Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
|---|
| characterization of srga, a salmonella enterica serovar typhimurium virulence plasmid-encoded paralogue of the disulfide oxidoreductase dsba, essential for biogenesis of plasmid-encoded fimbriae. | disulfide oxidoreductases are viewed as foldases that help to maintain proteins on productive folding pathways by enhancing the rate of protein folding through the catalytic incorporation of disulfide bonds. srga, encoded on the virulence plasmid pstsr100 of salmonella enterica serovar typhimurium and located downstream of the plasmid-borne fimbrial operon, is a disulfide oxidoreductase. sequence analysis indicates that srga is similar to dsba from, for example, escherichia coli, but not as high ... | 2003 | 12533475 |
| 1-methylguanosine-deficient trna of salmonella enterica serovar typhimurium affects thiamine metabolism. | in salmonella enterica serovar typhimurium a mutation in the purf gene encoding the first enzyme in the purine pathway blocks, besides the synthesis of purine, the synthesis of thiamine when glucose is used as the carbon source. on carbon sources other than glucose, a purf mutant does not require thiamine, since the alternative pyrimidine biosynthetic (apb) pathway is activated. this pathway feeds into the purine pathway just after the purf biosynthetic step and upstream of the intermediate 4-am ... | 2003 | 12533450 |
| household contamination with salmonella enterica. | household contamination with salmonella enterica increases when occupational exposure exists (cattle farms with known salmonellosis in cattle, a salmonella research laboratory, or a veterinary clinic experiencing an outbreak of salmonellosis). fifteen of 55 (27.2%) vacuum cleaner bags from households with occupational exposure to s. enterica were positive versus 1 of 24 (4.2%) without known exposure. use of a carpet cleaner and several cleaners/disinfectants reduced, but failed to eliminate, s. ... | 2003 | 12533294 |
| therapeutic efficacy of an e coli strain carrying an ovalbumin allergenic peptide as a fused protein to ompc in a murine model of allergic airway inflammation. | an escherichia coli strain expressing the ovalbumin (ova) 323-329 allergenic peptide on the bacterial surface was evaluated for its ability to reduce the lung inflammatory response in mice allergic to ova. balb/c mice were rendered allergic by means of two intraperitoneal injections of ova suspended in alum 5 days apart, and one intratracheal boost 1 week later. the mice were then treated with two intranasal, 1 week apart, doses of 4x10(9) e. coli-uh302 transformed with plasmids pst13 or pst13-o ... | 2003 | 12531657 |
| animal models paving the way for clinical trials of attenuated salmonella enterica serovar typhi live oral vaccines and live vectors. | attenuated salmonella enterica serovar typhi (s. typhi) strains can serve as safe and effective oral vaccines to prevent typhoid fever and as live vectors to deliver foreign antigens to the immune system, either by the bacteria expressing antigens through prokaryotic expression plasmids or by delivering foreign genes carried on eukaryotic expression systems (dna vaccines). the practical utility of such live vector vaccines relies on achieving a proper balance between minimizing the vaccine's rea ... | 2003 | 12531639 |
| towards new immunotherapies: targeting recombinant cytokines to the immune system using live attenuated salmonella. | we have used salmonella as a delivery system for eukaryotic expression plasmids encoding cytokines, and assessed its capacity to modulate immune responses in different experimental models. plasmids encoding mouse il-4 and il-18 under cytomegalovirus promoter were constructed and transformed into live attenuated salmonella enterica serovar typhi strain cvd 908-htra, and salmonella enterica serovar typhimurium strain sl3261. we have shown that systemic as well as mucosal immunization with such con ... | 2003 | 12531363 |
| isolated splenic infarction owing to group b salmonella: case report. | the clinical spectrum of extra-intestinal salmonellosis, comprising enteric fever and invasive infections owing to non-typhoidal salmonellae, is well known. we report an otherwise healthy patient with isolated splenic infarction caused by group b salmonella. she was seropositive for the o antigen of salmonella group b and stool cultures were positive for group b salmonellae. after appropriate antimicrobial therapy, her complaints disappeared and microbiological tests for salmonellae became negat ... | 2002 | 12530289 |
| the interplay between salmonella typhimurium and its macrophage host--what can it teach us about innate immunity? | salmonella enterica sv. typhimurium (s. typhimurium) is a genetically tractable, facultative intracellular pathogen, whose capacity to cause systemic disease in mice depends upon its ability to survive and replicate within macrophages. the identification of salmonella mutants that lack this activity, has provided a tool with which to dissect the mechanisms used by salmonella to establish a permissive niche, and identify host activities which it must overcome in order to achieve this. salmonella ... | 2003 | 12527226 |
| caenorhabditis elegans innate immune response triggered by salmonella enterica requires intact lps and is mediated by a mapk signaling pathway. | compared to mammals, insects, and plants, relatively little is known about innate immune responses in the nematode caenorhabditis elegans. previous work showed that salmonella enterica serovars cause a persistent infection in the c. elegans intestine that triggers gonadal programmed cell death (pcd) and that c. elegans cell death (ced) mutants are more susceptible to salmonella-mediated killing. to further dissect the role of pcd in c. elegans innate immunity, we identified both c. elegans and s ... | 2003 | 12526744 |
| regulation of capsule synthesis and cell motility in salmonella enterica by the essential gene igaa. | mutants of salmonella enterica carrying the igaa1 allele, selected as able to overgrow within fibroblast cells in culture, are mucoid and show reduced motility. mucoidy is caused by derepression of wca genes (necessary for capsule synthesis); these genes are regulated by the rcsc/yojn/rcsb phosphorelay system and by the rcsa coregulator. the induction of wca expression in an igaa1 mutant is suppressed by mutations in rcsa and rcsc. reduced motility is caused by lowered expression of the flagella ... | 2002 | 12524328 |
| antimicrobial resistance of salmonella serotypes isolated from slaughter-age pigs and environmental samples. | the aim of this study was to determine the antimicrobial resistance patterns of salmonella strains isolated from slaughter-age pigs and environmental samples collected at modern swine raising facilities in brazil. seventeen isolates of six serotypes of salmonella enterica subsp. enterica were isolated out of 1,026 collected samples: salmonella typhimurium (1), salmonella agona (5), salmonella sandiego (5), salmonella rissen (1), salmonella senftenberg (4), and salmonella javiana (1). resistance ... | 2002 | 12523640 |
| phenotypic and genotypic characterization of food animal isolates of salmonella with reduced sensitivity to ciprofloxacin. | reports of nontyphoidal salmonella enterica subsp. enterica showing reduced sensitivity to ciprofloxacin (rsc) have increased rapidly during the past decade. infection in humans with salmonella possessing rsc may compromise the effectiveness of ciprofloxacin therapy. nineteen among 4,357 salmonella strains isolated from food animals in canada from 1998 to 1999 showed rsc; 17 were from turkeys and 2 from chickens. all were resistant to nalidixic acid and sulfisoxazole and possessed rsc at a level ... | 2002 | 12523636 |
