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filter-based pathogen enrichment technology for detection of multiple viable foodborne pathogens in 1 day.conventional foodborne pathogen assays currently used in the food industry often require long culture enrichments to increase pathogen levels so they can be detected. even using sensitive real-time pcr assays, culture enrichment at least overnight is necessary especially for detection of pathogens with slow growth rates such as listeria monocytogenes. to eliminate this cumbersome enrichment step and detect minute amounts of pathogens within 1 day, filter-based pathogen enrichment technology was ...201222947467
on the different growth conditions affecting silver antimicrobial efficacy on listeria monocytogenes and salmonella enterica.silver is known to inhibit microorganisms and therefore it is an ideal candidate for its incorporation in a wide variety of materials for food applications. however, there is still a need for understanding how silver prolonged exposure to bacterial contamination affects the bioavailability of the active silver species. in the present study, growth curves of listeria monocytogenes and salmonella enterica were performed for 3-5 days in tryptic soy broth (tsb) and m9 minimal medium (m9) in the pres ...201222835228
reduction in resident microflora, and experimentally inoculated salmonella enterica, on spinach leaves treated with vinegar and canola oil.in this study, we explored the use of vinegar, or vinegar and canola oil as a salad dressing, to reduce bacterial levels on spinach leaves. we found that incubation of spinach leaves with various types of vinegar substantially reduced the predominantly gram-negative microflora. a similar response was observed when spinach leaves were incubated with white vinegar mixed in various proportions with canola oil, as used in salad dressing. we assessed the effects of vinegar, or vinegar and oil, on spi ...201222828283
evaluation of near-infrared pasteurization in controlling escherichia coli o157:h7, salmonella enterica serovar typhimurium, and listeria monocytogenes in ready-to-eat sliced ham.this study was conducted to investigate the efficacy of near-infrared (nir) heating to reduce salmonella enterica serovar typhimurium, escherichia coli o157:h7, and listeria monocytogenes in ready-to-eat (rte) sliced ham compared to conventional convective heating, and the effect of nir heating on quality was determined by measuring the color and texture change. a cocktail of three pathogens was inoculated on the exposed or protected surfaces of ham slices, followed by nir or conventional heatin ...201222773635
oral vaccination with attenuated salmonella enterica serovar typhimurium expressing cap protein of pcv2 and its immunogenicity in mouse and swine models.attenuated salmonella enterica serovar typhimurium (s. typhimurium) was selected as a transgenic vehicle for the development of oral vaccines against porcine circovirus type 2 (pcv2). the cap-encoding gene of pcv2 was amplified by pcr and cloned into expression vector pya3341. the recombinant plasmid pya3341-cap was transformed into attenuated s. typhimurium x4550. balb/c mice were inoculated orally with various doses of attenuated s. typhimurium x4550/pya3341-cap. the bacterium was safe to mice ...201222326539
flagellin from recombinant attenuated salmonella enterica serovar typhimurium reveals a fundamental role in chicken innate immunity.recombinant attenuated salmonella vaccines have been extensively studied, with a focus on eliciting specific immune responses against foreign antigens. however, very little is known about the innate immune responses, particularly the role of flagellin, in the induction of innate immunity triggered by recombinant attenuated salmonella in chickens. in the present report, we describe two salmonella enterica serovar typhimurium vaccine strains, wild-type (wt) or flagellin-deficient (flhd) salmonella ...201222237893
infection of zebrafish embryos with intracellular bacterial pathogens.zebrafish (danio rerio) embryos are increasingly used as a model for studying the function of the vertebrate innate immune system in host-pathogen interactions. the major cell types of the innate immune system, macrophages and neutrophils, develop during the first days of embryogenesis prior to the maturation of lymphocytes that are required for adaptive immune responses. the ease of obtaining large numbers of embryos, their accessibility due to external development, the optical transparency of ...201222453760
mitsuokella jalaludinii inhibits growth of salmonella enterica serovar typhimurium.salmonella continues to be a significant human health threat, and the objective of this study was to identify microorganisms with the potential to improve porcine food-safety through their antagonism of salmonella. anaerobic culture supernatants of 973 bacterial isolates from the gastrointestinal tract and feces of swine were screened for their capacity to inhibit the growth of salmonella enterica serovar typhimurium. growth inhibition of 1000-fold or greater was observed from 16 isolates, and 1 ...201222503601
[protection against salmonella via immunization with recombinant lactic acid bacteria].mucosal immunization of hens may be effective to prevent contamination of salmonella enterica serovar enteritidis (se) in eggs. lactic acid bacteria have been considered potential vaccine delivery agents because they are safe, immunogenic, and inexpensive. our research group has been investigating the development of oral vaccines against se using a lactobacillus casei strain as an antigen delivery vehicle. recombinant lactobacilli expressing se antigens flic and sipc have been constructed and ad ...201222894061
enhanced influenza virus-like particle vaccines containing the extracellular domain of matrix protein 2 and a toll-like receptor ligand.the extracellular domain of matrix protein 2 (m2e) is conserved among influenza a viruses. the goal of this project is to develop enhanced influenza vaccines with broad protective efficacy using the m2e antigen. we designed a membrane-anchored fusion protein by replacing the hyperimmunogenic region of salmonella enterica serovar typhimurium flagellin (flic) with four repeats of m2e (4.m2e-tflic) and fusing it to a membrane anchor from influenza virus hemagglutinin (ha). the fusion protein was in ...201222647270
glycerol supplementation enhances l. reuteri's protective effect against s. typhimurium colonization in a 3-d model of colonic epithelium.the probiotic effects of lactobacillus reuteri have been speculated to partly depend on its capacity to produce the antimicrobial substance reuterin during the reduction of glycerol in the gut. in this study, the potential of this process to protect human intestinal epithelial cells against infection with salmonella enterica serovar typhimurium was investigated. we used a three-dimensional (3-d) organotypic model of human colonic epithelium that was previously validated and applied to study inte ...201222693569
[real-time pcr detection and quantification of emerging waterborne pathogens (ewps) and antibiotic resistance genes (args) in the downstream area of jiulong river].the emerging waterborne pathogens (ewps) and antibiotic resistance genes (args) are important for drinking water safety. the detection and quantification of 7 ewps and 4 args were carried out in jiulong river, which is the main water source of southwestern fujian province. the water samples were collected from four sites of the jiulong river downstream area and a drinking water treatment plant nearby. dna was extracted and quantified by real-time (sybr green) pcr methods after the samples were f ...201223213891
