Publications

TitleAbstractYear(sorted ascending)
Filter
PMID
Filter
bacteriophage receptor binding protein based assays for the simultaneous detection of campylobacter jejuni and campylobacter coli.campylobacter jejuni and campylobacter coli are the most common bacterial causes of foodborne gastroenteritis which is occasionally followed by a debilitating neuropathy known as guillain-barré syndrome. rapid and specific detection of these pathogens is very important for effective control and quick treatment of infection. most of the diagnostics available for these organisms are time consuming and require technical expertise with expensive instruments and reagents to perform. bacteriophages bi ...201323874996
tripping on acid: trans-kingdom perspectives on biological acids in immunity and pathogenesis. 201323874196
infections in children admitted with complicated severe acute malnutrition in niger.although malnutrition affects thousands of children throughout the sahel each year and predisposes them to infections, there is little data on the etiology of infections in these populations. we present a clinical and biological characterization of infections in hospitalized children with complicated severe acute malnutrition (sam) in maradi, niger.201323874731
prevalence of gastrointestinal pathogens in developed and developing countries: systematic review and meta-analysis.diarrhoeal illness is a leading cause of child mortality and morbidity worldwide. there are no precise or current estimates of the types and prevalence of pathogens associated with diarrheal illnesses in developed and developing settings. this systematic review assessed data from 60 studies published in the english language from five developing regions and developed countries worldwide to provide regional estimates of enteric pathogens affecting children. the random-effect method was used to est ...201325170480
contingency nature of helicobacter bizzozeronii oxygen-insensitive nad(p)h-nitroreductase (hbzc1_00960) and its role in metronidazole resistance.genomic analysis of a metronidazole resistant h. bizzozeronii strain revealed a frame length extension of the oxygen-insensitive nad(p)h-nitroreductase hbzc1_00960 (rdxa), associated with the disruption of the c-terminal cysteine-containing conserved region (iaclxalgk). this was the result of the extension (from c8 to c9) of a simple sequence cytosine repeat (sscr) located in the 3' of the gene. a 3' sscr is also present in the rdxa homolog of h. heilmannii sensu stricto, but not in h. pylori. w ...201323865636
gastrointestinal cell lines form polarized epithelia with an adherent mucus layer when cultured in semi-wet interfaces with mechanical stimulation.mucin glycoproteins are secreted in large quantities by mucosal epithelia and cell surface mucins are a prominent feature of the glycocalyx of all mucosal epithelia. currently, studies investigating the gastrointestinal mucosal barrier use either animal experiments or non-in vivo like cell cultures. many pathogens cause different pathology in mice compared to humans and the in vitro cell cultures used are suboptimal because they are very different from an in vivo mucosal surface, are often not p ...201323869232
epithelial toll-like receptor 9 signaling in colorectal inflammation and cancer: clinico-pathogenic aspects.toll-like receptors (tlrs) recognize specific motifs which are frequently present in bacteria, fungi, prokaryotes and viruses. amongst tlrs, tlr9 can be activated by such bacterial or viral dna fragments, immunoglobulin-dna complexes or synthetic oligonucleotides, which all contain unmethylated cytosine-guanine nucleotide sequences (cpgs). emerging data indicate that tlr9 signaling has a role in, and may influence, colorectal carcinogenesis and colonic inflammation. cpgs are classified into thre ...201323864774
dual oxidases control release of hydrogen peroxide by the gastric epithelium to prevent helicobacter felis infection and inflammation in mice.dual oxidases (duox) are conserved reduced nicotinamide adenine dinucleotide phosphate oxidases that produce h2o2 at the epithelial cell surface. the duox enzyme comprises the duox and duox maturation factor (duoxa) subunits. mammalian genomes encode 2 duox isoenzymes (duox1/duoxa1 and duox2/duoxa2). expression of these genes is up-regulated during bacterial infections and chronic inflammatory diseases of the luminal gastrointestinal tract. the roles of duox in cellular interactions with microbe ...201323860501
colonize, evade, flourish: how glyco-conjugates promote virulence of helicobacter pylori.helicobacter pylori is an adapted gastric pathogen that colonizes the human stomach, causing severe gastritis and gastric cancer. a hallmark of infection is the ability of this organism to evade detection by the human immune system. h. pylori has evolved a number of features to achieve this, many of which involve glyco-conjugates including the lipopolysaccharide, peptidoglycan layer, glycoproteins, and glucosylated cholesterol. these major bacterial components possess unique features from those ...201323859890
do antibiotic residues in soils play a role in amplification and transmission of antibiotic resistant bacteria in cattle populations?when we consider factors that contribute to the emergence, amplification, and persistence of antibiotic resistant bacteria, the conventional assumption is that antibiotic use is the primary driver in these processes and that selection occurs primarily in the patient or animal. evidence suggests that this may not always be the case. experimental trials show that parenteral administration of a third-generation cephalosporin (ceftiofur) in cattle has limited or short-term effects on the prevalence ...201323874327
structure and function of the salmonella typhi chimaeric a(2)b(5) typhoid toxin.salmonella enterica serovar typhi (s. typhi) differs from most other salmonellae in that it causes a life-threatening systemic infection known as typhoid fever. the molecular bases for its unique clinical presentation are unknown. here we find that the systemic administration of typhoid toxin, a unique virulence factor of s. typhi, reproduces many of the acute symptoms of typhoid fever in an animal model. we identify specific carbohydrate moieties on specific surface glycoproteins that serve as ...201323842500
lack of homologous protection against campylobacter jejuni cg8421 in a human challenge model.campylobacter jejuni is a common cause of diarrhea and is associated with serious postinfectious sequelae. although symptomatic and asymptomatic infections are recognized, protective immunity is not well understood. previous data suggests that interferon γ (ifn-γ) may be associated with protection. to better define the clinical and immunologic development of protective immunity to c. jejuni, we assessed the ability of an initial infection to prevent clinical illness after a second experimental i ...201323840001
human health risk assessment (hhra) for environmental development and transfer of antibiotic resistance.only recently has the environment been clearly implicated in the risk of antibiotic resistance to clinical outcome, but to date there have been few documented approaches to formally assess these risks.201323838256
