and complement studies of the physiology of bacteria in contact with surfaces. Recent studies from a range of fields in science and engineering are poised to guide future investigations in this area. This review summarizes recent studies on bacteria-surface interactions, discusses mechanisms of surface sensing and consequences of cell attachment, provides an overview of surfaces that have been used in bacterial studies, and highlights unanswered questions in this field. PMID:23930134
de Freitas, Amanda Osório Ayres; Alviano, Celuta Sales; Alviano, Daniela Sales; Siqueira, José Freitas; Nojima, Lincoln Issamu; Nojima, Matilde da Cunha Gonçalves
Peri-implant inflammation contributes for loss of secondary stability of orthodontic mini-implants. The investigation of microbial colonization in this area would benefit its control, and consequently favor the long-term success of mini-implants. Therefore, the aim of this study was to determine the establishment and the evolution of microbial colonization process in orthodontic mini-implants for 3 months, since the time of their installation. One-hundred and fifty samples collected from 15 mini-implants were investigated from baseline up to 3 months. The biological material was obtained from peri-implant area using paper points. Nonspecific, Streptococcus spp, Lactobacillus casei and Candida spp colonizations were analyzed by cell growth methods. Porphyromonas gingivalis colonization was observed by 16S rDNA-directed polymerase chain reaction. Data from cell growth were submitted to the Wilcoxon sign rank test and results from molecular analysis were presented in a descriptive way. There was no significant difference in the microbial colonization among the examined time intervals, except for Streptococcus spp, between baseline and 24 h, which characterized the initial colonization in this time interval. Lactobacillus casei and Candida spp colonizations were insignificant. No Porphyromonas gingivalis was detected among the analyzed samples. The microbial colonization of mini-implants did not significantly change during the study. However, it should be monitored by orthodontists, since it is an important factor for mini-implants success.
Nasser, Salah; Mabrouk, Amr; Maher, Ashraf
A prospective study was carried out on 70 burned patients admitted to the Burn Unit, Ain Shams University Hospital, Cairo, with the aim to verify the pattern of microbial colonization of burn wounds. Throughout the study period starting from 1 June 1999 till 31 May 2001, 281 sampling procedures (surface swabs) were performed from the burn wounds. A total of 301 microbial isolates were grown in cultures. Eight different species of bacteria, and only one species of Candida (C. albicans) were detected. There was no incidence of recovery of anaerobic microorganisms. Our results revealed that the most frequent isolate was Pseudomonas aeruginosa (21.6%), followed by Klebsiella pneumoniae (15.2%), then Escherichia coli (13.6%), Staphylococcus aureus (13.2%), coagulase-negative Staphylococci (11.6%), Streptococcus pyogenes (8.3%), Enterobacter species (6.6%), and lastly Streptococcus faecalis and Candida albicans (5.9 and 3.6%, respectively). Studying the time-related changes in burn wound microbial colonization showed an initial predominance of gram-positive cocci upon admission (70.7%) over gram-negative bacilli (27.6%). During the first 5 days, gram-negative bacilli started to predominate (55.7%) over gram-positive cocci (40.3%). Burn wound sampling performed starting from the sixth day onwards, revealed further prevalence of gram-negative bacilli (72.7%) over gram-positive cocci (22.7%). As for Candida albicans, there was a gradual increase in the frequency of its recovery as time elapsed from admission. It is crucial for every burn institution to determine the specific pattern of burn wound microbial colonization, the time-related changes in the dominant flora, and the antimicrobial sensitivity profiles. This would enable early treatment of imminent septic episodes with proper empirical systemic antibiotics, without waiting for culture results, thus improving the overall infection-related morbidity and mortality.
Vos, Aurin M; Heijboer, Amber; Boschker, Henricus T S; Bonnet, Barbara; Lugones, Luis G; Wösten, Han A B
Agaricus bisporus mushrooms are commercially produced on a microbe rich compost. Here, fungal and bacterial biomass was quantified in compost with and without colonization by A. bisporus. Chitin content, indicative of total fungal biomass, increased during a 26-day period from 576 to 779 nmol N-acetylglucosamine g(-1) compost in the absence of A. bisporus (negative control). A similar increase was found in the presence of this mushroom forming fungus. The fungal phospholipid-derived fatty acid (PLFA) marker C18:2ω6, indicative of the living fraction of the fungal biomass, decreased from 575 to 280 nmol g(-1) compost in the negative control. In contrast, it increased to 1200 nmol g(-1) compost in the presence of A. bisporus. Laccase activity was absent throughout culturing in the negative control, while it correlated with the fungal PLFA marker in the presence of A. bisporus. PLFA was also used to quantify living bacterial biomass. In the negative control, the bacterial markers remained constant at 3000-3200 nmol PLFA g(-1) compost. In contrast, they decreased to 850 nmol g(-1) compost during vegetative growth of A. bisporus, implying that bacterial biomass decreased from 17.7 to 4.7 mg g(-1) compost. The relative amount of the Gram positive associated PLFA markers a15:0 and a17:0 and the Gram negative PLFA associated markers cy17:0 and cy19:0 increased and decreased, respectively, suggesting that Gram negative bacteria are more suppressed by A. bisporus. Together, these data indicate that fungal biomass can make up 6.8% of the compost after A. bisporus colonization, 57% of which being dead. Moreover, results show that A. bisporus impacts biomass and composition of bacteria in compost.
Davis, Cindy D.; Milner, John A.
Evidence is emerging that the intestinal microbiota is intrinsically linked with overall health, including cancer risk. Moreover, its composition is not fixed, but can be influenced by several dietary components. Dietary modifiers, including the consumption of live bacteria (probiotics), nondigestible or limited digestible food constituents such as oligosaccharides (prebiotics) and polyphenols, or both (synbiotics), are recognized modifiers of the numbers and types of microbes and have been reported to reduce colon cancer risk experimentally. Microorganisms also have the ability to generate bioactive compounds from food components. Examples include equol from isoflavones, enterodiol and enterolactone from lignans, and urolithins from ellagic acid, which have also been demonstrated to retard experimentally induced cancers. The gastrointestinal microbiota can also influence both sides of the energy balance equation; namely, as a factor influencing energy utilization from the diet and as a factor that influences host genes that regulate energy expenditure and storage. Because of the link between obesity and cancer incidence and mortality, this complex relationship deserves greater attention. Thus, a complex interrelationship exists between the intestinal microbiota and colon cancer risk which can be modified by dietary components and eating behaviors. PMID:19716282
Buddrus-Schiemann, Katharina; Schmid, Michael; Schreiner, Karin; Welzl, Gerhard; Hartmann, Anton
Over the last few decades, the ability of rhizosphere bacteria to promote plant growth has been considered to be of scientific, ecological, and economic interest. The properties and mechanisms of interaction of these root-colonizing bacteria have been extensively investigated, and plant protection agents that are based on these bacterial strains have been developed for agricultural applications. In the present study, the root colonization of barley by Pseudomonas sp. DSMZ 13134, that is contained in the commercially available plant protection agent Proradix, was examined using the fluorescence in situ hybridization method with oligonucleotide probes and specific gfp-tagging of the inoculant strain in combination with confocal laser scanning microscopy. In the first phase of root colonization, the inoculant strain competed successfully with seed and soil-borne bacteria (including Pseudomonads) for the colonization of the rhizoplane. Pseudomonas sp. DSMZ 13134 could be detected in all parts of the roots, although it did not belong to the dominant members of the root-associated bacterial community. Gfp-tagged cells were localized particularly in the root hair zone, and high cell densities were apparent on the root hair surface. To investigate the impact of the application of Proradix on the structure of the dominant root-associated bacterial community of barley, T-RFLP analyses were performed. Only a transient community effect was found until 3 weeks post-application.
Kleinberg, Michael; Sorkin, John D.; Netzer, Giora; Johnson, Jennifer K.; Shardell, Michelle; Thom, Kerri A.; Harris, Anthony D.; Roghmann, Mary-Claire
We hypothesized that prior colonization with antibiotic-resistant Gram-negative bacteria is associated with increased risk of subsequent antibiotic-resistant Gram-negative bacteremia among cancer patients. We performed a matched case-control study. Cases were cancer patients with a blood culture positive for antibiotic-resistant Gram-negative bacteria. Controls were cancer patients with a blood culture not positive for antibiotic-resistant Gram-negative bacteria. Prior colonization was defined as any antibiotic-resistant Gram-negative bacteria in surveillance or non-sterile-site cultures obtained 2–365 days before the bacteremia. Thirty-two (37%) of 86 cases and 27 (8%) of 323 matched controls were previously colonized by any antibiotic-resistant Gram-negative bacteria. Prior colonization was strongly associated with antibiotic-resistant Gram-negative bacteremia (odds ratio [OR] 7.2, 95% confidence interval [CI] 3.5–14.7) after controlling for recent treatment with piperacillin-tazobactam (OR 2.5, 95% CI 1.3–4.8). In these patients with suspected bacteremia, prior cultures may predict increased risk of antibiotic-resistant Gram-negative bacteremia. PMID:24582582
Keesee, Susan K.; Meneghini, Marc D.; Szaro, Robert P.; Wu, Ying-Jye
The nuclear matrix is the nonchromatin scaffolding of the nucleus. This structure confers nuclear shape, organizes chromatin, and appears to contain important regulatory proteins. Tissue specific nuclear matrix proteins have been found in the rat, mouse, and human. In this study we compared high-resolution two-dimensional gel electropherograms of nuclear matrix protein patterns found in human colon tumors with those from normal colon epithelia. Tumors were obtained from 18 patients undergoing partial colectomy for adenocarcinoma of the colon and compared with tissue from 10 normal colons. We have identified at least six proteins which were present in 18 of 18 colon tumors and 0 of 10 normal tissues, as well as four proteins present in 0 of 18 tumors and in 10 of 10 normal tissues. These data, which corroborate similar findings of cancer-specific nuclear matrix proteins in prostate and breast, suggest that nuclear matrix proteins may serve as important markers for at least some types of cancer.
I elaborate an hypothesis to explain inconsistent empirical findings comparing phenotypic plasticity in colonizing populations or species with plasticity from their native or ancestral range. Quantitative genetic theory on the evolution of plasticity reveals that colonization of a novel environment can cause a transient increase in plasticity: a rapid initial increase in plasticity accelerates evolution of a new optimal phenotype, followed by slow genetic assimilation of the new phenotype and reduction of plasticity. An association of colonization with increased plasticity depends on the difference in the optimal phenotype between ancestral and colonized environments, the difference in mean, variance and predictability of the environment, the cost of plasticity, and the time elapsed since colonization. The relative importance of these parameters depends on whether a phenotypic character develops by one-shot plasticity to a constant adult phenotype or by labile plasticity involving continuous and reversible development throughout adult life.
Wang, B-Y; Deutch, A; Hong, J; Kuramitsu, H K
Streptococcus mutans is the primary cariogen that produces several virulence factors that are modulated by a competence-stimulating peptide (CSP) signaling system. In this study, we sought to determine if proteases produced by early dental plaque colonizers such as Streptococcus gordonii interfere with the subsequent colonization of S. mutans BM71 on the existing streptococcal biofilms. We demonstrated that S. mutans BM71 colonized much less efficiently in vitro on streptococcal biofilms than on Actinomyces naeslundii biofilms. Several oral streptococci, relative to A. naeslundii, produced proteases that inactivated the S. mutans CSP. We further demonstrated that cell protein extracts from S. gordonii, but not from A. naeslundii, interfered with S. mutans BM71 colonization. In addition, S. mutans BM71 colonized more efficiently on the sgc protease knockout mutant of S. gordonii than on the parent biofilms. In conclusion, proteases of early colonizers can interfere with subsequent colonization by S. mutans in vitro.