a modified weibull model for growth and survival of listeria innocua and salmonella typhimurium in chicken breasts during refrigerated and frozen storage.the potential of food-borne pathogens to survive and grow during refrigerated and frozen storage has raised serious concerns over the safety of stored poultry products. in this study, the effect of refrigeration and freezing temperatures (-20, -12, 0, 4, and 8°c) on growth and survival of listeria innocua and salmonella enterica serovar typhimurium in raw chicken breasts for storage times of 3, 7, 10, 14, and 21 d were investigated. a modified weibull model was also developed to analyze the micr ...201222582310
transcriptome mapping of par060302, a blacmy-2-positive broad-host-range inca/c plasmid.the multidrug resistance-encoding plasmids belonging to the inca/c incompatibility group have recently emerged among escherichia coli and salmonella enterica strains in the united states. these plasmids have a unique genetic structure compared to other enterobacterial plasmid types, a broad host range, and a propensity to acquire large numbers of antimicrobial resistance genes via their accessory regions. using e. coli strain dh5α harboring the prototype inca/c plasmid par060302, we sought to de ...201222344651
dynamics of salmonella small rna expression in non-growing bacteria located inside eukaryotic cells.small non-coding regulatory rnas (srnas) have been studied in many bacterial pathogens during infection. however, few studies have focused on how intracellular pathogens modulate srna expression inside eukaryotic cells. here, we monitored expression of all known srnas of salmonella enterica serovar typhimurium (s. typhimurium) in bacteria located inside fibroblasts, a host cell type in which this pathogen restrains growth. srna sequences known in s. typhimurium and escherichia coli were searched ...201222336761
role of anionic charges of osmoregulated periplasmic glucans of salmonella enterica serovar typhimurium sl1344 in mice virulence.opgb gene of salmonella enterica serovar typhimurium was identified earlier in a genome-wide screen for mice virulence (valentine et al. in infect immun 66:3378-3383, 1998). although mutation in opgb resulted in avirulent salmonella strain, how this gene contributes to pathogenesis remains unclear. based on dna homology, opgb is predicted to be responsible for adding phosphoglycerate residues to osmoregulated periplasmic glucans (opgs) giving them anionic characteristics. in escherichia coli, ye ...201222278765
pathogenic and multidrug-resistant escherichia fergusonii from broiler chicken.an escherichia spp. isolate, ecd-227, was previously identified from the broiler chicken as a phylogenetically divergent and multidrug-resistant escherichia coli possessing numerous virulence genes. in this study, whole genome sequencing and comparative genome analysis was used to further characterize this isolate. the presence of known and putative antibiotic resistance and virulence open reading frames were determined by comparison to pathogenic (e. coli o157:h7 tw14359, apec o1:k1:h7, and upe ...201222252367
carriage of antibiotic-resistant enteric bacteria varies among sites in galapagos reptiles.increased overlap between humans and wildlife populations has increased the risk for novel disease emergence. detecting contacts with a high risk for transmission of pathogens requires the identification of dependable measures of microbial exchange. we evaluated antibiotic resistance as a molecular marker for the intensity of human-wildlife microbial connectivity in the galápagos islands. we isolated escherichia coli and salmonella enterica from the feces of land iguanas (conolophus sp.), marine ...201222247374
gut inflammation can boost horizontal gene transfer between pathogenic and commensal enterobacteriaceae.the mammalian gut harbors a dense microbial community interacting in multiple ways, including horizontal gene transfer (hgt). pangenome analyses established particularly high levels of genetic flux between gram-negative enterobacteriaceae. however, the mechanisms fostering intraenterobacterial hgt are incompletely understood. using a mouse colitis model, we found that salmonella-inflicted enteropathy elicits parallel blooms of the pathogen and of resident commensal escherichia coli. these blooms ...201222232693
arginine 66 residue of fur is required for the regulatory function of this protein in the acid adaptation mechanism of helicobacter pylori.helicobacter pylori colonizes the gastric mucosa and must survive the acid ph of that environment. like other enteric bacterial pathogens, including salmonella enterica, h. pylori develops an acid tolerance response that is dependent on the function of the transcriptional regulator protein fur.201222221611
reduced na+ affinity increases turnover of salmonella enterica serovar typhimurium melb.the melibiose permease of salmonella enterica serovar typhimurium (melb(st)) catalyzes symport of melibiose with na(+), li(+), or h(+). bioinformatics and mutational analyses indicate that a conserved gly117 (helix iv) is a component of the na(+)-binding site. in this study, gly117 was mutated to ser, asn, or cys. all three mutations increase the maximum rate (v(max)) for melibiose transport in escherichia coli dw2 and greatly decrease na(+) affinity, indicating that intracellular release of na( ...201222865849
whole blood-derived microrna signatures in mice exposed to lipopolysaccharides.lipopolysaccharide (lps) is recognized as the most potent microbial mediator presaging the threat of invasion of gram-negative bacteria that implicated in the pathogenesis of sepsis and septic shock. this study was designed to examine the microrna (mirna) expression in whole blood from mice injected with intraperitoneal lps.201222849760
study on antibacterial alginate-stabilized copper nanoparticles by ft-ir and 2d-ir correlation spectroscopy.the objective of this study was to clarify the intermolecular interaction between antibacterial copper nanoparticles (cu nps) and sodium alginate (naalg) by fourier transform infrared spectroscopy (ft-ir) and to process the spectra applying two-dimensional infrared (2d-ir) correlation analysis. to our knowledge, the addition of naalg as a stabilizer of copper nanoparticles has not been previously reported. it is expected that the obtained results will provide valuable additional information on: ...201222848180
supported lipopolysaccharide bilayers.in this report, the formation of supported lipopolysaccharide bilayers (lps-slbs) is studied with extracted native and glycoengineered lps from escherichia coli ( e. coli ) and salmonella enterica sv typhimurium ( s. typhimurium ) to assemble a platform that allows measurement of lps membrane structure and the detection of membrane tethered saccharide-protein interactions. we present quartz crystal microbalance with dissipation monitoring (qcm-d) and fluorescence recovery after photobleaching (f ...201222830310
thymus maroccanus essential oil, a membranotropic compound active on gram-negative bacteria and resistant isolates.the effects of thymus maroccanus essential oil (eo) on the integrity of the cell membranes and the permeability of the outer membrane (om) and inner membrane (im) of escherichia coli, enterobacter aerogenes and salmonella enterica typhimurium were investigated.201222809088
