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macrolide- and rifampin-resistant rhodococcus equi on a horse breeding farm, kentucky, usa.macrolide and rifampin resistance developed on a horse breeding farm after widespread use was instituted for treatment of subclinical pulmonary lesions in foals. resistance occurred in 6 (24%) of 25 pretreatment and 8 (62%) of 13 (62%) posttreatment isolates from affected foals. drug-resistant isolates formed 2 distinct genotypic clusters.201323347878
hypothesis: bacteria control host appetites.to help investigate the relationship between inflammatory and other diseases and the composition of the gut microbiota, we propose that a positive-feedback loop exists between the preferences of the host for a particular dietary regimen, the composition of the gut microbiota that depends on this regimen, and the preferences of the host as influenced by the gut microbiota. we cite evidence in support of this hypothesis and make testable predictions.201323144247
intracellularly induced cyclophilins play an important role in stress adaptation and virulence of brucella abortus.brucella is an intracellular bacterial pathogen that causes the worldwide zoonotic disease brucellosis. brucella virulence relies on its ability to transition to an intracellular lifestyle within host cells. thus, this pathogen must sense its intracellular localization and then reprogram gene expression for survival within the host cell. a comparative proteomic investigation was performed to identify differentially expressed proteins potentially relevant for brucella intracellular adaptation. tw ...201323230297
eptc of campylobacter jejuni mediates phenotypes involved in host interactions and virulence.campylobacter jejuni is a natural commensal of the avian intestinal tract. however, the bacterium is also the leading cause of acute bacterial diarrhea worldwide and is implicated in development of guillain-barré syndrome. like many bacterial pathogens, c. jejuni assembles complex surface structures that interface with the surrounding environment and are involved in pathogenesis. recent work in c. jejuni identified a gene encoding a novel phosphoethanolamine (petn) transferase, eptc (cj0256), th ...201323184526
carbon storage regulator a contributes to the virulence of haemophilus ducreyi in humans by multiple mechanisms.the carbon storage regulator a (csra) controls a wide variety of bacterial processes, including metabolism, adherence, stress responses, and virulence. haemophilus ducreyi, the causative agent of chancroid, harbors a homolog of csra. here, we generated an unmarked, in-frame deletion mutant of csra to assess its contribution to h. ducreyi pathogenesis. in human inoculation experiments, the csra mutant was partially attenuated for pustule formation compared to its parent. deletion of csra resulted ...201323230298
general aspects and recent advances on bacterial protein toxins.bacterial pathogens produce protein toxins to influence host-pathogen interactions and tip the outcome of these encounters toward the benefit of the pathogen. protein toxins modify host-specific targets through posttranslational modifications (ptms) or noncovalent interactions that may inhibit or activate host cell physiology to benefit the pathogen. recent advances have identified new ptms and host targets for toxin action. understanding the mechanisms of toxin action provides a basis to develo ...201323378599
do globins in microaerophilic campylobacter jejuni confer nitrosative stress tolerance under oxygen limitation?the microaerophilic pathogen campylobacter jejuni possesses inducible systems for resisting no. two globins--cgb (a single-domain globin) and ctb (a truncated globin)--are up-regulated in response to no via the positively acting transcription factor nssr. our aims were to determine whether these oxygen-binding globins also function in severely oxygen-limited environments, as in the host. at growth-limiting oxygen transfer rates, bacteria were more s-nitrosoglutathione (gsno) sensitive, irrespect ...201322816769
functional dissection of the multi-domain di-heme cytochrome c(550) from thermus thermophilus.in bacteria, oxidation of sulfite to sulfate, the most common strategy for sulfite detoxification, is mainly accomplished by the molybdenum-containing sulfite:acceptor oxidoreductases (sors). bacterial sors are very diverse proteins; they can exist as monomers or homodimers of their core subunit, as well as heterodimers with an additional cytochrome c subunit. we have previously described the homodimeric sor from thermus thermophilus hb8 (sor(tthb8)), identified its physiological electron accept ...201323383080
staphylococcus aureus α-toxin-dependent induction of host cell death by membrane-derived vesicles.staphylococcus aureus causes a wide spectrum of infections in humans, ranging from superficial cutaneous infections, infections in the circum-oral region, to life-threatening bacteremia. it was recently demonstrated that gram-positive organisms such as s. aureus liberate membrane-derived vesicles (mvs), which analogously to outer membrane vesicles (omvs) of gram-negative bacteria can play a role in delivering virulence factors to host cells. in the present study we have shown that cholesterol-de ...201323382935
acta promotes listeria monocytogenes aggregation, intestinal colonization and carriage.listeria monocytogenes (lm) is a ubiquitous bacterium able to survive and thrive within the environment and readily colonizes a wide range of substrates, often as a biofilm. it is also a facultative intracellular pathogen, which actively invades diverse hosts and induces listeriosis. so far, these two complementary facets of lm biology have been studied independently. here we demonstrate that the major lm virulence determinant acta, a prfa-regulated gene product enabling actin polymerization and ...201323382675
recent advances in bacteriophage based biosensors for food-borne pathogen detection.foodborne diseases are a major health concern that can have severe impact on society and can add tremendous financial burden to our health care systems. rapid early detection of food contamination is therefore relevant for the containment of food-borne pathogens. conventional pathogen detection methods, such as microbiological and biochemical identification are time-consuming and laborious, while immunological or nucleic acid-based techniques require extensive sample preparation and are not amen ...201323364199
weakness and the inability to ambulate in a 14-month-old female: a case report and concise review of guillain-barre syndrome.guillain-barre syndrome (gbs) is an acquired disease of the peripheral nervous system which causes demyelination and leads to weakness, ataxia, and areflexia. there are a variety of forms of the syndrome, and although it is found in all age groups, it is rare in children less than two years of age. the present complaint of weakness, ataxia, or lower extremity pain in the pediatric population should cause the practitioner to consider gbs in the differential. we describe a case of a 14-month-old g ...201323431480