of energy and survival incognito: a relationship between viable but non-culturable cells formation and inorganic polyphosphate and formate metabolism in campylobacter jejuni.campylobacter jejuni is a gram-negative food-borne bacterium that can cause mild to serious diseases in humans. a variety of stress conditions including exposure to formic acid, a weak organic acid, can cause c. jejuni to form viable but non-culturable cells (vbnc), which was proposed as a potential survival mechanism. the inability to detect c. jejuni vbnc using standard culturing techniques may increase the risk of exposure to foods contaminated with this pathogen. however, little is known abo ...201323847606
neutrophil activation by campylobacter concisus.campylobacter concisus is an emerging enteric pathogen associated with prolonged diarrhoea and possibly inflammatory bowel disease in children as well as adults, but the interaction with cells of the innate immune system is unclear. the magnitude of systemic immunoglobulin response in acute infection is unknown.201323819746
photodynamic inactivation of biofilm: taking a lightly colored approach to stubborn infection.microbial biofilms are responsible for a variety of microbial infections in different parts of the body, such as urinary tract infections, catheter infections, middle-ear infections, gingivitis, caries, periodontitis, orthopedic implants, and so on. the microbial biofilm cells have properties and gene expression patterns distinct from planktonic cells, including phenotypic variations in enzymic activity, cell wall composition and surface structure, which increase the resistance to antibiotics an ...201323879608
common variable immunodeficiency.common variable immunodeficiency (cvid) is a common primary immunodeficiency characterized by a failure in b-cell differentiation with defective immunoglobulin production. affected patients are uniquely susceptible to recurrent infection with encapsulated organisms and have an increased propensity for the development of inflammatory and autoimmune manifestations. the diagnosis of cvid is commonly delayed and the underlying cause of the disorder is not understood. replacement antibody therapy red ...201323883805
commentary. 201324250177
gut feelings: bacteria and the brain. 201324116266
reactive arthritis induced by bacterial vaginosis: prevention with an effective treatment.we report a 42-year-old woman with reactive arthritis induced by bacterial vaginosis who presented with oligoarthritis with an additive form, arthralgia, and enthesitis. she hasn't had a history of diarrhea or dysuria or vaginal secretion, or sexually transmitted infections (stis). the laboratory tests were normal except for a high erythrocyte sedimentation rate (esr). her pelvic examination revealed homogeneous white grey and malodorous vaginal discharge on the vaginal wall and pap smear and gr ...201324049604
clinical application of volatile organic compound analysis for detecting infectious diseases.this review article introduces the significance of testing of volatile organic compounds (vocs) in clinical samples and summarizes important features of some of the technologies. compared to other human diseases such as cancer, studies on voc analysis in cases of infectious diseases are limited. here, we have described results of studies which have used some of the appropriate technologies to evaluate voc biomarkers and biomarker profiles associated with infections. the publications reviewed inc ...201323824368
genome-wide association study identifies vitamin b5 biosynthesis as a host specificity factor in campylobacter.genome-wide association studies have the potential to identify causal genetic factors underlying important phenotypes but have rarely been performed in bacteria. we present an association mapping method that takes into account the clonal population structure of bacteria and is applicable to both core and accessory genome variation. campylobacter is a common cause of human gastroenteritis as a consequence of its proliferation in multiple farm animal species and its transmission via contaminated m ...201323818615
campylobacter jejuni in hospitalized patients with diarrhea, kolkata, india. 201323763834
crystal structure of the c-terminal globular domain of the third paralog of the archaeoglobus fulgidus oligosaccharyltransferases.protein n-glycosylation occurs in the three domains of life. oligosaccharyltransferase (ost) transfers an oligosaccharide chain to the asparagine residue in the n-glycosylation sequons. the catalytic subunits of the ost enzyme are stt3 in eukaryotes, aglb in archaea and pglb in eubacteria. the genome of a hyperthermophilic archaeon, archaeoglobus fulgidus, encodes three paralogous aglb proteins. we previously solved the crystal structures of the c-terminal globular domains of two paralogs, aglb- ...201323815857
the dot/icm effector sdha is necessary for virulence of legionella pneumophila in galleria mellonella and a/j mice.legionella pneumophila is an intracellular bacterium that resides within amoebae and macrophages in a specialized compartment termed the legionella-containing vacuole (lcv). as well as providing an intracellular niche for replication, the lcv helps to prevent the release of bacterial components into the cytoplasm. recognition of these components as danger signals by the host activates immune responses leading to clearance of the bacterium. here, we examined the role of two important virulence fa ...201323649096
enumeration of salmonella and campylobacter spp. in environmental farm samples and processing plant carcass rinses from commercial broiler chicken flocks.a prospective cohort study was performed to evaluate the prevalences and loads of salmonella and campylobacter spp. in farm and processing plant samples collected from 55 commercial broiler chicken flocks. environmental samples were collected from broiler houses within 48 h before slaughter, and carcass rinses were performed on birds from the same flocks at 4 different stages of processing. salmonella was detected in farm samples of 50 (90.9%) flocks and in processing samples of 52 (94.5%) flock ...201323624481
role of the gut microbiota in health and chronic gastrointestinal disease: understanding a hidden metabolic organ.the human gut microbiota has become the subject of extensive research in recent years and our knowledge of the resident species and their potential functional capacity is rapidly growing. our gut harbours a complex community of over 100 trillion microbial cells which influence human physiology, metabolism, nutrition and immune function while disruption to the gut microbiota has been linked with gastrointestinal conditions such as inflammatory bowel disease and obesity. here, we review the many s ...201323814609
antimicrobial resistance in the food chain: a review.antimicrobial resistant zoonotic pathogens present on food constitute a direct risk to public health. antimicrobial resistance genes in commensal or pathogenic strains form an indirect risk to public health, as they increase the gene pool from which pathogenic bacteria can pick up resistance traits. food can be contaminated with antimicrobial resistant bacteria and/or antimicrobial resistance genes in several ways. a first way is the presence of antibiotic resistant bacteria on food selected by ...201323812024