leuo is a global regulator of gene expression in salmonella enterica serovar typhimurium.we report the first investigation of the binding of the salmonella enterica leuo lysr-type transcription regulator to its genomic targets in vivo. chromatin-immunoprecipitation-on-chip identified 178 leuo binding sites on the chromosome of s. enterica serovar typhimurium strain sl1344. these sites were distributed across both the core and the horizontally acquired genome, and included housekeeping genes and genes known to contribute to virulence. sixty-eight leuo targets were co-bound by the glo ...201222804842
convergent molecular evolution of genomic cores in salmonella enterica and escherichia coli.one of the strongest signals of adaptive molecular evolution of proteins is the occurrence of convergent hot spot mutations: repeated changes in the same amino acid positions. we performed a comparative genome-wide analysis of mutation-driven evolution of core (omnipresent) genes in 17 strains of salmonella enterica subspecies i and 22 strains of escherichia coli. more than 20% of core genes in both salmonella and e. coli accumulated hot spot mutations, with a predominance of identical changes h ...201222797756
a single residue determines the cooperative binding property of a primosomal dna replication protein, prib, to single-stranded dna.prib is a primosomal protein required for re-initiation of replication in bacteria. we characterized and compared the dna-binding properties of prib from salmonella enterica serovar typhimurium lt2 (stprib) and escherichia coli (ecprib). only one residue of ecprib, v6, was different in stprib (replaced by a6). previous structural information revealed that this residue is located on the putative dimer-dimer interface of prib and is not involved in single-stranded dna (ssdna) binding. the cooperat ...201222790931
fima, fimf, and fimh are necessary for assembly of type 1 fimbriae on salmonella enterica serovar typhimurium.salmonella enterica serovar typhimurium is a gram-negative member of the family enterobacteriaceae and is a common cause of bacterial food poisoning in humans. the fimbrial appendages are found on the surface of many enteric bacteria and enable the bacteria to bind to eukaryotic cells. s. typhimurium type 1 fimbriae are characterized by mannose-sensitive hemagglutination and are assembled via the chaperone/usher pathway. s. typhimurium type 1 fimbrial proteins are encoded by the fim gene cluster ...201222778099
is nalidixic acid screening still valid for the detection of reduced susceptibility of fluoroquinolone with salmonella typhi?considering the limitations of screening with nalidixic acid to detect reduced susceptibility to fluoroquinolones of salmonella enterica serovar typhi (s.typhi) strains, we evaluated the use of a 30 µg nalidixic acid disc screening method in pakistan.201223103891
bloodstream infection among children presenting to a general hospital outpatient clinic in urban nepal.there are limited data on the etiology and characteristics of bloodstream infections in children presenting in hospital outpatient settings in south asia. previous studies in nepal have highlighted the importance of murine typhus as a cause of febrile illness in adults and enteric fever as a leading bacterial cause of fever among children admitted to hospital.201223115652
tigecycline challenge triggers srna production in salmonella enterica serovar typhimurium.bacteria employ complex transcriptional networks involving multiple genes in response to stress, which is not limited to gene and protein networks but now includes small rnas (srnas). these regulatory rna molecules are increasingly shown to be able to initiate regulatory cascades and modulate the expression of multiple genes that are involved in or required for survival under environmental challenge. despite mounting evidence for the importance of srnas in stress response, their role upon antibi ...201222958399
construction and immunological evaluation of dual cell surface display of hiv-1 gag and salmonella enterica serovar typhimurium flic in lactobacillus acidophilus for vaccine delivery.oral vaccines that elicit a mucosal immune response may be effective against human immunodeficiency virus type 1 (hiv-1) because its transmission occurs mainly at the mucosa. the aim of this study was to construct recombinant lactobacillus for oral delivery of oral vaccines against hiv-1 and to evaluate their immunogenicity. a recombinant lactobacillus acidophilus strain expressing the hiv-1 gag on the bacterial cell surface was established by fusion with the signal peptide and anchor motif of a ...201222761297
enhancement of th1-biased protective immunity against avian influenza h9n2 virus via oral co-administration of attenuated salmonella enterica serovar typhimurium expressing chicken interferon-α and interleukin-18 along with an inactivated vaccine.control of currently circulating re-assorted low-pathogenicity avian influenza (lpai) h9n2 is a major concern for both animal and human health. thus, an improved lpai h9n2 vaccination strategy is needed to induce complete immunity in chickens against lpai h9n2 virus strains. cytokines play a crucial role in mounting both the type and extent of an immune response generated following infection with a pathogen or after vaccination. to improve the efficacy of inactivated lpai h9n2 vaccine, attenuate ...201222776696
improved immune responses against avian influenza virus following oral vaccination of chickens with ha dna vaccine using attenuated salmonella typhimurium as carrier.this study evaluates the immune responses of single avian influenza virus (aiv) ha dna vaccine immunization using attenuated salmonella enterica sv. typhimurium as an oral vaccine carrier and intramuscular (im) dna injection. one-day-old specific-pathogen-free (spf) chicks immunized once by oral gavage with 10(9) salmonella colony-forming units containing plasmid expression vector encoding the ha gene of a/ck/malaysia/5858/04 (h5n1) (pcdna3.1.h5) did not show any clinical manifestations. serum h ...201222512819
differential modulation of intracellular survival of cytosolic and vacuolar pathogens by curcumin.curcumin, a principal component of turmeric, acts as an immunomodulator regulating the host defenses in response to a diseased condition. the role of curcumin in controlling certain infectious diseases is highly controversial. it is known to alleviate symptoms of helicobacter pylori infection and exacerbate that of leishmania infection. we have evaluated the role of curcumin in modulating the fate of various intracellular bacterial pathogens. we show that pretreatment of macrophages with curcumi ...201222890770
the mammalian microrna response to bacterial infections.micrornas are small rnas that post-transcriptionally regulate eukaryotic gene expression. in addition to their involvement in a wide range of physiological and pathological processes, including viral infections, micrornas are increasingly implicated in the eukaryotic response to bacterial pathogens. recent studies have characterized changes in host microrna expression following infection with exclusively extracellular (helicobacter pylori) or intracellular (salmonella enterica) gram-negative bac ...201222664920
structural characterization of the h-ns protein from xylella fastidiosa and its interaction with dna.the nucleoid-associated protein h-ns is a major component of the bacterial nucleoid involved in dna compaction and transcription regulation. the nmr solution structure of the xylella fastidiosa h-ns c-terminal domain (residues 56-134) is presented here and consists of two beta-strands and two alpha helices, with one loop connecting the two beta-strands and a second loop connecting the second beta strand and the first helix. the amide (1)h and (15)n chemical shift signals for a sample of xfh-ns(5 ...201222772065