| the acrb multidrug transporter plays a major role in high-level fluoroquinolone resistance in salmonella enterica serovar typhimurium phage type dt204. | salmonella enterica serovar typhimurium phage type dt204 strains isolated from cattle and animal feed in belgium were characterized for high-level fluoroquinolone resistance mechanisms [mics to enrofloxacin (enr) and ciprofloxacin (cip), 64 and 32 microg/ml, respectively]. these strains isolated during the periods 1991-1994, and in 2000 were clonally related as shown by pulsed-field gel electrophoresis (pfge). selected strains studied carried several mutations in the quinolone target genes, i.e. ... | 2002 | 12523625 |
| characterization of the first extended-spectrum beta-lactamase-producing salmonella isolate identified in canada. | a single salmonella enterica serovar typhimurium isolate with an ut2 phage type producing an extended-spectrum beta-lactamase (esbl) was identified in canada in 2000. the isolate harbored two plasmids, one containing a bla(tem-1) gene and the other containing a bla(shv-2a) gene. the esbl gene was located on a 70-kb transferable plasmid which also carried tetracycline and trimethoprim resistance elements. | 2003 | 12517894 |
| subtyping of salmonella enterica serotype enteritidis strains by manual and automated psti-sphi ribotyping. | salmonella enterica subsp. enterica serotype enteritidis is not readily subtyped beyond the level of phage type (pt). a recently developed method for ribotyping of this organism, which uses a mixture of psti and sphi (ps) for restriction of dna (ps ribotyping), has proved useful for further subtyping of a number of pts of this organism, including pt 4. however, it has not been extensively tested with pt 8. in the present study the ps ribotyping method was used to investigate outbreaks of both s. ... | 2003 | 12517821 |
| inactivation of salmonella enterica serovar enteritidis by ultrasonic waves under pressure at different water activities. | the inactivation of salmonella enterica serovar enteritidis by ultrasonic waves (20 khz; 117- microm wavelength) under pressure (175 kpa) at nonlethal temperatures (manosonication [ms]) and lethal temperatures (manothermosonication [mts]) in media of different water activities has been investigated. heat decimal reduction time values increased 30 times when the water activity was decreased from nearly 1 to 0.96, but the ms resistance was increased only twofold. the inactivation of salmonella ser ... | 2003 | 12514058 |
| growth dynamics of salmonella enterica strains on alfalfa sprouts and in waste seed irrigation water. | alfalfa sprouts and other seed sprouts have been implicated in numerous outbreaks of salmonellosis. the source of these epidemics appears to have been low-level contamination of seeds by salmonella bacteria that developed into clinically significant populations during the seed germination process. to test the possibility that salmonella enterica strains carry host range determinants that allow them to grow on alfalfa, strains isolated from alfalfa or other sources were surveyed for their ability ... | 2003 | 12514040 |
| high ph during trisodium phosphate treatment causes membrane damage and destruction of salmonella enterica serovar enteritidis. | trisodium phosphate (tsp) is now widely used during the processing of poultry and red meats, but the mechanism whereby it inactivates gram-negative bacteria such salmonella spp. remains unclear. thus, salmonella enterica serovar enteritidis (atcc 4931) cells were treated with different concentrations of tsp (1.5, 2.0, and 2.5% [wt/vol]) and compared with (i) cells treated with the same ph as the tsp treatments (ph 10.0, 10.5, and 11.0, respectively) and (ii) cells treated with different concentr ... | 2003 | 12513986 |
| flagella and motility in actinobacillus pleuropneumoniae. | actinobacillus pleuropneumoniae has been considered nonmotile and nonflagellate. in this work, it is demonstrated that a. pleuropneumoniae produces flagella composed of a 65-kda protein with an n-terminal amino acid sequence that shows 100% identity with those of escherichia coli, salmonella, and shigella flagellins. the dna sequence obtained through pcr of the flic gene in a. pleuropneumoniae showed considerable identity (93%) in its 5' and 3' ends with the dna sequences of corresponding genes ... | 2003 | 12511514 |
| genomic comparison of salmonella enterica serovars and salmonella bongori by use of an s. enterica serovar typhimurium dna microarray. | the genus salmonella consists of over 2,200 serovars that differ in their host range and ability to cause disease despite their close genetic relatedness. the genetic factors that influence each serovar's level of host adaptation, how they evolved or were acquired, their influence on the evolution of each serovar, and the phylogenic relationships between the serovars are of great interest as they provide insight into the mechanisms behind these differences in host range and disease progression. ... | 2003 | 12511502 |
| transcription of the salmonella invasion gene activator, hila, requires hild activation in the absence of negative regulators. | salmonella enterica serovar typhimurium causes human gastroenteritis and a systemic typhoid-like infection in mice. infection is initiated by entry of the bacteria into intestinal epithelial cells and is mediated by a type iii secretion system that is encoded by genes in salmonella pathogenicity island 1. the expression of invasion genes is tightly regulated by environmental conditions such as oxygen and osmolarity, as well as by many bacterial factors. the hila gene encodes an ompr/toxr family ... | 2003 | 12511499 |
| salmonella enterica serovar typhimurium rdoa is growth phase regulated and involved in relaying cpx-induced signals. | the disulfide oxidoreductase, dsba, mediates disulfide bond formation in proteins as they enter or pass through the periplasm of gram-negative bacteria. although dsba function has been well characterized, less is known about the factors that control its expression. previous studies with escherichia coli demonstrated that dsba is part of a two-gene operon that includes an uncharacterized, upstream gene, yihe, that is positively regulated via the cpx stress response pathway. to clarify the role of ... | 2003 | 12511488 |
| effect of previous antimicrobial treatment on fecal shedding of salmonella enterica subsp. enterica serogroup b in new york dairy herds with recent clinical salmonellosis. | the association of herd- and sample-level factors with the isolation of salmonella group b from cattle fecal samples was analyzed. study farms were 65 dairy herds with a recent history of laboratory-confirmed clinical salmonella infections. herds were visited once per month for three months to collect data and samples for bacteriological culture. herd size varied widely from 34 to 3700 total cattle on the farm (median=370). salmonella serogroup b was isolated from 270 of 2726 samples tested. the ... | 2003 | 12507855 |
| mg2+ sensing by the mg2+ sensor phoq of salmonella enterica. | the phop/phoq two-component regulatory system governs the adaptation to low mg(2+) environments and virulence in several gram-negative species. during growth in low mg(2+), the sensor phoq modifies the activity of the response regulator phop promoting gene transcription, whereas growth in high mg(2+) represses transcription of phop-activated genes. the phoq protein harbors a periplasmic domain of 146 amino acid residues that binds mg(2+) in vitro and is required for mg(2+)-mediated repression in ... | 2003 | 12507481 |
| [community-acquired bacterial infections]. | corticosteroids in bacterial meningitis: a randomised multicentre study on meningitis in adults versus a placebo showed significant benefits of corticoids in terms of reduction in mortality and neurological complications. these results were essentially observed in pneumococcal infections. the interest in monitoring blood cultures: several works on staphylococcus aureus bacteremia have confirmed the necessity of monitoring hemocultures, 48-72 hours following initiation of treatment. the persisten ... | 2002 | 12497721 |