global distribution of campylobacter jejuni penner serotypes: a systematic review.penner serotyping has been the principal method for differentiating campylobacter isolates since its inception. campylobacter capsule polysaccharide (cps), the principal serodeterminant on which penner serotyping is based, is presently of interest as a vaccine component. to determine the required valency of an effective cps-based vaccine, a comprehensive understanding of cps distribution is needed. because of the association between penner serotype and cps, we conducted a systematic review to es ...201323826280
comparative genomics reveal that host-innate immune responses influence the clinical prevalence of legionella pneumophila serogroups.legionella pneumophila is the primary etiologic agent of legionellosis, a potentially fatal respiratory illness. amongst the sixteen described l. pneumophila serogroups, a majority of the clinical infections diagnosed using standard methods are serogroup 1 (sg1). this high clinical prevalence of sg1 is hypothesized to be linked to environmental specific advantages and/or to increased virulence of strains belonging to sg1. the genetic determinants for this prevalence remain unknown primarily due ...201323826259
guillain-barré syndrome, influenza vaccination, and antecedent respiratory and gastrointestinal infections: a case-centered analysis in the vaccine safety datalink, 2009-2011.guillain-barré syndrome (gbs) can be triggered by gastrointestinal or respiratory infections, including influenza. during the 2009 influenza a (h1n1) pandemic in the united states, monovalent inactivated influenza vaccine (miv) availability coincided with high rates of wildtype influenza infections. several prior studies suggested an elevated gbs risk following miv, but adjustment for antecedent infection was limited.201323840621
bacteria in the nose of young adults during wellness and rhinovirus colds: detection by culture and microarray methods in 100 nasal lavage specimens.patients  with  viral respiratory infections/viral rhinitis/common colds are often treated with antibiotic; however, there is little information on whether or how bacterial microbiota in the nose and nasopharynx might influence the course of viral illnesses.201323801660
rapid detection and simultaneous genotyping of cronobacter spp. (formerly enterobacter sakazakii) in powdered infant formula using real-time pcr and high resolution melting (hrm) analysis.cronobacter spp. is an emerging pathogen that causes meningitis, sepsis, bacteremia, and necrotizing enterocolitis in neonates and children. the present study developed an assay integrating real-time pcr and high resolution melting (hrm) analysis targeting the ompa gene for the specific detection and rapid identification of cronobacter spp. (formerly enterobacter sakazakii) in powdered infant formula. eleven cronobacter field isolates and 25 reference strains were examined using one pair of prim ...201323825624
antimicrobial resistance mechanisms among campylobacter.campylobacter jejuni and campylobacter coli are recognized as the most common causative agents of bacterial gastroenteritis in the world. humans most often become infected by ingesting contaminated food, especially undercooked chicken, but also other sources of bacteria have been described. campylobacteriosis is normally a self-limiting disease. antimicrobial treatment is needed only in patients with more severe disease and in those who are immunologically compromised. the most common antimicrob ...201323865047
shelf life and storage stability of spray-dried bovine colostrum powders under different storage conditions.spray dried bovine colostrum (sdbc) powders were packaged in aluminium-laminated polyethylene (alpe) and polyethylene terephthalate (pet) pouches and then stored under different conditions (25 °c and 50 % relative humidity (rh), 4 °c and 40-70 % rh, 50 °c and 20-50 % rh). the shelf life of sdbc powder was evaluated as 425.5 and 86.5 days in alpe and pet pouches under 25 °c and 50 % rh, respectively. the storage stability of sdbc powder in terms of quality parameters including thiobarbituric acid ...201325694704
shelf life and storage stability of spray-dried bovine colostrum powders under different storage conditions.spray dried bovine colostrum (sdbc) powders were packaged in aluminium-laminated polyethylene (alpe) and polyethylene terephthalate (pet) pouches and then stored under different conditions (25 °c and 50 % relative humidity (rh), 4 °c and 40-70 % rh, 50 °c and 20-50 % rh). the shelf life of sdbc powder was evaluated as 425.5 and 86.5 days in alpe and pet pouches under 25 °c and 50 % rh, respectively. the storage stability of sdbc powder in terms of quality parameters including thiobarbituric acid ...201325694704
aggregatibacter actinomycetemcomitans leukotoxin utilizes a cholesterol recognition/amino acid consensus site for membrane association.aggregatibacter actinomycetemcomitans produces a repeats-in-toxin (rtx) leukotoxin (ltxa) that selectively kills human immune cells. binding of ltxa to its β2 integrin receptor (lymphocyte function-associated antigen-1 (lfa-1)) results in the clustering of the toxin·receptor complex in lipid rafts. clustering occurs only in the presence of lfa-1 and cholesterol, and ltxa is unable to kill cells lacking either lfa-1 or cholesterol. here, the interaction of ltxa with cholesterol was measured using ...201323792963
extreme genetic fragility of the hiv-1 capsid.genetic robustness, or fragility, is defined as the ability, or lack thereof, of a biological entity to maintain function in the face of mutations. viruses that replicate via rna intermediates exhibit high mutation rates, and robustness should be particularly advantageous to them. the capsid (ca) domain of the hiv-1 gag protein is under strong pressure to conserve functional roles in viral assembly, maturation, uncoating, and nuclear import. however, ca is also under strong immunological pressur ...201323818857
dynamics of fecal microbial communities in children with diarrhea of unknown etiology and genomic analysis of associated streptococcus lutetiensis.the sequences of the 16s rrna genes extracted from fecal samples provide insights into the dynamics of fecal microflora. this potentially gives valuable etiological information for patients whose conditions have been ascribed to unknown pathogens, which cannot be accomplished using routine culture methods. we studied 33 children with diarrhea who were admitted to the children's hospital in shanxi province during 2006.201323782707
fluorescent probes for investigation of isoprenoid configuration and size discrimination by bactoprenol-utilizing enzymes.undecaprenyl pyrophosphate synthase (upps) is an enzyme critical to the production of complex polysaccharides in bacteria, as it produces the crucial bactoprenol scaffold on which these materials are assembled. methods to characterize the systems associated with polysaccharide production are non-trivial, in part due to the lack of chemical tools to investigate their assembly. in this report, we develop a new fluorescent tool using upps to incorporate a powerful fluorescent anthranilamide moiety ...201323816045
