| sequence analysis and clinical significance of the icea gene from helicobacter pylori strains in japan. | the helicobacter pylori icea gene was recently identified as a genetic marker for the development of peptic ulcer in a western population. to assess the significance of icea subtypes of h. pylori in relation to peptic ulcer, 140 japanese clinical isolates (88 from fukui and 52 from okinawa) were characterized. sequence analysis of the icea1 gene from 25 representative japanese strains was also carried out to identify the differences in icea between the ulcer group and the gastritis group. the ic ... | 2000 | 10655332 |
| antimicrobial resistance of neisseria gonorrhoeae and high prevalence of ciprofloxacin-resistant isolates in japan, 1993 to 1998. | to assess the antimicrobial resistance of neisseria gonorrhoeae isolated from 1993 through 1998 in japan, susceptibility testing was conducted on 502 isolates. selected isolates were characterized by auxotype and analysis for mutations within the quinolone resistance-determining region (qrdr) in the gyra and parc genes, which confer fluoroquinolone resistance on the organism. plasmid-mediated penicillin resistance (penicillinase-producing n. gonorrhoeae) decreased significantly from 1993-1994 (7 ... | 2000 | 10655338 |
| analysis of icea1 transcription in helicobacter pylori. | transcription of the helicobacter pylori icea1 gene is induced following adherence of the bacterium to gastric epithelial cells in vitro, suggesting that this gene might be involved in h. pylori pathogenesis. consequently, the current studies were undertaken to characterize icea1 transcription and to define the structure of icea1-containing transcripts to evaluate the potential of this gene to encode functional proteins. | 2000 | 10672045 |
| molecular and biological analysis of eight genetic islands that distinguish neisseria meningitidis from the closely related pathogen neisseria gonorrhoeae. | the pathogenic species neisseria meningitidis and neisseria gonorrhoeae cause dramatically different diseases despite strong relatedness at the genetic and biochemical levels. n. meningitidis can cross the blood-brain barrier to cause meningitis and has a propensity for toxic septicemia unlike n. gonorrhoeae. we previously used subtractive hybridization to identify dna sequences which might encode functions specific to bacteremia and invasion of the meninges because they are specific to n. menin ... | 2000 | 10722605 |
| mathematical modelling of infection and disease due to neisseria meningitidis and neisseria lactamica. | invasive meningococcal disease, due to neisseria meningitidis, is an important cause of morbidity and mortality in young children and adolescents. nasopharyngeal carriage of meningococci (mc), is most prevalent in young adults whereas carriage of neisseria lactamica (lc), a related non-pathogenic organism, is most prevalent in young children. the objective of this study was to use modelling techniques to test hypotheses on the processes that govern the incidence of meningococcal disease (md). | 2000 | 10750621 |
| genetic organization and heterogeneity of the icea locus of helicobacter pylori. | the genetic organization and sequence heterogeneity of the icea locus of helicobacter pylori was studied, and the existence of two distinct gene families, icea1 and icea2, at this locus was confirmed. icea1 has significant sequence homology to nlaiiir, encoding an endonuclease in neisseria lactamica, but the similarity at the protein level is limited, due to frameshift mutations of icea1 in most h. pylori strains. in only five of the 19 icea1 strains studied, a full-length open reading frame (or ... | 2000 | 10767527 |
| dynamics of meningococcal long-term carriage among university students and their implications for mass vaccination. | in the 1997-98 academic year, we conducted a longitudinal study of meningococcal carriage and acquisition among first-year students at nottingham university, nottingham, united kingdom. we examined the dynamics of long-term meningococcal carriage with detailed characterization of the isolates. pharyngeal swabs were obtained from 2,453 first-year students at the start of the academic year (october), later on during the autumn term, and again in march. swabs were immediately cultured on selective ... | 2000 | 10834994 |
| frequent interspecific genetic exchange between commensal neisseriae and neisseria meningitidis. | natural sequence variation was investigated among serogroup a subgroup iv-1 neisseria meningitidis isolated from diseased patients and healthy carriers in the gambia, west africa. the frequencies of dna import were analysed by sequencing fragments of four linked genes encoding the immunogenic outer membrane proteins tbpb (transferrin binding protein b) and opaa (an adhesin) plus two housekeeping enzymes. seventeen foreign tbpb alleles were independently imported into the 98 strains tested, appar ... | 2000 | 10844690 |
| lipooligosaccharide p(k) (galalpha1-4galbeta1-4glc) epitope of moraxella catarrhalis is a factor in resistance to bactericidal activity mediated by normal human serum. | moraxella catarrhalis is a respiratory pathogen responsible for acute bacterial otitis media in children and exacerbation of chronic bronchitis in adults. m. catarrhalis strains are frequently resistant to the bactericidal activity of normal human serum. in order to determine if the lipooligosaccharide (los) of m. catarrhalis has a role in serum resistance, the udp-glucose-4-epimerase (gale) gene was identified, cloned, and sequenced and a deletion/insertion mutation was introduced into m. catar ... | 2000 | 10948153 |
| carriage rate of neisseria meningitidis among university students. further data are needed. | | 2000 | 10991568 |
| quantitative detection of helicobacter pylori gene expression in vivo and relationship to gastric pathology. | the icea locus of helicobacter pylori includes one of two mutually exclusive gene families, icea1 and icea2. colonization with icea1 strains is associated with enhanced acute mucosal inflammation, and adherence to gastric epithelial cells in vitro induces expression of icea1 but not icea2 mrna; however, both transcripts can be detected in vivo. the aim of this study was to determine whether differing levels of icea transcription in vivo may contribute to disease pathogenesis. rna from 41 h. pylo ... | 2000 | 10992444 |
| carriage of n. lactamica in a population at high risk of meningococcal disease. | carriage of neisseria lactamica among household contacts of meningococcal disease (mcd) cases was investigated during an epidemic in auckland, new zealand. the overall carriage rate for n. lactamica was 10.5% (95% ci 7.4-13.5%) with a peak carriage rate in 2-year-olds of 61.5% (95% ci 26.6-88.1%). factors associated with a significant (p < 0.05) increase in the likelihood of carriage included runny nose, the number of people per bedroom and youth. genetic analysis of isolates revealed a striking ... | 2000 | 11057965 |
| degradation of heme in gram-negative bacteria: the product of the hemo gene of neisseriae is a heme oxygenase. | a full-length heme oxygenase gene from the gram-negative pathogen neisseria meningitidis was cloned and expressed in escherichia coli. expression of the enzyme yielded soluble catalytically active protein and caused accumulation of biliverdin within the e. coli cells. the purified hemo forms a 1:1 complex with heme and has a heme protein spectrum similar to that previously reported for the purified heme oxygenase (hmuo) from the gram-positive pathogen corynebacterium diphtheriae and for eukaryot ... | 2000 | 11073924 |
