Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| characterisation of cmy-4, an ampc-type plasmid-mediated beta-lactamase in a tunisian clinical isolate of proteus mirabilis. | a strain of proteus mirabilis resistant to beta-lactams, including cefoxitin, was isolated from the urine of a woman from tunisia. its antibiotic susceptibility pattern and that of the escherichia coli transconjugant suggested the presence of an ampc-type beta-lactamase. two bands of beta-lactamase activity (pi 5.4 and 9.2) were detected by isoelectric focusing. the nucleotide sequence of the gene encoding the ampc-type enzyme was determined. the deduced amino acid sequence was 98-99% identical ... | 1998 | 9868767 |
| analysis of enterohemorrhagic escherichia coli serotype o157:h7 by flow cytometry using monoclonal antibodies. | to develop a rapid and specific method to detect and/or identify enterohemorrhagic escherichia coli o157:h7, two mouse monoclonal antibodies (mabs) were prepared. specificities of these two mabs (1d9 and 3e8) were determined by flow cytometry method (fcm). mabs 3e8 and 1d9 were found to react with e. coli o157:h7, citrobacter freundii and salmonella group n (o:30), but not with escherichia hermannii. with a mixture containing strains of e. coli o157:h7 and e. coli o6:h1, two different peaks appe ... | 1998 | 9879532 |
| gram type-specific broad-range pcr amplification for rapid detection of 62 pathogenic bacteria. | broad-range pcr has proven to be useful for the detection of bacteria. a set of broad-range pcr primers directed against conserved regions in the 16s rrna gene was designed to specifically amplify either gram-positive or gram-negative bacteria. the gram type-specific broad-range pcr correctly classified all 62 pathogenic species tested. | 1999 | 9889245 |
| the spi-3 pathogenicity island of salmonella enterica. | pathogenicity islands are chromosomal clusters of pathogen-specific virulence genes often found at trna loci. we have determined the molecular genetic structure of spi-3, a 17-kb pathogenicity island located at the selc trna locus of salmonella enterica serovar typhimurium. the g+c content of spi-3 (47.5%) differs from that of the salmonella genome (52%), consistent with the notion that these sequences have been horizontally acquired. spi-3 harbors 10 open reading frames organized in six transcr ... | 1999 | 9922266 |
| a novel chromogenic ester agar medium for detection of salmonellae. | a novel agar medium, chromogenic salmonella esterase (cse) agar, for the differentiation of salmonellae is described. the agar contains peptones and nutrient extracts together with the following (grams per liter unless otherwise specified): 4-[2-(4-octanoyloxy-3, 5-dimethoxyphenyl)-vinyl]-quinolinium-1-(propan-3-yl carboxylic acid) bromide (slpa-octanoate; bromide form), 0.3223; lactose, 14. 65; trisodium citrate dihydrate, 0.5; tween 20, 3.0; ethyl 4-dimethylaminobenzoate, 0.035% (wt/vol), novo ... | 1999 | 9925620 |
| isolation of fecal coliform bacteria from the diamondback terrapin (malaclemys terrapin centrata). | total and fecal coliform bacteria were isolated from the cloaca and feces of the estuarine diamondback terrapin. the majority of samples contained fecal coliforms. escherichia coli was the predominant fecal coliform species isolated, and members of the genus salmonella were isolated from 2 of 39 terrapins. fecal coliform numbers are used to regulate shellfish harvests, and diamondback terrapins inhabit the brackish-water habitats where oyster beds are found; therefore, these findings have implic ... | 1999 | 9925633 |
| analysis of the type 1 pilin gene cluster fim in salmonella: its distinct evolutionary histories in the 5' and 3' regions. | the type 1 pilin encoded by fim is present in both escherichia coli and salmonella natural isolates, but several lines of evidence indicate that similarities at the fim locus may be an example of independent acquisition rather than common ancestry. for example, the fim gene cluster is found at different chromosomal locations and with distinct gene orders in these closely related species. in this work we examined the fim gene cluster of salmonella, the genes of which show high nucleotide sequence ... | 1999 | 9973358 |
| comparison of agar dilution, disk diffusion, microscan, and vitek antimicrobial susceptibility testing methods to broth microdilution for detection of fluoroquinolone-resistant isolates of the family enterobacteriaceae. | fluoroquinolone resistance appears to be increasing in many species of bacteria, particularly in those causing nosocomial infections. however, the accuracy of some antimicrobial susceptibility testing methods for detecting fluoroquinolone resistance remains uncertain. therefore, we compared the accuracy of the results of agar dilution, disk diffusion, microscan walk away neg combo 15 conventional panels, and vitek gns-f7 cards to the accuracy of the results of the broth microdilution reference m ... | 1999 | 9986809 |