adaptive mechanisms of campylobacter jejuni to erythromycin treatment.macrolide is the drug of choice to treat human campylobacteriosis, but campylobacter resistance to this antibiotic is rising. the mechanisms employed by campylobacter jejuni to adapt to erythromycin treatment remain unknown and are examined in this study. the transcriptomic response of c. jejuni nctc 11168 to erythromycin (ery) treatment was determined by competitive microarray hybridizations. representative genes identified to be differentially expressed were further characterized by constructi ...201323767761
targeted identification of glycosylated proteins in the gastric pathogen helicobacter pylori (hp).virulence of the gastric pathogen helicobacter pylori (hp) is directly linked to the pathogen's ability to glycosylate proteins; for example, hp flagellin proteins are heavily glycosylated with the unusual nine-carbon sugar pseudaminic acid, and this modification is absolutely essential for hp to synthesize functional flagella and colonize the host's stomach. although hp's glycans are linked to pathogenesis, hp's glycome remains poorly understood; only the two flagellin glycoproteins have been f ...201323754784
massive lower gastrointestinal haemorrhage in a teenager caused by campylobacter enteritis.a 14-year-old boy presented with a very unusual complication of massive lower gastrointestinal bleeding mimicking bleeding from meckel's diverticulum who needed blood transfusions and required mini-exploration. he was found to have campylobacter enteritis with bleeding from multiple mucosal ulcers in the ileocaecal region, which is presented with a review of the literature.201323771973
combination of aidp and pyramidal signs associated with antecedent hepatitis a infection: a rare (co)occurrence.guillain-barré syndrome (gbs) is a postinfectious illness and commonly occurs in association with infective agents such as campylobacter jejuni, cytomegalovirus, epstein-barr virus, mycoplasma pneumoniae, hiv, shigella, clostridium, haemophilus influenzae; occasionally with acute hepatitis b, c, e; and more rarely with hepatitis a, as documented in various case reports. classically, gbs presents with hyporeflexia or areflexia, but preserved and brisk reflexes have been described in context with ...201323761608
the mycobacterium tuberculosis secreted protein rv0203 transfers heme to membrane proteins mmpl3 and mmpl11.mycobacterium tuberculosis is the causative agent of tuberculosis, which is becoming an increasingly global public health problem due to the rise of drug-resistant strains. while residing in the human host, m. tuberculosis needs to acquire iron for its survival. m. tuberculosis has two iron uptake mechanisms, one that utilizes non-heme iron and another that taps into the vast host heme-iron pool. to date, proteins known to be involved in mycobacterial heme uptake are rv0203, mmpl3, and mmpl11. w ...201323760277
shiga toxin-producing escherichia coli in yaks (bos grunniens) from the qinghai-tibetan plateau, china.shiga toxin (stx)-producing escherichia coli (stec) are recognized as important human pathogens of public health concern. many animals are the sources of stec. in this study we determined the occurrence and characteristics of the stec in yaks (bos grunniens) from the qinghai-tibetan plateau, china. a total of 728 yak fecal samples was collected from june to august, 2012 and was screened for the presence of the stx 1 and stx 2 genes by taqman real-time pcr after the sample was enriched in modifie ...201323776496
random and site-specific mutagenesis of the helicobacter pylori ferric uptake regulator provides insight into fur structure-function relationships.the ferric uptake regulator (fur) of helicobacter pylori is a global regulator that is important for colonization and survival within the gastric mucosa. h. pylori fur is unique in its ability to activate and repress gene expression in both the iron-bound (fe-fur) and apo forms (apo-fur). in the current study we combined random and site-specific mutagenesis to identify amino acid residues important for both fe-fur and apo-fur function. we identified 25 mutations that affected fe-fur repression a ...201323710935
characterization of putative cholesterol recognition/interaction amino acid consensus-like motif of campylobacter jejuni cytolethal distending toxin c.cytolethal distending toxin (cdt) produced by campylobacter jejuni comprises a heterotrimeric complex formed by cdta, cdtb, and cdtc. among these toxin subunits, cdta and cdtc function as essential proteins that mediate toxin binding to cytoplasmic membranes followed by delivery of cdtb into the nucleus. the binding of cdta/cdtc to the cell surface is mediated by cholesterol, a major component in lipid rafts. although the putative cholesterol recognition/interaction amino acid consensus (crac) d ...201323762481
phage biocontrol of enteropathogenic and shiga toxin-producing escherichia coli in meat products.ten bacteriophages were isolated from faeces and their lytic effects assayed on 103 pathogenic and non-pathogenic enterobacteriaceae. two phages (dt1 and dt6) were selected based on their host ranges, and their lytic effects on pathogenic e. coli strains inoculated on pieces of beef were determined. we evaluated the reductions of viable cells of escherichia coli o157:h7 and non-o157 shiga toxigenic e. coli strains on meat after exposure to dt6 at 5 and 24°c for 3, 6, and 24 h and the effect of b ...201323761050
real-time polymerase chain reaction for detection of strongyloides stercoralis in stool.the use of real-time polymerase chain reaction (pcr) for detection of strongyloides stercoralis in stool has recently been described. we compared five dna extraction methods by using normal human stool spiked with strongyloides ratti and tested by using a real-time pcr. the powersoil kit was found to be the best technique in terms of sensitivity and ease of use. the pcr detected dna extracted from one spiked s. ratti larva diluted 10⁻². the powersoil kit was then used to extract dna from 160 hum ...201323568289
biosynthesis of udp-n,n'-diacetylbacillosamine in acinetobacter baumannii: biochemical characterization and correlation to existing pathways.the gram-negative, opportunistic pathogen acinetobacter baumannii has recently captured headlines due to its ability to circumvent current antibiotic therapies. herein we show that the multi-drug resistant (mdr) aye strain of a. baumannii contains a gene locus that encodes three enzymes responsible for the biosynthesis of the highly-modified bacterial nucleotide sugar, udp-n,n'-diacetylbacillosamine (udp-dinacbac). previously, this udp-sugar has been implicated in the pgl pathway of campylobacte ...201323747578
streptococcus pneumoniae serotype 11d has a bispecific glycosyltransferase and expresses two different capsular polysaccharide repeating units.streptococcus pneumoniae (pneumococcus) expresses a capsular polysaccharide (cps) that protects against host immunity and is synthesized by enzymes in the capsular polysaccharide synthesis (cps) locus. serogroup 11 has six members (11a to -e) and the cps structure of all members has been solved, except for serotype 11d. the cps loci of 11a and 11d differ by one codon (n112s) in wcrl, which putatively encodes a glycosyltransferase that adds the fourth sugar of the cps repeating unit (ru). gas chr ...201323737526