| carried meningococci in the czech republic: a diverse recombining population. | population and evolutionary analyses of pathogenic bacteria are frequently hindered by sampling strategies that concentrate on isolates from patients with invasive disease. this is especially so for the gram-negative diplococcus neisseria meningitidis, a cause of septicemia and meningitis worldwide. meningococcal isolate collections almost exclusively comprise organisms originating from patients with invasive meningococcal disease, although this bacterium is a commensal inhabitant of the human n ... | 2000 | 11101585 |
| production and characterization of a new monoclonal antibody against neisseria meningitidis: study of the cross-reactivity with different bacterial genera. | we have generated a hybridoma cell line which produces an 8c7br1 clone of the igm antibody isotype. it recognizes the 50-, 65-, and 60-kda antigens and is reactive with strains of n. meningitidis in the 98% of local neisseria genera by dot-elisa assays. two percent of the strains of n. meningitidis b do not present reactivity with the 8c7br1 monoclonal antibody (mab). the antibody reacted against n. meningitidis of serogroups a, b, c, x, y, z, and different serotypes and subtypes of n. meningiti ... | 2000 | 11152396 |
| circumvention of herd immunity during an outbreak of meningococcal disease could be correlated to escape mutation in the pora gene of neisseria meningitidis. | meningococcal strains isolated during an outbreak were shown to belong to the et-5 complex and to harbor a mutation in the vr2 region of the pora gene. they were less susceptible to the bactericidal effect of normal human serum than was the et-5 wild-type strain. these results are of concern, as pora is a potential target in vaccine design. | 2001 | 11179386 |
| analysis of lipooligosaccharide biosynthesis in the neisseriaceae. | neisserial lipooligosaccharide (los) contains three oligosaccharide chains, termed the alpha, beta, and gamma chains. we used southern hybridization experiments on dna isolated from various neisseria spp. to determine if strains considered to be nonpathogenic possessed dna sequences homologous with genes involved in the biosynthesis of these oligosaccharide chains. the presence or absence of specific genes was compared to the los profiles expressed by each strain, as characterized by their mobil ... | 2001 | 11208792 |
| diagnostics of neisseriaceae and moraxellaceae by ribosomal dna sequencing: ribosomal differentiation of medical microorganisms. | fast and reliable identification of microbial isolates is a fundamental goal of clinical microbiology. however, in the case of some fastidious gram-negative bacterial species, classical phenotype identification based on either metabolic, enzymatic, or serological methods is difficult, time-consuming, and/or inadequate. 16s or 23s ribosomal dna (rdna) bacterial sequencing will most often result in accurate speciation of isolates. therefore, the objective of this study was to find a hypervariable ... | 2001 | 11230407 |
| rho is not essential for viability or virulence in staphylococcus aureus. | we have identified the gene for transcription termination factor rho in staphylococcus aureus. deletion of rho in s. aureus reveals that it is not essential for viability or virulence. we also searched the available bacterial genomic sequences for homologs of rho and found that it is broadly distributed and highly conserved. exceptions include streptococcus pneumoniae, streptococcus pyogenes, mycoplasma genitalium, mycoplasma pneumoniae, ureaplasma urealyticum, and synechocystis sp. strain pcc68 ... | 2001 | 11257021 |
| prevention and elimination of upper respiratory colonization of mice by group a streptococci by using a bacteriophage lytic enzyme. | bacteriophage lytic enzymes quickly destroy the cell wall of the host bacterium to release progeny phage. because such lytic enzymes specifically kill the species in which they were produced, they may represent an effective way to control pathogenic bacteria without disturbing normal microflora. in this report, we studied a murein hydrolase from the streptococcal bacteriophage c(1) termed lysin. this enzyme is specific for groups a, c, and e streptococci, with little or no activity toward severa ... | 2001 | 11259652 |
| phenotypic and genotypic approaches to characterization of isolates of neisseria meningitidis from patients and their close family contacts. | characterization of isolates of neisseria meningitidis obtained from patients with meningococcal disease or from pharyngeal swabs of asymptomatic carriers can be achieved by several approaches which provide different levels of discrimination. a total of 45 gram negative, oxidase-positive diplococcus strains isolated from 15 individuals with meningococcal disease and 30 of their family contacts were examined by three approaches: serological typing, multilocus enzyme electrophoresis (mlee), and mu ... | 2001 | 11283034 |
| simultaneous detection of neisseria meningitidis, haemophilus influenzae, and streptococcus pneumoniae in suspected cases of meningitis and septicemia using real-time pcr. | a single-tube 5' nuclease multiplex pcr assay was developed on the abi 7700 sequence detection system (taqman) for the detection of neisseria meningitidis, haemophilus influenzae, and streptococcus pneumoniae from clinical samples of cerebrospinal fluid (csf), plasma, serum, and whole blood. capsular transport (ctra), capsulation (bexa), and pneumolysin (ply) gene targets specific for n. meningitidis, h. influenzae, and s. pneumoniae, respectively, were selected. using sequence-specific fluoresc ... | 2001 | 11283086 |
| fit genotypes and escape variants of subgroup iii neisseria meningitidis during three pandemics of epidemic meningitis. | the genetic variability at six polymorphic loci was examined within a global collection of 502 isolates of subgroup iii, serogroup a neisseria meningitidis. nine "genoclouds" were identified, consisting of genotypes that were isolated repeatedly plus 48 descendent genotypes that were isolated rarely. these genoclouds have caused three pandemic waves of disease since the mid-1960s, the most recent of which was imported from east asia to europe and africa in the mid-1990s. many of the genotypes ar ... | 2001 | 11287631 |
| genetic diversity of neisseria lactamica strains from epidemiologically defined carriers. | we assessed the genetic diversity of 26 neisseria lactamica strains from epidemiologically related sources, i.e., groups of kindergartens and primary schools in three bavarian towns, by the partial sequencing of the argf, rho, reca, and 16s ribosomal genes. we found a total of 17 genotypes, of which 12 were found only in one strain. the genotypes comprised 5 alleles of the argf gene, 9 of rho, 8 of reca, and 10 of the 16s ribosomal dna. sequence analysis by determination of homoplasy ratios and ... | 2001 | 11325979 |
| evolution and function of the neisserial dam-replacing gene. | phase variation through slippage-like mechanisms involving homopolymeric tracts depends in part on the absence of dam-methylase in several pathogenic isolates of neisseria meningitidis. in dam-defective strains drg (dam-replacing gene), flanked by pseudo-transposable small repeated elements (sres), replaced dam. we demonstrate that drg encodes a restriction endonuclease (nmebii) that cleaves 5'-gmeatc-3'. drg is also present in 50% of neisseria lactamica strains, but in most of them it is inacti ... | 2001 | 11334887 |