Thibodeau, Alexandre; Fravalo, Philippe; Yergeau, Étienne; Arsenault, Julie; Lahaye, Ludovic; Letellier, Ann
Campylobacter jejuni is an important zoonotic foodborne pathogen causing acute gastroenteritis in humans. Chickens are often colonized at very high numbers by C. jejuni, up to 109 CFU per gram of caecal content, with no detrimental effects on their health. Farm control strategies are being developed to lower the C. jejuni contamination of chicken food products in an effort to reduce human campylobacteriosis incidence. It is believed that intestinal microbiome composition may affect gut colonization by such undesirable bacteria but, although the chicken microbiome is being increasingly characterized, information is lacking on the factors affecting its modulation, especially by foodborne pathogens. This study monitored the effects of C. jejuni chicken caecal colonization on the chicken microbiome in healthy chickens. It also evaluated the capacity of a feed additive to affect caecal bacterial populations and to lower C. jejuni colonization. From day-0, chickens received or not a microencapsulated feed additive and were inoculated or not with C. jejuni at 14 days of age. Fresh caecal content was harvested at 35 days of age. The caecal microbiome was characterized by real time quantitative PCR and Ion Torrent sequencing. We observed that the feed additive lowered C. jejuni caecal count by 0.7 log (p<0.05). Alpha-diversity of the caecal microbiome was not affected by C. jejuni colonization or by the feed additive. C. jejuni colonization modified the caecal beta-diversity while the feed additive did not. We observed that C. jejuni colonization was associated with an increase of Bifidobacterium and affected Clostridia and Mollicutes relative abundances. The feed additive was associated with a lower Streptococcus relative abundance. The caecal microbiome remained relatively unchanged despite high C. jejuni colonization. The feed additive was efficient in lowering C. jejuni colonization while not disturbing the caecal microbiome. PMID:26161743
Lone, Abdul G.; Selinger, L. Brent; Uwiera, Richard R. E.; Xu, Yong; Inglis, G. Douglas
Background Campylobacter jejuni causes enterocolitis in humans, but does not incite disease in asymptomatic carrier animals. To survive in the intestine, C. jejuni must successfully compete with the microbiota and overcome the host immune defense. Campylobacter jejuni colonization success varies considerably amongst individual mice, and we examined the degree to which the intestinal microbiota was affected in mice (i.e. a model carrier animal) colonized by C. jejuni at high relative to low densities. Methods Mice were inoculated with C. jejuni or buffer, and pathogen shedding and intestinal colonization were measured. Histopathologic scoring and quantification of mRNA expression for α-defensins, toll-like receptors, and cytokine genes were conducted. Mucosa-associated bacterial communities were characterized by two approaches: multiplexed barcoded pyrosequencing and terminal restriction fragment length polymorphism analysis. Results Two C. jejuni treatments were established based on the degree of cecal and colonic colonization; C. jejuni Group A animals were colonized at high cell densities, and C. jejuni Group B animals were colonized at lower cell densities. Histological examination of cecal and colonic tissues indicated that C. jejuni did not incite visible pathologic changes. Although there was no significant difference among treatments in expression of mRNA for α-defensins, toll-like receptors, or cytokine genes, a trend for increased expression of toll-like receptors and cytokine genes was observed for C. jejuni Group A. The results of the two methods to characterize bacterial communities indicated that the composition of the cecal microbiota of C. jejuni Group A mice differed significantly from C. jejuni Group B and Control mice. This difference was due to a reduction in load, diversity and richness of bacteria associated with the cecal mucosa of C. jejuni Group A mice. Conclusions High density colonization by C. jejuni is associated with a dysbiosis in
Thibodeau, Alexandre; Fravalo, Philippe; Yergeau, Étienne; Arsenault, Julie; Lahaye, Ludovic; Letellier, Ann
Campylobacter jejuni is an important zoonotic foodborne pathogen causing acute gastroenteritis in humans. Chickens are often colonized at very high numbers by C. jejuni, up to 10(9) CFU per gram of caecal content, with no detrimental effects on their health. Farm control strategies are being developed to lower the C. jejuni contamination of chicken food products in an effort to reduce human campylobacteriosis incidence. It is believed that intestinal microbiome composition may affect gut colonization by such undesirable bacteria but, although the chicken microbiome is being increasingly characterized, information is lacking on the factors affecting its modulation, especially by foodborne pathogens. This study monitored the effects of C. jejuni chicken caecal colonization on the chicken microbiome in healthy chickens. It also evaluated the capacity of a feed additive to affect caecal bacterial populations and to lower C. jejuni colonization. From day-0, chickens received or not a microencapsulated feed additive and were inoculated or not with C. jejuni at 14 days of age. Fresh caecal content was harvested at 35 days of age. The caecal microbiome was characterized by real time quantitative PCR and Ion Torrent sequencing. We observed that the feed additive lowered C. jejuni caecal count by 0.7 log (p<0.05). Alpha-diversity of the caecal microbiome was not affected by C. jejuni colonization or by the feed additive. C. jejuni colonization modified the caecal beta-diversity while the feed additive did not. We observed that C. jejuni colonization was associated with an increase of Bifidobacterium and affected Clostridia and Mollicutes relative abundances. The feed additive was associated with a lower Streptococcus relative abundance. The caecal microbiome remained relatively unchanged despite high C. jejuni colonization. The feed additive was efficient in lowering C. jejuni colonization while not disturbing the caecal microbiome.
Genome analysis using next generation sequencing technologies has revolutionized the characterization of lactic acid bacteria and complete genomes of all major groups are now available. Comparative genomics has provided new insights into the natural and laboratory evolution of lactic acid bacteria and their environmental interactions. Moreover, functional genomics approaches have been used to understand the response of lactic acid bacteria to their environment. The results have been instrumental in understanding the adaptation of lactic acid bacteria in artisanal and industrial food fermentations as well as their interactions with the human host. Collectively, this has led to a detailed analysis of genes involved in colonization, persistence, interaction and signaling towards to the human host and its health. Finally, massive parallel genome re-sequencing has provided new opportunities in applied genomics, specifically in the characterization of novel non-GMO strains that have potential to be used in the food industry. Here, we provide an overview of the state of the art of these functional genomics approaches and their impact in understanding, applying and designing lactic acid bacteria for food and health. PMID:25186768
Douillard, François P; de Vos, Willem M
Genome analysis using next generation sequencing technologies has revolutionized the characterization of lactic acid bacteria and complete genomes of all major groups are now available. Comparative genomics has provided new insights into the natural and laboratory evolution of lactic acid bacteria and their environmental interactions. Moreover, functional genomics approaches have been used to understand the response of lactic acid bacteria to their environment. The results have been instrumental in understanding the adaptation of lactic acid bacteria in artisanal and industrial food fermentations as well as their interactions with the human host. Collectively, this has led to a detailed analysis of genes involved in colonization, persistence, interaction and signaling towards to the human host and its health. Finally, massive parallel genome re-sequencing has provided new opportunities in applied genomics, specifically in the characterization of novel non-GMO strains that have potential to be used in the food industry. Here, we provide an overview of the state of the art of these functional genomics approaches and their impact in understanding, applying and designing lactic acid bacteria for food and health.
Purcell, Erin B; Tamayo, Rita
The nucleotide second messenger 3'-5' cyclic diguanylate monophosphate (c-di-GMP) is a central regulator of the transition between motile and non-motile lifestyles in bacteria, favoring sessility. Most research investigating the functions of c-di-GMP has focused on Gram-negative species, especially pathogens. Recent work in Gram-positive species has revealed that c-di-GMP plays similar roles in Gram-positives, though the precise targets and mechanisms of regulation may differ. The majority of bacterial life exists in a surface-associated state, with motility allowing bacteria to disseminate and colonize new environments. c-di-GMP signaling regulates flagellum biosynthesis and production of adherence factors and appears to be a primary mechanism by which bacteria sense and respond to surfaces. Ultimately, c-di-GMP influences the ability of a bacterium to alter its transcriptional program, physiology and behavior upon surface contact. This review discusses how bacteria are able to sense a surface via flagella and type IV pili, and the role of c-di-GMP in regulating the response to surfaces, with emphasis on studies of Gram-positive bacteria.
Debove, Clotilde; Lefèvre, Jérémie H; Parc, Yann
On the same principle than total mesorectal excision in rectal cancer, the effect of complete mesocolic excision on short and long-term outcomes is actually evaluated for colonic adenocarcinoma. This method, usually performed for left colectomy, offers a surgical specimen of higher quality, with a larger number of lymph nodes harvested. For right colectomy, surgical specifications make it less common complete mesocolic excision and conventional surgery offer comparable outcomes, as regards to postoperative morbidity and mortality rates. No differences are identified between laparoscopic and open surgery. On oncologic outcomes, only two studies report a higher free-disease survival after complete mesocolic excision. Then, there is evidence that complete mesocolic excision offers a higher rate of specimen with extensive lymph node resection, without increased morbidity rate. However, there is limited evidence that it leads to improve long-term oncological outcomes.
Huang, Hsien-Hao; Ting, Ching-Heng; Syu, Yu-Fong; Chang, Shi-Chuan; Chen, Chih-Yen
AIM To explore the relationship between colonic secretory function and colonic motility. METHODS Using a rat model chronically implanted with intracerebroventricular (ICV) and cecal catheters, we validated the correlation between colonic secretion and colonic motor functions, as well as the role of ICV injection volume. RESULTS Compared to saline controls (5 μL/rat), ICV acyl ghrelin at 1 nmol/5 μL enhanced the total fecal weight, accelerated the colonic transit time, and increased the fecal pellet output during the first hour post-injection, while ICV des-acyl ghrelin at 1 nmol/5 μL only accelerated the colonic transit time. These stimulatory effects on colonic motility and/or secretion from acyl ghrelin and des-acyl ghrelin disappeared when the ICV injection volume increased to 10 μL compared with saline controls (10 μL/rat). Additionally, the ICV injection of 10 μL of saline significantly shortened the colonic transit time compared with the ICV injection of 5 μL of saline. The total fecal weight during the first hour post-injection correlated with the colonic transit time and fecal pellet output after the ICV injection of acyl ghrelin (1 nmol/5 μL), whereas the total fecal weight during the first hour post-injection correlated with the fecal pellet output but not the colonic transit time after the ICV injection of des-acyl ghrelin (1 nmol/5 μL). CONCLUSION Colonic secretion does not always correlate with colonic motility in response to different colonic stimulations. Acyl ghrelin stimulates colonic secretion. PMID:28028362
Raisch, Jennifer; Rolhion, Nathalie; Dubois, Anaëlle; Darfeuille-Michaud, Arlette; Bringer, Marie-Agnès
Intestinal dysbiosis has been reported in patients with colorectal cancer, and there is a high prevalence of Escherichia coli belonging to B2 phylogroup and producing a genotoxin, termed colibactin. Macrophages are one of the predominant tumor-infiltrating immune cells supporting key processes in tumor progression by producing protumoral factors such as cyclooxygenase-2 (COX-2). Here, we investigated whether B2 E. coli colonizing colon tumors could influence protumoral activities of macrophages. In contrast to commensal or nonpathogenic E. coli strains that were efficiently and rapidly degraded by macrophages at 24 h after infection, colon cancer-associated E. coli were able to resist killing by human THP-1 macrophages, to replicate intracellularly, and to persist inside host cells until at least 72 h after infection. Significant increases in COX-2 expression were observed in macrophages infected with colon cancer E. coli compared with macrophages infected with commensal and nonpathogenic E. coli strains or uninfected cells at 72 h after infection. Induction of COX-2 expression required live bacteria and was not due to colibactin production, as similar COX-2 levels were observed in macrophages infected with the wild-type colon cancer-associated E. coli 11G5 strain or a clbQ mutant unable to produce colibactin. Treatment of macrophages with ofloxacin, an antibiotic with intracellular tropism, efficiently decreased the number of intracellular bacteria and suppressed bacteria-induced COX-2 expression. This study provides new insights into the understanding of how tumor- infiltrating bacteria could influence cancer progression through their interaction with immune cells. Manipulation of microbes associated with tumors could have a deep influence on the secretion of protumoral molecules by infiltrating macrophages.
Hammes, Frederik; Boon, Nico; Vital, Marius; Ross, Petra; Magic-Knezev, Aleksandra; Dignum, Marco
Pellet softening reactors are used in centralized and decentralized drinking water treatment plants for the removal of calcium (hardness) through chemically induced precipitation of calcite. This is accomplished in fluidized pellet reactors, where a strong base is added to the influent to increase the pH and facilitate the process of precipitation on an added seeding material. Here we describe for the first time the opportunistic bacterial colonization of the calcite pellets in a full-scale pellet softening reactor and the functional contribution of these colonizing bacteria to the overall drinking water treatment process. ATP analysis, advanced microscopy, and community fingerprinting with denaturing gradient gel electrophoretic (DGGE) analysis were used to characterize the biomass on the pellets, while assimilable organic carbon (AOC), dissolved organic carbon, and flow cytometric analysis were used to characterize the impact of the biological processes on drinking water quality. The data revealed pellet colonization at concentrations in excess of 500 ng of ATP/g of pellet and reactor biomass concentrations as high as 220 mg of ATP/m3 of reactor, comprising a wide variety of different microorganisms. These organisms removed as much as 60% of AOC from the water during treatment, thus contributing toward the biological stabilization of the drinking water. Notably, only a small fraction (about 60,000 cells/ml) of the bacteria in the reactors was released into the effluent under normal conditions, while the majority of the bacteria colonizing the pellets were captured in the calcite structures of the pellets and were removed as a reusable product. PMID:21148700
Hammes, Frederik; Boon, Nico; Vital, Marius; Ross, Petra; Magic-Knezev, Aleksandra; Dignum, Marco
Pellet softening reactors are used in centralized and decentralized drinking water treatment plants for the removal of calcium (hardness) through chemically induced precipitation of calcite. This is accomplished in fluidized pellet reactors, where a strong base is added to the influent to increase the pH and facilitate the process of precipitation on an added seeding material. Here we describe for the first time the opportunistic bacterial colonization of the calcite pellets in a full-scale pellet softening reactor and the functional contribution of these colonizing bacteria to the overall drinking water treatment process. ATP analysis, advanced microscopy, and community fingerprinting with denaturing gradient gel electrophoretic (DGGE) analysis were used to characterize the biomass on the pellets, while assimilable organic carbon (AOC), dissolved organic carbon, and flow cytometric analysis were used to characterize the impact of the biological processes on drinking water quality. The data revealed pellet colonization at concentrations in excess of 500 ng of ATP/g of pellet and reactor biomass concentrations as high as 220 mg of ATP/m(3) of reactor, comprising a wide variety of different microorganisms. These organisms removed as much as 60% of AOC from the water during treatment, thus contributing toward the biological stabilization of the drinking water. Notably, only a small fraction (about 60,000 cells/ml) of the bacteria in the reactors was released into the effluent under normal conditions, while the majority of the bacteria colonizing the pellets were captured in the calcite structures of the pellets and were removed as a reusable product.