| comparison of chromagar salmonella medium and hektoen enteric agar for isolation of salmonellae from stool samples. | chromagar salmonella (cas), a new chromogenic medium, was retrospectively compared to hektoen enteric agar (hea) with 501 salmonella stock isolates and was then prospectively compared to hea for the detection and presumptive identification of salmonella spp. with 508 stool samples before and after enrichment. all stock cultures (100%), including cultures of h2s-negative isolates, yielded typical mauve colonies on cas, while 497 (99%) isolates produced typical lactose-negative, black-centered col ... | 1999 | 9986847 |
| abc medium, a new chromogenic agar for selective isolation of salmonella spp. | we describe a new chromogenic agar medium, abc medium (alphabeta-chromogenic medium), which includes two substrates, 3, 4-cyclohexenoesculetin-beta-d-galactoside and 5-bromo-4-chloro-3-indolyl-alpha-d-galactopyranoside, to facilitate the selective isolation of salmonella spp. this medium exploits the fact that salmonella spp. may be distinguished from other members of the family enterobacteriaceae by the presence of alpha-galactosidase activity in the absence of beta-galactosidase activity. a to ... | 1999 | 9986848 |
| study of rapidity and quality for the vitek susceptibility cards with 45 wells. | vitek 45 wells card was evaluated. recent clinical isolates of gram-positive cocci (107) and gram-negative bacilli (179) were antimicrobial susceptibility testing by vitek system in comparison with mic-2000 system. the antimicrobial susceptibility results were available within of 8 h for gram-positive cocci without a part of mrsa. enterobac-teriaceae were available within of 8 h and pseudomonas aeruginosa were from 8 to 11 h. the antimicrobial susceptibility data had disagreement of 60% with em, ... | 1998 | 10036375 |
| in vitro activities of aminomethyl-substituted analogs of novel tetrahydrofuranyl carbapenems. | cl 188,624, cl 190,294, and cl 191,121 are novel aminomethyl tetrahydrofuranyl (thf)-1 beta-methylcarbapenems. the in vitro antibacterial activities of these thf carbapenems were evaluated and compared with those of biapenem, imipenem, and meropenem against 554 recent clinical isolates obtained from geographically distinct medical centers across north america. the antibacterial activities of the thf carbapenems were equivalent to that of biapenem, and the thf carbapenems were slightly more activ ... | 1999 | 10049250 |
| structure-function studies of ser-289 in the class c beta-lactamase from enterobacter cloacae p99. | site-directed mutagenesis of ser-289 of the class c beta-lactamase from enterobacter cloacae p99 was performed to investigate the role of this residue in beta-lactam hydrolysis. this amino acid lies near the active site of the enzyme, where it can interact with the c-3 substituent of cephalosporins. kinetic analysis of six mutant beta-lactamases with five cephalosporins showed that ser-289 can be substituted by amino acids with nonpolar or polar uncharged side chains without altering the catalyt ... | 1999 | 10049265 |
| abdominal ascites in electric eels (electrophorus electricus) associated with hepatic hemosiderosis and elevated water ph. | six electric eels (electrophorus electricus) from various centers that house aquatic organisms presented clinically with abdominal distension following prolonged exposure to elevated environmental ph. postmortem examination revealed marked ascites. culture of the abdominal fluid from three of the eels yielded either aeromonas hydrophila or citrobacter freundii, which were most likely secondary invaders. histopathology showed marked iron accumulation in both hepatocytes and hepatic macrophage agg ... | 1998 | 10065849 |
| synthesis and evaluation of 2 beta-oxyimino and alkenylpenicillanic acid sulfone derivatives as beta-lactamase inhibitors. | the synthesis and in vitro synergies of 2 beta-alkenyl and oxyiminopenam sulfone derivatives are described. most of the compounds synthesized exhibited good inhibitory activities and synergistic antibacterial activities with piperacillin and ceftriaxone, respectively, against several beta-lactamase producing strains. particularly the 2 beta-alkenylpenam sulfone derivatives. 1e and 1g, showed good synergistic activity with ceftriaxone against citrobacter freundi nih 10018-68 and proteus vulgaris ... | 1999 | 10073138 |