| identification and functional characterization of arylamine n-acetyltransferases in eubacteria: evidence for highly selective acetylation of 5-aminosalicylic acid. | arylamine n-acetyltransferase activity has been described in various bacterial species. bacterial n-acetyltransferases, including those from bacteria of the gut flora, may be involved in the metabolism of xenobiotics, thereby exerting physiopathological effects. we characterized these enzymes further by steady-state kinetics, time-dependent inhibition, and dna hybridization in 40 species, mostly from the human intestinal microflora. we report for the first time n-acetyltransferase activity in 11 ... | 2001 | 11344150 |
| amplified fragment length polymorphism fingerprinting for identification of a core group of neisseria gonorrhoeae transmitters in the population attending a clinic for treatment of sexually transmitted diseases in amsterdam, the netherlands. | amplified fragment length polymorphism analysis seems well suited for studying the epidemiology of isolates of neisseria gonorrhoeae obtained from patients attending the sexually transmitted disease outpatient clinic in amsterdam, the netherlands. it shows potential to identify the core group of transmitters. | 2001 | 11376085 |
| promoters of the catg-specific methyltransferase gene hpyim differ between icea1 and icea2 helicobacter pylori strains. | helicobacter pylori strains can be divided into two groups, based on the presence of two unrelated genes, icea1 and icea2, that occupy the same genomic locus. hpyim, located immediately downstream of either gene, encodes a functional catg-specific methyltransferase. despite the strong conservation of the hpyim open reading frame (orf) among all h. pylori strains, the sequences upstream of the orf in icea1 and icea2 strains are substantially different. to explore the roles of these upstream seque ... | 2001 | 11395450 |
| all detectable high-molecular-mass penicillin-binding proteins are modified in a high-level beta-lactam-resistant clinical isolate of streptococcus mitis. | all detectable high-molecular-mass penicillin-binding proteins (hmm pbps) are altered in a clinical isolate of streptococcus mitis for which the beta-lactam mics are increased from those previously reported in our region (cefotaxime mic, 64 microg/ml). these proteins were hardly detected at concentrations that saturate all pbps in clinical isolates and showed, after densitometric analysis, 50-fold-lower radiotracer binding. resistance was related to mosaic structure in all hmm pbp-coding genes, ... | 2001 | 11408226 |
| directional gene movement from human-pathogenic to commensal-like streptococci. | group a streptococci (gas) are highly pathogenic for humans, and their closest genetic relatives, group c and g streptococci (gcs and ggs, respectively), are generally regarded as commensals, although they can be found in association with human disease. as part of an effort to better understand the evolution of virulence, the phylogenetic relationships between gas, gcs, and ggs were examined. the nucleotide sequence was determined for an internal portion of seven housekeeping (neutral) loci amon ... | 2001 | 11447161 |
| enhancing the specificity of the cobas amplicor ct/ng test for neisseria gonorrhoeae by retesting specimens with equivocal results. | the cobas amplicor ct/ng test for neisseria gonorrhoeae cross-reacts with certain strains of nonpathogenic neisseria species. in some strains, the target sequence is identical to that of n. gonorrhoeae, whereas other strains have a small number of mismatches within the regions recognized by the primers or probe used in the cobas amplicor ng test. these cross-reactive strains are occasionally present in urogenital specimens, causing false-positive results in the cobas amplicor ng test. analysis o ... | 2001 | 11526134 |
| soluble pilin of neisseria gonorrhoeae interacts with human target cells and tissue. | pili of neisseria gonorrhoeae are phase-variable surface structures that mediate adherence to host target cells. each pilus is composed of thousands of major pilus subunits, pilins, pilus-associated protein pilc, and possibly other components. piliated and nonpiliated gonococcal clones may secrete a soluble smaller pilin (s-pilin) that is cleaved after amino acid 39 of the mature pilin protein. here, purified s-pilin was found to migrate as a 61- to 64-kda double band on nondenaturing gels, sugg ... | 2001 | 11553586 |
| lactate stimulation of gonococcal metabolism in media containing glucose: mechanism, impact on pathogenicity, and wider implications for other pathogens. | | 2001 | 11598023 |
| acid stress upregulated outer membrane proteins in clinical isolates of neisseria gonorrhoeae, but not most commensal neisseria. | human immune serum recognition of outer membrane components from commensal and pathogenic neisseria cultured under neutral and acidic conditions was investigated. acid stress caused no detectable alterations in lipooligosaccharide migration and (or) staining, in outer membrane protein profiles, or in immune serum recognition of outer membrane components from neisseria mucosa or neisseria sicca. there was also no difference in the lipoologosaccharide electrophoretic pattern of acid- and neutral-g ... | 2001 | 11683469 |
| improved rate of isolation of neisseria meningitidis by direct plating of pharyngeal swabs. | culturing of pharyngeal swabs for neisseria meningitidis is an important clinical and epidemiological tool. routine methods include direct plating onto solid medium or later plating in the laboratory. a comparison of these methods used with 490 high school students found a significantly higher carriage rate with direct plating (11.8 versus 6.1%; p < 0.001). | 2001 | 11724888 |
| detection of meningococcal carriage by culture and pcr of throat swabs and mouth gargles. | the standard method for detecting meningococcal carriage is culture of throat swabs on selective media, but the levels of carriage determined depend heavily on the skills of the individuals taking the swab and interpreting the cultures. this study aimed to determine the most sensitive detection method for meningococcal carriage. throat swabs and saline mouth gargles, obtained from 89 university students, were processed in parallel by conventional culture and taqman ctra pcr. carriage of meningoc ... | 2002 | 11773095 |
| variations in chemoprophylaxis for meningococcal disease: a retrospective case note review, analysis of routine prescribing data and questionnaire of general practitioners. | invasive meningococcal disease is a significant cause of mortality and morbidity in the uk. administration of chemoprophylaxis to close contacts reduces the risk of a secondary case. however, unnecessary chemoprophylaxis may be associated with adverse reactions, increased antibiotic resistance and removal of organisms, such as neisseria lactamica, which help to protect against meningococcal disease. limited evidence exists to suggest that overuse of chemoprophylaxis may occur. this study aimed t ... | 2001 | 11806758 |
| characterization of humoral and cellular immune responses elicited by meningococcal carriage. | in order to study the immune response elicited by asymptomatic carriage of neisseria meningitidis, samples of serum, peripheral blood mononuclear cells (pbmcs), and saliva were collected from a cohort of more than 200 undergraduate students in nottingham, united kingdom, who were subject to high rates of acquisition and carriage of meningococci. serum immunoglobulin g levels were elevated following increases in the rate of carriage, and these responses were specific for the colonizing strains. i ... | 2002 | 11854214 |