chemoreceptors of escherichia coli cft073 play redundant roles in chemotaxis toward urine.community-acquired urinary tract infections (utis) are commonly caused by uropathogenic escherichia coli (upec). we hypothesize that chemotaxis toward ligands present in urine could direct upec into and up the urinary tract. wild-type e. coli cft073 and chemoreceptor mutants with tsr, tar, or aer deletions were tested for chemotaxis toward human urine in the capillary tube assay. wild-type cft073 was attracted toward urine, and tsr and tar were the chemoreceptors mainly responsible for mediating ...201323382874
altered responses to homeostatic cytokines in patients with idiopathic cd4 lymphocytopenia.idiopathic cd4 lymphocytopenia (icl) is a rare immune deficiency characterized by a protracted cd4(+) t cell loss of unknown etiology and by the occurrence of opportunistic infections similar to those seen in aids. we investigated whether a defect in responses to cytokines that control cd4(+) t cell homeostasis could play a role in icl. immunophenotype and signaling responses to interleukin-7 (il-7), il-2, and thymic stromal lymphopoietin (tslp) were analyzed by flow cytometry in cd4(+) t cells ...201323383227
phospholipids in milk fat: composition, biological and technological significance, and analytical strategies.glycerophospholipids and sphingolipids are quantitatively the most important phospholipids (pls) in milk. they are located on the milk fat globule membrane (mfgm) and in other membranous material of the skim milk phase. they include principally phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol and phosphatidylserine, while sphingomyelin is the dominant species of sphingolipids there is considerable evidence that pls have beneficial health effects, such as regulation of the infl ...201323434649
basolateral invasion and trafficking of campylobacter jejuni in polarized epithelial cells.campylobacter jejuni is a major cause of bacterial diarrheal disease. most enteropathogenic bacteria including c. jejuni can invade cultured eukaryotic cells via an actin- and/or microtubule-dependent and an energy-consuming uptake process. recently, we identified a novel highly efficient c. jejuni invasion pathway that involves bacterial migration into the subcellular space of non-polarized epithelial cells (termed subvasion) followed by invasion from the cell basis. here we report cellular req ...201323382959
enhanced surveillance for detection and management of infectious diseases: regional collaboration in the middle east.formed before international negotiations of the revised international health regulations (ihr), the middle east consortium for infectious disease surveillance (mecids) is a regional collaboration aimed at facilitating implementation of the revised ihr and, more broadly, improving the detection and control of infectious disease outbreaks among neighboring countries in an area of continuous dispute. initially focused on enhancing foodborne disease surveillance, mecids has expanded the scope of its ...201323362413
persistent digestive disorders in the tropics: causative infectious pathogens and reference diagnostic tests.persistent digestive disorders account for considerable disease burden in the tropics. despite advances in understanding acute gastrointestinal infections, important issues concerning epidemiology, diagnosis, treatment and control of most persistent digestive symptomatologies remain to be elucidated. helminths and intestinal protozoa are considered to play major roles, but the full extent of the aetiologic spectrum is still unclear. we provide an overview of pathogens causing digestive disorders ...201323347408
a "successful allele" at campylobacter jejuni contingency locus cj0170 regulates motility; "successful alleles" at locus cj0045 are strongly associated with mouse colonization.campylobacter jejuni is an important foodborne pathogen of humans and its primary reservoir is the gastrointestinal (gi) tract of chickens. our previous studies demonstrated that phase variation to specific "successful alleles" at c. jejuni contingency loci cj0045 (successful alleles carry 9g or 10g homopolymeric tracts) and cj0170 (successful allele carries a 10g homopolymeric tract) in c. jejuni populations is strongly associated with colonization and enteritis in c57bl/6 il-10 deficient mice. ...201323541212
distinct distal gut microbiome diversity and composition in healthy children from bangladesh and the united states.our current understanding of the composition and stability of the human distal gut microbiota is based largely on studies of infants and adults living in developed countries. in contrast, little is known about the gut microbiota and its variation over time in older children and adolescents, especially in developing countries.201323349750
cloning, annotation and developmental expression of the chicken intestinal muc2 gene.intestinal mucin 2 (muc2) encodes a heavily glycosylated, gel-forming mucin, which creates an important protective mucosal layer along the gastrointestinal tract in humans and other species. this first line of defense guards against attacks from microorganisms and is integral to the innate immune system. as a first step towards characterizing the innate immune response of muc2 in different species, we report the cloning of a full-length, 11,359 bp chicken muc2 cdna, and describe the genomic orga ...201323349743
reconstruction of phyletic trees by global alignment of multiple metabolic networks.in the last decade, a considerable amount of research has been devoted to investigating the phylogenetic properties of organisms from a systems-level perspective. most studies have focused on the classification of organisms based on structural comparison and local alignment of metabolic pathways. in contrast, global alignment of multiple metabolic networks complements sequence-based phylogenetic analyses and provides more comprehensive information.201323368411
bioengineered probiotics, a strategic approach to control enteric infections.enteric infections account for high morbidity and mortality and are considered to be the fifth leading cause of death at all ages worldwide. seventy percent of all enteric infections are foodborne. thus significant efforts have been directed toward the detection, control and prevention of foodborne diseases. many antimicrobials including antibiotics have been used for their control and prevention. however, probiotics offer a potential alternative intervention strategy owing to their general heal ...201323327986
effectiveness of the wc/rbs oral cholera vaccine in the prevention of traveler's diarrhea: a prospective cohort study.traveler's diarrhea (td) is the most frequent disease among people from industrialized countries who travel to less developed ones, especially sub-saharan africa, southern asia and south america. the most common bacteria causing td is enterotoxigenic escherichia coli (etec). the wc/rbs cholera vaccine (dukoral) has been shown to induce cross-protection against etec by means of the b subunit of the cholera toxin. the aim of the study was to evaluate the effectiveness of the wc/rbs cholera vaccine ...201323324573