differential expression of the transcription factors mara, rob, and soxs of salmonella typhimurium in response to sodium hypochlorite: down-regulation of rob by mara and soxs.to survive, salmonella enterica serovar typhimurium (s. typhimurium) must sense signals found in phagocytic cells and modulate gene expression. in the present work, we evaluated the expression and cross-regulation of the transcription factors mara, rob, and soxs in response to naocl. we generated strains δsoxs and δmara, which were 20 times more sensitive to naocl as compared to the wild-type strain; while δrob only 5 times. subsequently, we determined that mara and soxs transcript and protein l ...201222752112
construction of recombinant e. coli nissle 1917 (ecn) strains for the expression and secretion of defensins.the probiotic escherichia coli strain nissle 1917 (ecn) is one of the few probiotics licensed as a medication in several countries. best documented is its effectiveness in keeping patients suffering from ulcerative colitis (uc) in remission. this might be due to its ability to induce the production of human β-defensin 2 (hbd2) in a flagellin-dependent way in intestinal epithelial cells. in contrast to ulcerative colitis, for crohn's disease (cd) convincing evidence is lacking that ecn might be c ...201222748509
traditional copper water storage vessels and sub-lethal injury of salmonella enterica serovar typhi and vibrio cholerae.recent studies on escherichia coli have demonstrated sub-lethal injury-sensitivity to oxygen and selective agents prior to irreversible inactivation when kept in water in a brass vessel. the present study was carried out to investigate whether equivalent responses occur in copper vessels using the pathogens salmonella enterica serovar typhi and vibrio cholerae. bacterial suspensions were stored in water in a traditional copper vessel for up to 24 h at 30 °c. samples were withdrawn and plated on ...201222717752
scano-magneto immunoassay based on carbon nanotubes/gold nanoparticles nanocomposite for salmonella enterica serovar typhimurium detection.to improve sensitivity of s. enterica serovar typhimurium detection, multiwalled carbon nanotubes (mwcnts) and gold nanoparticles (aunps) were combined and used as a label to amplify signal in a scanometric based assay. in this study, the mwcnts/aunps nanocomposite was fabricated by directly assemble of au(3+) to mwcnts and allowed growing of aunps along the mwcnts surface. this mwcnts/aunps nanocomposite was then attached to anti-s. typhimurium antibody (mwcnts/aunps/ab(1)) and used as a detect ...201222705403
the application of stem and in situ controlled dehydration to bacterial systems using esem.transmission imaging with an environmental scanning electron microscope (esem) (wet stem) is a recent development in the field of electron microscopy, combining the simple preparation inherent to esem work with an alternate form of contrast available through a stem detector. because the technique is relatively new, there is little information available on how best to apply this technique and which samples it is best suited for. this work is a description of the sample preparation and microscopy ...201222689513
receptor-independent interaction of bacterial lipopolysaccharide with lipid and lymphocyte membranes; the role of cholesterol.lipopolysaccharide (lps) is a major constituent of bacterial outer membranes where it makes up the bulk of the outer leaflet and plays a key role as determinant of bacterial interactions with the host. membrane-free lps is known to activate t-lymphocytes through interactions with toll-like receptor 4 via multiprotein complexes. in the present study, we investigate the role of cholesterol and membrane heterogeneities as facilitators of receptor-independent lps binding and insertion, which underpi ...201222685597
impact of hfq on the intrinsic drug resistance of salmonella enterica serovar typhimurium.salmonella enterica is an important enteric pathogen, and its various serovars cause both systemic and intestinal diseases in humans and domestic animals. the emergence of multidrug-resistant strains of salmonella, leading to increased morbidity and mortality, has further complicated its management. hfq is an rna chaperon that mediates the binding of small rnas to mrna and assists in post-transcriptional gene regulation in bacteria. although hfq is related to important phenotypes including virul ...201222675323
antibiotic resistance of salmonella enterica serovar typhi in kolkata, india, and in vitro experiments on effect of combined chemotherapy.this communication states the changing patterns of salmonella enterica serovar typhi (s. typhi) isolates causing enteric fever in and around kolkata, india. among the isolates resistance to ampicillin (a), chloramphenicol (c), cotrimoxazole (co) and tetracycline (t) were plasmid mediated; the plasmid was unstable in s. typhi, and the other enteric bacteria like escherichia coli, klebsiella pneumoniae and proteus vulgaris were found to be the potential source of dissemination of such plasmids int ...201222666124
antimicrobial food packaging film based on the release of lae from evoh.the aim of this work was to develop antimicrobial films for active packaging applications containing the natural antimicrobial compound lae (lauramide arginine ethyl ester) in evoh copolymers with different mol % ethylene contents (i.e. evoh-29 and evoh-44). evoh-29 and evoh-44 films were made by casting and incorporating 0.25%, 1%, 5%, and 10% lae in the film forming solution (w/w with respect to polymer weight). previously, the minimum inhibitory concentration (mic) and the minimum bactericida ...201222640726
development of antimicrobial films for microbiological control of packaged salad.the aim of the present work was to characterize the antimicrobial efficiency of films consisting of pp/evoh structures with oregano essential oil and citral. both substances are known for their antimicrobial activity based on their interaction with the cell membrane. the films developed were used to pack minimally processed salads, combining modified atmosphere technology to extend shelf-life and active packaging technology to reduce possible microbiological risks. the antimicrobial activity of ...201222633535
community-acquired bacterial bloodstream infections in developing countries in south and southeast asia: a systematic review.information about community-acquired bacteraemia in developing countries in south and southeast asia is scarce. we aimed to establish the case fraction of bacteraemia in febrile patients admitted to hospital. we searched four databases and identified studies of south and southeast asia published between 1990 and 2010 that prospectively assessed patients admitted to hospital and from whom a blood culture was taken. we reviewed 17 eligible studies describing 40,644 patients. pathogenic organisms w ...201222632186
effects of indole on drug resistance and virulence of salmonella enterica serovar typhimurium revealed by genome-wide analyses.many gram-positive and gram-negative bacteria produce large quantities of indole as an intercellular signal in microbial communities. indole demonstrated to affect gene expression in escherichia coli as an intra-species signaling molecule. in contrast to e. coli, salmonella does not produce indole because it does not harbor tnaa, which encodes the enzyme responsible for tryptophan metabolism. our previous study demonstrated that e. coli-conditioned medium and indole induce expression of the acra ...201222632036