| what about antibiotic resistance in neisseria lactamica? | the in vitro activity of penicillin, ampicillin, cefotaxime, ceftriaxone, rifampicin and ciprofloxacin against 286 neisseria lactamica isolates was determined by agar dilution and the category of susceptibility was analysed in accordance with the criteria used for neisseria meningitidis. all isolates were considered to have intermediate susceptibility to penicillin. a total of 1.7% of the isolates were resistant to ampicillin but all were susceptible to cefotaxime and ceftriaxone. rifampicin mic ... | 2002 | 11864957 |
| prospective study of a serogroup x neisseria meningitidis outbreak in northern ghana. | after an epidemic of serogroup a meningococcal meningitis in northern ghana, a gradual disappearance of the epidemic strain was observed in a series of five 6-month carriage surveys of 37 randomly selected households. as serogroup a neisseria meningitidis carriage decreased, an epidemic of serogroup x meningococcal carriage occurred, which reached 18% (53/298) of the people sampled during the dry season of 2000, coinciding with an outbreak of serogroup x disease. these carriage patterns were unr ... | 2002 | 11865418 |
| the abundant class of nemis repeats provides rna substrates for ribonuclease iii in neisseriae. | about 2% of the neisseria meningitidis genome is made up by nemis, short dna sequences which feature long terminal inverted repeats (tirs). most nemis are interspersed with single-copy dna and are found at close distance from cellular genes. in this work, we demonstrate than rnas spanning nemis of different length and sequence compositions are specifically cleaved at hairpins formed by nemis termini by total cellular lysates derived from both escherichia coli and neisseria lactamica strains. the ... | 2002 | 12031482 |
| phenotypic and genotypic variation in methylases involved in type ii restriction-modification systems in helicobacter pylori. | to determine relationships between helicobacter pylori geographical origin and type ii methylase activity, we examined 122 strains from various locations around the world for methylase expression. most geographic regions possessed at least one strain resistant to digestion by each of 14 restriction endonucleases studied. across all of the strains studied, the average number of active methylases was 8.2 +/- 1.9 with no significant variation between the major geographic regions. although seven pai ... | 2002 | 12034832 |
| many carried meningococci lack the genes required for capsule synthesis and transport. | of 830 neisseria meningitidis isolates obtained from healthy carriers in bavaria, germany, 136 (16.4%) lacked the operons necessary for the synthesis, lipid modification, and transport of capsular polysaccharide. these operons were replaced by a non-coding intergenic region either 113 or 114 bp in length, termed here the capsule null locus (cnl). comparisons of the nucleotide sequence of this region in the meningococcus and its acapsulate relatives, neisseria gonorrhoeae and neisseria lactamica, ... | 2002 | 12055301 |
| neisseria lactamica protects against experimental meningococcal infection. | immunological and epidemiological evidence suggests that the development of natural immunity to meningococcal disease results from colonization of the nasopharynx by commensal neisseria spp., particularly with n. lactamica. we report here that immunization with n. lactamica killed whole cells, outer membrane vesicles, or outer membrane protein (omp) pools and protected mice against lethal challenge by a number of diverse serogroup b and c meningococcal isolates in a model of bacteremic infection ... | 2002 | 12065503 |
| virulence genes in helicobacter pylori strains from west bengal residents with overt h. pylori-associated disease and healthy volunteers. | we compared putative molecular markers of virulence (vaca, caga, and icea) of helicobacter pylori strains isolated from 52 adult duodenal ulcer patients from west bengal, india, with those of h. pylori strains isolated from 48 adult healthy volunteers from the same region. on the basis of genotyping by pcr, we conclude that the h. pylori strains isolated from the two study groups were indistinguishable and that there are geographic variations in the association of certain putative h. pylori viru ... | 2002 | 12089290 |
| in vitro induction of memory-driven responses against neisseria meningitidis by priming with neisseria lactamica. | natural immunity against neisseria meningitidis is acquired during childhood and youth through successive colonizations by commensal neisseria, carrier n. meningitidis, and other bacterial genera sharing cross-reactive antigens with the meningococci. we have analyzed in mice the ability of neisseria lactamica strains to induce immunological memory so that, upon a later contact with n. meningitidis, quickly raise protective responses against antigens that show cross-reactivity with meningococcal ... | 2002 | 12126908 |
| isolation from a healthy carrier and characterization of a neisseria meningitidis strain that is deficient in gamma-glutamyl aminopeptidase activity. | gamma-glutamyl aminopeptidase (ggt) activity is used as a specific marker for the identification of neisseria meningitidis. we isolated from a healthy carrier and characterized an n. meningitidis isolate which lacked the activity due to the insertional mutation of the ggt gene, suggesting that naturally occurring n. meningitidis isolates do not always possess ggt activity. | 2002 | 12149372 |
| functional analysis of icea1, a catg-recognizing restriction endonuclease gene in helicobacter pylori. | icea1 in helicobacter pylori is a homolog of nlaiiir, which encodes the catg-specific restriction endonuclease nlaiii in neisseria lactamica. analysis of icea1 sequences from 49 h.pylori strains shows that a full-length nlaiii-like orf is present in 10 strains, including ch4, but in other strains, including strain 60190, the orfs are truncated due to a variety of mutations. our goal was to determine whether icea1 can encode a nlaiii-like endonuclease. overexpression in escherichia coli of icea1 ... | 2002 | 12202769 |
| analysis of neisseria lactamica antigens putatively implicated in acquisition of natural immunity to neisseria meningitidis. | sera from healthy human volunteers, patients convalescent from meningococcal meningitis, and mice immunized with outer membrane proteins from neisseria meningitidis and neisseria lactamica strains were used to analyze and identify antigens cross-reactive to both neisserial species. all classes of meningococcal proteins except class 1 (pora) and class 5 cross-reacted with n. lactamica proteins and two other proteins of 65 and 55 kda (an iron-regulated protein). results obtained with the mouse ser ... | 2002 | 12208601 |
| the class a macrophage scavenger receptor is a major pattern recognition receptor for neisseria meningitidis which is independent of lipopolysaccharide and not required for secretory responses. | macrophages (mphi) play a key role in the pathogenesis of invasive meningococcal infections. the roles of two pattern recognition molecules, the mphi scavenger receptor (sr-a) and toll-like receptor 4 (tlr-4), have been investigated using bone marrow culture-derived mphi (bmmphi). surprisingly, a comparison of bmmphi from wild-type and sr-a knockout (sr-a(-/-)) mice showed that nonopsonic phagocytosis of meningococci was mediated almost exclusively via sr-a. previous studies have demonstrated on ... | 2002 | 12228258 |