| oxyr acts as a repressor of catalase expression in neisseria gonorrhoeae. | it has been reported that neisseria gonorrhoeae possesses a very high level of catalase activity, but the regulation of catalase expression has not been investigated extensively. in escherichia coli and salmonella enterica serovar typhimurium, it has been demonstrated that oxyr is a positive regulator of hydrogen peroxide-inducible genes, including the gene encoding catalase. the oxyr gene from n. gonorrhoeae was cloned and used to complement an e. coli oxyr mutant, confirming its identity and f ... | 2003 | 12496210 |
| cholera toxin induces migration of dendritic cells from the subepithelial dome region to t- and b-cell areas of peyer's patches. | intestinal m cells deliver macromolecules, particles, and pathogens into the subepithelial dome (sed) region of peyer's patch mucosa, an area rich in dendritic cells (dcs). we tested whether uptake of the mucosal adjuvant cholera toxin (ct) or live salmonella bacteria can induce dc migration within peyer's patches. virus-sized, fluorescent polystyrene microparticles were efficiently transported by m cells and ingested by cd11c(+), cd11b(-), and cd8a(-) dcs in the sed region. dcs loaded with micr ... | 2003 | 12496201 |
| the salmonella enterica serovar typhimurium translocated effectors ssej and sifb are targeted to the salmonella-containing vacuole. | the salmonella enterica serovar typhimurium type iii secretion system (ttss) encoded in salmonella pathogenicity island 2 (spi-2) promotes replication within host cells and systemic infection of mice. the spi-2 ttss is expressed following salmonella internalization into host cells and translocates effectors across the membrane of the salmonella-containing vacuole (scv). two effectors with similar amino-terminal domains, ssej and sifb, localize to the scv membrane in infected hep-2 cells and subs ... | 2003 | 12496192 |
| impact of vector priming on the immunogenicity of recombinant salmonella vaccines. | there are conflicting reports concerning the impact of prior vector priming on the immunogenicity of recombinant-salmonella-based vaccines. a comparison of experimental protocols identified two variables which might account for this inconsistency: the potential of the vector strain to colonize the murine gut-associated lymphoid tissue (galt) and the nature of the foreign antigen subsequently delivered by the recombinant salmonella construct. the former was investigated by constructing an aroa mu ... | 2003 | 12496178 |
| identification of substrates and chaperone from the yersinia enterocolitica 1b ysa type iii secretion system. | all pathogenic yersinia enterocolitica strains carry the pyv plasmid encoding the ysc-yop type iii secretion (tts) system, which operates at 37 degrees c. in addition, biovar 1b y. enterocolitica strains possess a second, chromosomally encoded, tts system called ysa, which operates, at least in vitro, under low-temperature and high-salt (lths) conditions. six open reading frames, sycb, yspb, yspc, yspd, yspa, and acpy, neighbor the ysa genes encoding the ysa tts apparatus. here we show that yspa ... | 2003 | 12496172 |
| effective induction of acquired resistance to listeria monocytogenes by immunizing mice with in vivo-infected dendritic cells. | splenic dendritic cells (dcs) obtained from mice at 48 h after listeria monocytogenes infection exhibited up-regulation of cd80 and produced higher titers of gamma interferon (ifn-gamma) and interleukin-12 (il-12) than did dcs obtained from uninfected mice. mice immunized with dcs obtained from mice that had been infected with l. monocytogenes 48 h before acquired host resistance to lethal infection with l. monocytogenes at 4 and 8 weeks. immunization with dcs from heat-killed l. monocytogenes f ... | 2003 | 12496156 |
| interaction of pulmonary surfactant protein c with cd14 and lipopolysaccharide. | in addition to their effects on alveolar surface tension, some components of lung surfactant also have immunological functions. we found recently that the hydrophobic lung surfactant protein sp-c specifically binds to the lipid a region of lipopolysaccharide (lps). in this study, we show that sp-c also interacts with cd14. four observations showed cross talk between the three molecules sp-c, lps, and cd14. (i) like lbp, sp-c allows the binding of a fluorescent lps to cells expressing cd14 (the o ... | 2003 | 12496149 |
| oral immunization with atp-dependent protease-deficient mutants protects mice against subsequent oral challenge with virulent salmonella enterica serovar typhimurium. | we evaluated the efficacy of mutants with a deletion of the stress response protease gene as candidates for live oral vaccine strains against salmonella infection through infection studies with mice by using a salmonella enterica serovar typhimurium mutant with a disruption of the clpxp or lon protease. in vitro, the clpxp protease regulates flagellum synthesis and the clpxp-deficient mutant strain exhibits hyperflagellated bacterial cells (t. tomoyasu et al., j. bacteriol. 184:645-653, 2002). o ... | 2003 | 12496146 |
| molecular pathogenesis of salmonella enterica serotype typhimurium-induced diarrhea. | 2003 | 12496143 | |
| cytopathic effects observed upon expression of a repressed collagenase gene present in salmonella and related pathogens: mimicry of a cytotoxin from multiple antibiotic-resistant salmonella enterica serotype typhimurium phagetype dt104. | recently, we reported that certain strains of salmonella enterica serovar typhimurium phagetype dt104 (dt104) secrete a putative cytotoxin. while searching for the gene that encodes this toxin, we noted a previously reported but uncharacterized dna fragment (clg) in salmonella that could be potentially relevant to cytotoxin-like activity. therefore, we cloned and expressed clg in cytotoxin-negative escherichia coli and salmonella and subsequently assessed the bioactivity of clg in vitro and in v ... | 2002 | 12495674 |
| prevalence and antimicrobial susceptibility of salmonella serotypes in patients from ribeirão preto, são paulo, brazil, between 1985 and 1999. | salmonella strains isolated from 1,138 samples representing 28,199 biological materials (stool, urine, blood and other fluids), collected between january 1985 and january 1999 at a reference university hospital in ribeirão preto, são paulo, brazil, were studied. the most frequently detected serotypes were salmonella enterica subspecies enterica serotype 4,5,12:i:- (s. i 4,5,12:i:) (21.2%), s. agona (15.8%) and s. enteritidis (11.3%). a changing pattern of salmonella serotypes was observed betwee ... | 2002 | 12495606 |
| sir2-dependent activation of acetyl-coa synthetase by deacetylation of active lysine. | acetyl-coenzyme a (coa) synthetase (acs) is an enzyme central to metabolism in prokaryotes and eukaryotes. acs synthesizes acetyl coa from acetate, adenosine triphosphate, and coa through an acetyl-adenosine monophosphate (amp) intermediate. immunoblotting and mass spectrometry analysis showed that salmonella enterica acs enzyme activity is posttranslationally regulated by acetylation of lysine-609. acetylation blocks synthesis of the adenylate intermediate but does not affect the thioester-form ... | 2002 | 12493915 |
| resistance phenotypes and genotypes of multiresistant salmonella enterica subsp. enterica serovar typhimurium var. copenhagen isolates from animal sources. | 2003 | 12493808 | |