the acyl homoserine lactone receptor, sdia, of escherichia coli and salmonella enterica serovar typhimurium does not respond to indole.in this study, we tested the hypothesis that the sdia proteins of escherichia coli and salmonella enterica serovar typhimurium respond to indole. while indole was found to have effects on gene expression and biofilm formation, these effects were not sdia dependent. however, high concentrations of indole did inhibit n-acyl-l-homoserine lactone (ahl) sensing by sdia. we conclude that sdia does not respond to indole but indole can inhibit sdia activity in e. coli and salmonella.201222610437
instability of escherichia coli r-factors in salmonella enterica serovar typhi involves formation of recombinant composite plasmid structures.in spite of a well-documented ability of samonella enterica typhi strains to receive r factors from escherichia coli and other enterobacteria, epidemiological data show that typhi is a rather poor host of antibiotic-resistance genes and in fact, of plasmids, suggesting that most of the plasmids naturally acquired by typhi strains become unstable and eventually segregate. we have previously reported evidence that each of three plasmids conjugatively transferred to s. enterica typhi experienced de ...201222579995
c1 inhibitor suppresses the endotoxic activity of a wide range of lipopolysaccharides and interacts with live gram-negative bacteria.human c1 inhibitor (c1inh) prevents endotoxin shock via a direct interaction with gram-negative bacterial lipopolysaccharide (lps) and improves survival in animal models of sepsis. in this report, we further characterize the interaction of c1inh with lps and whole live bacteria. we investigate c1inh interactions with lps from five different strains of gram-negative enteric bacteria known to participate in the pathogenesis of human sepsis. treatment with c1inh improved survival in mice with endot ...201222576004
characterization of salmonella enterica and detection of the virulence genes specific to diarrheagenic escherichia coli from poultry carcasses in ouagadougou, burkina faso.one hundred chicken carcasses purchased from three markets selling poultry in ouagadougou, burkina faso, between june 2010 and october 2010 were examined for their microbiological quality. the presence of salmonella was investigated using standard bacteriological procedures, and the isolates obtained were serotyped and tested for antimicrobial susceptibility. the presence of virulence-associated genes of the five main pathogroups of diarrheagenic escherichia coli-shiga toxin-producing e. coli (s ...201222551070
conversion of viable but nonculturable enteric bacteria to culturable by co-culture with eukaryotic cells.viable but nonculturable (vbnc) vibrio cholerae non-o1/non-o139, v. parahaemolyticus, enterohemorrhagic escherichia coli, enterotoxigenic e. coli, enteropathogenic e. coli, shigella flexneri, and salmonella enterica were converted to the culturable state by co-culture with selected eukaryotic cells, e.g., ht-29, caco-2, t84, hela, intestine 407, and cho cells.201222537150
variability of rna quality extracted from biofilms of foodborne pathogens using different kits impacts mrna quantification by qpcr.the biofilm formation by foodborne pathogens is known to increase the problem related with surface disinfection procedure in the food processing environment and consequent transmission of these pathogens into the population. messenger rna has been increasingly used to understand the action and the consequences of disinfectants in the virulence on such biofilms. rna quality is an important requirement for any rna-based analysis since the quality can impair the mrna quantification. therefore, we e ...201222526569
antioxidant and antibacterial activities of the leaf essential oil and its constituents furanodienone and curzerenone from lindera pulcherrima (nees.) benth. ex hook. f.lindera pulcherrima (nees.) benth. ex hook. f. (family: lauraceae), an evergreen shrub, is an important medicinal plant distributed in temperate himalayan regions. the leaves and bark are used as spice in cold, fever, and cough.201222518079
detection and characterization of pct-like plasmid vectors for blactx-m-14 in escherichia coli isolates from humans, turkeys and cattle in england and wales.to detect and characterize escherichia coli strains and pct-like plasmids implicated in the dissemination of the ctx-m-14 gene in animals and humans, in england and wales.201222514265
the missing link in coenzyme a biosynthesis: panm (formerly yhhk), a yeast gcn5 acetyltransferase homologue triggers aspartate decarboxylase (pand) maturation in salmonella enterica.coenzyme a (coa) is an essential cofactor for all forms of life. the biochemistry underpinning the assembly of coa in escherichia coli and other enterobacteria is well understood, except for the events leading to maturation of the l-aspartate-α-decarboxylase (pand) enzyme that converts pantothenate to β-alanine. pand is synthesized as pro-pand, which undergoes an auto-proteolytic cleavage at residue ser25 to yield the catalytic pyruvoyl moiety of the enzyme. since 1990, it has been known that e. ...201222497218
salmonella chemoreceptors mcpb and mcpc mediate a repellent response to l-cystine: a potential mechanism to avoid oxidative conditions.chemoreceptors mcpb and mcpc in salmonella enterica have been reported to promote chemotaxis in lb motility-plate assays. of the chemicals tested as potential effectors of these receptors, the only response was towards l-cysteine and its oxidized form, l-cystine. although enhanced radial migration in plates suggested positive chemotaxis to both amino acids, capillary assays failed to show an attractant response to either, in cells expressing only these two chemoreceptors. in vivo fluorescence re ...201222486902
functional and expressional analyses of the anti-flhd4c2 factor gene ydiv in escherichia coli.although escherichia coli and salmonella enterica serovar typhimurium have a similar flagellar regulatory system, the response of flagellar synthesis to nutrient conditions is quite different between the two: that is, in low-nutrient conditions, flagellar synthesis is inhibited in salmonella and enhanced in e. coli. in salmonella, this inhibition is mediated by an anti-flhd(4)c(2) factor, ydiv, which is expressed in low-nutrient conditions and binds to flhd(4)c(2) to inhibit the expression of th ...201222461489
extracellular proteins from lactobacillus plantarum bmcm12 prevent adhesion of enteropathogens to mucin.the aim of this study was to study the interference of the extracellular proteins produced by lactobacillus plantarum bmcm12 with the adhesion of some well-known gut pathogens. the extracellular proteins secreted by l. plantarum bmcm12 in mrs broth were precipitated, resolved by sds-page, and identified by tandem mass spectrometry. discordances between the observed and the theoretical molecular masses of several proteins suggested the presence of protein glycosylation, corroborated with specific ...201222461079