| determination of methylation site of dna-methyltransferase nlax by a hybrid method. | using a new method based on a combination of bisulfite reaction, the repair enzyme uracil-dna glycosylase, and synthetic oligodeoxyribonucleotides, the methylation site of dna-methyltransferase nlax (m.nlax) from neisseria lactamica was established to be the inner cytosine in the double-stranded pentanucleotide recognition sequence 5'-ccngg-3' (where n = any nucleoside). 5-methylcytosine (m5c) type modification by m-n1ax was confirmed by the use of oligonucleotide substrates that contain 5-fluor ... | 2002 | 12238762 |
| asymtomatic carriage of neisseria meningitidis and neisseria lactamica in relation to streptococcus pneumoniae and haemophilus influenzae colonization in healthy children: apropos of 1400 children sampled. | meningococcal disease is one of the most important causes of morbidity and mortality among children in many parts of the world. main reservoir of carriage and site of meningococcal dissemination appears to be the upper respiratory tract. colonization of neisseria meningitidis and lactamica and factors affecting this carriage were determined in a group of healthy children aged 0-10 years. meningococcus and n. lactamica carriage were detected in 17 (1.23%) and 245 (17.7%) of 1382 subjects, respect ... | 2001 | 12380714 |
| rates of detection of neisseria meningitidis in tonsils differ in relation to local incidence of invasive disease. | nasopharyngeal swabbing substantially underestimates carriage of neisseria meningitidis. real-time pcr assays were employed to examine the presence of a broad range of bacteria and of n. meningitidis groups b and c, respectively, in tonsils from 26 individuals from oxford, england, and 72 individuals from zurich, switzerland. the detection limit of each pcr system was dna from one bacterial cell per reaction mixture. tonsillar dna did not inhibit amplification of meningococcal gene sequences, an ... | 2002 | 12409352 |
| sulphonamide resistant commensal neisseria with alterations in the dihydropteroate synthase can be isolated from carriers not exposed to sulphonamides. | development of sulphonamide resistance in neisseria meningitidis has been suggested to involve horizontal dna-transfer from a commensal neisseria species. in this study, we isolated commensal neisseria from throat specimens and examined the isolates with respect to sulphonamide resistance. | 2002 | 12435277 |
| comparative genomics identifies the genetic islands that distinguish neisseria meningitidis, the agent of cerebrospinal meningitis, from other neisseria species. | neisseria meningitidis colonizes the nasopharynx and, unlike commensal neisseria species, is capable of entering the bloodstream, crossing the blood-brain barrier, and invading the meninges. the other pathogenic neisseria species, neisseria gonorrhoeae, generally causes an infection which is localized to the genitourinary tract. in order to investigate the genetic basis of this difference in disease profiles, we used a strategy of genomic comparison. we used dna arrays to compare the genome of n ... | 2002 | 12438387 |
| molecular assays for detection of human metapneumovirus. | the recent description of the respiratory pathogen human metapneumovirus (hmpv) has highlighted a deficiency in current diagnostic techniques for viral agents associated with acute lower respiratory tract infections. we describe two novel approaches to the detection of viral rna by use of reverse transcriptase pcr (rt-pcr). the pcr products were identified after capture onto a solid-phase medium by hybridization with a sequence-specific, biotinylated oligonucleotide probe. the assay was applied ... | 2003 | 12517833 |
| identification of haemophilus influenzae serotypes by standard slide agglutination serotyping and pcr-based capsule typing. | to resolve discrepancies in slide agglutination serotyping (sast) results from state health departments and the centers for disease control and prevention (cdc), we characterized 141 of 751 invasive haemophilus influenzae isolates that were identified in the united states from january 1998 to december 1999 through an active, laboratory-based, surveillance program coordinated by the cdc. we found discrepancies between the results of sast performed at state health departments and those of pcr caps ... | 2003 | 12517878 |
| divergence and transcriptional analysis of the division cell wall (dcw) gene cluster in neisseria spp. | three of the 18 open reading frames in the division and cell wall synthesis cluster of the pathogenic neisseria spp. are not present in the clusters of other bacterial species. the region containing two of these, dcab and dcac, displays interstrain and interspecies variability uncharacteristic of such clusters. 3' of dcab is a correia repeat enclosed element (cree), which is only present in some strains. it has been suggested that this cree is a transcriptional terminator, although we demonstrat ... | 2003 | 12519193 |
| evaluation of the bacticard neisseria for identification of pathogenic neisseria species and moraxella catarrhalis. | the bacticard neisseria (remel, usa) is a chromogenic enzyme substrate system for identifying neisseria gonorrhoeae, neisseria meningitidis, neisseria lactamica, and moraxella catarrhalis. the identification system consists of a card with four test circles impregnated with chromogenic substrates for indoxyl butyrate esterase (ib), prolyl aminopeptidase (pro), gamma-glutamyl aminopeptidase (glut), and ss-galactosidase (bgal). these substrates permit the identification of moraxella catarrhalis, ne ... | 2002 | 12525923 |
| gene expression profile in neisseria meningitidis and neisseria lactamica upon host-cell contact: from basic research to vaccine development. | differential gene regulation in the human pathogen neisseria meningitidis group b (menb) and in neisseria lactamica, a human commensal species, was studied by whole genome microarray after bacterial interaction with epithelial cells. host-cell contact induced changes in the expression of 347 and 285 genes in menb and n. lactamica, respectively. of these, only 167 were common to menb and n. lactamica, suggesting that a different subset of genes is activated by pathogens and commensals. change in ... | 2002 | 12538166 |
| evaluation of the specificities of five dna amplification methods for the detection of neisseria gonorrhoeae. | the intragenus specificities of five molecular diagnostic methods for neisseria gonorrhoeae were determined. three assays were considered suboptimal. molecular detection of n. gonorrhoeae from sites where other neisseria spp. commonly occur or from any site in low-prevalence settings should be confirmed by a test targeting a different genetic locus. | 2003 | 12574295 |
| quantitative detection of moraxella catarrhalis in nasopharyngeal secretions by real-time pcr. | the recognition of moraxella catarrhalis as an important cause of respiratory tract infections has been protracted, mainly because it is a frequent commensal organism of the upper respiratory tract and the diagnostic sensitivity of blood or pleural fluid culture is low. given that the amount of m. catarrhalis bacteria in the upper respiratory tract may change during infection, quantification of these bacteria in nasopharyngeal secretions (npss) by real-time pcr may offer a suitable diagnostic ap ... | 2003 | 12682118 |
| phosphorylation of the lipid a region of meningococcal lipopolysaccharide: identification of a family of transferases that add phosphoethanolamine to lipopolysaccharide. | a gene, nmb1638, with homology to the recently characterized gene encoding a phosphoethanolamine transferase, lpt-3, has been identified from the neisseria meningitidis genome sequence and was found to be present in all meningococcal strains examined. homology comparison with other database sequences would suggest that nmb1638 and lpt-3 represent genes coding for members of a family of proteins of related function identified in a wide range of gram-negative species of bacteria. when grown and is ... | 2003 | 12754224 |