Dean, E A; Whipp, S C; Moon, H W
Neonatal (less than 1-day-old), 3- and 7-day old, and older (3-week-old postweaning) pigs were challenged by intragastric inoculation with 987P-piliated (987P+) enterotoxigenic Escherichia coli (ETEC) 987. Neonatal pigs were colonized (i.e., there were greater than or equal to 10(8) CFU of test strain per 10-cm ileal segment) and developed diarrhea. Intestinal colonization and the incidence and severity of diarrhea were lower in 3- and 7-day old pigs than in neonates. Older pigs were not colonized and did not develop diarrhea following oral inoculation with five strains of 987P+ ETEC. Strain 987 (987P+) adhered in vitro to intestinal epithelial cell brush borders isolated from both neonatal (sensitive) and older (resistant) pigs. The in vivo growth and expression of 987P pilus by strain 987 in ligated ileal loops created in neonatal and older pigs were similar. The in vivo adherence of 987P+ ETEC to intestinal epithelium in ligated ileal loops in neonatal and older pigs was compared. In neonatal pigs, most of the bacteria were in layers associated with the villous epithelium. In older pigs, most of the bacteria were associated with mucus-like material in the intestinal lumen. We concluded that swine develop an innate resistance to 987P+ ETEC by 3 weeks of age. This resistance does not appear to be due to an absence of 987P-specific receptors in the intestines of the older pig or to an inability of 987P+ bacteria to grow and express pili in the older pig. We hypothesized that the resistance of older pigs to 987P-mediated disease is due to release of 987P-specific receptors into the intestinal lumen, where these receptors facilitate bacterial clearance rather than bacterial adherence to intestinal epithelium and colonization. Images PMID:2562837
Dean, E A; Whipp, S C; Moon, H W
Neonatal (less than 1-day-old), 3- and 7-day old, and older (3-week-old postweaning) pigs were challenged by intragastric inoculation with 987P-piliated (987P+) enterotoxigenic Escherichia coli (ETEC) 987. Neonatal pigs were colonized (i.e., there were greater than or equal to 10(8) CFU of test strain per 10-cm ileal segment) and developed diarrhea. Intestinal colonization and the incidence and severity of diarrhea were lower in 3- and 7-day old pigs than in neonates. Older pigs were not colonized and did not develop diarrhea following oral inoculation with five strains of 987P+ ETEC. Strain 987 (987P+) adhered in vitro to intestinal epithelial cell brush borders isolated from both neonatal (sensitive) and older (resistant) pigs. The in vivo growth and expression of 987P pilus by strain 987 in ligated ileal loops created in neonatal and older pigs were similar. The in vivo adherence of 987P+ ETEC to intestinal epithelium in ligated ileal loops in neonatal and older pigs was compared. In neonatal pigs, most of the bacteria were in layers associated with the villous epithelium. In older pigs, most of the bacteria were associated with mucus-like material in the intestinal lumen. We concluded that swine develop an innate resistance to 987P+ ETEC by 3 weeks of age. This resistance does not appear to be due to an absence of 987P-specific receptors in the intestines of the older pig or to an inability of 987P+ bacteria to grow and express pili in the older pig. We hypothesized that the resistance of older pigs to 987P-mediated disease is due to release of 987P-specific receptors into the intestinal lumen, where these receptors facilitate bacterial clearance rather than bacterial adherence to intestinal epithelium and colonization.
Wang, Mei; Radlowski, Emily C; Monaco, Marcia H; Fahey, George C; Gaskins, H Rex; Donovan, Sharon M
Colonization of the intestinal microbiota after birth plays an important role in development of the neonatal gastrointestinal and immune systems. Two key environmental factors that influence the colonization pattern are delivery mode and nutrition. In this study, the impact of delivery mode and nutrition on microbial colonization and metabolic activity was investigated in the pig model. Vaginally (VD) or caesarean- (CD) delivered piglets were sow-reared (SR) or fed formula alone (FF) or with 4 g/L prebiotics [1:1 ratio of short-chain fructo-oligosaccharides (scFOS) and polydextrose (PDX); FP]. Intestinal contents were collected on d 7 and 14. SR piglets harbored different microbial populations from FF and FP piglets in ileum and ascending colon (AC). On d 7, FF piglets had a greater abundance of Clostridium XIVa in AC, but lower total bacteria, Clostridium XIVa, and Lactobacillus spp. in ileum and Fecalibacterium prausnitzii in AC compared with FP piglets. On d 14, total bacteria were more abundant in FP than FF piglets. Butyrate, isobutyrate, valerate, and isovalerate concentrations in AC were greater in SR piglets compared with FF or FP piglets. At both sampling days, acetate concentrations in AC were similar between the SR and FF groups, whereas propionate was higher in the SR compared with FF group. Delivery mode also significantly affected microbial populations. Bacterial densities differed in AC for Bacteroides-Prevotella at d 7 and Clostridium XIVa at d 14, being higher in VD piglets. Correspondingly, VD piglets had higher propionate in ileum and propionate and butyrate in AC compared with CD piglets. Our results indicate that both delivery mode and nutrition affect microbial composition and metabolic activity. Supplementation of scFOS/PDX to formula modulates microbial colonization and produces a SCFA pattern closer to that of SR piglets.
Raveh-Sadka, Tali; Thomas, Brian C; Singh, Andrea; Firek, Brian; Brooks, Brandon; Castelle, Cindy J; Sharon, Itai; Baker, Robyn; Good, Misty; Morowitz, Michael J; Banfield, Jillian F
Premature infants are highly vulnerable to aberrant gastrointestinal tract colonization, a process that may lead to diseases like necrotizing enterocolitis. Thus, spread of potential pathogens among hospitalized infants is of great concern. Here, we reconstructed hundreds of high-quality genomes of microorganisms that colonized co-hospitalized premature infants, assessed their metabolic potential, and tracked them over time to evaluate bacterial strain dispersal among infants. We compared microbial communities in infants who did and did not develop necrotizing enterocolitis. Surprisingly, while potentially pathogenic bacteria of the same species colonized many infants, our genome-resolved analysis revealed that strains colonizing each baby were typically distinct. In particular, no strain was common to all infants who developed necrotizing enterocolitis. The paucity of shared gut colonizers suggests the existence of significant barriers to the spread of bacteria among infants. Importantly, we demonstrate that strain-resolved comprehensive community analysis can be accomplished on potentially medically relevant time scales. DOI: http://dx.doi.org/10.7554/eLife.05477.001 PMID:25735037
Philippeau, C; Sadet-Bourgeteau, S; Varloud, M; Julliand, V
This study aimed at assessing the impact of four barley forms on total tract apparent digestibility of dietary fibre in horses fed a large amount of starch in the morning meal (0.27% BW). Processed barley forms had a greater pre-caecal starch digestibility than the whole form. Based on this result, we hypothesised that using barley-processing methods would limit the potential dumping of undegraded starch in the hindgut of horses and, consequently, the potential negative effect on fibre degradation in the hindgut. In a 4×4 latin square design, four mature geldings fitted with a right ventral colon-fistula were fed a meadow hay : concentrate (62 : 38; dry matter (DM) basis) diet at 1.7% BW. The concentrate was made of 80% barley distributed either as whole grain or as processed forms: 2.5 mm ground, pelleted or steam-flaked. For each period, total tract apparent digestibilities of DM, NDF and ADF were determined over 3 consecutive days by total faecal collection, whereas pH, volatile fatty acids (VFA) concentrations and cultural functional bacteria counts (total anaerobic, cellulolytic bacteria, lactic acid producers, amylolytic bacteria and lactic acid utilisers) in colonic content were evaluated on 1 day 4 h after the morning meal. Total tract apparent digestibility of DM and dietary fibre was influenced (P<0.05) by barley form. Diets including thermo-mechanically treated barley forms led to a higher (P<0.05) total tract apparent digestibility of NDF than those constituted of ground barley and also led to a greater (P<0.05) total tract apparent digestibility of ADF than those made of whole or ground barley forms. However, no significant difference was observed in colonic pH, VFA concentrations and cultural bacteria concentrations. Owing to a high starch supply in the morning meal, the concentration of the functional bacteria in the colonic content averaged 7.8 log CFU/ml, 5.9 NPM/ml, 6.9 and 7.3 CFU/ml for total anaerobic, cellulolytic, amylolytic and lactic acid
Band, Victor I.; Weiss, David S.
Cationic antimicrobial peptides (CAMPs) are important innate immune defenses that inhibit colonization by pathogens and contribute to clearance of infections. Gram-negative bacterial pathogens are a major target, yet many of them have evolved mechanisms to resist these antimicrobials. These resistance mechanisms can be critical contributors to bacterial virulence and are often crucial for survival within the host. Here, we summarize methods used by Gram-negative bacteria to resist CAMPs. Understanding these mechanisms may lead to new therapeutic strategies against pathogens with extensive CAMP resistance. PMID:25927010
Band, Victor I; Weiss, David S
Cationic antimicrobial peptides (CAMPs) are important innate immune defenses that inhibit colonization by pathogens and contribute to clearance of infections. Gram-negative bacterial pathogens are a major target, yet many of them have evolved mechanisms to resist these antimicrobials. These resistance mechanisms can be critical contributors to bacterial virulence and are often crucial for survival within the host. Here, we summarize methods used by Gram-negative bacteria to resist CAMPs. Understanding these mechanisms may lead to new therapeutic strategies against pathogens with extensive CAMP resistance.
Heo, Seok-Mo; Ruhl, Stefan; Scannapieco, Frank A.
An important function of salivary proteins is to interact with microorganisms that enter the oral cavity. For some microbes, these interactions promote microbial colonization. For others, these interactions are deleterious and result in the elimination of the microbe from the mouth, This paper reviews recent studies of the interaction of salivary proteins with two model bacteria; the commensal species Streptococcus gordonii, and the facultative pathogen Staphylococcus aureus. These organisms selectively interact with a variety of salivary proteins to influence important functions such as bacterial adhesion to surfaces, evasion of host defense, bacterial nutrition and metabolism and gene expression. PMID:24707190
Labbe, Jessy L.; Weston, David J.; Dunkirk, Nora; Pelletier, Dale A.; Tuskan, Gerald A.
Mycorrhiza helper bacteria (MHB) are known to increase host root colonization by mycorrhizal fungi but the molecular mechanisms and potential tripartite trophic interactions are poorly understood. Through an effort to study Populus microbiome, we isolated 21 Pseudomonas strains from native Populus deltoides roots. These bacterial isolates were characterized and screened for MHB effectiveness on the Populus-Laccaria system. Two other Pseudomonas strains (i.e., Pf-5 and BBc6R8) from existing collections were also included as reference in the screening process. We analyzed Laccaria bicolor S238N growth rate, mycelial architecture and transcriptional changes induced by the contrasting Pseudomonas strains (i.e., inhibitory, neutral and beneficial). We characterized 17 out of the 21 Pseudomonas strains from the Populus rhizosphere with positive effects on L. bicolor S238N growth, as well as on Populus root architecture and colonization by L. bicolor S238N across three Populus species. Four of seven reporter genes, Tra1, Tectonin2, Gcn5 and Cipc1, thought to be specific to the interaction with strain BBc6R8, were induced or repressed while interacting with six (i.e., GM17, GM33, GM41, GM48, Pf-5 and BBc6R8) of the tested Pseudomonas strains. GM41 promoted the highest roots colonization across three Populus species but most notably in P. deltoides, which is otherwise, poorly colonized by L. bicolor. Here we report novel MHB strains isolated from native Populus that improve roots colonization. This tripartite relationship could be exploited in nursery production for target Populus species/genotypes as a means of improving establishment and survival in marginal lands.
Labbe, Jessy L.; Weston, David J.; Dunkirk, Nora; ...
Mycorrhiza helper bacteria (MHB) are known to increase host root colonization by mycorrhizal fungi but the molecular mechanisms and potential tripartite trophic interactions are poorly understood. Through an effort to study Populus microbiome, we isolated 21 Pseudomonas strains from native Populus deltoides roots. These bacterial isolates were characterized and screened for MHB effectiveness on the Populus-Laccaria system. Two other Pseudomonas strains (i.e., Pf-5 and BBc6R8) from existing collections were also included as reference in the screening process. We analyzed Laccaria bicolor S238N growth rate, mycelial architecture and transcriptional changes induced by the contrasting Pseudomonas strains (i.e., inhibitory, neutral and beneficial).more » We characterized 17 out of the 21 Pseudomonas strains from the Populus rhizosphere with positive effects on L. bicolor S238N growth, as well as on Populus root architecture and colonization by L. bicolor S238N across three Populus species. Four of seven reporter genes, Tra1, Tectonin2, Gcn5 and Cipc1, thought to be specific to the interaction with strain BBc6R8, were induced or repressed while interacting with six (i.e., GM17, GM33, GM41, GM48, Pf-5 and BBc6R8) of the tested Pseudomonas strains. GM41 promoted the highest roots colonization across three Populus species but most notably in P. deltoides, which is otherwise, poorly colonized by L. bicolor. Here we report novel MHB strains isolated from native Populus that improve roots colonization. This tripartite relationship could be exploited in nursery production for target Populus species/genotypes as a means of improving establishment and survival in marginal lands.« less
Vreeland, Russell H.
Recent highly publicized experiments conducted on salt crystals taken from the Permian Salado Formation in Southeastern New Mexico have shown that some ancient crystals contain viable microorganisms trapped within fluid inclusions. Stringent geological and microbiological selection criteria were used to select crystals and conduct all sampling. This talk will focus on how each of these lines of data support the conclusion that such isolated bacteria are as old as the rock in which they are trapped. In this case, the isolated microbes are salt tolerant bacilli that grow best in media containing 8% NaCl, and respond to concentrated brines by forming spores. One of the organisms is phylogenetically related to several bacilli, but does have several unique characteristics. This talk will trace the interdisciplinary data and procedures supporting these discoveries, and describe the various isolated bacteria.
Vreeland, Russell H.
Recent highly publicized experiments conducted on salt crystals taken from the Permian Salado Formation in Southeastern New Mexico have shown that some ancient crystals contain viable microorganisms trapped within fluid inclusions. Stringent geological and microbiological selection criteria were used to select crystals and conduct all sampling. This talk will focus on how each of these lines of data support the conclusion that such isolated bacteria are as old as the rock in which they are trapped. In this case, the isolated microbes are salt tolerant bacilli that grow best in media containing 8% NaCl, and respond to concentrated brines by forming spores. One of the organisms is phylogenetically related to several bacilli, but does have several unique characteristics. This talk will trace the interdisciplinary data and procedures supporting these discoveries, and describe the various isolated bacteria.
Muller, J. A.; Ross, R. P.; Fitzgerald, G. F.; Stanton, C.
Lactic acid bacteria (LAB) have been used for many years as natural biopreservatives in fermented foods. A small group of LAB are also believed to have beneficial health effects on the host, so called probiotic bacteria. Probiotics have emerged from the niche industry from Asia into European and American markets. Functional foods are one of the fastest growing markets today, with estimated growth to 20 billion dollars worldwide by 2010 (GIA, 2008). The increasing demand for probiotics and the new food markets where probiotics are introduced, challenges the industry to produce high quantities of probiotic cultures in a viable and stable form. Dried concentrated probiotic cultures are the most convenient form for incorporation into functional foods, given the ease of storage, handling and transport, especially for shelf-stable functional products. This chapter will discuss various aspects of the challenges associated with the manufacturing of probiotic cultures.