acidic ph: enemy or ally for enteric bacteria?the first stress that foodborne pathogens find upon ingestion is the very acidic ph of the stomach of the host. in addition, intracellular pathogens like salmonella are submitted to low ph inside the host cells. two general acid survival systems are found in these organisms: acid resistance mechanisms and acid tolerance responses. these mechanisms involve the synthesis of a series of acid shock proteins. only a subset of these proteins is directly involved in acid survival. this is related to th ...201222460638
high-density transcriptional initiation signals underline genomic islands in bacteria.genomic islands (gis), frequently associated with the pathogenicity of bacteria and having a substantial influence on bacterial evolution, are groups of "alien" elements which probably undergo special temporal-spatial regulation in the host genome. are there particular hallmark transcriptional signals for these "exotic" regions? we here explore the potential transcriptional signals that underline the gis beyond the conventional views on basic sequence composition, such as codon usage and gc prop ...201222448273
loss of flhe in the flagellar type iii secretion system allows proton influx into salmonella and escherichia coli.flhe belongs to the flhbae flagellar operon in enterobacteria, whose first two members function in type iii secretion (t3s). in salmonella enterica, absence of flhe affects swarming, but not swimming, motility. based on a chance observation of a 'green' colony phenotype of flhe mutants on ph indicator plates containing glucose, we have established that this phenotype is associated with lysis of flagellated cells in an acidic environment created by glucose metabolism. the flhe mutant phenotype of ...201222435757
a simple method for construction of pir+ enterobacterial hosts for maintenance of r6k replicon plasmids.the r6k replicon is one of the best studied bacterial plasmid replicons. replication of the r6k plasmid and derivatives harboring its γ origin of replication (ori(r6kγ)) is dependent on the pir gene-encoded π protein. originally encoded by r6k, this protein is usually provided in trans in hosts engineered to support replication of plasmids harboring ori(r6kγ). in escherichia coli this is commonly achieved by chromosomal integration of pir either via lysogenization with a λpir phage or homologous ...201222433797
riboswitch control of rho-dependent transcription termination.riboswitches are rna sensors that regulate gene expression upon binding specific metabolites or ions. bacterial riboswitches control gene expression primarily by promoting intrinsic transcription termination or by inhibiting translation initiation. we now report a third general mechanism of riboswitch action: governing the ability of the rna-dependent helicase rho to terminate transcription. we establish that rho promotes transcription termination in the mg(2+)-sensing mgta riboswitch from salmo ...201222431636
bacteriophage-encoded bacterial virulence factors and phage-pathogenicity island interactions.the role of bacteriophages as natural vectors for some of the most potent bacterial toxins is well recognized and includes classical type i membrane-acting superantigens, type ii pore-forming lysins, and type iii exotoxins, such as diphtheria and botulinum toxins. among gram-negative pathogens, a novel class of bacterial virulence factors called effector proteins (eps) are phage encoded among pathovars of escherichia coli, shigella spp., and salmonella enterica. this chapter gives an overview of ...201222420852
functional characterization of udp-glucose:undecaprenyl-phosphate glucose-1-phosphate transferases of escherichia coli and caulobacter crescentus.escherichia coli k-12 wcaj and the caulobacter crescentus hfse, pssy, and pssz enzymes are predicted to initiate the synthesis of colanic acid (ca) capsule and holdfast polysaccharide, respectively. these proteins belong to a prokaryotic family of membrane enzymes that catalyze the formation of a phosphoanhydride bond joining a hexose-1-phosphate with undecaprenyl phosphate (und-p). in this study, in vivo complementation assays of an e. coli k-12 wcaj mutant demonstrated that wcaj and pssy can c ...201222408159
microelectrode array biosensor for studying carbohydrate-mediated interactions.carbohydrate-mediated host-pathogen interactions are essential to bacterial and viral pathogenesis, and represent an attractive target for the development of antiadhesives to prevent infection. we present a versatile microelectrode array-based platform to investigate carbohydrate-mediated protein and bacterial binding, with the objective of developing a generalizable method for screening inhibitors of host-microbe interactions. microelectrode arrays are well suited for interrogating biological b ...201222405843
discovery and characterization of coturnix chinensis avian β-defensin 10, with broad antibacterial activity.a novel avian β-defensin (avbd), avbd10, was discovered in the liver and bone marrow tissues from chinese painted quail (coturnix chinensis) in the present study. the complete nucleotide sequence of quail avbd10 contains a 207-bp open reading frame that encodes 68 amino acids. the quail avbd10 was expressed widely in all the tissues from quails except the tongue, crop, breast muscle, and thymus and was highly expressed in the bone marrow. in contrast to the expression pattern of avbd10 in tissue ...201222389044
stability, entrapment and variant formation of salmonella genomic island 1.the salmonella genomic island 1 (sgi1) is a 42.4 kb integrative mobilizable element containing several antibiotic resistance determinants embedded in a complex integron segment in104. the numerous sgi1 variants identified so far, differ mainly in this segment and the explanations of their emergence were mostly based on comparative structure analyses. here we provide experimental studies on the stability, entrapment and variant formation of this peculiar gene cluster originally found in s. typhim ...201222384263
studies on extended spectrum beta lactamase (esbl) producing salmonella isolates from clinical samples of nepal.present study was carried out among the patients of age 2-60 years from november 2009 to november 2011 to assess the production of extended spectrum beta lactamase (esbl) by salmonella enterica serotype (typhi and paratyphi a) at kanti children's hospital (kch), nepal medical college (nmc), kathmandu medical college (kmc), national public health laboratory (nphl) and sankata laboratory (skl) of nepal. blood cultures were obtained from 4,820 patients with febrile illnesses. 400 strains of salmone ...201224047016
mobile effector proteins on phage genomes.bacteriophage genomes found in a range of bacterial pathogens encode a diverse array of virulence factors ranging from superantigens or pore forming lysins to numerous exotoxins. recent studies have uncovered an entirely new class of bacterial virulence factors, called effector proteins or effector toxins, which are encoded within phage genomes that reside among several pathovars of escherichia coli and salmonella enterica. these effector proteins have multiple domains resulting in proteins that ...201223275865
a novel target of iscs in escherichia coli: participating in dna phosphorothioation.many bacterial species modify their dna with the addition of sulfur to phosphate groups, a modification known as dna phosphorothioation. dnda is known to act as a cysteine desulfurase, catalyzing a key biochemical step in phosphorothioation. however, bioinformatic analysis revealed that 19 out of the 31 known dnd gene clusters, contain only four genes (dndb-e), lacking a key cysteine desulfurase corresponding gene. there are multiple cysteine desulfurase genes in escherichia coli, but which one ...201223240007