| comparison of commercial dna extraction kits for extraction of bacterial genomic dna from whole-blood samples. | the demand for molecular diagnostic tests in medical microbiology has highlighted the need for efficient methods of dna extraction. in addition, it is preferable for these methods to be automated. an example of such a requirement is for the confirmation of meningococcal disease where rapid, sensitive, and specific procedures are required for public health management purposes. previous studies have shown that whole blood is the preferred method for the isolation of bacterial dna in meningococcal ... | 2003 | 12791861 |
| carriage of neisseria meningitidis and neisseria lactamica in northern greece. | in response to an increase in the number of cases of invasive meningococcal disease (imd) in northern regions of greece, a survey was carried out to determine if there was an increase in carriage of neisseria meningitidis, particularly in areas where there have been increases in immigrant populations from neighbouring countries. the second objective was to determine if there was an increase in the serogroup c:2a:p1.5,2 a phenotype associated with recent outbreaks or changes in antibiotic sensiti ... | 2003 | 14556992 |
| conformational epitopes recognized by protective anti-neisserial surface protein a antibodies. | nspa is a conserved membrane protein that elicits protective antibody responses in mice against neisseria meningitidis. a recent crystallographic study showed that nspa adopts an eight-stranded beta-barrel structure when reconstituted in detergent. in order to define the segments of nspa-containing epitopes recognized by protective murine anti-nspa antibodies, we studied the binding of two bactericidal and protective anti-nspa monoclonal antibodies (mabs), al12 and 14c7. neither mab binds to ove ... | 2003 | 14638771 |
| infection with an avirulent phop mutant of neisseria meningitidis confers broad cross-reactive immunity. | successful vaccines against serogroup a and c meningococcal strains have been developed, but current serogroup b vaccines provide protection against only a limited range of strains. the ideal meningococcal vaccine would provide cross-reactive immunity against the variety of strains that may be encountered in any community, but it is unclear whether the meningococcus possesses immune targets that have the necessary level of cross-reactivity. we have generated a phop mutant of the meningococcus by ... | 2004 | 14688113 |
| development, characterization, and functional activity of a panel of specific monoclonal antibodies to inner core lipopolysaccharide epitopes in neisseria meningitidis. | a panel of six murine monoclonal antibodies (mabs) recognizing inner core lipopolysaccharide (lps) epitopes of neisseria meningitidis was prepared and characterized in order to determine the diversity of inner core lps glycoforms among disease and carrier isolates. two of these mabs, l2-16 (immunoglobulin g2b [igg2b]) and lpt3-1 (igg2a), together with a third, previously described mab, l3b5 (igg3), showed reactivity, either individually or in combination, with all except 3 of 143 disease and car ... | 2004 | 14688137 |
| detection of the bacillus anthracis gyra gene by using a minor groove binder probe. | identification of chromosomal markers for rapid detection of bacillus anthracis is difficult because significant chromosomal homology exists among b. anthracis, bacillus cereus, and bacillus thuringiensis. we evaluated the bacterial gyra gene as a potential chromosomal marker for b. anthracis. a real-time pcr assay was developed for the detection of b. anthracis. after analysis of the unique nucleotide sequence of the b. anthracis gyra gene, a fluorescent 3' minor groove binding probe was tested ... | 2004 | 14715750 |
| use of real-time pcr to resolve slide agglutination discrepancies in serogroup identification of neisseria meningitidis. | neisseria meningitidis is a leading cause of bacterial meningitis and septicemia in children and young adults in the united states. rapid and reliable identification of n. meningitidis serogroups is crucial for judicious and expedient response to cases of meningococcal disease, including decisions about vaccination campaigns. from 1997 to 2002, 1,298 n. meningitidis isolates, collected in the united states through the active bacterial core surveillance (abcs), were tested by slide agglutination ... | 2004 | 14715772 |
| analysis of moraxella catarrhalis outer membrane antigens cross-reactive with neisseria meningitidis and neisseria lactamica. | mouse sera against outer membrane proteins from moraxella catarrhalis, neisseria meningitidis and neisseria lactamica, and human sera from both healthy individuals and patients convalescing from meningococcal meningitis were used to identify cross-reactive antigens. mouse anti-n. meningitidis and anti-n. lactamica sera recognized 77, 62 and 32 kda outer membrane antigens in m. catarrhalis strains; on the contrary, the meningococcal porin porb (38-42 kda) was recognized by one of the two anti-m. ... | 2004 | 14734192 |
| smallpox and pan-orthopox virus detection by real-time 3'-minor groove binder taqman assays on the roche lightcycler and the cepheid smart cycler platforms. | we designed, optimized, and extensively tested several sensitive and specific real-time pcr assays for rapid detection of both smallpox and pan-orthopox virus dnas. the assays are based on taqman 3'-minor groove binder chemistry and were performed on both the rapid-cycling roche lightcycler and the cepheid smart cycler platforms. the hemagglutinin (ha) j7r, b9r, and b10r genes were used as targets for the variola virus-specific assays, and the ha and dna polymerase-e9l genes were used as targets ... | 2004 | 14766823 |
| vaccine potential of the neisseria meningitidis 2086 lipoprotein. | a novel antigen that induces cross-reactive bactericidal antibodies against a number of neisseria meningitidis strains is described. this antigen, a approximately 28-kda lipoprotein called lp2086, was first observed within a complex mixture of soluble outer membrane proteins (somps) following a series of fractionation, protein purification, and proteomics steps. approximately 95 different neisserial isolates tested positive by western blotting and pcr screening methods for the presence of the pr ... | 2004 | 15039331 |
| neisseria meningitidis, neisseria lactamica and moraxella catarrhalis share cross-reactive carbohydrate antigens. | carriage of commensal bacteria species is associated with the development of natural immunity to meningococcal disease, with lipo-oligosaccharides (los) of meningococci being one of the main virulence factors associated with severity of meningococcal disease. meningococcal reference strains and isolates from the commensal species neisseria lactamica and moraxella catarrhalis were assessed for the presence of cross-reactive glycoconjugate antigens. binding of human blood group antibodies of the p ... | 2004 | 15040943 |
| nada diversity and carriage in neisseria meningitidis. | nada is a novel vaccine candidate recently identified in neisseria meningitidis and involved in adhesion to host tissues. the nada gene has been found in approximately 50% of the strains isolated from patients and in three of the four hypervirulent lineages of non-serogroup a strains. here we investigated the presence of the nada gene in 154 meningococcal strains isolated from healthy people (carrier strains). only 25 (16.2%) of the 154 carrier isolates harbored the nada gene. the commensal spec ... | 2004 | 15213166 |