transfer of multidrug-resistant bacteria between intermingled ecological niches: the interface between humans, animals and the environment.the use of antimicrobial agents has been claimed to be the driving force for the emergence and spread of microbial resistance. however, several studies have reported the presence of multidrug-resistant bacteria in populations exposed to low levels of antimicrobial drugs or even never exposed. for many pathogens, especially those organisms for which asymptomatic colonization typically precedes infection (e.g., enterococcus spp. and escherichia coli), the selective effects of antimicrobial use can ...201323343983
significant variation in transformation frequency in streptococcus pneumoniae.the naturally transformable bacterium streptococcus pneumoniae is able to take up extracellular dna and incorporate it into its genome. maintaining natural transformation within a species requires that the benefits of transformation outweigh its costs. although much is known about the distribution of natural transformation among bacterial species, little is known about the degree to which transformation frequencies vary within species. here we find that there is significant variation in transfor ...201323303370
cellular interactions of the cytolethal distending toxins from escherichia coli and haemophilus ducreyi.the cytolethal distending toxins (cdts) compose a subclass of intracellularly acting genotoxins produced by many gram-negative pathogenic bacteria that disrupt the normal progression of the eukaryotic cell cycle. here, the intoxication mechanisms of cdts from escherichia coli (ec-cdt) and haemophilus ducreyi (hd-cdt), which share limited amino acid sequence homology, were directly compared. ec-cdt and hd-cdt shared comparable in vitro dnase activities of the cdtb subunits, saturable cell surface ...201323306199
role of endogenous microbiota, probiotics and their biological products in human health.although gut diseases such as inflammatory bowel disease, mucositis and the alimentary cancers share similar pathogenetic features, further investigation is required into new treatment modalities. an imbalance in the gut microbiota, breached gut integrity, bacterial invasion, increased cell apoptosis to proliferation ratio, inflammation and impaired immunity may all contribute to their pathogenesis. probiotics are defined as live bacteria, which when administered in sufficient amounts, exert ben ...201323306189
the immunomodulatory effect of plant lectins: a review with emphasis on artinm properties.advances in the glycobiology and immunology fields have provided many insights into the role of carbohydrate-protein interactions in the immune system. we aim to present a comprehensive review of the effects that some plant lectins exert as immunomodulatory agents, showing that they are able to positively modify the immune response to certain pathological conditions, such as cancer and infections. the present review comprises four main themes: (1) an overview of plant lectins that exert immunomo ...201323299509
live-cell video microscopy of fungal pathogen phagocytosis.phagocytic clearance of fungal pathogens, and microorganisms more generally, may be considered to consist of four distinct stages: (i) migration of phagocytes to the site where pathogens are located; (ii) recognition of pathogen-associated molecular patterns (pamps) through pattern recognition receptors (prrs); (iii) engulfment of microorganisms bound to the phagocyte cell membrane, and (iv) processing of engulfed cells within maturing phagosomes and digestion of the ingested particle. studies t ...201323329139
paediatric t-cell lymphoma of the appendix: a case report.a 7-year-old boy with no history of malnutrition or diarrhoea complained of acute abdominal pain, was diagnosed with acute appendicitis, and underwent appendectomy. histologically, a diffuse infiltrate of large atypical lymphoid cells was found in the entire appendiceal wall. immunohistochemical examination revealed that the tumour cells expressed t-cell receptor (tcr)-βf1, cd3, cd4, cd25, cytotoxic-related protein tia1 and granzyme-b, but were negative for cd8, foxp3, cd20, cd30 and cd56. polym ...201323302373
gene function hypotheses for the campylobacter jejuni glycome generated by a logic-based approach.increasingly, experimental data on biological systems are obtained from several sources and computational approaches are required to integrate this information and derive models for the function of the system. here, we demonstrate the power of a logic-based machine learning approach to propose hypotheses for gene function integrating information from two diverse experimental approaches. specifically, we use inductive logic programming that automatically proposes hypotheses explaining the empiric ...201323103756
orthopaedic manifestations and diagnostic clues in children with guillain-barré syndrome.guillain-barré syndrome (gbs) is an acute inflammatory demyelinating polyneuropathy characterized by symmetric limb weakness. children with gbs sometimes consult the orthopaedists because of limb pain and gait disturbance. the orthopaedists, however, are unfamiliar with gbs, since it has rarely been delineated in detail in the orthopaedic literature. in the present study, we specifically describe orthopaedic manifestations and diagnostic clues in pediatric gbs.201323755090
broad conditions favor the evolution of phase-variable loci.simple sequence repeat (ssr) tracts produce stochastic on-off switching, or phase variation, in the expression of a panoply of surface molecules in many bacterial commensals and pathogens. a change to the number of repeats in a tract may alter the phase of the translational reading frame, which toggles the on-off state of the switch. here, we construct an in silico ssr locus with mutational dynamics calibrated to those of the haemophilus influenzae mod locus. we simulate its evolution in a regim ...201323300246
an adult case of fisher syndrome subsequent to mycoplasma pneumoniae infection.reported herein is an adult case of fisher syndrome (fs) that occurred as a complication during the course of community-acquired pneumonia caused by mycoplasma pneumoniae. a 38-yr-old man who had been treated with antibiotics for serologically proven m. pneumoniae pneumonia presented with a sudden onset of diplopia, ataxic gait, and areflexia. a thorough evaluation including brain imaging, cerebrospinal fluid examination, a nerve conduction study, and detection of serum anti-ganglioside gq1b ant ...201323341726
cardiovascular disease after escherichia coli o157:h7 gastroenteritis.escherichia coli o157:h7 is one cause of acute bacterial gastroenteritis, which can be devastating in outbreak situations. we studied the risk of cardiovascular disease following such an outbreak in walkerton, ontario, in may 2000.201323166291
innate immune recognition of flagellin limits systemic persistence of brucella.brucella are facultative intracellular bacteria that cause chronic infections by limiting innate immune recognition. it is currently unknown whether brucella flic flagellin, the monomeric subunit of flagellar filament, is sensed by the host during infection. here, we used two mutants of brucella melitensis, either lacking or overexpressing flagellin, to show that flic hinders bacterial replication in vivo. the use of cells and mice genetically deficient for different components of inflammasomes ...201323227931