| surface motility of serratia liquefaciens mg1. | 1999 | 10074060 | |
| identification and characterization of is2404 and is2606: two distinct repeated sequences for detection of mycobacterium ulcerans by pcr. | molecular analysis of mycobacterium ulcerans has revealed two new insertion sequences (iss), is2404 and is2606. is2404 was identified by complete sequencing of a previously described repetitive dna segment from m. ulcerans. this element is 1,274 bp long, contains 12-bp inverted repeats and a single open reading frame (orf) potentially encoding a protein of 327 amino acids (aa), and apparently generates 7-bp direct repeats upon transposition. amino acid similarity was found between the putative t ... | 1999 | 10074520 |
| beta1-chain integrins are not essential for intimin-mediated host cell attachment and enteropathogenic escherichia coli-induced actin condensation. | intimin is a bacterial outer membrane protein required for intimate attachment of enterohemorrhagic and enteropathogenic escherichia coli (ehec and epec) to mammalian cells. beta1-chain integrins have been proposed as candidate receptors for intimin. we found that binding of mammalian cells to immobilized intimin was not detectable unless mammalian cells were preinfected with epec or ehec. beta1-chain integrin antagonists or inactivation of the gene encoding the beta1-chain did not affect bindin ... | 1999 | 10085058 |
| [spontaneous bacterial peritonitis due to citrobacter freundii]. | 1999 | 10089713 | |
| cloning and overexpression in escherichia coli of the gene encoding dihydroxyacetone kinase isoenzyme i from schizosaccharomyces pombe, and its application to dihydroxyacetone phosphate production. | the gene dak1 encoding a dihydroxyacetone kinase (dhak) isoenzyme i, one of two isoenzymes in the schizosaccharomyces pombe ifo 0354 strain, was cloned and sequenced. the dak1 gene comprises 1743 bp and encodes a protein of 62,245 da. the deduced amino acid sequence showed a similarity to a putative dhak of saccharomyces cerevisiae and dhak of citrobacter freundii. the dak1 gene was expressed at a high level in escherichia coli, and the recombinant enzyme was purified to homogeneity and characte ... | 1999 | 10091325 |
| a periplasmic d-alanyl-d-alanine dipeptidase in the gram-negative bacterium salmonella enterica. | the vanx protein is a d-alanyl-d-alanine (d-ala-d-ala) dipeptidase essential for resistance to the glycopeptide antibiotic vancomycin. while this enzymatic activity has been typically associated with vancomycin- and teicoplainin-resistant enterococci, we now report the identification of a d-ala-d-ala dipeptidase in the gram-negative species salmonella enterica. the salmonella enzyme is only 36% identical to vanx but exhibits a similar substrate specificity: it hydrolyzes d-ala-d-ala, dl-ala-dl-p ... | 1999 | 10094694 |
| plasmid-encoded ampc beta-lactamases: how far have we gone 10 years after the discovery? | the dogma that ampc genes are located exclusively on the chromosome was dominant until about 10 years ago. since 1989 over 15 different plasmid-encoded ampc beta-lactamases have been reported from several countries. most of these enzymes evolved in two clusters. the major cluster includes several enzymes with a high similarity to cmy-2, which is the closest related chromosomal ampc enzyme of citrobacter freundii. a second cluster centers around cmy-1. it is less homogeneous and not closely relat ... | 1998 | 10097678 |
| aminoglycosides: activity and resistance. | 1999 | 10103173 | |
| in vitro and in vivo antibacterial activities of a novel glycylcycline, the 9-t-butylglycylamido derivative of minocycline (gar-936). | the 9-t-butylglycylamido derivative of minocycline (tbg-mino) is a recently synthesized member of a novel group of antibiotics, the glycylcyclines. this new derivative, like the first glycylcyclines, the n,n-dimethylglycylamido derivative of minocycline and 6-demethyl-6-deoxytetracycline, possesses activity against bacterial isolates containing the two major determinants responsible for tetracycline resistance: ribosomal protection and active efflux. the in vitro activities of tbg-mino and the c ... | 1999 | 10103174 |
| cloning, sequence analyses, expression, and distribution of ampc-ampr from morganella morganii clinical isolates. | shotgun cloning experiments with restriction enzyme-digested genomic dna from morganella morganii 1, which expresses high levels of cephalosporinase, into the pbkcmv cloning vector gave a recombinant plasmid, ppon-1, which encoded four entire genes: ampc, ampr, an hybf family gene, and orf-1 of unknown function. the deduced ampc beta-lactamase of pi 7.6 shared structural and functional homologies with ampc from citrobacter freundii, escherichia coli, yersinia enterocolitica, enterobacter cloacae ... | 1999 | 10103179 |