| diversity in pathogenicity can cause outbreaks of meningococcal disease. | neisseria meningitidis, the meningococcus, is a major cause of bacterial meningitis and septicemia worldwide. infection in most cases leads to asymptomatic carriage and only rarely to disease. meningococcal disease often occurs in outbreaks, which are both sporadic and highly unpredictable. the occurrence of disease outbreaks in a host population in which the etiological agent is widely carried is not well understood. a potential explanation lies in the fact that meningococci are diverse with re ... | 2004 | 15218099 |
| detection of haemophilus influenzae type b by real-time pcr. | a real-time pcr assay targeting the capsulation locus of haemophilus influenzae type b (hib) was developed. the linear detection range was from 1 to 10(6) microorganisms per reaction mixture. no h. influenzae other than hib or any other control bacteria typically found in the upper respiratory tract was detected. | 2004 | 15297536 |
| molecular characterization of trichomonas tenax causing pulmonary infection. | | 2004 | 15297557 |
| neisseria meningitidis: an overview of the carriage state. | during periods of endemic disease, about 10 % of the general population harbour neisseria meningitidis in the nasopharynx. since n. meningitidis is a strict human pathogen and most patients have not been in contact with other cases, asymptomatic carriers are presumably the major source of the pathogenic strains. most carrier isolates are shown to lack capsule production. the capsule deficient state of meningococcal strains in the nasopharynx may aid evasion of the human immune defence and hence ... | 2004 | 15314188 |
| rapid characterization of outer-membrane proteins in neisseria lactamica by seldi-tof-ms (surface-enhanced laser desorption ionization-time-of-flight ms) for use in a meningococcal vaccine. | immunological and epidemiological evidence suggests that the development of natural immunity to meningococcal disease results from colonization of the nasopharynx by commensal neisseria species, particularly with neisseria lactamica. we have reported previously that immunization with n. lactamica outer-membrane vesicles containing the major omps (outer-membrane proteins) protected mice against lethal challenge with meningococci of diverse serogroups and serotypes and has the potential to form th ... | 2005 | 15315478 |
| meningococcal vaccines. | meningococcal disease is one of the most feared and serious infections in the young and its prevention by vaccination is an important goal. the high degree of antigenic variability of the organism makes the meningococcus a challenging target for vaccine prevention. meningococcal polysaccharide vaccines against serogroup a and c are efficacious and have been widely used, often in combination with serogroup y and w135 components. their relative lack of immunogenicity in young children and infants ... | 2004 | 15339202 |
| functional diversity of three different dsba proteins from neisseria meningitidis. | the genome of neisseria meningitidis serogroup b strain mc58 contains three genes - nmb0278, nmb0294 and nmb0407 - encoding putative homologues of dsba, a periplasmic thiol disulphide oxidoreductase protein-folding catalyst of the dsb protein family. dsba assists the folding of periplasmic and membrane proteins in diverse organisms. while all three cloned genes complemented the dtt sensitivity of dsba-null escherichia coli, they showed different activities in folding specific target proteins in ... | 2004 | 15347757 |
| putative vaccine antigens from neisseria meningitidis recognized by serum antibodies of young children convalescing after meningococcal disease. | serum samples from 31 children < or = 4 years old who were convalescing after meningococcal disease were used in a quantitative hybridization assay to establish antibody reactivity to 94 candidate meningococcal vaccine antigens. genes encoding 22 of 23 strongly recognized proteins were found in > or = 94% of the patients' meningococcal strains, and most were also widely prevalent in neisseria lactamica and other commensal neisseria species. similar antibody reactivity was found in serum samples ... | 2004 | 15378443 |
| real-time pcr assay for a unique chromosomal sequence of bacillus anthracis. | real-time pcr has become an important method for the rapid identification of bacillus anthracis since the 2001 anthrax mailings. most real-time pcr assays for b. anthracis have been developed to detect virulence genes located on the pxo1 and pxo2 plasmids. in contrast, only two published chromosomal targets exist, the rpob gene and the gyra gene. in the present study, subtraction-hybridization with a plasmid-cured b. anthracis tester strain and a bacillus cereus driver was used to find a unique ... | 2004 | 15583318 |
| emergence and spread of neisseria gonorrhoeae clinical isolates harboring mosaic-like structure of penicillin-binding protein 2 in central japan. | of 150 clinical isolates of neisseria gonorrhoeae recovered in 2001, we examined 55 clinical isolates of n. gonorrhoeae for which cefixime mics were > or=0.125 microg/ml and randomly selected 15 isolates for which cefixime mics were < or =0.06 microg/ml for analysis of alterations in the penicillin-binding protein 2 (pbp 2) gene. we found insertion of an extra codon (asp-345a) in the transpeptidase domain of pbp 2, and this insertion occurred alone or in conjunction with other amino acid substit ... | 2005 | 15616287 |
| analysis of the piv recombinase-related gene family of neisseria gonorrhoeae. | neisseria gonorrhoeae (the gonococcus) is an obligate human pathogen and the causative agent of the disease gonorrhea. the gonococcal pilus undergoes antigenic variation through high-frequency recombination events between unexpressed pils silent copies and the pilin expression locus pile. the machinery involved in pilin antigenic variation identified to date is composed primarily of genes involved in homologous recombination. however, a number of characteristics of antigenic variation suggest th ... | 2005 | 15687191 |
| the development of a meningococcal disease vaccine based on neisseria lactamica outer membrane vesicles. | serogroup b meningococcal disease remains a serious problem in many countries and no effective vaccine is currently available. immunological and epidemiological evidence suggests that carriage of commensal neisseria species is involved in the development of natural immunity against meningococcal disease. neisseria lactamica has many surface structures in common with neisseria meningitidis and may be the most important of these species. we have produced extensive pre-clinical data, which indicate ... | 2005 | 15755597 |
| function of neisserial outer membrane phospholipase a in autolysis and assessment of its vaccine potential. | outer membrane phospholipase a (ompla) is an outer membrane-localized enzyme, present in many gram-negative bacterial species. it is implicated in the virulence of several pathogens. here, we investigated the presence, function, and vaccine potential of ompla in the human pathogen neisseria meningitidis. immunoblot analysis showed the presence of ompla in 28 out of 33 meningococcal strains investigated. the ompla-negative strains all contained a plda gene, but these alleles contained premature s ... | 2005 | 15784566 |