decoding system for the aua codon by trnaile with the uau anticodon in mycoplasma mobile.deciphering the genetic code is a fundamental process in all living organisms. in many bacteria, aua codons are deciphered by trna(ile2) bearing lysidine (l) at the wobble position. l is a modified cytidine introduced post-transcriptionally by trna(ile)-lysidine synthetase (tils). some bacteria, including mycoplasma mobile, do not carry the tils gene, indicating that they have established a different system to decode aua codons. in this study, trna(ile2) has been isolated from m. mobile and was ...201323295668
genomic analysis of melioribacter roseus, facultatively anaerobic organotrophic bacterium representing a novel deep lineage within bacteriodetes/chlorobi group.melioribacter roseus is a moderately thermophilic facultatively anaerobic organotrophic bacterium representing a novel deep branch within bacteriodetes/chlorobi group. to better understand the metabolic capabilities and possible ecological functions of m. roseus and get insights into the evolutionary history of this bacterial lineage, we sequenced the genome of the type strain p3m-2(t). a total of 2838 open reading frames was predicted from its 3.30 mb genome. the whole proteome analysis support ...201323301019
brain-reactive antibodies and disease.autoimmune diseases currently affect 5-7% of the world's population; in most diseases there are circulating autoantibodies. brain-reactive antibodies are present in approximately 2-3% of the general population but do not usually contribute to brain pathology. these antibodies penetrate brain tissue only early in development or under pathologic conditions. this restriction on their pathogenicity and the lack of correlation between serum titers and brain pathology have, no doubt, contributed to a ...201323516983
regulation of bacterial pathogenesis by intestinal short-chain fatty acids.the human gut microbiota is inextricably linked to health and disease. one important function of the commensal organisms living in the intestine is to provide colonization resistance against invading enteric pathogens. because of the complex nature of the interaction between the microbiota and its host, multiple mechanisms likely contribute to resistance. in this review, we dissect the biological role of short-chain fatty acids (scfa), which are fermentation end products of the intestinal microb ...201323942149
identifying and testing candidate genetic polymorphisms in irritable bowel syndrome: association with tnfsf15 and tumor necrosis factor-α 201324714487
eosinophils in infection and intestinal immunity.inflammatory bowel diseases (ibds, e.g., crohn's disease and ulcerative colitis) are thought to be a consequence of an uncontrolled inflammatory response against luminal antigens, including commensal bacteria. the observed link between eosinophil levels and severity and remission rates in ibd has led to speculation that eosinophils may contribute to the antimicrobial inflammatory response in ibd.201323132211
guillain-barré syndrome in pregnancy: an unusual case.guillain-barré syndrome (gbs) is rare in pregnancy with an estimated incidence between 1.2 and 1.9 cases per 100,000 people annually, and it carries a high maternal risk. we report a 29-year-old primigravida who had pain and progressive heaviness of both lower limbs in her third trimester of pregnancy. the attending gynecologist ascribed these symptoms to ongoing pregnancy. the intrapartum period (lower segment caesarian section) passed uneventfully. on third postpartum day, the patient develope ...201324479054
increased guillain-barre syndrome admissions in shiraz, southern iran.guillain-barre syndrome (gbs) is an acute immune-mediated peripheral neuropathy usually after an incident. this study was performed to investigate the basic epidemiologic features of gbs in south of iran.201324250891
in vitro susceptibility of campylobacter jejuni from kuwait to tigecycline & other antimicrobial agents.there is an increasing frequency of resistance of campylobacter jejuni to antimicrobial agents making treatment difficult. in this study, the in vitro susceptibility of c. jejuni isolates collected over an eight year period was tested against tigecycline, a glycylcycline, the previously tested antimicrobial agents in kuwait, ciprofloxacin, erythromycin and tetracycline, and other antimicrobial agents not previously tested in kuwait, amoxicillin-clavulanic acid, gentamicin, imipenem and meropenem ...201323481071
phytochemical analysis and antibacterial evaluation of the ethyl acetate extract of the stem bark of bridelia micrantha.plant cells fundamentally are chemical factories containing a rich supply of therapeutically useful phytocompounds that have the potential of being developed into potent antimicrobial agents.201323661993
mechanism of tetracycline resistance by ribosomal protection protein tet(o).tetracycline resistance protein tet(o), which protects the bacterial ribosome from binding the antibiotic tetracycline, is a translational gtpase with significant similarity in both sequence and structure to the elongation factor ef-g. here, we present an atomic model of the tet(o)-bound 70s ribosome based on our cryo-electron microscopic reconstruction at 9.6-å resolution. this atomic model allowed us to identify the tet(o)-ribosome binding sites, which involve three characteristic loops in dom ...201323403578
molecular characterization of human-pathogenic microsporidia and cyclospora cayetanensis isolated from various water sources in spain: a year-long longitudinal study.recent studies suggest the involvement of water in the epidemiology of cyclospora cayetanensis and some microsporidia. a total of 223 samples from four drinking water treatment plants (dwtps), seven wastewater treatment plants (wwtps), and six locations of influence (li) on four river basins from madrid, spain, were analyzed from spring 2008 to winter 2009. microsporidia were detected in 49% of samples (109/223), cyclospora spp. were detected in 9% (20/223), and both parasites were found in 5.4% ...201323124243
insertion mutations in helicobacter pylori flha reveal strain differences in rpon-dependent gene expression.flagellar biogenesis in the gastric pathogen helicobacter pylori involves a transcriptional hierarchy that utilizes all three sigma factors found in this bacterium (rpod, rpon and flia). transcription of the rpon-dependent genes requires the sensor kinase flgs and response regulator flgr. it is thought that flgs senses some cellular cue to regulate transcription of the rpon-dependent flagellar genes, but this signal has yet to be identified. previous studies showed that transcription of the rpon ...201323154969
the intestinal microbiota dysbiosis and clostridium difficile infection: is there a relationship with inflammatory bowel disease?gut microbiota is a compilation of microorganisms dwelling in the entire mammalian gastrointestinal tract. they display a symbiotic relationship with the host contributing to its intestinal health and disease. even a slight fluctuation in this equipoise may be deleterious to the host, leading to many pathological conditions like clostridium difficile infection or inflammatory bowel disease (ibd). in this review, we focus on the role of microbial dysbiosis in initiation of c. difficile infection ...201323320050