relapsing campylobacter jejuni systemic infections in a child with x-linked agammaglobulinemia.x-linked agammaglobulinemia (xla) is a primary immunodeficiency of the humoral compartment, due to a mutation in the bruton tyrosine kinase (btk) gene, characterized by a severe defect of circulating b cells and serum immunoglobulins. recurrent infections are the main clinical manifestations; although they are especially due to encapsulated bacteria, a specific association with campylobacter species has been reported. here, we report the case of a boy with xla who presented with relapsing campyl ...201323862092
validation of drop plate technique for bacterial enumeration by parametric and nonparametric tests.drop plate technique has a priority and preference compared with the spread plate procedure, because of less time, quantity of media, effort requirement, little incubator space, and less labor intensive. the objective of this research was to compare the accuracy and fidelity of drop plate method vs. spread plate method by parametric and nonparametric statistical tests. for bacterial enumeration by drop and spread plate methods, successive dilutions of second subculture of lactobacillus casei and ...201325653794
application of zataria multiflora boiss. and cinnamon zeylanicum essential oils as two natural preservatives in cake.oxidation of oils has an important effect on nutritional and organoleptic properties of foodstuffs. nowadays, new tendency has created a necessity to use natural compounds such as essential oils for producing functional foods. in this study, antioxidant, antifungal, and organoleptic properties of zataria multiflora boiss. (zmeo) and cinnamon zeylanicum essential oils (czeo) have been checked as two natural preservatives in the cakes.201325050280
the ferric uptake regulator of helicobacter pylori: a critical player in the battle for iron and colonization of the stomach.helicobacter pylori is arguably one of the most successful pathogens; it colonizes the stomachs of more than half of the human population. colonization and persistence in such an inhospitable niche requires the presence of exquisite adaptive mechanisms. one of the proteins that contributes significantly to the remarkable adaptability of h. pylori is the ferric uptake regulator (fur), which functions as a master regulator of gene expression. in addition to genes directly related to iron homeostas ...201323701330
detection of non-jejuni and -coli campylobacter species from stool specimens with an immunochromatographic antigen detection assay.the stat! campy immunochromatographic assay for campylobacter antigen was compared to culture for 500 clinical stool specimens. antigen was detected in six culture-negative, pcr-positive specimens. c. upsaliensis, a pathogenic species that is traditionally difficult to recover in routine stool cultures, was detected in two of these culture-negative specimens. this study provides evidence that antigen testing may cross-react with at least one additional non-jejuni and -coli campylobacter species ...201323554192
microbiological diagnosis of severe diarrhea in kidney transplant recipients by use of multiplex pcr assays.diarrhea is a frequent complication after kidney transplantation, ascribed to adverse effects of the immunosuppressive therapy in case of negative microbiological examination of the stools. the aim of this study was to improve the microbiological diagnosis by implementing molecular tests. fifty-four severe diarrhea events that occurred in 49 adult kidney transplant recipients from september 2010 to november 2011 were investigated. one or several enteric pathogens were detected in 13 (23%) stool ...201323554205
enhanced, sialoadhesin-dependent uptake of guillain-barre syndrome-associated campylobacter jejuni strains by human macrophages.molecular mimicry between campylobacter jejuni sialylated lipooligosaccharides (los) and human nerve gangliosides can trigger the production of cross-reactive antibodies which induce guillain-barré syndrome (gbs). to better understand the immune events leading to gbs, it is essential to know how sialylated los are recognized by the immune system. here, we show that gbs-associated c. jejuni strains bind to human sialoadhesin (hsn), a conserved, mainly macrophage-restricted i-type lectin. using hs ...201323529622
comparison of genotypes and antibiotic resistances of campylobacter jejuni and campylobacter coli on chicken retail meat and at slaughter.multilocus sequence typing (mlst) and antibiotic resistance patterns of campylobacter jejuni and campylobacter coli from retail chicken meat showed high overlap with isolates collected at slaughterhouses, indicating little selection along the production chain. they also showed significant common sequence types with human clinical isolates, revealing chicken meat as a likely source for human infection.201323584778
molecular detection of campylobacter spp. and fecal indicator bacteria during the northern migration of sandhill cranes (grus canadensis) at the central platte river.the risk to human health of the annual sandhill crane (grus canadensis) migration through nebraska, which is thought to be a major source of fecal pollution of the central platte river, is unknown. to better understand potential risks, the presence of campylobacter species and three fecal indicator bacterial groups (enterococcus spp., escherichia coli, and bacteroidetes) was assayed by pcr from crane excreta and water samples collected during their stopover at the platte river, nebraska, in 2010 ...201323584775
guillain-barre syndrome as a paraneoplastic manifestation of disseminated squamous cell carcinoma.we describe a 65-year-old woman who developed ascending, symmetrical paraesthesia and weakness. this was on a background of metastatic disseminated squamous cell carcinoma, with a likely recurrent mandibular primary. serum testing for antiganglioside antibodies was strongly positive. despite a 5-day course of intravenous immunoglobulin, the patient passed away on day 34 of admission. this is the first case, to our knowledge, of guillain-barré syndrome in association with squamous cell carcimoma.201323729714
claudins in intestines: distribution and functional significance in health and diseases.intestines are organs that not only digest food and absorb nutrients, but also provide a defense barrier against pathogens and noxious agents ingested. tight junctions (tjs) are the most apical component of the junctional complex, providing one form of cell-cell adhesion in enterocytes and playing a critical role in regulating paracellular barrier permeability. alteration of tjs leads to a number of pathophysiological diseases causing malabsorption of nutrition and intestinal structure disruptio ...201324478939
identification of a functional type vi secretion system in campylobacter jejuni conferring capsule polysaccharide sensitive cytotoxicity.the pathogen campylobacter jejuni is the principal cause of bacterial food-borne infections. the mechanism(s) that contribute to bacterial survival and disease are still poorly understood. in other bacterial species, type vi secretion systems (t6ss) are increasingly recognized to contribute to bacterial pathogenesis by toxic effects on host cells or competing bacterial species. here we report the presence of a functional type vi secretion system in c. jejuni. proteome and genetic analyses reveal ...201323737749