| in vitro antibacterial properties of pexiganan, an analog of magainin. | pexiganan, a 22-amino-acid antimicrobial peptide, is an analog of the magainin peptides isolated from the skin of the african clawed frog. pexiganan exhibited in vitro broad-spectrum antibacterial activity when it was tested against 3,109 clinical isolates of gram-positive and gram-negative, anaerobic and aerobic bacteria. the pexiganan mic at which 90% of isolates are inhibited (mic90) was 32 micrograms/ml or less for staphylococcus spp., streptococcus spp., enterococcus faecium, corynebacteriu ... | 1999 | 10103181 |
| structure of in31, a blaimp-containing pseudomonas aeruginosa integron phyletically related to in5, which carries an unusual array of gene cassettes. | the location and environment of the acquired blaimp gene, which encodes the imp-1 metallo-beta-lactamase, were investigated in a japanese pseudomonas aeruginosa clinical isolate (isolate 101/1477) that produced the enzyme. in this isolate, blaimp was carried on a 36-kb plasmid, and similar to the identical alleles found in serratia marcescens and klebsiella pneumoniae clinical isolates, it was located on a mobile gene cassette inserted into an integron. the entire structure of this integron, nam ... | 1999 | 10103196 |
| development and characterization of a fluorescent-bacteriophage assay for detection of escherichia coli o157:h7. | in this paper we describe evaluation and characterization of a novel assay that combines immunomagnetic separation and a fluorescently stained bacteriophage for detection of escherichia coli o157:h7 in broth. when it was combined with flow cytometry, the fluorescent-bacteriophage assay (fba) was capable of detecting 10(4) cells/ml. a modified direct epifluorescent-filter technique (deft) was employed in an attempt to estimate bacterial concentrations. using regression analysis, we calculated tha ... | 1999 | 10103228 |
| variation in resistance of natural isolates of escherichia coli o157 to high hydrostatic pressure, mild heat, and other stresses. | strains of escherichia coli o157 isolated from patients with clinical cases of food-borne illness and other sources exhibited wide differences in resistance to high hydrostatic pressure. the most pressure-resistant strains were also more resistant to mild heat than other strains. strain c9490, a representative pressure-resistant strain, was also more resistant to acid, oxidative, and osmotic stresses than the pressure-sensitive strain nctc 12079. most of these differences in resistance were obse ... | 1999 | 10103251 |
| detection of small numbers of campylobacter jejuni and campylobacter coli cells in environmental water, sewage, and food samples by a seminested pcr assay. | a rapid and sensitive assay was developed for detection of small numbers of campylobacter jejuni and campylobacter coli cells in environmental water, sewage, and food samples. water and sewage samples were filtered, and the filters were enriched overnight in a nonselective medium. the enrichment cultures were prepared for pcr by a rapid and simple procedure consisting of centrifugation, proteinase k treatment, and boiling. a seminested pcr based on specific amplification of the intergenic sequen ... | 1999 | 10103261 |
| production of l-dopa(3,4-dihydroxyphenyl-l-alanine) from benzene by using a hybrid pathway. | as an alternative approach to the production of l-dopa from a cheap raw material, we constructed a hybrid pathway consisting of toluene dioxygenase, toluene cis-glycol dehydrogenase, and tyrosine phenol-lyase. in this pathway, catechol is formed from benzene through the sequential action of toluene dioxygenase and toluene cis-glycol dehydrogenase, and l-dopa is synthesized from the resulting catechol in the presence of pyruvate and ammonia by tyrosine phenol-lyase cloned from citrobacter freundi ... | 1998 | 10191414 |
| multiple conformations of the acylenzyme formed in the hydrolysis of methicillin by citrobacter freundii beta-lactamase: a time-resolved ftir spectroscopic study. | time-resolved infrared difference spectroscopy has been used to show that the carbonyl group of the acylenzyme reaction intermediate in the citrobacter freundii beta-lactamase-catalyzed hydrolysis of methicillin can assume at least four conformations. a single-turnover experiment shows that all four conformations decline during deacylation with essentially the same rate constant. the conformers are thus in exchange on the reaction time scale, assuming that deacylation takes place only from the c ... | 1999 | 10194295 |