solution structure of escherichia coli feoa and its potential role in bacterial ferrous iron transport.iron is an indispensable nutrient for most organisms. ferric iron (fe(3+)) predominates under aerobic conditions, while during oxygen limitation ferrous (fe(2+)) iron is usually present. the feo system is a bacterial ferrous iron transport system first discovered in escherichia coli k-12. it consists of three genes, feoa, feob, and feoc (yhgg). feob is thought to be the main transmembrane transporter while feoc is considered to be a transcriptional regulator. using multidimensional nuclear magne ...201323104801
identification of burkholderia cenocepacia strain h111 virulence factors using nonmammalian infection hosts.burkholderia cenocepacia h111, a strain isolated from a cystic fibrosis patient, has been shown to effectively kill the nematode caenorhabditis elegans. we used the c. elegans model of infection to screen a mini-tn5 mutant library of b. cenocepacia h111 for attenuated virulence. of the approximately 5,500 b. cenocepacia h111 random mini-tn5 insertion mutants that were screened, 22 showed attenuated virulence in c. elegans. except for the quorum-sensing regulator cepr, none of the mutated genes c ...201323090963
colonization of campylobacter spp. in broiler chickens and laying hens reared in tropical climates with low-biosecurity housing.the onset and prevalence of campylobacter colonization in broilers and layers at commercial farms with low biosecurity in tropical climates were tested. despite the presence of positive animals at the same farms, the broiler flocks tested negative until, on average, 21 days. prelaying flocks showed a higher prevalence than laying flocks.201323087035
characterization of the polymyxin b resistome of pseudomonas aeruginosa.multidrug resistance in pseudomonas aeruginosa is increasingly becoming a threat for human health. indeed, some strains are resistant to almost all currently available antibiotics, leaving very limited choices for antimicrobial therapy. in many such cases, polymyxins are the only available option, although as their utilization increases so does the isolation of resistant strains. in this study, we screened a comprehensive pa14 mutant library to identify genes involved in changes of susceptibilit ...201323070157
novel aminoglycoside 2''-phosphotransferase identified in a gram-negative pathogen.aminoglycoside 2″-phosphotransferases are the major aminoglycoside-modifying enzymes in clinical isolates of enterococci and staphylococci. we describe a novel aminoglycoside 2″-phosphotransferase from the gram-negative pathogen campylobacter jejuni, which shares 78% amino acid sequence identity with the aph(2″)-ia domain of the bifunctional aminoglycoside-modifying enzyme aminoglycoside (6') acetyltransferase-ie/aminoglycoside 2″-phosphotransferase-ia or aac(6')-ie/aph(2″)-ia from gram-positive ...201323129050
periplasmic flagellar export apparatus protein, flih, is involved in post-transcriptional regulation of flab, motility and virulence of the relapsing fever spirochete borrelia hermsii.spirochetes are bacteria characterized in part by rotating periplasmic flagella that impart their helical or flat-wave morphology and motility. while most other bacteria rely on a transcriptional cascade to regulate the expression of motility genes, spirochetes employ post-transcriptional mechanism(s) that are only partially known. in the present study, we characterize a spontaneous non-motile mutant of the relapsing fever spirochete borrelia hermsii that was straight, non-motile and deficient i ...201324009690
evaluation of the immunogenicity of campylobacter jejuni cjaa protein delivered by salmonella enterica sv. typhimurium strain with regulated delayed attenuation in chickens.campylobacter spp. are regarded as the most common bacterial cause of gastroenteritis worldwide, and consumption of chicken meat contaminated by campylobacter is considered to be one of the most frequent sources of human infection in developed countries. here we evaluated the immunogenicity and protective efficacy of salmonella typhimurium χ9718 producing the campylobacter jejuni cjaa protein as a chicken anti-campylobacter vaccine. in this study chickens were orally immunized with a new generat ...201323913025
evaluation of the immunogenicity of campylobacter jejuni cjaa protein delivered by salmonella enterica sv. typhimurium strain with regulated delayed attenuation in chickens.campylobacter spp. are regarded as the most common bacterial cause of gastroenteritis worldwide, and consumption of chicken meat contaminated by campylobacter is considered to be one of the most frequent sources of human infection in developed countries. here we evaluated the immunogenicity and protective efficacy of salmonella typhimurium χ9718 producing the campylobacter jejuni cjaa protein as a chicken anti-campylobacter vaccine. in this study chickens were orally immunized with a new generat ...201323913025
protein-linked glycans in periodontal bacteria: prevalence and role at the immune interface.protein modification with complex glycans is increasingly being recognized in many pathogenic and non-pathogenic bacteria, and is now thought to be central to the successful life-style of those species in their respective hosts. this review aims to convey current knowledge on the extent of protein glycosylation in periodontal pathogenic bacteria and its role in the modulation of the host immune responses. the available data show that surface glycans of periodontal bacteria orchestrate dendritic ...201324146665
a surface-exposed neuraminidase affects complement resistance and virulence of the oral spirochaete treponema denticola.neuraminidases (sialidases) catalyse the removal of terminal sialic acid from glycoconjugates. bacterial pathogens often utilize neuraminidases to scavenge host sialic acid, which can be utilized either as a nutrient or as a decorating molecule to disguise themselves from host immune attacks. herein, a putative neuraminidase (tde0471) was identified in treponema denticola, an oral spirochaete associated with human periodontitis. tde0471 is a cell surface-exposed exo-neuraminidase that removes si ...201323808705
lessons learned and unlearned in periodontal microbiology.periodontal diseases are initiated by bacterial species living in polymicrobial biofilms at or below the gingival margin and progress largely as a result of the inflammation elicited by specific subgingival species. in the past few decades, efforts to understand the periodontal microbiota have led to an exponential increase in information about biofilms associated with periodontal health and disease. in fact, the oral microbiota is one of the best-characterized microbiomes that colonize the huma ...201323574465
motility is crucial for the infectious life cycle of borrelia burgdorferi.the lyme disease spirochete, borrelia burgdorferi, exists in a zoonotic cycle involving an arthropod tick and mammalian host. dissemination of the organism within and between these hosts depends upon the spirochete's ability to traverse through complex tissues. additionally, the spirochete outruns the host immune cells while migrating through the dermis, suggesting the importance of b. burgdorferi motility in evading host clearance. b. burgdorferi's periplasmic flagellar filaments are composed p ...201323529620