the antibiotic resistance "mobilome": searching for the link between environment and clinic.antibiotic resistance is an ancient problem, owing to the co-evolution of antibiotic-producing and target organisms in the soil and other environments over millennia. the environmental "resistome" is the collection of all genes that directly or indirectly contribute to antibiotic resistance. many of these resistance determinants originate in antibiotic-producing organisms (where they serve to mediate self-immunity), while others become resistance determinants only when mobilized and over-express ...201323755047
elucidating the aetiology of human campylobacter coli infections.there has been little research on the determinants of campylobacter coli infection, despite its contributing up to 10% of human campylobacter infections. a case-control and two case-case study methods explored the aetiology of c. coli over a one year period across scotland. the case-control multivariate model found an increased risk of c. coli infection in people older than 19 years (o.r. = 3.352), and during the summer months (o.r. = 2.596), while residing in an urban area decreased the risk (o ...201323734204
rapid identification of novel immunodominant proteins and characterization of a specific linear epitope of campylobacter jejuni.campylobacter jejuni remains one of the major gut pathogens of our time. its zoonotic nature and wide-spread distribution in industrialized countries calls for a quick and reliable diagnostic tool. antibody-based detection presents a suitable means to identify pathogenic bacteria. however, the knowledge about immunodominant targets is limited. thus, an approach is presented, which allows for the rapid screening of numerous cdna derived expression clones to identify novel antigens. the deeper und ...201323734261
campylobacteriosis outbreak associated with consumption of undercooked chicken liver pâté in the east of england, september 2011: identification of a dose-response risk.a foodborne outbreak with 49 cases (22 culture positive for campylobacter sp.) following a wedding party in the east of england was investigated. a retrospective cohort study identified an association between consumption of chicken liver pâté and infection with campylobacter jejuni/coli. there was a statistically significant association between dose (amount of chicken liver pâté eaten) and the risk of disease ['tasted': odds ratio (or) 1·5, 95% confidence interval (ci) 0·04-∞; 'partly eaten': or ...201323711104
campylobacteriosis outbreak associated with consumption of undercooked chicken liver pâté in the east of england, september 2011: identification of a dose-response risk.a foodborne outbreak with 49 cases (22 culture positive for campylobacter sp.) following a wedding party in the east of england was investigated. a retrospective cohort study identified an association between consumption of chicken liver pâté and infection with campylobacter jejuni/coli. there was a statistically significant association between dose (amount of chicken liver pâté eaten) and the risk of disease ['tasted': odds ratio (or) 1·5, 95% confidence interval (ci) 0·04-∞; 'partly eaten': or ...201323711104
a refined palate: bacterial consumption of host glycans in the gut.the human intestine houses a dense microbial ecosystem in which the struggle for nutrients creates a continual and dynamic selective force. host-produced mucus glycans provide a ubiquitous source of carbon and energy for microbial species. not surprisingly, many gut resident bacteria have become highly adapted to efficiently consume numerous distinct structures present in host glycans. we propose that sophistication in mucus consumption is a trait most likely to be found in gut residents that ha ...201323720460
quorum-sensing autoinducers resuscitate dormant vibrio cholerae in environmental water samples.cholera epidemics have long been known to spread through water contaminated with human fecal material containing the toxigenic bacterium vibrio cholerae. however, detection of v. cholerae in water is complicated by the existence of a dormant state in which the organism remains viable, but resists cultivation on routine bacteriological media. growth in the mammalian intestine has been reported to trigger "resuscitation" of such dormant cells, and these studies have prompted the search for resusci ...201323716683
antibody to a conserved antigenic target is protective against diverse prokaryotic and eukaryotic pathogens.microbial capsular antigens are effective vaccines but are chemically and immunologically diverse, resulting in a major barrier to their use against multiple pathogens. a β-(1→6)-linked poly-n-acetyl-d-glucosamine (pnag) surface capsule is synthesized by four proteins encoded in genetic loci designated intercellular adhesion in staphylococcus aureus or polyglucosamine in selected gram-negative bacterial pathogens. we report that many microbial pathogens lacking an identifiable intercellular adhe ...201323716675
systemic use of fluoroquinolone in children.fluoroquinolones are an important class of antibiotics that are widely used in adult patients because of their broad spectrum of activity, good tissue penetration, and oral bioavailability. however, fluoroquinolone use in children is limited because juvenile animals developed arthropathy in previous experiments on fluoroquinolone use. indications for fluoroquinolone use in patients younger than 18 years, as stated by the u.s. food and drug administration, include treatment of complicated urinary ...201323741232
implications of lymphocyte anergy to glycolipids in multiple sclerosis (ms): inkt cells may mediate the ms infectious trigger.immunogenic lipids may play key roles in host defenses against infection and in generating autoimmune inflammation and organ-specific damage. in multiple sclerosis (ms) there are unequivocal autoimmune features and vulnerability to aggravation or induction by microbial or viral infection. we have found glycolipid-driven anergy of circulating lymphocytes in ms indicating that this immune response is affected in ms and the robust effects of inkt activation with potent cellular and cytokine activit ...201326347308
igg subclass antibodies to human and bacterial hsp60 are not associated with disease activity and progression over time in axial spondyloarthritis.spondyloarthritis (spa), an interrelated group of rheumatic diseases, has been suggested to be triggered by bacterial infections prior to the development of an autoimmune response that causes inflammation of the spinal and peripheral joints. because human heat shock protein 60 (hsp60), recently renamed hspd1, and bacterial hsp60 are highly homologous, immunological cross-reactivity has been proposed as a mechanism of disease initiation. however, previous investigations of the humoral immune resp ...201323705835
expression, crystallization and preliminary crystallographic study of glub from corynebacterium glutamicum.glub is a substrate-binding protein (sbp) which participates in the uptake of glutamic acid in corynebacterium glutamicum, a gram-positive bacterium. it is part of an atp-binding cassette (abc) transporter system. together with the transmembrane proteins gluc and glud and the cytoplasmic protein glua, which couples the hydrolysis of atp to the translocation of glutamate, they form a highly active glutamate-uptake system. as part of efforts to study the amino-acid metabolism, especially the metab ...201323722846