Liu, Haoyu; Ivarsson, Emma; Dicksved, Johan; Lundh, Torbjörn
The content and composition of prebiotic plant fiber in the diet is important in promoting gut-related health. This study investigated the effects of the dietary inclusion of chicory forage and roots on the intestinal microenvironment of pigs. Thirty-seven-week-old pigs were fed 1 of 5 diets for 18 days, including a cereal-based control diet and 4 diets with the inclusion of 80 and 160 g kg−1 of body weight chicory forage (CF80 and CF160), 80 g kg−1 chicory root (CR80), and a mix of 80 g kg−1 forage and 80 g kg−1 chicory root (CFR). The animals maintained good performance and health irrespective of diet. Bacterial community structure and diversity in ileal and colonic samples was assessed using terminal restriction fragment length polymorphism (T-RFLP), combined with cloning and sequencing. Samples clustered perfectly according to gut segment with a higher bacterial diversity in colon than ileum. Distal ileum was dominated by lactic acid bacteria (LAB), and the relative amount of this group was increased by the CF160 and CFR diets. The colonic bacterial community was dominated by butyrate-producing bacteria and Prevotella. The increased relative abundance of butyrate-producing bacteria in the colon was positively correlated with the molar proportion of acetic acid and furthermore linked to the chicory forage diets (CF80 and CF160). Diets including chicory roots (CR80 and CFR) were correlated with a higher colonic abundance of Megasphaera elsdenii. The fermentation products and pH in digesta responded to diet type and were correlated with shifts in the microbiota, showing that chicory influences the intestinal microenvironment of pigs. PMID:22492453
Liu, Haoyu; Ivarsson, Emma; Dicksved, Johan; Lundh, Torbjörn; Lindberg, Jan Erik
The content and composition of prebiotic plant fiber in the diet is important in promoting gut-related health. This study investigated the effects of the dietary inclusion of chicory forage and roots on the intestinal microenvironment of pigs. Thirty-seven-week-old pigs were fed 1 of 5 diets for 18 days, including a cereal-based control diet and 4 diets with the inclusion of 80 and 160 g kg(-1) of body weight chicory forage (CF80 and CF160), 80 g kg(-1) chicory root (CR80), and a mix of 80 g kg(-1) forage and 80 g kg(-1) chicory root (CFR). The animals maintained good performance and health irrespective of diet. Bacterial community structure and diversity in ileal and colonic samples was assessed using terminal restriction fragment length polymorphism (T-RFLP), combined with cloning and sequencing. Samples clustered perfectly according to gut segment with a higher bacterial diversity in colon than ileum. Distal ileum was dominated by lactic acid bacteria (LAB), and the relative amount of this group was increased by the CF160 and CFR diets. The colonic bacterial community was dominated by butyrate-producing bacteria and Prevotella. The increased relative abundance of butyrate-producing bacteria in the colon was positively correlated with the molar proportion of acetic acid and furthermore linked to the chicory forage diets (CF80 and CF160). Diets including chicory roots (CR80 and CFR) were correlated with a higher colonic abundance of Megasphaera elsdenii. The fermentation products and pH in digesta responded to diet type and were correlated with shifts in the microbiota, showing that chicory influences the intestinal microenvironment of pigs.
Yao, Jianhua; Chowdhury, Ananda S.; Aman, Javed; Summers, Ronald M.
Colon unfolding provides an efficient way to navigate the colon in CT colonography. Most existing unfolding techniques only computed forward projections. When radiologists find abnormalities or conduct measurements on the unfolded view (which is often quicker and easier), it is difficult to locate the corresponding region on the 3D view for further examination (which is more accurate and reliable). To address this, we propose a reversible projection technique for colon unfolding. The method makes use of advanced algorithms including rotation-minimizing frames, recursive ring sets, mesh skinning and cylindrical projection. Both forward and reverse transformations are computed for points on the colon surface. Therefore, it allows for detecting and measuring polyps on the unfolded view and mapping them back to the 3D surface. We generated realistic colon simulation incorporating most colon characteristics such as curved centerline, variable distention, haustral folds, teniae coli and colonic polyps. Our method was tested on both the simulated data and 110 clinical CT colonography data. Comparison of polyp size measurements on the unfolded view and the 3D view clearly demonstrates the importance of our reversible projection technique. PMID:20542756
inversion symmetry and time reversal symmetry by dissipat - ing energy , and breaking both these symmetries allows ratcheting. The ability of...durations. All of these devices take advantage of the conversion of chemical energy into propulsion that occurs within bacteria. These devices break spatial...micromachines relying on energy that microorganisms would dissipate “anyway” even in the absence of ratchet structures suggests that researchers could
Corpet, Denis E.; Yin, Y.; Zhang, X. M.; Rémésy, C.; Stamp, D.; Medline, A.; Thompson, L.U.; Bruce, W. R.; Archer, M. C.
Thermolyzed casein is known to promote the growth of aberrant crypt foci (ACF) and colon cancer when it is fed to rats that have been initiated with azoxymethane. We speculated that the promotion was a consequence of increased colonic protein fermentation (i.e., that the thermolysis of the casein decreases its digestibility, increases the amount of protein reaching the colon, and increases colonic protein fermentation and that the potentially toxic products of this fermentation promote colon carcinogenesis). We found that the thermolysis of casein reduces its digestibility and increases colonic protein fermentation, as assessed by fecal ammonium and urinary phenol, cresol, and indol-3-ol. Thermolysis of two other proteins, soy and egg white protein, also increases colonic protein fermentation with increased fecal ammonia and urinary phenols, and thermolysis of all three proteins increases the levels of ammonia and butyric, valeric, and i-valeric acids in the cecal contents. We found, however, that the increased protein fermentation observed with thermolysis is not associated with promotion of colon carcinogenesis. With casein, the kinetics of protein fermentation with increasing thermolysis time are clearly different from the kinetics of promotion of ACF growth. The formation of the fermentation products was highest when the protein was thermolyzed for one hour, whereas promotion was highest for protein that had been thermolyzed for two or more hours. With soy and egg white, thermolysis increased colonic protein fermentation but did not promote colon carcinogenesis. Thus, although thermolysis of dietary casein increases colonic protein fermentation, products of this fermentation do not appear to be responsible for the promotion of colon carcinogenesis. Indeed, the results suggest that protein fermentation products do not play an important role in colon cancer promotion. PMID:7603887
Ortega Morente, Elena; Fernández-Fuentes, Miguel Angel; Grande Burgos, Maria José; Abriouel, Hikmate; Pérez Pulido, Rubén; Gálvez, Antonio
Biocides have been employed for centuries, so today a wide range of compounds showing different levels of antimicrobial activity have become available. At the present time, understanding the mechanisms of action of biocides has also become an important issue with the emergence of bacterial tolerance to biocides and the suggestion that biocide and antibiotic resistance in bacteria might be linked. While most of the mechanisms providing antibiotic resistance are agent specific, providing resistance to a single antimicrobial or class of antimicrobial, there are currently numerous examples of efflux systems that accommodate and, thus, provide tolerance to a broad range of structurally unrelated antimicrobials, both antibiotics and biocides. If biocide tolerance becomes increasingly common and it is linked to antibiotic resistance, not only resistant (even multi-resistant) bacteria could be passed along the food chain, but also there are resistance determinants that can spread and lead to the emergence of new resistant microorganisms, which can only be detected and monitored when the building blocks of resistance traits are understood on the molecular level. This review summarizes the main advances reached in understanding the mechanism of action of biocides, the mechanisms of bacterial resistance to both biocides and antibiotics, and the incidence of biocide tolerance in bacteria of concern to human health and the food industry.
Kwakman, Paulus H S; te Velde, Anje A; de Boer, Leonie; Speijer, Dave; Vandenbroucke-Grauls, Christina M J E; Zaat, Sebastian A J
With the rise in prevalence of antibiotic-resistant bacteria, honey is increasingly valued for its antibacterial activity. To characterize all bactericidal factors in a medical-grade honey, we used a novel approach of successive neutralization of individual honey bactericidal factors. All bacteria tested, including Bacillus subtilis, methicillin-resistant Staphylococcus aureus, extended-spectrum beta-lactamase producing Escherichia coli, ciprofloxacin-resistant Pseudomonas aeruginosa, and vancomycin-resistant Enterococcus faecium, were killed by 10-20% (v/v) honey, whereas > or = 40% (v/v) of a honey-equivalent sugar solution was required for similar activity. Honey accumulated up to 5.62 +/- 0.54 mM H(2)O(2) and contained 0.25 +/- 0.01 mM methylglyoxal (MGO). After enzymatic neutralization of these two compounds, honey retained substantial activity. Using B. subtilis for activity-guided isolation of the additional antimicrobial factors, we discovered bee defensin-1 in honey. After combined neutralization of H(2)O(2), MGO, and bee defensin-1, 20% honey had only minimal activity left, and subsequent adjustment of the pH of this honey from 3.3 to 7.0 reduced the activity to that of sugar alone. Activity against all other bacteria tested depended on sugar, H(2)O(2), MGO, and bee defensin-1. Thus, we fully characterized the antibacterial activity of medical-grade honey.
Parikh, Alexander A.; Fan, Fan; Liu, Wen Biao; Ahmad, Syed A.; Stoeltzing, Oliver; Reinmuth, Niels; Bielenberg, Diane; Bucana, Corazon D.; Klagsbrun, Michael; Ellis, Lee M.
Neuropilin-1 (NRP-1), a recently identified co-receptor for vascular endothelial growth factor, is expressed by several nongastrointestinal tumor types and enhances prostate cancer angiogenesis and growth in preclinical models. We investigated the expression and regulation of NRP-1 and the effect of NRP-1 overexpression on angiogenesis and growth of human colon adenocarcinoma by immunohistochemistry and in situ hybridization. NRP-1 was expressed in 20 of 20 human colon adenocarcinoma specimens but not in the adjacent nonmalignant colonic mucosa. By reverse transcriptase-polymerase chain reaction analysis, NRP-1 mRNA was expressed in seven of seven colon adenocarcinoma cell lines. Subcutaneous xenografts of stably transfected KM12SM/LM2 human colon cancer cells overexpressing NRP-1 led to increased tumor growth and angiogenesis in nude mice. In in vitro assays, conditioned medium from NRP-1-transfected cell lines led to an increase in endothelial cell migration, but did not affect endothelial cell growth. Epidermal growth factor (EGF) led to induction of NRP-1 in human colon adenocarcinoma cells and selective blockade of the epidermal growth factor receptor (EGFR) decreased constitutive and EGF-induced NRP-1 expression. Blockade of the Erk 1/2 and P38 mitogen-activated protein kinase signaling pathways also led to a decrease in constitutive and EGF-induced NRP-1 expression. These findings demonstrate the ubiquitous expression of NRP-1 in human colon cancer and suggest that NRP-1 may contribute to colon cancer angiogenesis and growth. This study also suggests that EGF and mitogen-activated protein kinase signaling pathways play an important role in NRP-1 regulation in colon cancer cells. PMID:15161648
Hochstein, L. I.; Tomlinson, G. A.
Extremely halophilic bacteria were isolated from widely separated sites by anaerobic enrichment in the presence of nitrate. The anaerobic growth of several of these isolates was accompanied by the production of nitrite, nitrous oxide, and dinitrogen. These results are a direct confirmation of the existence of extremely halophilic denitrifying bacteria, and suggest that such bacteria may be common inhabitants of hypersaline environments.
Zagólski, Olaf; Stręk, Paweł; Kasprowicz, Andrzej; Białecka, Anna
Background Polyvalent bacterial lysate (PBL) is an oral immunostimulating vaccine consisting of bacterial standardized lysates obtained by lysis of different strains of bacteria. Autovaccines are individually prepared based on the results of smears obtained from the patient. Both types of vaccine can be used to treat an ongoing chronic infection. This study sought to determine which method is more effective against nasal colonization by potential respiratory tract pathogens. Material/Methods We enrolled 150 patients with aerobic Gram stain culture and count results indicating bacterial colonization of the nose and/or throat by potential pathogens. The participants were randomly assigned to each of the following groups: 1. administration of PBL, 2. administration of autovaccine, and 3. no intervention (controls). Results Reduction of the bacterial count in Streptococcus pneumoniae-colonized participants was significant after the autovaccine (p<0.001) and PBL (p<0.01). Reduction of the bacterial count of other β-hemolytic streptococcal strains after treatment with the autovaccine was significant (p<0.01) and was non-significant after PBL. In Haemophilus influenzae colonization, significant reduction in the bacterial count was noted in the PBL group (p<0.01). Methicillin-resistant Staphylococcus aureus colonization did not respond to either treatment. Conclusions The autovaccine is more effective than PBL for reducing bacterial count of Streptococcus pneumoniae and β-hemolytic streptococci, while PBL was more effective against Haemophilus influenzae colonization. PMID:26434686
Ballhausen, Max-Bernhard; van Veen, Johannes A.; Hundscheid, Maria P. J.; de Boer, Wietse
Mycophagous soil bacteria are able to obtain nutrients from living fungal hyphae. However, with exception of the soil bacterial genus Collimonas, occurrence of this feeding strategy has not been well examined. Evaluation of the importance of mycophagy in soil bacterial communities requires targeted isolation methods. In this study, we compared two different approaches to obtain mycophagous bacteria from rhizospheric soil. A short-term method based on baiting for bacteria that can rapidly adhere to fungal hyphae and a long-term method based on the enrichment of bacteria on fungal hyphae via repeated transfer. Hyphae-adhering bacteria were isolated, identified by 16S rDNA sequencing and tested for antifungal activity and the ability to feed on fungi as the sole source of carbon. Both methods yielded a range of potentially mycophagous bacterial isolates with little phylogenetic overlap. We also found indications for feeding preferences among the potentially mycophagous bacteria. Our results indicate that mycophagy could be an important growth strategy for rhizosphere bacteria. To our surprise, we found several potential plant pathogenic bacteria among the mycophagous isolates. We discuss the possible benefits that these bacteria might gain from colonizing fungal hyphae. PMID:26733962
Fry, Donald E.