high-resolution transcriptome maps reveal strain-specific regulatory features of multiple campylobacter jejuni isolates.campylobacter jejuni is currently the leading cause of bacterial gastroenteritis in humans. comparison of multiple campylobacter strains revealed a high genetic and phenotypic diversity. however, little is known about differences in transcriptome organization, gene expression, and small rna (srna) repertoires. here we present the first comparative primary transcriptome analysis based on the differential rna-seq (drna-seq) of four c. jejuni isolates. our approach includes a novel, generic method ...201323696746
veillonella, firmicutes: microbes disguised as gram negatives.the firmicutes represent a major component of the intestinal microflora. the intestinal firmicutes are a large, diverse group of organisms, many of which are poorly characterized due to their anaerobic growth requirements. although most firmicutes are gram positive, members of the class negativicutes, including the genus veillonella, stain gram negative. veillonella are among the most abundant organisms of the oral and intestinal microflora of animals and humans, in spite of being strict anaerob ...201324976898
ceg: a database of essential gene clusters.essential genes are indispensable for the survival of living entities. they are the cornerstones of synthetic biology, and are potential candidate targets for antimicrobial and vaccine design.201324209780
identification of leptospira interrogans phospholipase c as a novel virulence factor responsible for intracellular free calcium ion elevation during macrophage death.leptospira-induced macrophage death has been confirmed to play a crucial role in pathogenesis of leptospirosis, a worldwide zoonotic infectious disease. intracellular free ca(2+) concentration ([ca(2+)]i) elevation induced by infection can cause cell death, but [ca(2+)]i changes and high [ca(2+)]i-induced death of macrophages due to infection of leptospira have not been previously reported.201324124502
a method for molecular analysis of catalase gene diversity in seawater.catalase plays an important role in the metabolism of marine bacteria and has potential impact on the marine environment. four pcr primers were designed to amplify the catalase gene fragments in marine bacteria by applying metagenomic dna from yellow sea surface water as the template. of the four reproducible target pcr products, the longest one with 900 bp were chosen for catalase gene library construction by the t-vector and the white escherichia coli colonies in the library was screened throu ...201324426153
discovery of chlamydial peptidoglycan reveals bacteria with murein sacculi but without ftsz.chlamydiae are important pathogens and symbionts with unique cell biological features. they lack the cell-division protein ftsz, and the existence of peptidoglycan (pg) in their cell wall has been highly controversial. ftsz and pg together function in orchestrating cell division and maintaining cell shape in almost all other bacteria. using electron cryotomography, mass spectrometry and fluorescent labelling dyes, here we show that some environmental chlamydiae have cell wall sacculi consisting ...201324292151
regulatory protein ompr influences the serum resistance of yersinia enterocolitica o:9 by modifying the structure of the outer membrane.the envz/ompr two-component system constitutes a regulatory pathway involved in bacterial adaptive responses to environmental cues. our previous findings indicated that the ompr regulator in yersinia enterocolitica o:9 positively regulates the expression of flhdc, the master flagellar activator, which influences adhesion/invasion properties and biofilm formation. here we show that a strain lacking ompr grown at 37°c exhibits extremely high resistance to the bactericidal activity of normal human ...201324260242
characterization of a novel zinc transporter znua acquired by vibrio parahaemolyticus through horizontal gene transfer.vibrio parahaemolyticus is a clinically important foodborne pathogen that causes acute gastroenteritis worldwide. it has been shown that horizontal gene transfer (hgt) contributes significantly to virulence development of v. parahaemolyticus. in this study, we identified a novel znua homolog (vpa1307) that belongs to a novel subfamily of znua, a bacterial zinc transporter. the vpa1307 gene is located upstream of the v. parahaemolyticus pathogenicity island (vp-pais) in both tdh-positive and trh- ...201324133656
pathogenomic inference of virulence-associated genes in leptospira interrogans.leptospirosis is a globally important, neglected zoonotic infection caused by spirochetes of the genus leptospira. since genetic transformation remains technically limited for pathogenic leptospira, a systems biology pathogenomic approach was used to infer leptospiral virulence genes by whole genome comparison of culture-attenuated leptospira interrogans serovar lai with its virulent, isogenic parent. among the 11 pathogen-specific protein-coding genes in which non-synonymous mutations were foun ...201324098822
pathogen-driven selection in the human genome.infectious diseases and epidemics have always accompanied and characterized human history, representing one of the main causes of death. even today, despite progress in sanitation and medical research, infections are estimated to account for about 15% of deaths. the hypothesis whereby infectious diseases have been acting as a powerful selective pressure was formulated long ago, but it was not until the availability of large-scale genetic data and the development of novel methods to study molecul ...201323533945
microbial modulation of host immunity with the small molecule phosphorylcholine.all microorganisms dependent on persistence in a host for survival rely on either hiding from or modulating host responses to infection. the small molecule phosphorylcholine, or choline phosphate (chop), is used for both of these purposes by a wide array of bacterial and parasitic microbes. while the mechanisms underlying chop acquisition and expression are diverse, a unifying theme is the use of chop to reduce the immune response to infection, creating an advantage for chop-expressing microorga ...201323230294
genome reduction promotes increase in protein functional complexity in bacteria.obligate pathogenic and endosymbiotic bacteria typically experience gene loss due to functional redundancy, asexuality, and genetic drift. we hypothesize that reduced genomes increase their functional complexity through protein multitasking, in which many genes adopt new roles to counteract gene loss. comparisons of interaction networks among six bacteria that have varied genome sizes (mycoplasma pneumoniae, treponema pallidum, helicobacter pylori, campylobacter jejuni, synechocystis sp., and my ...201323114380
impact of crispr immunity on the emergence and virulence of bacterial pathogens.crispr-cas systems protect prokaryotes from viruses and plasmids and function primarily as an adaptive immune system in these organisms. recent discoveries, however, revealed unexpected roles for crispr loci as barriers to horizontal gene transfer and as modulators of gene expression. we review how both of these functions of crispr-cas systems can affect the emergence and virulence of human bacterial pathogens.201324581697