| unravelling the biology of macrophage infection by gene expression profiling of intracellular salmonella enterica. | for intracellular pathogens such as salmonellae, mycobacteriae and brucellae, infection requires adaptation to the intracellular environment of the phagocytic cell. the transition from extracellular to intravacuolar environment has been expected to involve a global modulation of bacterial gene expression, but the precise events have been difficult to determine. we now report the complete transcriptional profile of intracellular salmonella enterica sv. typhimurium following macrophage infection. ... | 2003 | 12492857 |
| lack of flagella disadvantages salmonella enterica serovar enteritidis during the early stages of infection in the rat. | the roles of flagella and five fimbriae (sef14, sef17, sef21, pef, lpf) in the early stages (up to 3 days) of salmonella enterica serovar enteritidis (s. enteritidis) infection have been investigated in the rat. wild-type strains la5 and s1400 (fim+/fla+) and insertionally inactivated mutants unable to express the five fimbriae (fim-/fla+), flagella (fim+/fla-) or fimbriae and flagella (fim-/fla-) were used. all wild-type and mutant strains were able to colonize the gut and spread to the mesente ... | 2003 | 12488571 |
| comparison of intestinal invasion and macrophage response of salmonella gallinarum and other host-adapted salmonella enterica serovars in the avian host. | the purpose of this investigation was to study the host specific infection of salmonella gallinarum in chickens and to determine the contribution of intestinal invasion and macrophage survival in relation to systemic infection in the host. this was carried out by comparing the kinetics of infection of s. gallinarum to that of other salmonella host-adapted (s. cholerae-suis, s. dublin and s. typhimurium) and host-specific (s. pullorum and s. abortus-ovis) serovars. establishment of the rate of co ... | 2003 | 12488070 |
| membrane topology of the zntb efflux system of salmonella enterica serovar typhimurium. | the membrane topology of the zntb zn(2+) transport protein of salmonella enterica serovar typhimurium was determined by constructing deletion derivatives of the protein and genetically fusing them to blam or lacz cassettes. the enzymatic activities of the hybrid proteins indicate that zntb is a bitopic integral membrane protein consisting largely of two independent domains. the first 266 amino acids form a large, highly charged domain within the cytoplasm, while the remaining 61 residues form a ... | 2003 | 12486076 |
| the stm4066 gene product of salmonella enterica serovar typhimurium has aminoimidazole riboside (airs) kinase activity and allows airs to satisfy the thiamine requirement of pur mutant strains. | in bacteria the biosynthetic pathways for purine mononucleotides and the hydroxymethyl pyrimidine moiety of thiamine share five reactions that result in the formation of aminoimidazole ribotide, the last metabolite common to both pathways. here we describe the characterization of a salmonella enterica mutant strain that has gained the ability to efficiently use exogenous aminoimidazole riboside (airs) as a source of thiamine. the lesion responsible for this phenotype is a null mutation in a tran ... | 2003 | 12486071 |
| lack of the apbc or apbe protein results in a defect in fe-s cluster metabolism in salmonella enterica serovar typhimurium. | the isc genes function in the assembly of fe-s clusters and are conserved in many prokaryotic and eukaryotic organisms. in most bacteria studied, the isc operon can be deleted without loss of cell viability, indicating that additional systems for fe-s cluster assembly must exist. several laboratories have described nutritional and biochemical defects resulting from mutations in the isc operon. here we demonstrate that null mutations in two genes of unknown function, apbc and apbe, result in simi ... | 2003 | 12486045 |
| o-antigen expression in salmonella enterica serovar typhi is regulated by nitrogen availability through rpon-mediated transcriptional control of the rfah gene. | the authors previously reported increased expression of the salmonella enterica serovar typhi (s. typhi) rfah gene when the bacterial cells reach stationary phase. in this study, using a lacz fusion to the rfah promoter region, they demonstrate that growth-dependent regulation of rfah expression occurs at the level of transcription initiation. it was also observed that production of the lipopolysaccharide (lps) o-antigen by s. typhi ty2 correlated with the differential expression of rfah during ... | 2002 | 12480883 |
| phage mediated horizontal transfer of the sope1 gene increases enteropathogenicity of salmonella enterica serotype typhimurium for calves. | epidemiological evidence shows that the sope1 gene is associated with salmonella typhimurium phage types causing epidemics in cattle. in this study we demonstrate that horizontal transfer of the sope1 gene by lysogenic conversion with the sopephi increased enteropathogenicity of s. typhimurium in the bovine ligated ileal loop model. these data support the hypothesis that phage mediated horizontal transfer of the sope1 gene contributes to the emergence of epidemic cattle-associated s. typhimurium ... | 2002 | 12480111 |
| co-localization of quantitative trait loci regulating resistance to salmonella typhimurium infection and specific antibody production phenotypes. | salmonella enterica serotype typhimurium is a facultative intracellular bacteria that induces systemic infection in mice. resistance to this pathogen is under polygenic control in which nramp1 is the major gene involved. lines of mice obtained by selective breeding for high (hiii) or low (liii) antibody response to flagellar antigens of salmonellae showed significant susceptibility differences, although both the lines display nramp1(r) alleles. the hiii line was extremely susceptible to infectio ... | 2002 | 12475631 |
| oxidation of propionate to pyruvate in escherichia coli. involvement of methylcitrate dehydratase and aconitase. | the pathway of the oxidation of propionate to pyruvate in escherichia coli involves five enzymes, only two of which, methylcitrate synthase and 2-methylisocitrate lyase, have been thoroughly characterized. here we report that the isomerization of (2s,3s)-methylcitrate to (2r,3s)-2-methylisocitrate requires a novel enzyme, methylcitrate dehydratase (prpd), and the well-known enzyme, aconitase (acnb), of the tricarboxylic acid cycle. acnb was purified as 2-methylaconitate hydratase from e. coli ce ... | 2002 | 12473114 |
| identification of the gene responsible for the cblb complementation group of vitamin b12-dependent methylmalonic aciduria. | the methylmalonic acidurias are metabolic disorders resulting from deficient methylmalonyl-coa mutase activity, a vitamin b(12)-dependent enzyme. we have cloned the gene for the cblb complementation group caused by deficient activity of a cob(i)alamin adenosyltransferase. this was accomplished by searching bacterial genomes for genes in close proximity to the methylmalonyl-coa mutase gene that might encode a protein with the properties of an adenosyltransferase. a candidate was identified in the ... | 2002 | 12471062 |
| alive but non-infectious. | 2002 | 12467699 | |
| results of a 5-year prospective surveillance study of antibiotic resistance among salmonella enterica isolates and ceftriaxone therapy among children hospitalized for acute diarrhea. | the spread of resistant salmonella strains continues to increase worldwide. it is necessary to establish epidemiologic information to determine an appropriate empiric antibiotic regimen (when indicated) in infants and children with suspected salmonella infections for whom the results of susceptibility tests are not yet available. | 2002 | 12462288 |