Infections at the surgical site continue to occur in as many as 20% of elective colon resection cases. Methods to reduce these infections are inconsistently applied. Surgical site infection (SSI) is the result of multiple interactive variables including the inoculum of bacteria that contaminate the site, the virulence of the contaminating microbes, and the local environment at the surgical site. These variables that promote infection are potentially offset by the effectiveness of the host defense. Reduction in the inoculum of bacteria is achieved by appropriate surgical site preparation, systemic preventive antibiotics, and use of mechanical bowel preparation in conjunction with the oral antibiotic bowel preparation. Intraoperative reduction of hematoma, necrotic tissue, foreign bodies, and tissue dead space will reduce infections. Enhancement of the host may be achieved by perioperative supplemental oxygenation, maintenance of normothermia, and glycemic control. These methods require additional research to identify optimum application. Uniform application of currently understood methods and continued research into new methods to reduce microbial contamination and enhancement of host responsiveness can lead to better outcomes. PMID:24455434
Philosophical and scientific cosmological theory may impact human motivation to colonize space. Isotropic theories regarding cosmic structure and function offer no a-priori advantages to the habitation of any given cosmic zone, and therefore deprive colonization ideology of a cosmological motive. In contrast, certain aniso- tropic theories, which assign superior qualities to some cosmic zones over others, provide such motives. It follows that future space colonization may partially depend on the emergence of anisotropic cosmological theories, some of which are already contained in Western intellectual tradition but are not currently accepted.
Hentschke, Isabell; Graser, Anna; Melichar, Volker O.; Kiefer, Alexander; Zimmermann, Theodor; Kroß, Bettina; Haag, Patricia; Xepapadaki, Paraskevi; Papadopoulos, Nikolaos G.; Bogdan, Christian; Finotto, Susetta
Here we investigated the relationship between local bacterial colonization and anti-bacterial immune responses in pre-school asthmatic and control children within the EU-wide study PreDicta. In this cohort of pre-school asthmatic children, nasopharyngeal colonization with Gram-negative bacteria such as Haemophilus influenzae and Moraxella catarrhalis was found to be associated with the highest interferon beta (IFNβ) and IL-33 levels in the nasal pharyngeal fluids (NPF). IL33R-ST2 was found induced in the blood of asthmatic children with additional Gram + bacteria in the nasopharynx (Gr+/−). Furthermore, asthmatic children had more episodes of infection that required antibiotic therapy than the control group. Treatment with antibiotics associated with reduced ST2 in blood cells of both asthmatic and control children and reduced IL-33 levels in the airways of asthmatic children. In the absence of Staphylococcus (S.) aureus in NPF, antibiotic therapy associated with decreased IL-33 levels in the NPF and lower ST2 values in the blood of control children but not of asthmatic children. These data suggest that, in asthmatic children, Gram- bacteria, which persist after antibiotic therapy, contributes to IL-33 locally and associated with Gr + bacteria colonization in the airways, inhibited IFN-β and in the absence of Staphylococcus (S.) aureus, induced ST2 bearing cells in their blood. PMID:28262704
Pauly, John L; Paszkiewicz, Geraldine
Chronic inflammation associated with cigarette smoke fosters malignant transformation and tumor cell proliferation and promotes certain nonneoplastic pulmonary diseases. The question arises as to whether chronic inflammation and/or colonization of the airway can be attributed, at least in part, to tobacco-associated microbes (bacteria, fungi, and spores) and/or microbial toxins (endotoxins and mycotoxins) in tobacco. To address this question, a literature search of documents in various databases was performed. The databases included PubMed, Legacy Tobacco Documents Library, and US Patents. This investigation documents that tobacco companies have identified and quantified bacteria, fungi, and microbial toxins at harvest, throughout fermentation, and during storage. Also characterized was the microbial flora of diverse smoking and smokeless tobacco articles. Evidence-based health concerns expressed in investigations of microbes and microbial toxins in cigarettes, cigarette smoke, and smokeless tobacco products are reasonable; they warrant review by regulatory authorities and, if necessary, additional investigation to address scientific gaps.
Pauly, John L.; Paszkiewicz, Geraldine
Chronic inflammation associated with cigarette smoke fosters malignant transformation and tumor cell proliferation and promotes certain nonneoplastic pulmonary diseases. The question arises as to whether chronic inflammation and/or colonization of the airway can be attributed, at least in part, to tobacco-associated microbes (bacteria, fungi, and spores) and/or microbial toxins (endotoxins and mycotoxins) in tobacco. To address this question, a literature search of documents in various databases was performed. The databases included PubMed, Legacy Tobacco Documents Library, and US Patents. This investigation documents that tobacco companies have identified and quantified bacteria, fungi, and microbial toxins at harvest, throughout fermentation, and during storage. Also characterized was the microbial flora of diverse smoking and smokeless tobacco articles. Evidence-based health concerns expressed in investigations of microbes and microbial toxins in cigarettes, cigarette smoke, and smokeless tobacco products are reasonable; they warrant review by regulatory authorities and, if necessary, additional investigation to address scientific gaps. PMID:21772847
Ridlon, Jason M.; Harris, Spencer C.; Bhowmik, Shiva; Kang, Dae-Joong; Hylemon, Phillip B.
ABSTRACT Emerging evidence strongly suggest that the human “microbiome” plays an important role in both health and disease. Bile acids function both as detergents molecules promoting nutrient absorption in the intestines and as hormones regulating nutrient metabolism. Bile acids regulate metabolism via activation of specific nuclear receptors (NR) and G-protein coupled receptors (GPCRs). The circulating bile acid pool composition consists of primary bile acids produced from cholesterol in the liver, and secondary bile acids formed by specific gut bacteria. The various biotransformation of bile acids carried out by gut bacteria appear to regulate the structure of the gut microbiome and host physiology. Increased levels of secondary bile acids are associated with specific diseases of the GI system. Elucidating methods to control the gut microbiome and bile acid pool composition in humans may lead to a reduction in some of the major diseases of the liver, gall bladder and colon. PMID:26939849
Chu, Xian-Ming; Yu, Hua; Sun, Xue-Xia; An, Yi; Li, Bing; Li, Xue-Bin
Background Recent researches revealed that asymptomatic bacterial colonization on PMs might be ubiquitous and increase the risk of clinical PM infection. Early diagnosis of patients with asymptomatic bacterial colonization could provide opportunity for targeted preventive measures. Objective The present study explores the incidence of bacterial colonization of generator pockets in pacemaker replacement patients without signs of infection, and to analyze risk factors for asymptomatic bacterial colonization. Methods From June 2011 to December 2013, 118 patients underwent pacemaker replacement or upgrade. Identification of bacteria was carried out by bacterial culture and 16S rRNA sequencing. Clinical risk characteristics were analyzed. Results The total bacterial positive rate was 37.3% (44 cases), and the coagulase-negative Staphylococcus aureus detection rate was the highest. Twenty two (18.6%) patients had positive bacterial culture results, of which 50% had coagulase-negative staphylococcus. The bacterial DNA detection rate was 36.4 % (43 cases). Positive bacterial DNA results from pocket tissues and the surface of the devices were 22.0% and 29.7%, respectively. During follow-up (median, 27.0 months), three patients (6.8%, 3/44) became symptomatic with the same genus of microorganism, S. aureus (n=2) and S. epidermidis (n=1). Multivariable logistic regression analysis showed that history of bacterial infection, use of antibiotics, application of antiplatelet drugs, replacement frequency were independent risk factors for asymptomatic bacterial colonization. Conclusion There was a high incidence of asymptomatic bacterial colonization in pacemaker patients with independent risk factors. Bacterial culture combined genetic testing could improve the detection rate. PMID:25768661
Gibson, G R; Cummings, J H; Macfarlane, G T; Allison, C; Segal, I; Vorster, H H; Walker, A R
Hydrogen gas, which is produced during fermentation in the human colon, is either excreted in breath or metabolised by gut bacteria through a variety of pathways. These may include methanogenesis, dissimilatory sulphate reduction, and acetogenesis. To determine which of these routes predominates in the large intestine, stools were taken from 30 healthy subjects and incubated as 5% (w/v) slurries with Lintner's starch. In 23 of 30 subjects, methane production was the main method of hydrogen disposal. In the remaining seven, high rates of sulphate reduction were recorded together with raised production of H2S. All samples showed relatively low rates of hydrogen evolution and of acetate formation from CO2 and H2. Sulphate reduction and methanogenesis seem to be mutually exclusive in the colon and this is probably linked to sulphate availability. Sulphate reduction, methanogenesis, and acetogenesis were strongly influenced by pH. Sulphate reduction was optimal at alkaline pH values whereas methane production was maximal at a neutral pH and acetogenesis favoured acidic conditions. Faecal H2S values were related to carriage of sulphate reducing bacteria. These data show that a number of competing pathways for hydrogen disposal are possible in the large gut and that a variety of factors such as colonic pH and sulphate availability can determine which of these mechanisms predominates.
Gao, N; Zhao, Y; Xiao, X
The purpose of this in vitro study was to investigate the effects of microbial colonization on different crown or fixed bridge-used restorative materials and discuss the standards for evaluating those materials microscopically. Four kinds of restorative materials such as SDA-II type medium alloy, ceramic-fused-to-metal material, heat cure composite resin for crown restoration, Plat castable ceramics and four species of precedent subgingival flora (A. viscosus, F. nucleterm, C. ochracea, S. sanguis) were used. The material specimen had been continuously anaerobic cultured with the experimental bacterial fluid for 3, 7 and 14 days respectively, then the OD values of the specimenwashing fluid which could stand for the biomass of colonized bacteria on the surfaces of materials were measured. The results indicated that the quantity of precedent subgingival flora colonization on the surfaces of different restorative materials varied among different species of bacteria, which might concern with the surface structure, composition, property of anticorrosion and antisoluability of those materials.
Brooks, John F.
ABSTRACT Bacterial colonization of animal epithelial tissue is a dynamic process that relies on precise molecular communication. Colonization of Euprymna scolopes bobtail squid by Vibrio fischeri bacteria requires bacterial aggregation in host mucus as the symbiont transitions from a planktonic lifestyle in seawater to a biofilm-associated state in the host. We have identified a gene, binK (biofilm inhibitor kinase; VF_A0360), which encodes an orphan hybrid histidine kinase that negatively regulates the V. fischeri symbiotic biofilm (Syp) in vivo and in vitro. We identified binK mutants as exhibiting a colonization advantage in a global genetic screen, a phenotype that we confirmed in controlled competition experiments. Bacterial biofilm aggregates in the host are larger in strains lacking BinK, whereas overexpression of BinK suppresses biofilm formation and squid colonization. Signaling through BinK is required for temperature modulation of biofilm formation at 28°C. Furthermore, we present evidence that BinK acts upstream of SypG, the σ54-dependent transcriptional regulator of the syp biofilm locus. The BinK effects are dependent on intact signaling in the RscS-Syp biofilm pathway. Therefore, we propose that BinK antagonizes the signal from RscS and serves as an integral component in V. fischeri biofilm regulation. IMPORTANCE Bacterial lifestyle transitions underlie the colonization of animal hosts from environmental reservoirs. Formation of matrix-enclosed, surface-associated aggregates (biofilms) is common in beneficial and pathogenic associations, but investigating the genetic basis of biofilm development in live animal hosts remains a significant challenge. Using the bobtail squid light organ as a model, we analyzed putative colonization factors and identified a histidine kinase that negatively regulates biofilm formation at the host interface. This work reveals a novel in vivo biofilm regulator that influences the transition of bacteria from their
Anyan, M.; Shrout, J. D.
Pseudomonas aeruginosa is a ubiquitous, Gram-negative bacterium that utilizes several different modes of motility to colonize surfaces, including swarming, which is the coordinated movement of cells over surfaces in groups. Swarming facilitates surface colonization and biofilm development for P. aeruginosa, and it is known that swarming behavior is influenced by changes in nutrient composition and surface moisture. To understand the fate and cycling of heavy metals in the environment, it is important to understand the interaction and toxicity of these metals upon bacteria. While previous studies have shown surface-attached bacterial biofilms to be highly resistant to heavy metal toxicity, little is known about the influence of heavy metals upon surface motile bacteria and developing biofilms. Using a combination of laboratory assays we examined differences in bacterial behavior in response to two metals, Cd and Ni. We find that surface swarming bacteria are able to grow on 4x and 2.5x more Cd and Ni, respectively, than planktonic cells (i.e., test tube cultures). P. aeruginosa was able to swarm in the presence ≤0.051mM Ni and ≤0.045mM Cd. To investigate the bioavailability of metals to bacteria growing under our examined conditions, we separated cell and supernatant fractions of P. aeruginosa cultures, and used ICP-MS techniques to measure Cd and Ni sorption. A greater percentage of Cd than Ni was sorbed by both cells and supernatant (which contains rhamnolipid, a surfactant known to sorb some metals and improve swarming). While we show that cell products such as rhamnolipid bind heavy metals (as expected) and should limit metal bioavailability, our results suggest at least one additional mechanism (as yet undetermined) that promotes cell survival during swarming in the presence of these heavy metals.
Gallo Reynoso, S; Candelaria Hernández, M G
We report all patients with neoplastic polyps endoscopically excised during 10 years, performed in different hospitals in Mexico City. All ages, both sexes and socio-economic levels were seen in several endoscopy services both, public and private. We find 190 patients (100 females) with 268 polyps and a mean age of 54.5 (range 18-86). Tubulo-villous adenomas have the less frequency (8%). Villous adenomas were the largest and had a 11% frequency, almost all were confined to recto-sigmoid region its mean age was 6 years. Villous adenomas were the most frequent (69%) distributed in all colonic segments, its mean age was 54.5 years with the widest range (18-80 years); they have highest dysplasia rate (8.1%). Carcinomas arising in polyps were all located in recto-sigmoid region, with female predominance (2.3:1) and oldest mean age of presentation (66.3 years). Neoplastic polyps in Mexico City general population has a low frequency; endoscopic polypectomy is safe and had a low morbi-mortality rate.