impact of crispr immunity on the emergence and virulence of bacterial pathogens.crispr-cas systems protect prokaryotes from viruses and plasmids and function primarily as an adaptive immune system in these organisms. recent discoveries, however, revealed unexpected roles for crispr loci as barriers to horizontal gene transfer and as modulators of gene expression. we review how both of these functions of crispr-cas systems can affect the emergence and virulence of human bacterial pathogens.201324581697
protein selection and export via outer membrane vesicles.outer membrane vesicles (omvs) are constitutively produced by all gram-negative bacteria. omvs form when buds from the outer membrane (om) of cells encapsulate periplasmic material and pinch off from the om to form spheroid particles approximately 10 to 300nm in diameter. omvs accomplish a diversity of functional roles yet the omv's utility is ultimately determined by its unique composition. inclusion into omvs may impart a variety of benefits to the protein cargo, including: protection from pro ...201324370777
protein selection and export via outer membrane vesicles.outer membrane vesicles (omvs) are constitutively produced by all gram-negative bacteria. omvs form when buds from the outer membrane (om) of cells encapsulate periplasmic material and pinch off from the om to form spheroid particles approximately 10 to 300nm in diameter. omvs accomplish a diversity of functional roles yet the omv's utility is ultimately determined by its unique composition. inclusion into omvs may impart a variety of benefits to the protein cargo, including: protection from pro ...201324370777
feon-feoff: the helicobacter pylori fur regulator commutates iron-responsive transcription by discriminative readout of opposed dna grooves.most transcriptional regulators bind nucleotide motifs in the major groove, although some are able to recognize molecular determinants conferred by the minor groove of dna. here we report a transcriptional commutator switch that exploits the alternative readout of grooves to mediate opposite output regulation for the same input signal. this mechanism accounts for the ability of the helicobacter pylori fur regulator to repress the expression of both iron-inducible and iron-repressible genes. when ...201324322295
feon-feoff: the helicobacter pylori fur regulator commutates iron-responsive transcription by discriminative readout of opposed dna grooves.most transcriptional regulators bind nucleotide motifs in the major groove, although some are able to recognize molecular determinants conferred by the minor groove of dna. here we report a transcriptional commutator switch that exploits the alternative readout of grooves to mediate opposite output regulation for the same input signal. this mechanism accounts for the ability of the helicobacter pylori fur regulator to repress the expression of both iron-inducible and iron-repressible genes. when ...201324322295
communication between bacteria and their hosts.it is clear that a dialogue is occurring between microbes and their hosts and that chemical signals are the language of this interkingdom communication. microbial endocrinology shows that, through their long coexistence with animals and plants, microorganisms have evolved sensors for detecting eukaryotic hormones, which the microbe uses to determine that they are within proximity of a suitable host and to optimally time the expression of genes needed for host colonisation. it has also been shown ...201324381789
the microbiome and cancer.microbiota and host form a complex 'super-organism' in which symbiotic relationships confer benefits to the host in many key aspects of life. however, defects in the regulatory circuits of the host that control bacterial sensing and homeostasis, or alterations of the microbiome, through environmental changes (infection, diet or lifestyle), may disturb this symbiotic relationship and promote disease. increasing evidence indicates a key role for the bacterial microbiota in carcinogenesis. in this ...201324132111
role and regulation of heme iron acquisition in gram-negative pathogens.bacteria that reside in animal tissues and/or cells must acquire iron from their host. however, almost all of the host iron is sequestered in iron-containing compounds and proteins, the majority of which is found within heme molecules. thus, likely iron sources for bacterial pathogens (and non-pathogenic symbionts) are free heme and heme-containing proteins. furthermore, the cellular location of the bacterial within the host (intra or extracellular) influences the amount and nature of the iron c ...201324116354
luxs in bacteria isolated from 25- to 40-million-year-old amber.interspecies bacterial communication is mediated by autoinducer-2, whose synthesis depends on luxs. due to the apparent universality of luxs (present in more than 40 bacterial species), it may have an ancient origin; however, no direct evidence is currently available. we amplified luxs in bacteria isolated from 25- to 40-million-year-old amber. the phylogenies and molecular clocks of luxs and the 16s rrna gene from ancient and extant bacteria were determined as well. luminescence assays using vi ...201324102660
luxs in bacteria isolated from 25- to 40-million-year-old amber.interspecies bacterial communication is mediated by autoinducer-2, whose synthesis depends on luxs. due to the apparent universality of luxs (present in more than 40 bacterial species), it may have an ancient origin; however, no direct evidence is currently available. we amplified luxs in bacteria isolated from 25- to 40-million-year-old amber. the phylogenies and molecular clocks of luxs and the 16s rrna gene from ancient and extant bacteria were determined as well. luminescence assays using vi ...201324102660
adaptive strategies and pathogenesis of clostridium difficile from in vivo transcriptomics.clostridium difficile is currently the major cause of nosocomial intestinal diseases associated with antibiotic therapy in adults. in order to improve our knowledge of c. difficile-host interactions, we analyzed the genome-wide temporal expression of c. difficile 630 genes during the first 38 h of mouse colonization to identify genes whose expression is modulated in vivo, suggesting that they may play a role in facilitating the colonization process. in the ceca of the c. difficile-monoassociated ...201323897605
multilocus sequence typing of borrelia burgdorferi suggests existence of lineages with differential pathogenic properties in humans.the clinical manifestations of lyme disease, caused by borrelia burgdorferi, vary considerably in different patients, possibly due to infection by strains with varying pathogenicity. both rrna intergenic spacer and ospc typing methods have proven to be useful tools for categorizing b. burgdorferi strains that vary in their tendency to disseminate in humans. neither method, however, is suitable for inferring intraspecific relationships among strains that are important for understanding the evolut ...201324069170