alternative substrates selective for s-adenosylmethionine synthetases from pathogenic bacteria.s-adenosyl-l-methionine (adomet) synthetase catalyzes the production of adomet, the major biological methyl donor and source of methylene, amino, ribosyl, and aminopropyl groups in the metabolism of all known organism. in addition to these essential functions, adomet can also serve as the precursor for two different families of quorum sensing molecules that trigger virulence in gram-negative human pathogenic bacteria. the enzyme responsible for adomet biosynthesis has been cloned, expressed and ...201323711747
genome sequences of the guillain-barre syndrome outbreak-associated campylobacter jejuni strains icdccj07002 and icdccj07004.the first world-known and largest outbreak of 36 cases of guillain-barré syndrome caused by a preceding campylobacter jejuni infection was reported previously in china. during the outbreak, campylobacter jejuni strain icdccj07002 was isolated from a patient with persistent diarrhea for 21 days, and c. jejuni strain icdccj07004 was from a healthy carrier without any clinical symptoms at the same time. here, we report the draft genome sequence of strain icdccj07002 (1,698,407 bp, with a g+c conten ...201323704181
genetic mechanisms of antimicrobial resistance identified in salmonella enterica, escherichia coli, and enteroccocus spp. isolated from u.s. food animals.the prevalence of antimicrobial resistance (ar) in bacteria isolated from u.s. food animals has increased over the last several decades as have concerns of ar foodborne zoonotic human infections. resistance mechanisms identified in u.s. animal isolates of salmonella enterica included resistance to aminoglycosides (e.g., alleles of aacc, aada, aadb, ant, apha, and strab), β-lactams (e.g., bla cmy-2, tem-1, pse-1), chloramphenicol (e.g., flor, cmla, cat1, cat2), folate pathway inhibitors (e.g., al ...201323734150
helicobacter pylori seropositivity and cognitive performance among us adults: evidence from a large national survey.helicobacter pylori seropositivity is a potential risk for poor cognition among us adults.201323697465
a higher prevalence rate of campylobacter in retail beef livers compared to other beef and pork meat cuts.the objectives of this study were to determine the prevalence of campylobacter jejuni and campylobacter coli in retail beef, beef livers, and pork meats purchased from the tulsa (ok, usa) area and to further characterize the isolates obtained through antimicrobial susceptibility testing. a total of 97 chilled retail beef (50 beef livers and 47 other cuts), and 100 pork samples were collected. the prevalence of campylobacter in beef livers was 39/50 (78%), while no campylobacter was isolated from ...201323698698
prevalence, associated risk factors and antimicrobial susceptibility pattern of campylobacter species among under five diarrheic children at gondar university hospital, northwest ethiopia.recent reports indicate that campylobacter species are becoming one of the leading causes of bacterial diarrhoeal disease worldwide and most of the isolates are resistant to different antibiotics. this study aimed at determining the prevalence, associated risk factors and susceptibility pattern of campylobacter species in under-five diarrheic children.201323694714
the polyphosphate kinase gene ppk2 is required for mycobacterium tuberculosis inorganic polyphosphate regulation and virulence.the mycobacterium tuberculosis gene rv3232c/mt3329 (ppk2) encodes a class ii polyphosphate kinase, which hydrolyzes inorganic polyphosphate (poly p) to synthesize gtp. we assessed the role of ppk2 in m. tuberculosis poly p regulation, antibiotic tolerance, and virulence. a ppk2-deficient mutant (ppk2::tn) and its isogenic wild-type (wt) and complemented (comp) strains were studied. for each strain, the intrabacillary poly p content, mic of isoniazid, and growth kinetics during infection of j774 ...201323695835
comparison of predicted epimerases and reductases of the campylobacter jejuni d-altro- and l-gluco-heptose synthesis pathways.uniquely modified heptoses found in surface carbohydrates of bacterial pathogens are potential therapeutic targets against such pathogens. our recent biochemical characterization of the gdp-6-deoxy-d-manno- and gdp-6-deoxy-d-altro-heptose biosynthesis pathways has provided the foundation for elucidation of the more complex l-gluco-heptose synthesis pathway of campylobacter jejuni strain nctc 11168. in this work we use gdp-4-keto,6-deoxy-d-lyxo-heptose as a surrogate substrate to characterize thr ...201323689373
zoonoses in pet birds: review and perspectives.pet birds are a not-so-well known veterinarian's clientship fraction. bought individually or in couples, as families often do (which is a lucrative business for pet shops or local breeders) or traded (sometimes illegally) for their very high genetic or exotic value, these birds, commonly canaries, parakeets or parrots, are regularly sold at high prices. these animals, however, are potential carriers and/or transmitters of zoonotic diseases. some of them could have an important impact on human he ...201323687940
co-occurrence of anaerobic bacteria in colorectal carcinomas.numerous cancers have been linked to microorganisms. given that colorectal cancer is a leading cause of cancer deaths and the colon is continuously exposed to a high diversity of microbes, the relationship between gut mucosal microbiome and colorectal cancer needs to be explored. metagenomic studies have shown an association between fusobacterium species and colorectal carcinoma. here, we have extended these studies with deeper sequencing of a much larger number (n = 130) of colorectal carcinoma ...201324450771
comparative genome analysis of an avirulent and two virulent strains of avian pasteurella multocida reveals candidate genes involved in fitness and pathogenicity.pasteurella multocida is the etiologic agent of fowl cholera, a highly contagious and severe disease of poultry causing significant mortality and morbidity throughout the world. all types of poultry are susceptible to fowl cholera. turkeys are most susceptible to the peracute/acute forms of the disease while chickens are most susceptible to the acute and chronic forms of the disease. the whole genome of the pm70 strain of p. multocida was sequenced and annotated in 2001. the pm70 strain is not v ...201323672515
antibodies to glycoproteins shared by human peripheral nerve and campylobacter jejuni in patients with multifocal motor neuropathy.we have tested serum samples from 24 patients with multifocal motor neuropathy (mmn) for reactivity to ganglioside gm1 and to gal( β 1-3)galnac-bearing glycoproteins isolated from human peripheral nerve and from campylobacter jejuni (cj) serotype o:19. igm anti-gm1 antibodies were detected by elisa in 11 patients (45.8%) with mmn and in only one subject (4%) from the control group. western blots showed positive reactivity of sera from 6 patients (25%) with mmn to several gal( β 1-3)galnac-bearin ...201323762534