Nassif, Nadine; Bouvet, Odile; Noelle Rager, Marie; Roux, Cécile; Coradin, Thibaud; Livage, Jacques
The encapsulation of enzymes within silica gels has been extensively studied during the past decade for the design of biosensors and bioreactors. Yeast spores and bacteria have also been recently immobilized within silica gels where they retain their enzymatic activity, but the problem of the long-term viability of whole cells in an inorganic matrix has never been fully addressed. It is a real challenge for the development of sol-gel processes. Generic tests have been performed to check the viability of Escherichia coli bacteria in silica gels. Surprisingly, more bacteria remain culturable in the gel than in an aqueous suspension. The metabolic activity of the bacteria towards glycolysis decreases slowly, but half of the bacteria are still viable after one month. When confined within a mineral environment, bacteria do not form colonies. The exchange of chemical signals between isolated bacteria rather than aggregates can then be studied, a point that could be very important for 'quorum sensing'.
... Increase your risk of dehydration Lead to bowel perforations Increase the risk of infection Cause changes in ... problems. Stay well-hydrated by drinking lots of fluids while undergoing colon cleansing to prevent dehydration. With ...
An executable file (in GAUSS) that projects absolute colon cancer risk (with confidence intervals) according to NCI’s Colorectal Cancer Risk Assessment Tool (CCRAT) algorithm. GAUSS is not needed to run the program.
This page lists cancer drugs approved by the Food and Drug Administration (FDA) for use in colon cancer and rectal cancer. The list includes generic names, brand names, and common drug combinations, which are shown in capital letters.
Duncan, S H; Louis, P; Flint, H J
Knowledge of the composition of the colonic microbiota is important for our understanding of how the balance of these microbes is influenced by diet and the environment, and which bacterial groups are important in maintaining gut health or promoting disease. Molecular methodologies have advanced our understanding of the composition and diversity of the colonic microbiota. Importantly, however, it is the continued isolation of bacterial representatives of key groups that offers the best opportunity to conduct detailed metabolic and functional studies. This also permits bacterial genome sequencing which will accelerate the linkage to functionality. Obtaining new human colonic bacterial isolates can be challenging, because most of these are strict anaerobes and many have rather exact nutritional and physical requirements. Despite this many new species are being isolated and described that occupy distinct niches in the colonic microbial community. This review focuses on these under-studied yet important gut anaerobes.
Narang, Manish; Kumar, Manish; Shah, Dheeraj
Fraser cryptophthalmos syndrome is a severe genetic disorder comprising of cryptophthalmos, syndactyly and genitourinary abnormalities. Gastrointestinal malformations are also increasingly being described. We describe a neonate with this syndrome having colonic atresia leading to cecal rupture and pneumoperitoneum.
In this trial, patients with resected stage III colon cancer are being randomly assigned to receive FOLFOX chemotherapy for either 3 or 6 months and to take either a pill called celecoxib or a matching placebo pill for 3 years.
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In this phase III trial, people who have had curative surgery for colon cancer will be randomly assigned to take sulindac and a placebo, eflornithine and a placebo, both sulindac and eflornithine, or two placebo pills for 36 months.
Geng, Zhuo; Agrawal, Deepak; Singal, Amit G; Kircher, Stephen; Gupta, Samir
Complications of cecal retroflexion performed during colonoscopy have not previously been reported to occur. We report a case of contained colonic perforation secondary to using cecal retroflexion technique to examine the colon, and review available published reports of complications associated with this technique. We conclude that complications may rarely occur with use of cecal retroflexion, and that the clinical benefit of this technique is uncertain.
Gavert, Raymond B.
Space colonization is not part of NASA's mission planning. NASA's exploration vision, mission goals and program implementations, however, can have an important affect on private lunar programs leading towards colonization. NASA's exploration program has been described as a journey not a race. It is not like the Apollo mission having tight schedules and relatively unchanging direction. NASA of this era has competing demands from the areas of aeronautics, space science, earth science, space operations and, there are competing demands within the exploration program itself. Under the journey not a race conditions, an entrepreneur thinking about building a hotel on the Moon, with a road to an exploration site, might have difficulty determining where and when NASA might be at a particular place on the Moon. Lunar colonization advocates cannot depend on NASA or other nations with space programs to lead the way to colonization. They must set their own visions, mission goals and schedules. In implementing their colonization programs they will be resource limited. They would be like ``hitchhikers'' following the programs of spacefaring nations identifying programs that might have a fit with their vision and be ready to switch to other programs that may take them in the colonization direction. At times they will have to muster their own limited resources and do things themselves where necessary. The purpose of this paper is to examine current changes within NASA, as a lunar colonization advocate might do, in order to see where there might be areas for fitting into a lunar colonization strategy. The approach will help understand how the ``hitchhiking'' technique might be better utilized.
Levinson, J D; Ramanathan, V R; Nozick, J H
The case of a 39-year old white man with eosinophilic gastroenteritis is presented. The major clinical features were gastric outlet obstruction, diarrhea and massive ascites. At surgery, significant involvement of the entire gastrointestinal tract from the gastric antrum to the sigmoid colon was found. Histologic documentation of colon involvement was obtained. The response to corticosteroids was prompt and sustained. At present, he is maintained on an alternating day schedule of steroid administration.
Syed, Adnan K; Ghosh, Sudeshna; Love, Nancy G; Boles, Blaise R
The biocide triclosan is used in many personal care products, including toothpastes, soaps, clothing, and medical equipment. Consequently, it is present as a contaminant in the environment and has been detected in some human fluids, including serum, urine, and milk. Staphylococcus aureus is an opportunistic pathogen that colonizes the noses and throats of approximately 30% of the population. Colonization with S. aureus is known to be a risk factor for several types of infection. Here we demonstrate that triclosan is commonly found in the nasal secretions of healthy adults and the presence of triclosan trends positively with nasal colonization by S. aureus. We demonstrate that triclosan can promote the binding of S. aureus to host proteins such as collagen, fibronectin, and keratin, as well as inanimate surfaces such as plastic and glass. Lastly, triclosan-exposed rats are more susceptible to nasal colonization with S. aureus. These data reveal a novel factor that influences the ability of S. aureus to bind surfaces and alters S. aureus nasal colonization. IMPORTANCE Triclosan has been used as a biocide for over 40 years, but the broader effects that it has on the human microbiome have not been investigated. We demonstrate that triclosan is present in nasal secretions of a large portion of a test population and its presence correlates with Staphylococcus aureus nasal colonization. Triclosan also promotes the binding of S. aureus to human proteins and increases the susceptibility of rats to nasal colonization by S. aureus. These findings are significant because S. aureus colonization is a known risk factor for the development of several types of infections. Our data demonstrate the unintended consequences of unregulated triclosan use and contribute to the growing body of research demonstrating inadvertent effects of triclosan on the environment and human health.
Hirasawa, Kensuke; Nishikawa, Sandra G; Norman, Kara L; Alain, Tommy; Kossakowska, Anna; Lee, Patrick W K
Reovirus selectively replicates in and destroys cancer cells with an activated Ras signaling pathway. In this study, we evaluated the feasibility of using reovirus (serotype 3, strain Dearing) as an antihuman colon and ovarian cancer agent. In in vitro studies, reovirus infection in human colon and ovarian cell lines was assessed by cytopathic effect as detected by light microscopy, [(35)S]Methionine labeling of infected cells for viral protein synthesis and progeny virus production by plaque assay. We observed that reovirus efficiently infected all five human colon cancer cell lines (Caco-2, DLD-1, HCT-116, HT-29, and SW48) and four human ovarian cancer cell lines (MDAH2774, PA-1, SKOV3, and SW626) which were tested, but not a normal colon cell line (CCD-18Co) or a normal ovarian cell line (NOV-31). We also observed that the Ras activity in the human colon and ovarian cancer cell lines was elevated compared with that in normal colon and ovarian cell lines. In animal models, intraneoplastic as well as i.v. inoculation of reovirus resulted in significant regression of established s.c. human colon and ovarian tumors implanted at the hind flank. Histological studies revealed that reovirus infection in vivo was restricted to tumor cells, whereas the surrounding normal tissue remained uninfected. Additionally, in an i.p. human ovarian cancer xenograft model, inhibition of ascites tumor formation and the survival of animals treated with live reovirus was significantly greater than of control mice treated with UV-inactivated reovirus. Reovirus infection in ex vivo primary human ovarian tumor surgical samples was also confirmed, further demonstrating the potential of reovirus therapy. These results suggest that reovirus holds promise as a novel agent for human colon and ovarian cancer therapy.
Atopic dermatitis or eczema is characterized by skin rashes and itching is an inflammatory disease that affects 10-20% of children and 1-3% of adults. Staphylococcus aureus bacteria are present on the skin of nearly all patients with atopic dermatitis. Antibiotics that suppress colonization of S. au...
Marasco, Ramona; Mapelli, Francesca; Rolli, Eleonora; Mosqueira, Maria J.; Fusi, Marco; Bariselli, Paola; Reddy, Muppala; Cherif, Ameur; Tsiamis, George; Borin, Sara; Daffonchio, Daniele
Halophytes classified under the common name of salicornia colonize salty and coastal environments across tidal inundation gradients. To unravel the role of tide-related regimes on the structure and functionality of root associated bacteria, the rhizospheric soil of Salicornia strobilacea (synonym of Halocnemum strobilaceum) plants was studied in a tidal zone of the coastline of Southern Tunisia. Although total counts of cultivable bacteria did not change in the rhizosphere of plants grown along a tidal gradient, significant differences were observed in the diversity of both the cultivable and uncultivable bacterial communities. This observation indicates that the tidal regime is contributing to the bacterial species selection in the rhizosphere. Despite the observed diversity in the bacterial community structure, the plant growth promoting (PGP) potential of cultivable rhizospheric bacteria, assessed through in vitro and in vivo tests, was equally distributed along the tidal gradient. Root colonization tests with selected strains proved that halophyte rhizospheric bacteria (i) stably colonize S. strobilacea rhizoplane and the plant shoot suggesting that they move from the root to the shoot and (ii) are capable of improving plant growth. The versatility in the root colonization, the overall PGP traits and the in vivo plant growth promotion under saline condition suggest that such beneficial activities likely take place naturally under a range of tidal regimes. PMID:27597846
Guo, Fang-Fang; Yu, Ta-Chung; Hong, Jie; Fang, Jing-Yuan
Hydrogen sulfide (H2S) is a toxic gas that has been recognized as an important mediator of many physiological processes, such as neurodegeneration, regulation of inflammation, blood pressure, and metabolism. In the human colon, H2S is produced by both endogenous enzymes and sulfate-reducing bacteria (SRB). H2S is involved in the physiological and pathophysiological conditions of the colon, such as inflammatory bowel disease (IBD) and colorectal cancer (CRC), which makes the pharmacological modulation of H2S production and metabolism a potential chemical target for the treatment of colonic diseases. However, the exact mechanisms and pathways by which H2S-mediates normal physiological function and disease in the colon are not fully understood. Besides, the production and release of H2S are modulated by both endogenous and exogenous factors. This review will discuss the production and storage of H2S, its biological roles and the emerging importance in physiology and pathology of IBD and CRC. PMID:27199771
Topping, D L; Clifton, P M
Resistant starch (RS) is starch and products of its small intestinal digestion that enter the large bowel. It occurs for various reasons including chemical structure, cooking of food, chemical modification, and food mastication. Human colonic bacteria ferment RS and nonstarch polysaccharides (NSP; major components of dietary fiber) to short-chain fatty acids (SCFA), mainly acetate, propionate, and butyrate. SCFA stimulate colonic blood flow and fluid and electrolyte uptake. Butyrate is a preferred substrate for colonocytes and appears to promote a normal phenotype in these cells. Fermentation of some RS types favors butyrate production. Measurement of colonic fermentation in humans is difficult, and indirect measures (e.g., fecal samples) or animal models have been used. Of the latter, rodents appear to be of limited value, and pigs or dogs are preferable. RS is less effective than NSP in stool bulking, but epidemiological data suggest that it is more protective against colorectal cancer, possibly via butyrate. RS is a prebiotic, but knowledge of its other interactions with the microflora is limited. The contribution of RS to fermentation and colonic physiology seems to be greater than that of NSP. However, the lack of a generally accepted analytical procedure that accommodates the major influences on RS means this is yet to be established.
Krevsky, B.; Libster, B.; Maurer, A.H.; Chase, B.J.; Fisher, R.S.
The effects of endogenous and exogenous opioid substances on feline colonic transit were evaluated using colonic transit scintigraphy. Naloxone accelerated emptying of the cecum and ascending colon, and filling of the transverse colon. Endogenous opioid peptides thus appear to play a significant role in the regulation of colonic transit. At a moderate dose of morphine cecum and ascending colon transit was accelerated, while at a larger dose morphine had no effect. Since naloxone, a relatively nonspecific opioid antagonist, and morphine, a principally mu opioid receptor agonist, both accelerate proximal colonic transit, a decelerating role for at least one of the other opioid receptors is inferred.
Mullineaux, Conrad W
Even in clonal bacterial cultures, individual bacteria can show substantial stochastic variation, leading to pitfalls in the interpretation of data derived from millions of cells in a culture. In this issue of the Journal of Bacteriology, as part of their study on osmoadaptation in a cyanobacterium, Nanatani et al. describe employing an ingenious microfluidic device that gently cages individual cells (J Bacteriol 197:676-687, 2015, http://dx.doi.org/10.1128/JB.02276-14). The device is a welcome addition to the toolkit available to probe the responses of individual cells to environmental cues.