| combined application of simulated reuse and quantitative carrier tests to assess high-level disinfection: experiments with an accelerated hydrogen peroxide-based formulation. | heat-sensitive medical devices require chemical disinfection between patients, and certain formulations for this purpose can be reused for several days. because dilution, evaporation, and breakdown or neutralization of active ingredients can occur during reuse, it is vital to ensure that the solution retains its broad-spectrum germicidal activity even at the end of the recommended reuse period. | 2002 | 12461509 |
| identification of possible chicken intestinal mucosa receptors for sef21-fimbriated salmonella enterica serovar enteritidis. | in order to test whether glycosphingolipids (gsls) on the chicken intestinal mucosa serve as a receptor for salmonella enterica serovar enteritidis with fimbriae, we analyzed neutral gsls and gangliosides from chicken intestinal mucosa and investigated the binding of bacteria to neutral gsls and gangliosides. four kinds of neutral gsls, designated as n-1 to n-4 and four kinds of gangliosides, named g-1 to g-4, were identified on high-performance thin-layer chromatography (hptlc) plates. in tlc i ... | 2003 | 12458170 |
| entry and survival of salmonella enterica serotype enteritidis pt4 in chicken macrophage and lymphocyte cell lines. | various leukocytes are involved in the reaction to counter salmonella infection in chicken. the various leukocyte types react differently after an infection, since some clear the infection while others may cause dissemination of salmonella throughout the chicken. therefore, we investigated in vitro the entry and survival of salmonella enterica serotype enteritidis in chicken cell lines of various cell types, including two macrophage cell lines, hd11 and mq-ncsu (ncsu), two b-cell lines lscc-1104 ... | 2003 | 12458164 |
| molecular characterization of cephalosporin-resistant salmonella enterica serotype newport isolates from animals in pennsylvania. | multidrug-resistant (mdr) strains of salmonella enterica serotype newport have been described for many years. however, the recognition of newport strains with resistance to cephalosporin antibiotics is more recent. plasmid-mediated cmy-2 ampc beta-lactamases have been identified in salmonella in the united states, and the bla(cmy-2) gene has been shown to be present in salmonella serotype newport. this organism is currently undergoing epidemic spread in both animals and humans in the united stat ... | 2002 | 12454172 |
| multiple genetic typing of salmonella enterica serotype typhimurium isolates of different phage types (dt104, u302, dt204b, and dt49) from animals and humans in england, wales, and northern ireland. | salmonella enterica serotype typhimurium is a common cause of salmonellosis among humans and animals in england, wales, and northern ireland. phage types dt104 and u302 were the most prevalent types in both livestock and humans in 2001. in addition, salmonella serotype typhimurium dt204b was responsible for a recent international outbreak involving england. a total of 119 isolates from humans (n = 28) and animals or their environment (n = 91), belonging to dt104 (n = 66), u302 (n = 33), dt204b ( ... | 2002 | 12454135 |
| molecular diversity of the genetic loci responsible for lipopolysaccharide core oligosaccharide assembly within the genus salmonella. | the waa locus on the chromosome of salmonella enterica encodes enzymes involved in the assembly of the core oligosaccharide region of the lipopolysaccharide (lps) molecule. to date, there are two known core structures in salmonella, represented by serovars typhimurium (subspecies i) and arizonae (subspecies iiia). the waa locus for serovar typhimurium has been characterized. here, the corresponding locus from serovar arizonae is described, and the molecular basis for the distinctive structures i ... | 2002 | 12453217 |
| salmonella enterica subspecies enterica serotype typhimurium and escherichia coli o86 in wild birds at two garden sites in south-west scotland. | salmonella enterica subspecies enterica serotype typhimurium and escherchia coli o86:k61:nm are two bacteria that can cause outbreaks of mortality in garden birds visiting bird tables and other feeding stations. two sites in south-west scotland were monitored for the two organisms for 12 months. at site a, large numbers of birds fed throughout the year, and at site b smaller numbers of birds fed only in the winter months. samples of composite faeces were collected from the feeding stations and s ... | 2002 | 12452355 |
| bile stress response in listeria monocytogenes lo28: adaptation, cross-protection, and identification of genetic loci involved in bile resistance. | bile is one of many barriers that listeria monocytogenes must overcome in the human gastrointestinal tract in order to infect and cause disease. we demonstrated that stationary-phase cultures of l. monocytogenes lo28 were able to tolerate concentrations of bovine, porcine, and human bile and bile acids well in excess of those encountered in vivo. strain lo28 was relatively bile resistant compared with other clinical isolates of l. monocytogenes, as well as with listeria innocua, salmonella enter ... | 2002 | 12450822 |
| early epithelial invasion by salmonella enterica serovar typhimurium dt104 in the swine ileum. | salmonella enterica serovar typhimurium is an important intestinal pathogen in swine. this study was performed to document the early cellular invasion of salmonella serovar typhimurium in swine ileum. ileal gut-loops were surgically prepared in ten 4- to 5-week-old mixed-breed pigs and inoculated for 0-60 minutes. loops were harvested and prepared for both scanning and transmission electron microscopy (sem and tem, respectively). preferential bacterial adherence to microfold cells (m cells) was ... | 2002 | 12450202 |
| [report on salmonella nomenclature of judicial commission during iums general meeting in paris]. | 2002 | 12448841 | |
| influence of enrofloxacin and chloramphenicol on the level of igy in serum and egg yolk after immunostimulation of hens with salmonella enteritidis antigens. | in the chicken, maternal antibodies are transferred into the egg and subsequently transported into the developing embryo. igg (called igy) is the primary immunoglobulin isotype of the egg yolk. their level in serum depends on the correct function of immunological system in laying hens. many factors have a direct or indirect influence on antibody level in fowl. one of them is a commonly used antibiotic, but its influence on avian immune system is still unknown. the objective of the study was to d ... | 2002 | 12448078 |
| repression of glutamate dehydrogenase formation in klebsiella aerogenes requires two binding sites for the nitrogen assimilation control protein, nac. | in klebsiella aerogenes, the gdha gene codes for glutamate dehydrogenase, one of the enzymes responsible for assimilating ammonia into glutamate. expression of a gdhap-lacz transcriptional fusion was strongly repressed by the nitrogen assimilation control protein, nac. this strong repression (>50-fold under conditions of severe nitrogen limitation) required the presence of two separate nac binding sites centered at -89 and +57 relative to the start of gdha transcription. mutants lacking either o ... | 2002 | 12446647 |
| ribosylnicotinamide kinase domain of nadr protein: identification and implications in nad biosynthesis. | nad is an indispensable redox cofactor in all organisms. most of the genes required for nad biosynthesis in various species are known. ribosylnicotinamide kinase (rnk) was among the few unknown (missing) genes involved with nad salvage and recycling pathways. using a comparative genome analysis involving reconstruction of nad metabolism from genomic data, we predicted and experimentally verified that bacterial rnk is encoded within the 3' region of the nadr gene. based on these results and previ ... | 2002 | 12446641 |