characterization of curli a production on living bacterial surfaces by scanning probe microscopy.curli are adhesive surface fibers produced by many enterobacteriaceae, such as escherichia coli and salmonella enterica. they are implicated in bacterial attachment and invasion to epithelial cells. in this study, atomic force microscopy was used to determine the effects of curli on topology and mechanical properties of live e. coli cells. young's moduli of both curli-deficient and curli-overproducing mutants were significantly lower than that of their wild-type (wt) strain, while decay lengths ...201223083709
behaviour of co-inoculated pathogenic and spoilage bacteria on poultry following several decontamination treatments.the potential of chemical decontaminants to cause harmful effects on human health is among the causes of the rejection of antimicrobial treatments for removing surface contamination from poultry carcasses in the european union. this study was undertaken to determine whether decontaminants might give a competitive advantage to pathogenic bacteria on poultry and involve a potential risk to consumer. a total of 144 chicken legs were co-inoculated with similar concentrations of pathogenic bacteria ( ...201223072701
immunological characterization of recombinant salmonella enterica serovar typhi flic protein expressed in escherichia coli.like any other enteric pathogen, salmonella also encounters acidic stress in the stomach as well as within the host macrophage milieu. however, the pathogen is reported to combat this stress through acid tolerance response (atr), expressing a number of genes and eventually the proteins. recently, an acid induced outer membrane phenotype encoded by flic gene in salmonella enterica serovar typhi has been identified. in the present study, flic gene was cloned to study its biological implications. t ...201223067582
evolution of transcriptional regulation in closely related bacteria.the exponential growth of the number of fully sequenced genomes at varying taxonomic closeness allows one to characterize transcriptional regulation using comparative-genomics analysis instead of time-consuming experimental methods. a transcriptional regulatory unit consists of a transcription factor, its binding site and a regulated gene. these units constitute a graph which contains so-called "network motifs", subgraphs of a given structure. here we consider genomes of closely related enteroba ...201223039862
molecular characterization of the viab locus encoding the biosynthetic machinery for vi capsule formation in salmonella typhi.the vi capsular polysaccharide (cps) of salmonella enterica serovar typhi, the cause of human typhoid, is important for infectivity and virulence. the vi biosynthetic machinery is encoded within the viab locus composed of 10 genes involved in regulation of expression (tvia), polymer synthesis (tvib-tvie), and cell surface localization of the cps (vexa-vexe). we cloned the viab locus from s. typhi and transposon insertion mutants of individual viab genes were characterized in escherichia coli dh5 ...201223029132
fruit, a scar-free system for targeted chromosomal mutagenesis, epitope tagging, and promoter replacement in escherichia coli and salmonella enterica.recombineering is a widely-used approach to delete genes, introduce insertions and point mutations, and introduce epitope tags into bacterial chromosomes. many recombineering methods have been described, for a wide range of bacterial species. these methods are often limited by (i) low efficiency, and/or (ii) introduction of "scar" dna into the chromosome. here, we describe a rapid, efficient, pcr-based recombineering method, fruit, that can be used to introduce scar-free point mutations, deletio ...201223028641
ygiw homologous gene from pseudomonas aeruginosa 25w is responsible for tributyltin resistance.a tributyltin (tbt) resistance gene was isolated from the tbt-resistant marine origin bacterium pseudomonas aeruginosa 25w. this gene was identical to pa0320 deposited in the p. aeruginosa pao1 database (http://www.pseudomonas.com). the deduced amino acid sequence of pa0320 appears to be homologous to the ygiw proteins of escherichia coli and salmonella enterica. the deletion mutant of pa0320 showed a reduction of growth rate in the presence of tbt. a susceptibility test to cadmium, mercury, hyd ...201222990488
discovery and biological characterization of geranylated rna in bacteria.a general ms-based screen for unusually hydrophobic cellular small molecule-rna conjugates revealed geranylated rna in escherichia coli, enterobacter aerogenes, pseudomonas aeruginosa and salmonella enterica var. typhimurium. the geranyl group is conjugated to the sulfur atom in two 5-methylaminomethyl-2-thiouridine nucleotides. these geranylated nucleotides occur in the first anticodon position of trna(glu)(uuc), trna(lys)(uuu) and trna(gln)(uug) at a frequency of up to 6.7% (~400 geranylated n ...201222983156
a dual tag system for facilitated detection of surface expressed proteins in escherichia coli.the discovery of the autotransporter family has provided a mechanism for surface expression of proteins in laboratory strains of escherichia coli. we have previously reported the use of the aida-i autotransport system to express the salmonella enterica serovar enteritidis proteins sefa and h:gm. the sefa protein was successfully exposed to the medium, but the orientation of h:gm in the outer membrane could not be determined due to proteolytic cleavage of the n-terminal detection-tag. the goal of ...201222943700
escherichia coli strongly supports the growth of histomonas meleagridis, in a monoxenic culture, without influence on its pathogenicity.based on clonal cultures of histomonas meleagridis, monoxenic cultures have, to our knowledge for the first time, been established in a liquid medium. the faecal flora was exchanged for defined bacterial strains by selective destruction of the initial bacteria with a variety of antibiotics, keeping the flagellate alive. the growth of the protozoan parasite was found to depend on the bacteria, especially on their energy metabolism. escherichia coli was found to strongly support the growth of the ...201222921600
dbdiarrhea: the database of pathogen proteins and vaccine antigens from diarrheal pathogens.diarrhea occurs world-wide and is most commonly caused by gastrointestinal infections which kill around 2.2 million people globally each year, mostly children in developing countries. we describe here dbdiarrhea, which is currently the most comprehensive catalog of proteins implicated in the pathogenesis of diarrhea caused by major bacterial, viral and parasitic species. the current release of the database houses 820 proteins gleaned through an extensive and critical survey of research articles ...201222917656
rates of gyrase supercoiling and transcription elongation control supercoil density in a bacterial chromosome.gyrase catalyzes negative supercoiling of dna in an atp-dependent reaction that helps condense bacterial chromosomes into a compact interwound "nucleoid." the supercoil density (σ) of prokaryotic dna occurs in two forms. diffusible supercoil density (σ(d)) moves freely around the chromosome in 10 kb domains, and constrained supercoil density (σ(c)) results from binding abundant proteins that bend, loop, or unwind dna at many sites. diffusible and constrained supercoils contribute roughly equally ...201222916023