Beveridge, T J; Graham, L L
Since bacteria are so small, microscopy has traditionally been used to study them as individual cells. To this end, electron microscopy has been a most powerful tool for studying bacterial surfaces; the viewing of macromolecular arrangements of some surfaces is now possible. This review compares older conventional electron-microscopic methods with new cryotechniques currently available and the results each has produced. Emphasis is not placed on the methodology but, rather, on the importance of the results in terms of our perception of the makeup and function of bacterial surfaces and their interaction with the surrounding environment. Images PMID:1723487
Matsuoka, Hiroaki; Akiyama, Masaru; Kobayashi, Katsuichiro; Yamaji, Keiko
Our objective was simply to report a sedge species, Carex kobomugi Ohwi that has beneficial bacterial associations under low Fe and P conditions of the Hasaki coast, Japan. C. kobomugi is the dominant species in our study area and grows closest to the sea. C. kobomugi showed higher Fe and P content, while these nutrients were less available under alkaline root-zone soil. Within the roots, mycorrhizal fungal colonization was absent, and endophytic fungal colonization was low. On the contrary, endophytic bacteria (e.g. Bacillus sp., Streptomyces luteogriseus, and Pseudomonas fluorescens) were isolated, which exhibited both siderophore production and inorganic phosphate solubilization under Fe or P limited conditions. Our results suggest that colonization of root tissue by these bacteria contribute to the Fe and P uptakes by C. kobomugi by increasing availability in the soil.
We have been using a mutational approach to determine how plant-beneficial bacteria, such as Enterobacter cloacae, deal with complex nutritional environments found in association with subterranean plant parts during colonization and disease suppression. E. cloacae C10, a mini-Tn5 Km mutant of E. cl...
Hodgkinson, Alison J; Cakebread, Julie; Callaghan, Megan; Harris, Paul; Brunt, Rachel; Anderson, Rachel C; Armstrong, Kelly M; Haigh, Brendan
Secretory IgA (SIgA) from milk contributes to early colonization and maintenance of commensal/symbiotic bacteria in the gut, as well as providing defence against pathogens. SIgA binds bacteria using specific antigenic sites or non-specifically via its glycans attached to α-heavy-chain and secretory component. In our study, we tested the hypothesis that human and bovine SIgA have similar innate-binding activity for bacteria. SIgAs, isolated from human and bovine milk, were incubated with a selection of commensal, pathogenic and probiotic bacteria. Using flow cytometry, we measured numbers of bacteria binding SIgA and their level of SIgA binding. The percentage of bacteria bound by human and bovine SIgA varied from 30 to 90% depending on bacterial species and strains, but was remarkably consistent between human and bovine SIgA. The level of SIgA binding per bacterial cell was lower for those bacteria that had a higher percentage of SIgA-bound bacteria, and higher for those bacteria that had lower percentage of SIgA-bound bacteria. Overall, human and bovine SIgA interacted with bacteria in a comparable way. This contributes to longer term research about the potential benefits of bovine SIgA for human consumers.
Bhani, Deepa; Tomar, Vinay; Bachhiwal, Rekha; Yadav, Shersingh
Introduction Catheter Associated Urinary Tract Infections (CAUTI) are one of the most common cause of nosocomial infections. Many bacterial species show biofilm production, which provides survival benefit to them by providing protection from environmental stresses and causing decreased susceptibility to antimicrobial agents. Two most common types of catheters used in our setup are pure silicone catheter and silicone coated latex catheter. The advantage of pure silicone catheter for long term catheterization is well established. But there is still a controversy about any advantage of the silicone catheter regarding bacterial colonization rates and their biofilm production property. Aims The aim of our study was to compare the bacterial colonization and the biofilm formation property of the colonizing bacteria in patients with indwelling pure silicone and silicone coated latex catheters. Materials and Methods This prospective observational study was conducted in the Urology Department of our institute. Patients who needed catheterization for more than 5 days during the period July 2015 to January 2016 and had sterile precatheterisation urine were included in the study. Patients were grouped into 2 groups of 50 patients each, Group A with the pure silicone catheter and Group B with the silicone coated latex catheter. Urine culture was done on the 6th day of indwelling urinary catheter drainage. If growth was detected, then that bacterium was tested for biofilm production property by tissue culture plate method. Statistical Analysis Statistical analyses were performed using the Statistical Package for the Social Science Version 22 (SPSS-22). Results After 5 days of indwelling catheterization, the pure silicone catheter had significantly less bacterial colonization than the silicone coated latex catheter (p-value=0.03) and the biofilm forming property of colonizing bacteria was also significantly less in the pure silicone catheter as compared to the silicone coated
Ericsson, Aaron C; Hagan, Catherine E; Davis, Daniel J; Franklin, Craig L
Segmented filamentous bacteria (SFB) are commensal bacteria that were first identified in the ilea of mice and rats. Morphologically similar bacteria occur in a broad range of host species, but all strains have been refractory to in vitro culture thus far. Although SFB were once considered innocuous members of the intestinal microbiota of laboratory rodents, they are now known to affect the development of the immune system in rodents and, subsequently, the phenotype of models of both enteric and extraintestinal disease. Therefore, SFB represent long-recognized commensal bacteria serving as an intercurrent variable in studies using rodent models of disease. Here we describe the basic biology of SFB and discuss the immunologic and physiologic effects of colonization with SFB, with particular attention to their effects on rodent models of disease. In addition, we propose that SFB represent only the ‘tip of the iceberg’ in our understanding of the influence of the microbiota on model phenotypes. As next-generation sequencing techniques are increasingly used to investigate organisms that are refractory to culture, we are likely to identify other commensal microbes that alter the models we use. This review underscores the need to characterize such host–microbe interactions, given that animal research represents a critical tool that is particularly vulnerable to scrutiny in an era of decreasing financial resources and increasing accountability for the use of animal models. PMID:24674582
Brewer, A.R.; Stromberg, B.V. )
Adherence of bacteria to prosthetic grafting material is thought to play an important role in the ultimate development of prosthetic infections. To evaluate the role of bacterial adherence in the initiation and colonization of prosthetic materials, Proplast II, Gore-Tex, and silicone were evaluated for adherence of Escherichia coli and Staphylococcus aureus. Bacteria were radiolabeled and incubated with the study material. Adherence was determined by scintillation. Adherence to Proplast II and Gore-Tex reached a maximum at approximately 45 minutes of incubation and demonstrated a detachment phenomenon with E. coli. Similar results were noted with S. aureus, but with a maximal attachment at approximately 30 minutes. Interestingly, bacterial attachment to silicone continued to increase throughout the time of the incubation. In addition, adherence of S. aureus was at a faster rate than E. coli. Attachment of bacteria is a multifactorial process. However, the PTFE graft demonstrates a slower rate of attachment, lower total number of attached bacteria, and faster detachment. The importance of this phenomenon may help explain the foreign body effect of increased susceptibility to infection of foreign materials.
Lactic acid bacteria are among the powerhouses of the food industry, colonize the surfaces of plants and animals, and contribute to our health and well-being. The genomic characterization of LAB has rocketed and presently over 100 complete or nearly complete genomes are available, many of which serve as scientific paradigms. Moreover, functional and comparative metagenomic studies are taking off and provide a wealth of insight in the activity of lactic acid bacteria used in a variety of applications, ranging from starters in complex fermentations to their marketing as probiotics. In this new era of high throughput analysis, biology has become big science. Hence, there is a need to systematically store the generated information, apply this in an intelligent way, and provide modalities for constructing self-learning systems that can be used for future improvements. This review addresses these systems solutions with a state of the art overview of the present paradigms that relate to the use of lactic acid bacteria in industrial applications. Moreover, an outlook is presented of the future developments that include the transition into practice as well as the use of lactic acid bacteria in synthetic biology and other next generation applications. PMID:21995776
Tan, Mei-Fang; Gao, Ting; Liu, Wan-Quan; Zhang, Chun-Yan; Yang, Xi; Zhu, Jia-Wen; Teng, Mu-Ye; Li, Lu; Zhou, Rui
Acquisition and metabolism of carbohydrates are essential for host colonization and pathogenesis of bacterial pathogens. Different bacteria can uptake different lines of carbohydrates via ABC transporters, in which ATPase subunits energize the transport though ATP hydrolysis. Some ABC transporters possess their own ATPases, while some share a common ATPase. Here we identified MsmK, an ATPase from Streptococcus suis, an emerging zoonotic bacterium causing dead infections in pigs and humans. Genetic and biochemistry studies revealed that the MsmK was responsible for the utilization of raffinose, melibiose, maltotetraose, glycogen and maltotriose. In infected mice, the msmK-deletion mutant showed significant defects of survival and colonization when compared with its parental and complementary strains. Taken together, MsmK is an ATPase that contributes to multiple carbohydrates utilization and host colonization of S. suis. This study gives new insight into our understanding of the carbohydrates utilization and its relationship to the pathogenesis of this zoonotic pathogen.
Background Haemophilus influenzae is the most common colonizing bacteria of the bronchial tree in chronic obstructive pulmonary disease (COPD), and positive cultures for this potentially pathogenic microorganism (PPM) has been associated with local inflammation changes that may influence the relationships between H. influenzae and the bronchial mucosa. Methods A cross-sectional analysis of stable COPD patients enrolled in the Phenotype and Course of Chronic Obstructive Pulmonary Disease (PAC-COPD) Study, focusing on bronchial colonization by H. influenzae, was performed. Specific IgA against the PPM was measured by optical density, and metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) using ELISA in sputum samples. Levels in patients colonized by H. influenzae and non-colonized patients were compared. Results Sputum supernatant for the measurement of specific IgA against H. influenzae was available from 54 stable COPD patients, who showed levels of specific IgA significantly lower in colonized (n=21) than in non-colonized patients (n=33) (15 [4-37] versus 31 [10-75], p=0.033, Mann-Whitney U test). Proenzyme MMP-9 was measured in 44 patients, and it was higher in colonized (n=12, 1903 [1488-6699] ng/ml) than in non-colonized patients (n=32, 639 [373-972] ng/ml) (p<0.001, Mann-Whitney U test). Active form of MMP-9 was also higher in colonized (126 [25-277] ng/ml) than in non-colonized patients (39 [14-68] ng/ml) (p=0.021, Mann-Whitney U test), and the molar ratio between proenzyme MMP-9 and TIMP-1 was above 1 (2.1 [0.1-12.5]) in colonized patients, significantly higher than the ratio found in non-colonized patients (0.2 [0.08-0.5]) (p=0.030, Mann-Whitney U test). Conclusions Clinically stable COPD patients colonized by H. influenzae had lower levels of specific IgA against the microorganism and higher values of the active form of MMP-9 in their sputum supernatant than non-colonized patients. Bronchial colonization by H. influenzae may
Compant, Stéphane; Reiter, Birgit; Sessitsch, Angela; Nowak, Jerzy; Clément, Christophe; Ait Barka, Essaïd
Patterns of colonization of Vitis vinifera L. cv. Chardonnay plantlets by a plant growth-promoting bacterium, Burkholderia sp. strain PsJN, were studied under gnotobiotic conditions. Wild-type strain PsJN and genetically engineered derivatives of this strain tagged with gfp (PsJN::gfp2x) or gusA (PsJN::gusA11) genes were used to enumerate and visualize tissue colonization. The rhizospheres of 4- to 5-week-old plantlets with five developed leaves were inoculated with bacterial suspensions. Epiphytic and endophytic colonization patterns were then monitored by dilution plating assays and microscopic observation of organ sections. Bacteria were chronologically detected first on root surfaces, then in root internal tissues, and finally in the fifth internode and the tissues of the fifth leaf. Analysis of the PsJN colonization patterns showed that this strain colonizes grapevine root surfaces, as well as cell walls and the whole surface of some rhizodermal cells. Cells were also abundant at lateral root emergence sites and root tips. Furthermore, cell wall-degrading endoglucanase and endopolygalacturonase secreted by PsJN explained how the bacterium gains entry into root internal tissues. Host defense reactions were observed in the exodermis and in several cortical cell layers. Bacteria were not observed on stem and leaf surfaces but were found in xylem vessels of the fifth internode and the fifth leaf of plantlets. Moreover, bacteria were more abundant in the fifth leaf than in the fifth internode and were found in substomatal chambers. Thus, it seems that Burkholderia sp. strain PsJN induces a local host defense reaction and systemically spreads to aerial parts through the transpiration stream.
Stange, Kurt C.; Jacobs, Michael R.; Weiss, Judith K.; Bajaksouzian, Saralee; Bonomo, Robert A.
Background. Infants are virtually sterile at birth and frequently use antibiotics; our objective was to (1) characterize the longitudinal colonization with bacterial pathogens and associated antibiotic resistance in a cohort of community-dwelling infants in Northeast Ohio and (2) describe longitudinal concurrent antibiotic and daycare exposures. Methods. For 35 newborns, nasopharyngeal swabs were cultured for Streptococcus pneumoniae, anterior nasal for Staphylococcus aureus, and perirectal for extended-spectrum beta-lactamase (ESBL)-producing Gram-negative enteric bacteria, at 3-month intervals for 12 months. Infant and household antibiotics and daycare exposure were assessed longitudinally. Results. Thirteen infants received perinatal or nursery antibiotics. By 3 months, at least 22 were colonized with Gram-negative bacteria; 2 with S pneumoniae (type 19A, resistant; 15C, susceptible), 5 with methicillin-susceptible S aureus. By 12 months, at least 22 of 35 infants received antibiotics, 20 had household members with antibiotics, and 12 attended daycare; 7 more had household members with daycare exposure. The ESBL-producing organisms were not identified. At least 10 infants were colonized at some time with an antibiotic-resistant organism, 3 more with pathogens displaying intermediate resistance. Pathogen colonization and resistance were intermittent and inconsistent. Conclusions. In a community-based cohort followed from birth, early antibiotic and daycare exposures are common, especially considering perinatal maternal exposures. Colonization patterns of Gram-negative bacteria, S pneumoniae, S aureus, and resistant pneumococci are strikingly dynamic. Further research can identify key areas for potential interventions to maximize clinical antibiotic outcomes while minimizing future resistance. PMID:27957505
Suravajhala, Srinivasa Sandeep; Saini, Deepak; Nott, Prabhu
Luminescence in Vibrio fischeri is a model for quorum-sensing-gene-regulation in bacteria. We study luminescence response of V. fischeri to both internal and external cues at the single cell and population level. Experiments with ES114, a wild-type strain, and ainS mutant show that luminescence induction in cultures is not always proportional to cell-density and there is always a basal level of luminescence. At any given concentration of the exogenously added signals, C6-HSL and C8-HSL, luminescence per cell reaches a maximum during the exponential phase and decreases thereafter. We hypothesize that (1) C6-HSL production and LuxR activity are not proportional to cell-density, and (2) there is a shift in equilibrium from C6-HSL to C8-HSL during the later stages of growth of the culture. RT-PCR analysis of luxI and luxR shows that the expression of these genes is maximum corresponding to the highest level of luminescence. The shift in equilibrium is shown by studying competitive binding of C6-HSL and C8-HSL to LuxR. We argue that luminescence is a unicellular behaviour, and an intensive property like per cell luminescence is more important than gross luminescence of the population in understanding response of bacteria to chemical signalling. Funding from the Department of Science and Technology, India is acknowledged.