| the cysteine desulfurase iscs is required for synthesis of all five thiolated nucleosides present in trna from salmonella enterica serovar typhimurium. | deficiency of a modified nucleoside in trna often mediates suppression of +1 frameshift mutations. in salmonella enterica serovar typhimurium strain tr970 (hisc3737), which requires histidine for growth, a potential +1 frameshifting site, ccc-caa-uaa, exists within the frameshifting window created by insertion of a c in the hisc gene. this site may be suppressed by peptidyl-trnaprocmo5ugg (cmo(5)u is uridine-5-oxyacetic acid), making a frameshift when decoding the near-cognate codon ccc, provide ... | 2002 | 12446633 |
| cuid is a crucial gene for survival at high copper environment in salmonella enterica serovar typhimurium. | copper ion is an essential micronutrient but it is also extremely cytotoxic when it exists in excess. our studies have shown that salmonella enterica serovar typhimurium can survive potentially lethal copper exposures by the way of copper efflux system. a copper ion inducible gene was identified in virulent s. typhimurium by using the technique of mudj (km, lac)-directed laczya operon fusions. a copper ion inducible strain lf153 (cuid::mudj) has been identified. the cuid mutant exhibits a copper ... | 2002 | 12442888 |
| host-pathogen interactions: host resistance factor nramp1 up-regulates the expression of salmonella pathogenicity island-2 virulence genes. | nramp1 (natural resistance-associated macrophage protein-1; also known as slc11a1) is a host resistance gene that provides protection against several intracellular pathogens, including salmonella enterica serovar typhimurium. little is known about the dynamic interplay that occurs between mammalian host resistance determinants such as nramp1 and pathogens during infection. to explore these interactions, we examined the effect of nramp1 on expression of salmonella typhimurium (stm) virulence fact ... | 2002 | 12441401 |
| in vitro adhesion of an avian pathogenic escherichia coli o78 strain to surfaces of the chicken intestinal tract and to ileal mucus. | the role of fimbria in adherence of an avian pathogenic escherichia coli (apec) o78 strain 789 to chicken intestine was studied. bacterial adhesion to tissue sections representing the regions within the chicken intestinal tract was determined by using immunohistochemical methods. e. coli 789 grown to express the type 1 fimbria adhered efficiently to the crop epithelium, to the lamina propria of intestinal villi, and to the apical surfaces of both the mature as well as the crypt-located enterocyt ... | 2003 | 12441230 |
| genetic requirements for salmonella-induced cytopathology in human monocyte-derived macrophages. | infection of human macrophages with salmonella enterica serovar typhimurium or salmonella enterica serovar dublin produces delayed cytotoxicity characterized by cell detachment and associated apoptosis. using a site-specific mutant in the spvb active site, we verify that the adp-ribosylation activity of spvb is required for delayed cytotoxicity in human macrophages infected with salmonella: sipb and the type iii protein secretion system (ttss) encoded by salmonella pathogenicity island 1 (spi1) ... | 2002 | 12438395 |
| concomitant cytosolic delivery of two immunodominant listerial antigens by salmonella enterica serovar typhimurium confers superior protection against murine listeriosis. | during its interaction with host cells, salmonella enterica serovar typhimurium employs a type iii secretion system for cytosolic targeting of virulence factors. this protein translocation mechanism is a useful tool for heterologous antigen delivery by attenuated salmonella vaccine carrier strains. in the present study, we used the yersinia outer protein e (yope) as a carrier molecule for salmonella type iii-dependent cytosolic delivery of the immunodominant cd8 t-cell antigens listeriolysin o ( ... | 2002 | 12438393 |
| analysis of salmonella enterica serotype-host specificity in calves: avirulence of s. enterica serotype gallinarum correlates with bacterial dissemination from mesenteric lymph nodes and persistence in vivo. | host and bacterial factors that determine whether salmonella serotypes remain restricted to the gastrointestinal tract or penetrate beyond the mucosa and cause systemic disease remain largely undefined. here, factors influencing salmonella host specificity in calves were assessed by characterizing the pathogenesis of different serotypes. salmonella enterica serotype dublin was highly virulent intravenously, whereas s. enterica serotype choleraesuis was moderately virulent. both serotypes were vi ... | 2002 | 12438354 |
| identification and genetic characterization of pmra-regulated genes and genes involved in polymyxin b resistance in salmonella enterica serovar typhimurium. | salmonella enterica serovar typhimurium encounters antimicrobial peptides (ap) within the phagosomes of professional phagocytes and at intestinal mucosal surfaces. salmonella serovar typhimurium utilizes the two-component regulatory system pmra-pmrb, which is activated in response to the environmental conditions encountered in vivo, to regulate resistance to several ap, including polymyxin b (pm). random mudj transposon mutagenesis was used to identify pmra-pmrb-regulated genes, as well as genet ... | 2002 | 12438352 |
| the salmonella enterica subspecies i specific centisome 7 genomic island encodes novel protein families present in bacteria living in close contact with eukaryotic cells. | we have determined the genetic structure of the salmonella enterica centisome 7 genomic island (sci) located at the aspv loci in s. enterica subspecies i strains. the 47-kb long genomic island encodes 37 putative proteins, including the previously described saf fimbrial operon and the sinr transcriptional regulator. other open reading frames (designated sci a to z) in the island encode putative proteins with homologies to virulence-associated proteins in a number of gram-negative bacteria such a ... | 2002 | 12437215 |
| evolution of multiresistance in nontyphoid salmonella serovars from 1984 to 1998 in argentina. | molecular evolution of multiresistance in nontyphoid salmonella spp. was investigated with 155 isolates obtained in argentina from 1984 to 1998. in 74 isolates obtained from 1984 to 1988 resistance was associated with the presence of tn3, tn9, class i (in0) and ii (tn7) integrons, and the aac(3)-iia gene. extended-spectrum cephalosporin (esc) resistance in salmonella spp. emerged in 1989, and 81 isolates resistant to at least one esc and one aminoglycoside were collected thereafter. among these, ... | 2002 | 12435702 |
| an improved 16s rrna based pcr method for the specific detection of salmonella enterica. | a molecular method for the detection of salmonella enterica strains based on 16s rrna sequence analysis was developed by a modification of the previously described pcr primer 16sfi [j. appl. bacteriol. 80 (1996) 659], which was combined with a newly developed primer annealing at the position 66-82. only approximately two thirds of now determined salmonella 16s rrna sequences contained a region identical to the 16sfi primer sequence and the reverse primer 16siii was also not specific. combined, t ... | 2003 | 12430773 |
| magnetized carbonyl iron and insoluble zirconium hydroxide mixture facilitates bacterial concentration and separation from nonfat dry milk. | a mixture of magnetized carbonyl iron and insoluble zirconium hydroxide was investigated for its ability to concentrate various foodborne pathogens from 25-ml samples of reconstituted nonfat dry milk. each sample was artificially contaminated with 10(3) to 10(6) cfu/25 ml of representative foodborne pathogens (salmonella enterica serovar enteritidis, listeria monocytogenes, and bacillus cereus spores) and processed for bacterial concentration with high-speed centrifugation for the primary concen ... | 2002 | 12430708 |