bacteria and protozoa differentially modulate the expression of rab proteins.phagocytic cells represent an important line of innate defense against microorganisms. uptake of microorganisms by these cells involves the formation of a phagosome that matures by fusing with endocytic compartments, resulting in killing of the enclosed microbe. small gtpases of the rab family are key regulators of vesicular trafficking in the endocytic pathway. intracellular pathogens can interfere with the function of these proteins in order to subvert host immune responses. however, it is unk ...201222911692
molecular characterization of antibiotic-resistant bacteria in contaminated chicken meat sold at supermarkets in bangkok, thailand.we assessed contamination by antibiotic-resistant bacteria in chicken meat obtained from supermarkets in bangkok, thailand. the prevalence of salmonella enterica and escherichia coli was 18.7% (14/75) and 53% (106/200), respectively. most probable number (mpn) analysis showed that 56.7% of the samples (34/60) were in violation of the limit of allowable coliform bacteria in chicken meat, for which the maximum is 46,000 mpn/g. multidrug-resistant phenotypes of both s. enterica and e. coli were fou ...201223183206
complete genome sequence of the novel lytic avian pathogenic coliphage nj01.bacteriophages of the c3 morphotype, characterized by very long heads that exceed their width several times, are extremely rare among the podoviridae family members and constitute only 0.5% of over 5,500 phages that have been examined by the electron microscope (h. w. ackermann, arch. virol. 152:227-243, 2007; h. w. ackermann, arch. virol. 146:843-857, 2001). to date, among those phages proven to be c3, only coliphage phieco32, lactococcus phage ksy1, vibrio phage 71a-6, and salmonella enterica ...201223166270
solar inactivation of four salmonella serovars in fresh and marine waters.sunlight-mediated disinfection of water is of interest to both the drinking and recreational water quality community of researchers due to its potential to reduce microbial contamination and waterborne illness. photo-inactivation of enteric bacteria has primarily been investigated using escherichia coli and laboratory strains of model bacteria. the present study sought to document the photo-inactivation of environmental isolates of salmonella in filter-sterilized natural seawater and freshwater ...201223165707
a novel synthetic peptide from a tomato defensin exhibits antibacterial activities against helicobacter pylori.defensins are a class of cysteine-rich proteins, which exert broad spectrum antimicrobial activity. in this work, we used a bioinformatic approach to identify putative defensins in the tomato genome. fifteen proteins had a mature peptide that includes the well-conserved tetradisulfide array. we selected a representative member of the tomato defensin family; we chemically synthesized its γ-motif and tested its antimicrobial activity. here, we demonstrate that the synthetic peptide exhibits potent ...201223124812
lack of direct effects of agrochemicals on zoonotic pathogens and fecal indicator bacteria.agrochemicals, fecal indicator bacteria (fib), and pathogens frequently contaminate water simultaneously. no significant direct effects of fertilizer, atrazine, malathion, and chlorothalonil on the survival of escherichia coli, enterococcus faecalis, salmonella enterica, human polyomaviruses, and adenovirus were detected, supporting the assertion that previously observed effects of agrochemicals on fib were indirect.201222961900
no beneficial effects evident for enterococcus faecium ncimb 10415 in weaned pigs infected with salmonella enterica serovar typhimurium dt104.salmonella enterica serovar typhimurium dt 104 is the major pathogen for salmonellosis outbreaks in europe. we tested if the probiotic bacterium enterococcus faecium ncimb 10415 can prevent or alleviate salmonellosis. therefore, piglets of the german landrace breed that were treated with e. faecium (n = 16) as a feed additive and untreated controls (n = 16) were challenged with s. typhimurium 10 days after weaning. the presence of salmonellae in feces and selected organs, as well as the immune r ...201222544257
efficacy of multiple metals against copper-resistant bacterial strains.the antibacterial efficacy of zeolites containing copper (cu) or silver (ag) ions or a combination was assessed against several reported copper-resistant (cu(r)) bacterial strains.201222277101
immunostimulatory effects of recombinant erysipelothrix rhusiopathiae expressing porcine interleukin-18 in mice and pigs.interleukin-18 (il-18), which was originally called gamma interferon (ifn-γ)-inducing factor, has been shown to play an important role in innate and acquired immune responses. in this study, attenuated erysipelothrix rhusiopathiae strains were engineered to produce porcine il-18 (poil-18) and evaluated for their potential immunostimulatory effect in animals. recombinant poil-18 was successfully expressed in the recombinant e. rhusiopathiae strains ys-1/il-18 and ko/il-18. the culture supernatant ...201222761300
residual viral and bacterial contamination of surfaces after cleaning and disinfection.environmental surfaces contaminated with pathogens can be sources of indirect transmission, and cleaning and disinfection are common interventions focused on reducing contamination levels. we determined the efficacy of cleaning and disinfection procedures for reducing contamination by noroviruses, rotavirus, poliovirus, parechovirus, adenovirus, influenza virus, staphylococcus aureus, and salmonella enterica from artificially contaminated stainless steel surfaces. after a single wipe with water, ...201222941071
bioengineered nisin a derivatives with enhanced activity against both gram positive and gram negative pathogens.nisin is a bacteriocin widely utilized in more than 50 countries as a safe and natural antibacterial food preservative. it is the most extensively studied bacteriocin, having undergone decades of bioengineering with a view to improving function and physicochemical properties. the discovery of novel nisin variants with enhanced activity against clinical and foodborne pathogens has recently been described. we screened a randomized bank of nisin a producers and identified a variant with a serine to ...201223056510
assessment of a regulatory sanitization process in egyptian dairy plants in regard to the adherence of some food-borne pathogens and their biofilms.food-borne pathogens may develop certain strategies that enable them to defy harsh conditions such as chemical sanitization. biofilm formation represents a prominent one among those adopted strategies, by which food-borne pathogens protect themselves against external threats. thus, bacterial biofilm is considered as a major hazard for safe food production. this study was designed to investigate the adherence and the biofilm formation ability of some food-borne pathogens on stainless steel and po ...201222884171
glass wool filters for concentrating waterborne viruses and agricultural zoonotic pathogens.the key first step in evaluating pathogen levels in suspected contaminated water is concentration. concentration methods tend to be specific for a particular pathogen group, for example us environmental protection agency method 1623 for giardia and cryptosporidium, which means multiple methods are required if the sampling program is targeting more than one pathogen group. another drawback of current methods is the equipment can be complicated and expensive, for example the viradel method with th ...201222415031
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