Romero, Diego; Kolter, Roberto
The term amyloidosis is used to refer to a family of pathologies altering the homeostasis of human organs. Despite having a name that alludes to starch content, the amyloid accumulations are made up of proteins that polymerize as long and rigid fibers. Amyloid proteins vary widely with respect to their amino acid sequences but they share similarities in their quaternary structure; the amyloid fibers are enriched in β-sheets arranged perpendicular to the axis of the fiber. This structural feature provides great robustness, remarkable stability, and insolubility. In addition, amyloid proteins specifically stain with certain dyes such as Congo red and thioflavin-T. The aggregation into amyloid fibers, however, it is not restricted to pathogenic processes, rather it seems to be widely distributed among proteins and polypeptides. Amyloid fibers are present in insects, fungi and bacteria, and they are important in maintaining the homeostasis of the organism. Such findings have motivated the use of the term "functional amyloid" to differentiate these amyloid proteins from their toxic siblings. This review focuses on systems that have evolved in bacteria that control the expression and assembly of amyloid proteins on cell surfaces, such that the robustness of amyloid proteins are used towards a beneficial end.
Swidsinski, Alexander; Loening-Baucke, Vera; Schulz, Stefan; Manowsky, Julia; Verstraelen, Hans; Swidsinski, Sonja
Sections of fecal cylinders were analyzed using fluorescence in situ hybridization targeting 180 bacterial groups. Samples were collected from three groups of women (N=20 each) treated for bacterial vaginosis with ciprofloxacin+metronidazole. Group A only received the combined antibiotic regimen, whereas the A/Sb group received concomitant Saccharomyces boulardii CNCM I-745 treatment, and the A_Sb group received S. boulardii prophylaxis following the 14-day antibiotic course. The number of stool cylinders analyzed was 188 out of 228 in group A, 170 out of 228 in group A/Sb, and 172 out of 216 in group A_Sb. The colonic biomass was organized into a separate mucus layer with no bacteria, a 10-30μm broad unstirred transitional layer enriched with bacteria, and a patchy fermentative area that mixed digestive leftovers with bacteria. The antibiotics suppressed bacteria mainly in the fermentative area, whereas abundant bacterial clades retreated to the transitional mucus and survived. As a result, the total concentration of bacteria decreased only by one order. These effects were lasting, since the overall recovery of the microbial mass, bacterial diversity and concentrations were still below pre-antibiotic values 4 months after the end of antibiotic treatment. Sb-prophylaxis markedly reduced antibiotic effects and improved the recovery rates. Since the colon is a sophisticated bioreactor, the study indicated that the spatial anatomy of its biomass was crucial for its function.
Zhu, Xuezhu; Ni, Xue; Waigi, Michael Gatheru; Liu, Juan; Sun, Kai; Gao, Yanzheng
Endophytic bacteria can promote plant growth, induce plant defence mechanisms, and increase plant resistance to organic contaminants. The aims of the present study were to isolate highly PAH-degrading endophytic bacteria from plants growing at PAH-contaminated sites and to evaluate the capabilities of these bacteria to degrade polycyclic aromatic hydrocarbons (PAHs) in vitro, which will be beneficial for re-colonizing target plants and reducing plant PAH residues through the inoculation of plants with endophytic bacteria. Two endophytic bacterial strains P1 (Stenotrophomonas sp.) and P3 (Pseudomonas sp.), which degraded more than 90% of phenanthrene (PHE) within 7 days, were isolated from Conyza canadensis and Trifolium pretense L., respectively. Both strains could use naphthalene (NAP), PHE, fluorene (FLR), pyrene (PYR), and benzo(a)pyrene (B(a)P) as the sole sources of carbon and energy. Moreover, these bacteria reduced the contamination of mixed PAHs at high levels after inoculation for 7 days; strain P1 degraded 98.0% NAP, 83.1% FLR, 87.8% PHE, 14.4% PYR, and 1.6% B(a)P, and strain P3 degraded 95.3% NAP, 87.9% FLR, 90.4% PHE, 6.9% PYR, and negligible B(a)P. Notably, the biodegradation of PAHs could be promoted through additional carbon and nitrogen nutrients; therein, beef extract was suggested as the optimal co-substrate for the degradation of PAHs by these two strains (99.1% PHE was degraded within 7 days). Compared with strain P1, strain P3 has more potential for the use in the removal of PAHs from plant tissues. These results provide a novel perspective in the reduction of plant PAH residues in PAH-contaminated sites through inoculating plants with highly PAH-degrading endophytic bacteria. PMID:27517944
Zhu, Xuezhu; Ni, Xue; Waigi, Michael Gatheru; Liu, Juan; Sun, Kai; Gao, Yanzheng
Endophytic bacteria can promote plant growth, induce plant defence mechanisms, and increase plant resistance to organic contaminants. The aims of the present study were to isolate highly PAH-degrading endophytic bacteria from plants growing at PAH-contaminated sites and to evaluate the capabilities of these bacteria to degrade polycyclic aromatic hydrocarbons (PAHs) in vitro, which will be beneficial for re-colonizing target plants and reducing plant PAH residues through the inoculation of plants with endophytic bacteria. Two endophytic bacterial strains P₁ (Stenotrophomonas sp.) and P₃ (Pseudomonas sp.), which degraded more than 90% of phenanthrene (PHE) within 7 days, were isolated from Conyza canadensis and Trifolium pretense L., respectively. Both strains could use naphthalene (NAP), PHE, fluorene (FLR), pyrene (PYR), and benzo(a)pyrene (B(a)P) as the sole sources of carbon and energy. Moreover, these bacteria reduced the contamination of mixed PAHs at high levels after inoculation for 7 days; strain P₁ degraded 98.0% NAP, 83.1% FLR, 87.8% PHE, 14.4% PYR, and 1.6% B(a)P, and strain P₃ degraded 95.3% NAP, 87.9% FLR, 90.4% PHE, 6.9% PYR, and negligible B(a)P. Notably, the biodegradation of PAHs could be promoted through additional carbon and nitrogen nutrients; therein, beef extract was suggested as the optimal co-substrate for the degradation of PAHs by these two strains (99.1% PHE was degraded within 7 days). Compared with strain P₁, strain P₃ has more potential for the use in the removal of PAHs from plant tissues. These results provide a novel perspective in the reduction of plant PAH residues in PAH-contaminated sites through inoculating plants with highly PAH-degrading endophytic bacteria.
Martel, Guillaume; Boushey, Robin P
Since its first described case in 1991, laparoscopic colon surgery has lagged behind minimally invasive surgical methods for solid intra-abdominal organs in terms of acceptability, dissemination, and ease of learning. In colon cancer, initial concerns over port site metastases and adequacy of oncologic resection have considerably dampened early enthusiasm for this procedure. Only recently, with the publication of several large, randomized controlled trials, has the incidence of port site metastases been shown to be equivalent to that of open resection. Laparoscopic surgery for colon cancer has also been demonstrated to be at least equivalent to traditional laparotomy in terms of adequacy of oncologic resection, disease recurrence, and long-term survival. In addition, numerous reports have validated short-term benefits following laparoscopic resection for cancer, including shorter hospital stay, shorter time to recovery of bowel function, and decreased analgesic requirements, as well as other postoperative variables. In benign colonic disease, much less high-quality literature exists supporting the use of laparoscopic methods. Two recent randomized controlled trials have demonstrated some short-term benefits to laparoscopic ileocolic resection for CD, in addition to evident cosmetic advantages. On the other hand, the current evidence on laparoscopic surgery for UC does not support its routine use among nonexpert surgeons outside of specialized centers. Laparoscopic colonic resection for diverticular disease appears to provide several short-term benefits, although these advantages may not translate to cases of complicated diverticulitis. Despite the increasing acceptability of minimally invasive methods for the management of benign and malignant colonic pathologies, laparoscopic colon resection remains a prohibitively difficult technique to master. Numerous technological innovations have been introduced onto the market in an effort to decrease the steep learning
Paniagua, E; Paramá, A; Iglesias, R; Sanmartín, M L; Leiro, J
We analysed the influence of various bacteria on the in vitro growth of trophozoites of a Platyamoeba strain isolated from diseased gill tissues of cultured turbot. Little or no growth was shown by amoebae cultured in the presence of (1) the turbot-pathogenic bacteria Vibrio anguillarum, Aeromonas salmonicida or Streptococcus sp., (2) Pasteurella piscicida or Vibrio vulnificus (pathogenic for some fishes but not turbot), or (3) the non-pathogenic 'environmental' bacteria Vibrio campbelli, Vibrio fluvialis or Pseudomonas dondorofii. The only bacteria which were successfully utilized as food sources were Aeromonas hydrophila (pathogenic for some fishes but not turbot) and the non-pathogens Vibrio natriegens, Pseudomonas nautica and Escherichia coli. These results suggest that the colonization of the gills of cultured turbot by the epizoic amoeba Platyamoeba may be an indicator of faecal contamination.
Rodríguez, Juan M
Human milk is a source of bacteria to the infant gut; however, the origin of milk bacteria, as well as their impact on neonatal gut microbiota establishment, remains largely unknown. In the past years, results provided by different research groups suggest that certain bacteria from the maternal gastrointestinal tract could translocate through a mechanism involving mononuclear immune cells, migrate to the mammary glands via an endogenous cellular route (the bacterial entero-mammary pathway), and subsequently colonize the gastrointestinal tract of the breast-fed neonate. If such findings are confirmed in the future, we could exert a positive influence on infant health by modulating the maternal gut microbiota.
Soto-Rodriguez, S A; Simões, N; Jones, D A; Roque, A; Gomez-Gil, B
Available methods to study crustacean digestive tract colonization by bacteria are laborious, time-consuming, and do not permit in vivo assays and observation. This paper reports on a rapid and consistent technique to apply a fluorescent label to bacteria, which can then be presented to filter-feeding crustacea such as Artemia and penaeid larvae for later in situ bacterial distribution observation. Three luminescent Vibrio spp. were stained and observed inside Artemia nauplii, shrimp zoea and mysis stages, Vibrio harveyi type strain ATCC 14126, M(1) (pathogenic) and Ea (non-pathogenic). Factors such as dye (DTAF) concentration, exposure time/temperature and sonication time were evaluated. Viability of the dye and stained bacteria were tested at 4, -20 and -70 degrees C storage temperatures for up to 81 days. Results show that 4 and -20 degrees C storage temperatures are not recommended. At -70 degrees C, both bacteria and dye are optimally preserved. Monodispersed fluorescent-labeled bacterial cells can be observed inside the digestive tract of crustacean larvae at a density of inoculation as high as 5.2 x 10(6) CFU ml(-1). After 2 to 4 h, some leaching occurs, increasing difficulty in observation, although after 24 h, it is still possible to observe monodispersed FLB inside the digestive tract of crustacean larvae. Autofluorescence may complicate observation when filter-feeding crustacean larvae are co-fed with microalgae.
Yang, Qingxiang; Zhang, Hao; Guo, Yuhui; Tian, Tiantian
Animal manure is commonly used as fertilizer for agricultural crops worldwide, even though it is believed to contribute to the spread of antibiotic resistance from animal intestines to the soil environment. However, it is unclear whether and how there is any impact of manure fertilization on populations and community structure of antibiotic-resistant endophytic bacteria (AREB) in plant tissues. To investigate the effect of manure and organic fertilizer on endophytic bacterial communities, pot experiments were performed with pakchoi grown with the following treatments: (1) non-treated; (2) chicken manure-treated and (3) organic fertilizer-treated. Manure or organic fertilizer significantly increased the abundances of total cultivable endophytic bacteria (TCEB) and AREB in pakchoi, and the effect of chicken manure was greater than that of organic fertilizer. Further, 16S rDNA sequencing and the phylogenetic analysis indicated that chicken manure or organic fertilizer application increased the populations of multiple antibiotic-resistant bacteria (MARB) in soil and multiple antibiotic-resistant endophytic bacteria (MAREB) in pakchoi. The identical multiple antibiotic-resistant bacterial populations detected in chicken manure, manure- or organic fertilizer-amended soil and the vegetable endophytic system were Brevundimonas diminuta, Brachybacterium sp. and Bordetella sp., suggesting that MARB from manure could enter and colonize the vegetable tissues through manure fertilization. The fact that some human pathogens with multiple antibiotic resistance were detected in harvested vegetables after growing in manure-amended soil demonstrated a potential threat to human health. PMID:27376311
Banskota, Suhrid; Regmi, Sushil Chandra; Gautam, Jaya; Gurung, Pallavi; Lee, Yu-Jeong; Ku, Sae Kwang; Lee, Jin-Hyung; Lee, Jintae; Chang, Hyeun Wook; Park, Sang Joon; Kim, Jung-Ae
Adherent-invasive E. coli colonization and Toll-like receptor (TLR) expression are increased in the gut of inflammatory bowel disease (IBD) patients. However, the underlying mechanism of such changes has not been determined. In the current study, it was examined whether gut serotonin (5-hydroxytryptamine, 5-HT) can induce adherent-invasive E. coli colonization and increase TLR expression. In a co-culture system, commensal E. coli strain (BW25113, BW) adhered minimally to colon epithelial ce