| discrimination of burkholderia multivorans and burkholderia vietnamiensis from burkholderia cepacia genomovars i, iii, and iv by pcr. | we present a pcr procedure for identification of burkholderia cepacia, burkholderia multivorans, and burkholderia vietnamiensis. 16s and 23s ribosomal dnas (rdnas) of b. multivorans and b. vietnamiensis were sequenced and aligned with published sequences for definition of species-specific 18-mer oligonucleotide primers. specific antisense 16s rdna primers (for b. cepacia, 5'-agc act ccc rcc tct cag-3'; for b. multivorans, 5'-agc act ccc gaa tct ctt-3') and 23s rdna primers (for b. vietnamiensis, ... | 1999 | 10203482 |
| asymptomatic bacteriuria in pregnancy: epidemiological, clinical and microbiological approach. | asymptomatic urinary tract infection is a risk factor for fetal and maternal morbidity including development of pyelonephritis, premature labor and impaired intra-uterine development. in this study, 326 pregnant and 100 non-pregnant control women were screened for significant asymptomatic bacteriuria from april 8 to july 25, 1997 to gain insight into the prevalence rate, clinical characteristics of the disease and microbiological assessments of the causative agents. all the subjects were clinica ... | 1998 | 10214459 |
| in vitro and in vivo antimicrobial activities of t-3811me, a novel des-f(6)-quinolone. | the in vitro and in vivo activities of t-3811me, a novel des-f(6)-quinolone, were evaluated in comparison with those of some fluoroquinolones, including a newly developed one, trovafloxacin. t-3811, a free base of t-3811me, showed a wide range of antimicrobial spectra, including activities against chlamydia trachomatis, mycoplasma pneumoniae, and mycobacterium tuberculosis. in particular, t-3811 exhibited potent activity against various gram-positive cocci, with mics at which 90% of the isolates ... | 1999 | 10223917 |
| negative regulation of the pseudomonas aeruginosa outer membrane porin oprd selective for imipenem and basic amino acids. | pseudomonas aeruginosa oprd is a specific porin which facilitates the uptake of basic amino acids and imipenem, a carbapenem antibiotic. resistance to imipenem due to the loss of oprd is an important mechanism for the loss of clinical effectiveness. to investigate the negative regulatory mechanisms influencing oprd expression, a gene upstream of the coregulated mexef-oprn efflux operon, designated mext, was cloned. the predicted 304-amino-acid mature mext protein showed strong homology to lysr-t ... | 1999 | 10223918 |
| carbapenem resistance in escherichia coli associated with plasmid-determined cmy-4 beta-lactamase production and loss of an outer membrane protein. | three cefoxitin-resistant escherichia coli isolates from stool specimens of a patient with leukemia were either resistant, intermediate, or sensitive to imipenem. conjugation experiments showed that cefoxitin resistance, but not imipenem resistance, was transferable. all isolates were shown by isoelectric focusing to produce two beta-lactamases with isoelectric points of 5.4 (tem-1, confirmed by sequencing of a pcr product) and >8.5 (consistent with a class c beta-lactamase). the gene coding for ... | 1999 | 10223937 |
| differential expression of vibrio vulnificus capsular polysaccharide. | vibrio vulnificus is a human pathogen whose virulence has been associated with the expression of capsular polysaccharide (cps). multiple cps types have been described; however, virulence does not appear to correlate with a particular cps composition. reversible-phase variation for opaque and translucent colony morphologies is characterized by changes in cps expression, as suggested by electron microscopy of cells stained nonspecifically with ruthenium red. isolates with opaque colony morphologie ... | 1999 | 10225881 |
| enterohemorrhagic escherichia coli o157:h7 produces tir, which is translocated to the host cell membrane but is not tyrosine phosphorylated. | intimate attachment to the host cell leading to the formation of attaching and effacing (a/e) lesions is an essential feature of enterohemorrhagic escherichia coli (ehec) o157:h7 pathogenesis. in a related pathogen, enteropathogenic e. coli (epec), this activity is dependent upon translocation of the intimin receptor, tir, which becomes tyrosine phosphorylated within the host cell membrane. in contrast, the accumulation of tyrosine-phosphorylated proteins beneath adherent ehec bacteria does not ... | 1999 | 10225900 |