comprehensive antigen screening identifies moraxella catarrhalis proteins that induce protection in a mouse pulmonary clearance model.moraxella catarrhalis is one of the three most common causative bacterial pathogens of otitis media, however no effective vaccine against m. catarrhalis has been developed so far. to identify m. catarrhalis vaccine candidate antigens, we used carefully selected sera from children with otitis media and healthy individuals to screen small-fragment genomic libraries that are expressed to display frame-selected peptides on a bacterial cell surface. this antigenome technology led to the identificatio ...201323671716
short and long-term genome stability analysis of prokaryotic genomes.gene organization dynamics is actively studied because it provides useful evolutionary information, makes functional annotation easier and often enables to characterize pathogens. there is therefore a strong interest in understanding the variability of this trait and the possible correlations with life-style. two kinds of events affect genome organization: on one hand translocations and recombinations change the relative position of genes shared by two genomes (i.e. the backbone gene order); on ...201323651581
pif1 family helicases suppress genome instability at g-quadruplex motifs.the saccharomyces cerevisiae pif1 helicase is the prototypical member of the pif1 dna helicase family, which is conserved from bacteria to humans. here we show that exceptionally potent g-quadruplex unwinding is conserved among pif1 helicases. moreover, pif1 helicases from organisms separated by more than 3 billion years of evolution suppressed dna damage at g-quadruplex motifs in yeast. the g-quadruplex-induced damage generated in the absence of pif1 helicases led to new genetic and epigenetic ...201323657261
oral immunization with cholera toxin provides protection against campylobacter jejuni in an adult mouse intestinal colonization model.immunity to campylobacter jejuni, a major diarrheal pathogen, is largely penner serotype specific. for broad protection, a vaccine should be based on a common antigen(s) present in all strains. in our previous study (m. j. albert, s. haridas, d. steer, g. s. dhaunsi, a. i. smith, and b. adler, infect. immun. 75:3070-3073, 2007), we demonstrated that antibody to cholera toxin (ct) cross-reacted with the major outer membrane proteins (momps) of all campylobacter jejuni strains tested. in the curre ...201323653448
crystal structure of peroxide stress regulator from streptococcus pyogenes provides functional insights into the mechanism of oxidative stress sensing.regulation of oxidative stress responses by the peroxide stress regulator (perr) is critical for the in vivo fitness and virulence of group a streptococcus. to elucidate the molecular mechanism of dna binding, peroxide sensing, and gene regulation by perr, we performed biochemical and structural characterization of perr. sequence-specific dna binding by perr does not require regulatory metal occupancy. however, metal binding promotes higher affinity perr-dna interactions. perr metallated with ir ...201323645680
identification of bacterial protein o-oligosaccharyltransferases and their glycoprotein substrates.o-glycosylation of proteins in neisseria meningitidis is catalyzed by pgll, which belongs to a protein family including waal o-antigen ligases. we developed two hidden markov models that identify 31 novel candidate pgll homologs in diverse bacterial species, and describe several conserved sequence and structural features. most of these genes are adjacent to possible novel target proteins for glycosylation. we show that in the general glycosylation system of n. meningitidis, efficient glycosylati ...201323658772
neonatal immune adaptation of the gut and its role during infections.the intestinal tract is engaged in a relationship with a dense and complex microbial ecosystem, the microbiota. the establishment of this symbiosis is essential for host physiology, metabolism, and immune homeostasis. because newborns are essentially sterile, the first exposure to microorganisms and environmental endotoxins during the neonatal period is followed by a crucial sequence of active events leading to immune tolerance and homeostasis. contact with potent immunostimulatory molecules sta ...201323737810
exploitation of bacterial n-linked glycosylation to develop a novel recombinant glycoconjugate vaccine against francisella tularensis.glycoconjugate-based vaccines have proved to be effective at producing long-lasting protection against numerous pathogens. here, we describe the application of bacterial protein glycan coupling technology (pgct) to generate a novel recombinant glycoconjugate vaccine. we demonstrate the conjugation of the francisella tularensis o-antigen to the pseudomonas aeruginosa carrier protein exotoxin a using the campylobacter jejuni pglb oligosaccharyltransferase. the resultant recombinant f. tularensis g ...201323697804
assessing the inactivation of mycobacterium avium subsp. paratuberculosis during composting of livestock carcasses.mycobacterium avium subsp. paratuberculosis causes johne's disease (jd) in ruminants, with substantial economic impacts on the cattle industry. johne's disease is known for its long latency period, and difficulties in diagnosis are due to insensitivities of current detection methods. eradication is challenging as m. avium subsp. paratuberculosis can survive for extended periods within the environment, resulting in new infections in naïve animals (w. xu et al., j. environ. qual. 38:437-450, 2009) ...201323503307
genome-wide association analysis of avian resistance to campylobacter jejuni colonization identifies risk locus spanning the cdh13 gene.the enteropathogen campylobacter jejuni is a major worldwide health and economic burden, being one of the leading causes of bacterial gastroenteritis and commonly linked to postinfectious onset of autoimmune disease. chickens are a major vector for human infection and even though variation in avian colonization level is heritable, no previous studies have identified regions of the genome associated with colonization resistance. we performed a genome-wide association study of resistance to c. jej ...201323550144
construction of escherichia coli strains with chromosomally integrated expression cassettes for the synthesis of 2'-fucosyllactose.the trisaccharide 2'-fucosyllactose (2'-fl) is one of the most abundant oligosaccharides found in human milk. due to its prebiotic and anti-infective properties, 2'-fl is discussed as nutritional additive for infant formula. besides chemical synthesis and extraction from human milk, 2'-fl can be produced enzymatically in vitro and in vivo. the most promising approach for a large-scale formation of 2'-fl is the whole cell biosynthesis in escherichia coli by intracellular synthesis of gdp-l-fucose ...201323635327
rna type iii secretion signals that require hfq.salmonella virulence is largely mediated by two type iii secretion systems (t3ss) that deliver effector proteins from the bacterium to a host cell; however, the secretion signal is poorly defined. effector n termini are thought to contain the signal, but they lack homology, possess no identifiable motif, and adopt intrinsically disordered structures. alternative studies suggest that rna-encoded signals may also be recognized and that they can be located in the 5' untranslated leader sequence. we ...201323396917
Refresh
firstprev
...919293949596979899100...
nextlast
Displaying items 9701 - 9800 of 12694