| specificity of respiratory pathways involved in the reduction of sulfur compounds by salmonella enterica. | the tetrathionate (ttr) and thiosulfate (phs) reductases of salmonella enterica lt2, together with the polysulfide reductase (psr) of wolinella succinogenes, are unusual examples of enzymes containing a molybdopterin active-site cofactor since all formally catalyse sulfur-sulfur bond cleavage. this is in contrast to the oxygen or hydrogen transfer reactions exhibited by other molybdopterin enzymes. here the catalytic specificity of ttr and phs has been compared using both physiological and synth ... | 2002 | 12427953 |
| salmonella enterica serovar pullorum requires the salmonella pathogenicity island 2 type iii secretion system for virulence and carriage in the chicken. | functional mutations were made in the type iii secretion systems encoded by salmonella pathogenicity island 1 (spi 1) and salmonella pathogenicity island 2 (spi 2) of salmonella enterica serovar pullorum, the cause of pullorum disease in poultry. their role in cell invasion in vitro, and in virulence in vivo was determined. the spi 1 mutant showed decreased invasiveness for chicken cells but was capable of causing disease in orally infected 1-day-old chicks, although it showed some reduction in ... | 2002 | 12427344 |
| identification of a nipsnap homologue as host cell target for salmonella virulence protein spic. | salmonella enterica uses a type iii secretion system encoded by spi-2 to target specific virulence factors into the host cytosol of macrophages to inhibit the phagosomal-lysosomal maturation pathway. this ensures survival of salmonella inside its intracellular niche, the salmonella-containing vacuole (scv). one such virulence factor is spic, which was previously shown to interfere with intracellular vesicular trafficking. in this study we have used a yeast two-hybrid assay to identify a nipsnap ... | 2002 | 12427096 |
| dietary mannan-oligosaccharides and their effect on chicken caecal microflora in relation to salmonella enteritidis colonization. | this study first investigates the effects of mash diet, or mash supplemented with either 2.5% mannose-oligosaccharide (mos) or palm kernel meal (pkm), on the microflora of the hen caecal contents. second, it investigates the effect of caecal contents of hens (hcc) fed mash or mash supplemented with mos or pkm on the major microflora groups of chicks, and their inhibitory effect on salmonella enterica serovar enteritidis (pt4) colonization. finally, this study investigates the effect over time of ... | 2002 | 12425792 |
| quantitative comparison of intestinal invasion of zoonotic serotypes of salmonella enterica in poultry. | the aim of the present study was to compare the invasion of selected zoonotic salmonella serotypes of poultry in an in vivo chicken intestinal loop model and also in vitro in epithelial cell cultures. invasion was measured relative to a reference strain, salmonella typhimurium 4/74 invh201::tnphoa. two serotypes demonstrated intracellular log(10) counts that differed significantly from all other serotypes tested: salmonella enteritidis pt4 being 1.5 log(10) colony forming units (cfu) (31-fold) h ... | 2002 | 12425791 |
| interactive inhibition of meat spoilage and pathogenic bacteria by lysozyme, nisin and edta in the presence of nitrite and sodium chloride at 24 degrees c. | to develop a nisin- and lysozyme-based antimicrobial treatment for use with processed ham and bologna, in vitro experiments were conducted to determine whether inhibition enhancing interactions occur between the antimicrobials lysozyme, chrisin (a commercial nisin preparation), edta, nacl and nano(2). inhibitory interactions were observed between a number of agents when used against specific pathogenic and spoilage bacteria. the observed interactions included lysozyme with edta (enterococcus fae ... | 2003 | 12423927 |
| antimicrobial-resistant salmonella enterica serovars isolated from chickens in spain. | in order to analyze the antibiotic resistance of salmonella enterica serovars, a total of 112 salmonella strains were tested (54 s. enteritidis, 32 s. typhimurium, 11 s. heidelberg, 7 s. infantis, 4 s. virchow and 4 s. hadar). the bacteria were isolated from 691 samples of frozen and fresh chicken meat. identification of microorganisms and antimicrobial sensitivity testing were undertaken by means of the automated microscan autoscan 4 method (baxter in spain). 45.5% of 112 strains tested were su ... | 2002 | 12420851 |
| identification of salmonella enterica serovar typhimurium genes associated with growth suppression in stationary-phase nutrient broth cultures and in the chicken intestine. | over 2,800 tn 5 insertion mutants of salmonella enterica sv. typhimurium were screened for the loss of ability to suppress the multiplication of a spectinomycin-resistant (spc(r)) but otherwise isogenic s. enterica sv. typhimurium strain, when the spc(r) mutant was added to 24-h lb broth cultures of the mutants. selected "growth non-suppressive" (gns) mutants were defective in respiration (insertions in arca and fnr), amino acid biosynthesis (aroa and arod), nutrient uptake and its regulation (t ... | 2002 | 12420160 |
| common themes among bacteriophage-encoded virulence factors and diversity among the bacteriophages involved. | there are common themes among bacteriophage-encoded virulence factors, which include the well-characterized bacterial toxins and proteins that alter antigenicity as well as several new classes of bacteriophage-encoded proteins such as superantigens, effectors translocated by a type iii secretion system, and proteins required for intracellular survival and host cell attachment. these virulence factors are encoded by a diversity of bacteriophages, members of the viral families siphoviridae, podovi ... | 2002 | 12419617 |
| potential salmonella transmission from ornamental fountains. | besides the usual food and drinking-water vehicles, there are other routes by which salmonella can be transmitted, especially at outdoor locations. public fountains containing salmonella offer models of exposure routes beyond those usually considered in the context of recreational use. the authors studied the bacteriological quality of water sampled from five ornamental fountains in guadalajara, mexico during two periods of six and of 10 months. coliform bacteria and escherichia coli were detect ... | 2002 | 12415885 |
| salmonella vaccines for use in humans: present and future perspectives. | in recent years there has been significant progress in the development of attenuated salmonella enterica serovar typhi strains as candidate typhoid fever vaccines. in clinical trials these vaccines have been shown to be well tolerated and immunogenic. for example, the attenuated s. enterica var. typhi strains cvd 908-htra (aroc arod htra), ty800 (phop phoq) and chi4073 (cya crp cdt) are all promising candidate typhoid vaccines. in addition, clinical trials have demonstrated that s. enterica var. ... | 2002 | 12413664 |
| molecular and functional analysis of the type iii secretion signal of the salmonella enterica invj protein. | central to the pathogenicity of salmonella enterica is the function of a type iii secretion system (ttss) encoded within a pathogenicity island at centisome 63 (spi-1). an essential component of this system is a supramolecular structure termed the needle complex. proteins to be delivered into host cells possess specific signals that route them to the type iii secretion pathway. in addition, some bacterial proteins have signals that deliver them to the secretion complex to either become their str ... | 2002 | 12410834 |