| mechanisms of internalization of staphylococcus aureus by cultured human osteoblasts. | staphylococcus aureus is an important bone pathogen, and evidence shows that this organism is internalized by chick osteoblasts. here we report that s. aureus is internalized by human osteoblasts. internalization was inhibited by monodansylcadaverine and cytochalasin d and to a lesser extent by ouabain, monensin, colchicine, and nocodazole. we propose that internalization occurs via a receptor-mediated pathway, requiring the participation of cytoskeletal elements, principally actin. | 1999 | 10225942 |
| bacteriocin release protein triggers dimerization of outer membrane phospholipase a in vivo. | bacteriocin release protein is known to activate outer membrane phospholipase a (ompla), which results in the release of colicin from escherichia coli. in vivo chemical cross-linking experiments revealed that the activation coincides with dimerization of ompla. permeabilization of the cell envelope and dimerization were characterized by a lag time of 2 h. | 1999 | 10322034 |
| characterization of marr superrepressor mutants. | marr negatively regulates expression of the multiple antibiotic resistance (mar) locus in escherichia coli. superrepressor mutants, generated in order to study regions of marr required for function, exhibited altered inducer recognition properties in whole cells and increased dna binding to maro in vitro. mutations occurred in three areas of the relatively small marr protein (144 amino acids). it is surmised that superrepression results from increased dna binding activities of these mutant prote ... | 1999 | 10322039 |
| controlled clinical comparison of biomérieux vital and bactec nr-660 blood culture systems for detection of bacteremia and fungemia in adults. | a total of 9,446 blood cultures were collected from adult patients at three university-affiliated hospitals. of these, 8,943 cultures were received with both aerobic bottles filled adequately; 885 yielded 1,016 microorganisms, including 622 isolates (61%) that were the cause of sepsis, 337 isolates (33%) that were contaminants, and 57 isolates (6%) that were indeterminate as the cause of sepsis. with the exception of staphylococcus aureus, which was recovered more often from vital aerobic bottle ... | 1999 | 10325312 |
| antigenic and molecular conservation of the gonococcal nspa protein. | a low-molecular-weight protein named nspa (neisserial surface protein a) was recently identified in the outer membrane of all neisseria meningitidis strains tested. antibodies directed against this protein were shown to protect mice against an experimental meningococcal infection. hybridization experiments clearly demonstrated that the nspa gene was also present in the genomes of the 15 neisseria gonorrhoeae strains tested. cloning and sequencing of the nspa gene of n. gonorrhoeae b2 revealed an ... | 1999 | 10338491 |
| citrobacter rodentium infection in mice elicits a mucosal th1 cytokine response and lesions similar to those in murine inflammatory bowel disease. | citrobacter rodentium is a classically noninvasive pathogen of mice that is similar to enteropathogenic escherichia coli (epec) in man. following oral infection of young mice, the organism colonizes the distal colon, and within 1 week the colonic mucosa doubles in thickness and there is massive epithelial cell hyperplasia. since t-cell responses in mouse models of inflammatory bowel disease (ibd) also cause epithelial hyperplasia, we have investigated the possibility that c. rodentium promotes s ... | 1999 | 10338516 |
| metabolism of l(-)-carnitine by enterobacteriaceae under aerobic conditions. | different enterobacteriaceae, such as escherichia coli, proteus vulgaris and proteus mirabilis, are able to convert l(-)-carnitine, via crotonobetaine, into gamma-butyrobetaine in the presence of carbon and nitrogen sources under aerobic conditions. intermediates of l(-)-carnitine metabolism (crotonobetaine, gamma-butyrobetaine) could be detected by thin-layer chromatography. in parallel, l(-)-carnitine dehydratase, carnitine racemasing system and crotonobetaine reductase activities were determi ... | 1999 | 10339822 |
| the serodiagnosis of infections caused by verocytotoxin-producing escherichia coli. | patients with haemolytic uraemic syndrome (hus) and haemorrhagic colitis (hc) produce serum antibodies to the lipopolysaccharides (lps) of escherichia coli o157 and certain other e. coli serogroups. patients may also make salivary antibodies to the lps of e. coli o157. serological tests based on these antibodies can be used to provide evidence of infection in the absence of culturable vtec or the toxins they produce. serum antibodies to lps persist for several months following onset of disease, ... | 1999 | 10347867 |