topoisomerase iv is required for partitioning of circular chromosomes but not linear chromosomes in streptomyces.filamentous bacteria of the genus streptomyces possess linear chromosomes and linear plasmids. theoretically, linear replicons may not need a decatenase for post-replicational separation of daughter molecules. yet, streptomyces contain parc and pare that encode the subunits for the decatenase topoisomerase iv. the linear replicons of streptomyces adopt a circular configuration in vivo through telomere-telomere interaction, which would require decatenation, if the circular configuration persists ...201323999094
borrelia burgdorferi oxidative stress regulator bosr directly represses lipoproteins primarily expressed in the tick during mammalian infection.differential gene expression is a key strategy adopted by the lyme disease spirochaete, borrelia burgdorferi, for adaptation and survival in the mammalian host and the tick vector. many b. burgdorferi surface lipoproteins fall into two distinct groups according to their expression patterns: one group primarily expressed in the tick and the other group primarily expressed in the mammal. here, we show that the fur homologue in this bacterium, also known as borrelia oxidative stress regulator (bosr ...201323869590
cell extract-containing medium for culture of intracellular fastidious bacteria.the culture of fastidious microorganisms is a critical step in infectious disease studies. as a proof-of-concept experiment, we evaluated an empirical medium containing eukaryotic cell extracts for its ability to support the growth of coxiella burnetii. here, we demonstrate the exponential growth of several bacterial strains, including the c. burnetii nine mile phase i and phase ii strains, and c. burnetii isolates from humans and animals. low-oxygen-tension conditions and the presence of small ...201323740722
identification of the likely translational start of mycobacterium tuberculosis gyrb.bacterial dna gyrase is a validated target for antibacterial chemotherapy. it consists of two subunits, gyra and gyrb, which form an a₂b₂ complex in the active enzyme. sequence alignment of mycobacterium tuberculosis gyrb with other bacterial gyrbs predicts the presence of 40 potential additional amino acids at the gyrb n-terminus. there are discrepancies between the m. tuberculosis gyrb sequences retrieved from different databases, including sequences annotated with or without the additional 40 ...201323856181
iron in infection and immunity.iron is an essential nutrient for both humans and pathogenic microbes. because of its ability to exist in one of two oxidation states, iron is an ideal redox catalyst for diverse cellular processes including respiration and dna replication. however, the redox potential of iron also contributes to its toxicity; thus, iron concentration and distribution must be carefully controlled. given the absolute requirement for iron by virtually all human pathogens, an important facet of the innate immune sy ...201323684303
life without trnaarg-adenosine deaminase tada: evolutionary consequences of decoding the four cgn codons as arginine in mycoplasmas and other mollicutes.in most bacteria, two trnas decode the four arginine cgn codons. one trna harboring a wobble inosine (trna(arg)icg) reads the cgu, cgc and cga codons, whereas a second trna harboring a wobble cytidine (trna(arg)ccg) reads the remaining cgg codon. the reduced genomes of mycoplasmas and other mollicutes lack the gene encoding trna(arg)ccg. this raises the question of how these organisms decode cgg codons. examination of 36 mollicute genomes for genes encoding trna(arg) and the tada enzyme, respons ...201323658230
viral latency locus augments b-cell response in vivo to induce chronic marginal zone enlargement, plasma cell hyperplasia, and lymphoma.kaposi sarcoma (ks) is associated with ks-associated herpesvirus (kshv). this virus also causes b-cell lymphoma and b-cell hyperplasia. there exists no in vivo model for kshv-associated b-cell malignancies or premalignant persistence in b cells. we generated a transgenic mouse that expresses multiple viral latent genes, including lana, vflip, vcyc, all viral micro rnas, and kaposin under the transcriptional control of their natural regulatory region. this promoter is b-cell specific, though it i ...201323365457
the htra protease of borrelia burgdorferi degrades outer membrane protein bmpd and chemotaxis phosphatase chex.borrelia burgdorferi, the spirochaetal agent of lyme disease, codes for a single htra protein, htrabb (bb0104) that is homologous to degp of escherichia coli (41% amino acid identity). htrabb shows physical and biochemical similarities to degp in that it has the trimer as its fundamental unit and can degrade casein via its catalytic serine. recombinant htrabb exhibits proteolytic activity in vitro, while a mutant (htrabbs198a) does not. however, htrabb and degp have some important differences as ...201323565798
helicobacter pylori infection, chronic inflammation, and genomic transformations in gastric malt lymphoma.nowadays, it is believed that the main role in the development of gastric mucosa-associated lymphoid tissue (malt) lymphoma plays helicobacter pylori infection. this world-wide distributed bacteria is in charge of most cases of not only upper gastrointestinal tract disorders but also some of extragastric problems. constant stimulation of the immune system causes a b-lymphocytes proliferation, which is considered to be responsible for the neoplastic transformation. on the other hand, there are 10 ...201323606792
anti-gm2 ganglioside antibodies are a biomarker for acute canine polyradiculoneuritis.acute canine polyradiculoneuritis (acp) is considered to be the canine equivalent of the human peripheral nerve disorder guillain-barré syndrome (gbs); an aetiological relationship, however, remains to be demonstrated. in gbs, anti-glycolipid antibodies (abs) are considered as important disease mediators. to address the possibility of common ab biomarkers, the sera of 25 acp dogs, 19 non-neurological, and 15 epileptic control dogs were screened for igg abs to 10 glycolipids and their 1 : 1 heter ...201323521648
antimicrobial efflux pumps and mycobacterium tuberculosis drug tolerance: evolutionary considerations.the need for lengthy treatment to cure tuberculosis stems from phenotypic drug resistance, also known as drug tolerance, which has been previously attributed to slowed bacterial growth in vivo. we discuss recent findings that challenge this model and instead implicate macrophage-induced mycobacterial efflux pumps in antimicrobial tolerance. although mycobacterial efflux pumps may have originally served to protect against environmental toxins, in the pathogenic mycobacteria, they appear to have b ...201323242857
chagas' disease: an emergent urban zoonosis. the caracas valley (venezuela) as an epidemiological model.the unprecedented emergence of important public health and veterinary zoonoses is usually a result of exponential population growth and globalization of human activities. i characterized chagas' disease as an emergent zoonosis in the caracas valley (venezuela) due to the following findings: the presence of reservoirs (didelphis marsupialis, rattus rattus) and vectors (panstrongylus geniculatus, panstrongylus rufotuberculatus) infected with trypanosoma cruzi in urbanized or marginalized areas; th ...201425520950
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