| genetic diversity and carriage dynamics of neisseria lactamica in infants. | neisseria lactamica, a harmless human commensal found predominantly in the upper respiratory tracts of infants, is closely related to neisseria meningitidis, a pathogen of global significance. colonization with n. lactamica may be responsible for the increase in immunity to meningococcal disease that occurs during childhood, when rates of meningococcal carriage are low. this observation has led to the suggestion that n. lactamica whole cells or components are potential constituents of novel meni ... | 2005 | 15784588 |
| comparison of an internally controlled, large-volume lightcycler assay for detection of mycobacterium tuberculosis in clinical samples with the cobas amplicor assay. | we present a sensitive and specific assay for reliable and flexible detection of members of the mycobacterium tuberculosis complex (mtbc) in clinical samples. this real-time pcr assay, which uses the lightcycler 2.0 instrument and 100-mul glass capillaries, can provide a result within 1 h after dna extraction. the primers amplify a 206-bp fragment of the mtbc 16s rrna gene. the sensor hybridization probe targets a region highly specific to members of the mtbc. the assay also includes a novel typ ... | 2005 | 15814966 |
| a novel pora-based real-time pcr for detection of meningococcal carriage. | real-time pcr based on the capsule transfer gene (ctra) is a significant aid in the diagnosis of meningococcal infection but fails to detect a high proportion (60 %) of non-groupable strains associated with nasopharyngeal carriage. this study aimed to design a novel real-time (taqman) pcr that would detect more strains of meningococci and be suitable for large-scale carriage studies. primer and probe sequences were based on the meningococcal pora gene and designed specifically to exclude the hig ... | 2005 | 15824424 |
| [carriers of neisseria meningitidis among children from a primary school]. | a cross-sectional and descriptive study was conducted among 318 children from the "mártires del corynthia" primary school under the authorization of the municipal division of education and the informed consent of their parents aimed at knowing the prevalence of meningoccoco carriers in school children, determining the epidemiological markers of the isolated strains and establishing the possible relation existing between the carrier and variables, such as age, sex, acute respiratory infection his ... | 2003 | 15849920 |
| evaluation of conventional and real-time pcr assays using two targets for confirmation of results of the cobas amplicor chlamydia trachomatis/neisseria gonorrhoeae test for detection of neisseria gonorrhoeae in clinical samples. | two conventional pcr-enzyme immunoassays (pcr-eias) and two real-time pcr assays (lightcycler system; roche diagnostics) were evaluated as confirmation assays with cppb and 16s rrna genes as targets. of 765 male and female genitourinary and nasopharyngeal specimens positive for neisseria gonorrhoeae in the cobas amplicor chlamydia trachomatis/neisseria gonorrhoeae pcr test (roche diagnostics), 229 (30%) were confirmed positive; 13 of these (5.7%) were lacking the cppb gene. of the 534 samples (7 ... | 2005 | 15872247 |
| neisseria gonorrhoeae downregulates expression of the human antimicrobial peptide ll-37. | neisseria gonorrhoeae is a human pathogen causing the sexually transmitted disease gonorrhoeae. the bacteria preferentially attach to and invade epithelial cells of the genital tract. as these cells previously have been shown to express the human cathelicidin ll-37, we wanted to investigate the role of ll-37 during n. gonorrhoeae infection. the cervical epithelial cell line me180 was utilized and the expression of ll-37 was confirmed on both peptide and transcriptional levels. moreover, ll-37 ex ... | 2005 | 15953032 |
| clinical relevance of the vaca, icea, caga, and flaa genes of helicobacter pylori strains isolated in eastern taiwan. | the genotypes of helicobacter pylori flaa, caga, vaca, and icea were determined for dna isolated from patients with chronic gastritis or peptic ulcer in eastern taiwan. the vaca gene encoding the s1a subtype was found to predominate in peptic ulcer patients, and the icea1 genotype was associated with chronic gastritis. caga and flaa genes were not found to be associated with these types of disease. | 2005 | 15956417 |
| phenotypic and transcriptional characterization of the meningococcal phopq system, a magnesium-sensing two-component regulatory system that controls genes involved in remodeling the meningococcal cell surface. | we previously identified and characterized a two-component regulatory system in the meningococcus with homology to the phop-phoq system in salmonella and showed that allele replacement of the nmb0595 regulator gene led to loss of virulence, sensitivity to antimicrobial peptides, perturbed protein expression, and magnesium-sensitive growth. on the basis of these findings we proposed that the system should be designated the meningococcal phopq system. here we further characterized the nmb0595 muta ... | 2005 | 15995212 |
| can neisseria lactamica antigens provide an effective vaccine to prevent meningococcal disease? | neisseria lactamica is a commensal organism that is closely related to neisseria meningitidis, the causative agent of meningococcal disease. n. lactamica has many antigens in common with n. meningitidis, but it lacks a polysaccharide capsule and the serosubtyping antigen pora. carriage studies have demonstrated that n. lactamica is carried in the nasopharynx of young children at a time when meningococcal carriage is rare. however, natural immunity to meningococcal disease develops during this pe ... | 2005 | 16026250 |
| identification of candidate periodontal pathogens and beneficial species by quantitative 16s clonal analysis. | most studies of the bacterial etiology of periodontitis have used either culture-based or targeted dna approaches, and so it is likely that pathogens remain undiscovered. the purpose of this study was to use culture-independent, quantitative analysis of biofilms associated with chronic periodontitis and periodontal health to identify pathogens and beneficial species. samples from subjects with periodontitis and controls were analyzed using ribosomal 16s cloning and sequencing. several genera, ma ... | 2005 | 16081935 |
| use of the roche lightcycler strep b assay for detection of group b streptococcus from vaginal and rectal swabs. | the results for a real-time pcr assay, using the lightcycler strep b analyte-specific reagents (roche diagnostics corporation, indianapolis, ind.), were compared to a direct plate method combined with a broth enrichment culture method for detection of group b streptococcus colonization in pregnant women. two separate evaluations were conducted using two different automated nucleic extraction instruments, the magna pure lc instrument (roche diagnostics corporation) and the lower-capacity magna pu ... | 2005 | 16081949 |
| unusual genetic organization of a functional type i protein secretion system in neisseria meningitidis. | proteins secreted by neisseria meningitidis are thought to play important roles in the pathogenesis of meningococcal disease. these proteins include the iron-repressible repeat-in-toxin (rtx) exoprotein frpc. related proteins in other pathogens are secreted via a type i secretion system (toss), but such a system has not been demonstrated in n. meningitidis. an in silico search of the group b meningococcal genome suggested the presence of a uniquely organized toss. genes encoding homologs of the ... | 2005 | 16113272 |