| characterization and nucleotide sequence of a klebsiella oxytoca cryptic plasmid encoding a cmy-type beta-lactamase: confirmation that the plasmid-mediated cephamycinase originated from the citrobacter freundii ampc beta-lactamase. | plasmid ptkh11, originally obtained by electroporation of a klebsiella oxytoca plasmid preparation into escherichia coli xac, expressed a high level of an ampc-like beta-lactamase. the enzyme, designated cmy-5, conferred resistance to extended-spectrum beta-lactams in e. coli; nevertheless, the phenotype was cryptic in the k. oxytoca donor. determination of the complete nucleotide sequence of ptkh11 revealed that the 8,193-bp plasmid encoded seven open reading frames, including that for the cmy- ... | 1999 | 10348751 |
| use of microdilution panels with and without beta-lactamase inhibitors as a phenotypic test for beta-lactamase production among escherichia coli, klebsiella spp., enterobacter spp., citrobacter freundii, and serratia marcescens. | over the past decade, a number of new beta-lactamases have appeared in clinical isolates of enterobacteriaceae that, unlike their predecessors, do not confer beta-lactam resistance that is readily detected in routine antibiotic susceptibility tests. because optimal methodologies are needed to detect these important new beta-lactamases, a study was designed to evaluate the ability of a panel of various beta-lactam antibiotics tested alone and in combination with beta-lactamase inhibitors to discr ... | 1999 | 10348759 |
| evaluation of the in vitro activity of six broad-spectrum beta-lactam antimicrobial agents tested against over 2,000 clinical isolates from 22 medical centers in japan. japan antimicrobial resistance study group. | numerous broad-spectrum beta-lactam antimicrobial agents have been introduced into medical practice since 1985. although several of these compounds have advanced, infectious disease therapy resistances to them has also emerged world-wide. in 1997, a japanese 22 medical center investigation was initiated to assess the continued utility of these agents (oxacillin or piperacillin, ceftazidime, cefepime, cefpirome, cefoperazone/sulbactam [c/s], imipenem). the participating medical centers represente ... | 1999 | 10354863 |
| evaluation of statens serum institut enteric medium for detection of enteric pathogens. | the efficacy of the statens serum institut (ssi) enteric medium for isolation and direct identification of enteric pathogens was evaluated. six different biochemical reactions can be read by using the ssi enteric medium, allowing direct identification of a range of enteric pathogens. all 248 gram-negative bacterial species that were tested grew on the ssi enteric medium. only 10 of 248 bacteria (4%) showed discrepant results in the biochemical reactions, and none of these were enteric pathogens. ... | 1999 | 10364603 |
| clinical problems of sloths (bradypus sp. and choloepus sp.) in captivity. | a 20-yr retrospective study of disease prevalence was carried out for 51 sloths (34 bradypus sp. and 17 choloepus sp.) at the são paulo zoo. a total of 81 clinical disorders were detected, including nutritional (45.7%), digestive (12.3%), and respiratory (12.3%) problems and injuries (6.1%). a definitive diagnosis was not possible in 8.6% of the cases. the incidence of disease varied according to seasonal climate (winter, 32.5%; spring, 24%; summer, 22.9%; autumn, 20.5%), time in captivity (96.4 ... | 1999 | 10367647 |
| resistance to third-generation cephalosporins in adult gram-negative bacillary meningitis. | ninety-three patients with gram-negative bacillary meningitis (gnbm) were identified at kaohsiung chang gung memorial hospital, over a period of 12 years. among them, eight showed resistance to third-generation cephalosporins, accounting for 9% of the total gnbm cases and 29% of the postneurosurgical gnbm cases. the resistant pathogens included acinetobacter baumannii, klebsiella pneumoniae, citrobacter freundii and morganella morganii. these eight patients, six males and two females aged 18-61 ... | 1999 | 10378134 |
| development of primers to o-antigen biosynthesis genes for specific detection of escherichia coli o157 by pcr. | the chemical composition of each o-antigen subunit in gram-negative bacteria is a reflection of the unique dna sequences within each rfb operon. by characterizing dna sequences contained with each rfb operon, a diagnostic serotype-specific probe to escherichia coli o serotypes that are commonly associated with bacterial infections can be generated. recently, from an e. coli o157:h7 cosmid library, o-antigen-positive cosmids were identified with o157-specific antisera. by using the cosmid dnas as ... | 1999 | 10388689 |