| the salmonella enterica sv. typhimurium smva, yddg and ompd (porin) genes are required for the efficient efflux of methyl viologen. | in gram-negative bacteria, a subset of inner membrane proteins in the major facilitator superfamily (mfs) acts as efflux pumps to decrease the intracellular concentrations of multiple toxic substrates and confers multidrug resistance. the salmonella enterica sv. typhimurium smva gene encodes a product predicted to be an mfs protein most similar to qaca of staphylococcus aureus. like mutations in qaca, mutations in smva confer increased sensitivity to methyl viologen (mv). mutations in the adjace ... | 2002 | 12410826 |
| expanded-spectrum cephalosporin-resistant salmonella strains in romania. | thirteen salmonella enterica serotype typhimurium and one salmonella enterica serotype heidelberg strain resistant to expanded-spectrum cephalosporins were isolated from october 2000 to february 2001 from infants with gastroenteritis in iasi, romania. in all but one serotype typhimurium isolate, resistance was due to the production of a cmy-2 cephalosporinase encoded by a nonconjugative plasmid. the remaining isolate produced an shv-5-type beta-lactamase. typing by pulsed-field gel electrophores ... | 2002 | 12409424 |
| increasing genetic diversity of salmonella enterica serovar typhi isolates from papua new guinea over the period from 1992 to 1999. | pulsed-field gel electrophoresis (pfge) of xbai-digested chromosomal dna was performed on 133 strains of salmonella enterica serovar typhi obtained from papua new guinea, with the objective of assessing the temporal variation of these strains. fifty-two strains that were isolated in 1992 and 1994 were of one phage type, d2, and only two predominant pfge profiles, x1 and x2, were present. another 81 strains isolated between 1997 and 1999 have shown divergence, with four new phage types, uvs i (n ... | 2002 | 12409390 |
| detection of gyra mutations in quinolone-resistant salmonella enterica by denaturing high-performance liquid chromatography. | denaturing high-performance liquid chromatography (dhplc) was evaluated as a rapid screening and identification method for dna sequence variation detection in the quinolone resistance-determining region of gyra from salmonella serovars. a total of 203 isolates of salmonella were screened using this method. dhplc analysis of 14 isolates representing each type of novel or multiple mutations and the wild type were compared with lightcycler-based pcr-gyra hybridization mutation assay (gama) and sing ... | 2002 | 12409384 |
| serotype and phage type distribution of salmonella strains isolated from humans, cattle, pigs, and chickens in the netherlands from 1984 to 2001. | we studied serotypes and phage types of salmonella strains isolated from humans and animals in the netherlands over the period 1984 to 2001. all human strains (n = 59,168) were clinical isolates. the animal strains (n = 65,567) were from clinical and nonclinical infections. all isolates were serotyped, and salmonella enterica serovar typhimurium and serovar enteritidis strains were further phage typed. the most prevalent serotypes were as follows: in humans, serovars typhimurium and enteritidis; ... | 2002 | 12409362 |
| identification and functional analysis of enzymes required for precorrin-2 dehydrogenation and metal ion insertion in the biosynthesis of sirohaem and cobalamin in bacillus megaterium. | in bacillus megaterium, the hemaxbcdl genes were isolated and were found to be highly similar to the genes from bacillus subtilis that are required for the conversion of glutamyl-trna into uroporphyrinogen iii. overproduction and purification of hemc (porphobilinogen deaminase) and -d (uroporphyrinogen iii synthase) allowed these enzymes to be used for the in vitro synthesis of uroporphyrinogen iii from porphobilinogen. a second smaller cluster of three genes (termed sirabc) was also isolated an ... | 2003 | 12408752 |
| molecular characterization of spm-1, a novel metallo-beta-lactamase isolated in latin america: report from the sentry antimicrobial surveillance programme. | the gene encoding the metallo-beta-lactamase spm-1 was cloned from a genomic library of pseudomonas aeruginosa strain 48-1997 a. the insert carrying spm-1 possessed a gc content of 47%, indicating that it is of non-pseudomonas origin. upstream of spm-1 there is a small open reading frame (orf), which is homologous to the lysr family of proteins (69% identity to the lysr protein from salmonella enterica serovar typhimurium). downstream of spm-1 there is the start of an orf, the product of which s ... | 2002 | 12407123 |
| characterization of serracin p, a phage-tail-like bacteriocin, and its activity against erwinia amylovora, the fire blight pathogen. | serratia plymithicum j7 culture supernatant displayed activity against many pathogenic strains of erwinia amylovora, the causal agent of the most serious bacterial disease of apple and pear trees, fire blight, and against klebsiella pneumoniae, serratia liquefaciens, serratia marcescens, and pseudomonas fluorescens. this activity increased significantly upon induction with mitomycin c. a phage-tail-like bacteriocin, named serracin p, was purified from an induced culture supernatant of s. plymith ... | 2002 | 12406768 |
| molecular epidemiology of salmonella enterica serovar typhimurium isolates determined by pulsed-field gel electrophoresis: comparison of isolates from avian wildlife, domestic animals, and the environment in norway. | the molecular epidemiology of 142 isolates of salmonella enterica serovar typhimurium from avian wildlife, domestic animals, and the environment in norway was investigated using pulsed-field gel electrophoresis (pfge) and computerized numerical analysis of the data. the bacterial isolates comprised 79 isolates from wild-living birds, including 46 small passerines and 26 gulls, and 63 isolates of nonavian origin, including 50 domestic animals and 13 environmental samples. thirteen main clusters w ... | 2002 | 12406755 |
| salmonellae in avian wildlife in norway from 1969 to 2000. | postmortem records of wild-living birds in norway with laboratory-confirmed findings of salmonella infection were summarized for the period from 1969 to 2000. salmonella spp. were isolated from 470 birds belonging to 26 species. the salmonella-positive birds included 441 small passerines, 15 gulls, 5 waterfowl, 4 birds of prey, 3 doves, and 2 crows. the bullfinch (pyrrhula pyrrhula) was by far the most frequently recorded species (54% of the cases). salmonella enterica serover typhimurium was re ... | 2002 | 12406754 |
| low-shear modeled microgravity alters the salmonella enterica serovar typhimurium stress response in an rpos-independent manner. | we have previously demonstrated that low-shear modeled microgravity (low-shear mmg) serves to enhance the virulence of a bacterial pathogen, salmonella enterica serovar typhimurium. the salmonella response to low-shear mmg involves a signaling pathway that we have termed the low-shear mmg stimulon, though the identities of the low-shear mmg stimulon genes and regulatory factors are not known. rpos is the primary sigma factor required for the expression of genes that are induced upon exposure to ... | 2002 | 12406731 |
| diffraction quality crystals of prd1, a 66-mda dsdna virus with an internal membrane. | it has proved difficult to obtain well diffracting single crystals of macromolecular complexes rich in lipid. we report here the path that has led to crystals of the bacteriophage prd1, a particle containing approximately 2,000 protein subunits from 18 different protein species, around 10 of which are integral membrane proteins associated with a host-derived lipid bilayer of some 12,500 lipid molecules. these crystals are capable of diffracting x-rays to bragg spacings below 4a. it is hoped that ... | 2002 | 12406692 |