| cloning and characterization of a gene, pbpf, encoding a new penicillin-binding protein, pbp2b, in staphylococcus aureus. | a previously unrecognized penicillin binding protein (pbp) gene, pbpf, was identified in staphylococcus aureus. this gene encodes a protein of 691 amino acid residues with an estimated molecular mass of 78 kda. the molecular mass is very close to that of s. aureus pbp2 (81 kda), and the protein is tentatively named pbp2b. pbp2b has three motifs, ssvk, ssn, and ktg, that can be found in pbps and beta-lactamases. recombinant pbp2b (rpbp2b), which lacks a putative signal peptide at the n terminus a ... | 1999 | 10390206 |
| molecular characterization of tem-59 (irt-17), a novel inhibitor-resistant tem-derived beta-lactamase in a clinical isolate of klebsiella oxytoca. | a clinical isolate of klebsiella oxytoca (kox 443) was found to have a low-level resistance to broad-spectrum penicillins (mics of amoxicillin and ticarcillin, 256 and 32 microg/ml, respectively), without substantial potentiation by 2 microg of clavulanic acid per ml (amoxicillin- and ticarcillin-clavulanate, 128 and 8 microg/ml, respectively), while being fully susceptible to cephalosporins and other beta-lactam antibiotics. these resistances were carried by a ca. 50-kb conjugative plasmid that ... | 1999 | 10390218 |
| roles of beta-lactamases and porins in activities of carbapenems and cephalosporins against klebsiella pneumoniae. | two clinical isolates of extended-spectrum beta-lactamase (esbl)-producing klebsiella pneumoniae were noted to be less susceptible than expected to imipenem. both were missing outer membrane proteins that serve as channels for antibiotic entry. the role of beta-lactamase in resistance was investigated by eliminating the original esbl and introducing plasmids encoding various esbls and ampc beta-lactamase types, by studying the effect of an increased inoculum, and by evaluating interactions with ... | 1999 | 10390220 |
| sequence of the mir-1 beta-lactamase gene. | the complete nucleotide sequence of the plasmid-mediated mir-1 beta-lactamase gene confirms its relationship to chromosomally located ampc genes of enterobacter cloacae. blamir-1 is not part of a typical gene cassette but does lie near an element that could be involved in its capture on a plasmid. | 1999 | 10390237 |
| identification of a novel beta-lactamase produced by xanthomonas campestris, a phytopathogenic bacterium. | the xanthomonas campestris pv. campestris 11 chromosome encodes a periplasmic beta-lactamase of 30 kda. gene replacement and complementation confirmed the presence of this enzyme. its deduced amino acid sequence shows identity and conserved domains between it and stenotrophomonas maltophilia l2 and other ambler class a/bush group 2 beta-lactamases. southern hybridization detected a single homologous fragment in each of 12 other xanthomonas strains, indicating that the presence of a beta-lactamas ... | 1999 | 10390247 |
| use of a monoclonal antibody against an escherichia coli o26 surface protein for detection of enteropathogenic and enterohemorrhagic strains. | a monoclonal antibody (mab) was obtained from a mouse immunized with solubilized outer membrane proteins extracted from a bovine enterohemorrhagic strain of escherichia coli (ehec), o26. the mab produced a strong immunoblot reaction at approximately 21 kda for an o26 strain containing the intimin gene (eae) and verocytotoxin (vt), but not with an o26 eae- and vt-negative strain, or o157 eae- and vt-positive strains. the mab was used in a sandwich enzyme-linked immunosorbent assay (elisa) format ... | 1999 | 10391872 |
| [a consideration on the results of nationwide surveillance of antimicrobial susceptibilities--gram-negative bacilli]. | the results of the semi-annual nationwide surveillance of antimicrobial susceptibilities, conducted by the japanese ministry of health and welfare during the period of january 1993 to july 1995, were analyzed for typical gram-negative bacilli in the purpose of provision of an index for antimicrobial selection. during these 3 years, escherichia coli, citrobacter freundii, enterobacter aerogenes and proteus mirabilis showed slightly increasing tendency in susceptibility to fosfomycin (fom) and cit ... | 1999 | 10396690 |
| isolation and characterization of mutations in the escherichia coli regulatory protein xapr. | in this work, the lysr-type protein xapr has been subjected to a mutational analysis. xapr regulates the expression of xanthosine phosphorylase (xapa), a purine nucleoside phosphorylase in escherichia coli. in the wild type, full expression of xapa requires both a functional xapr protein and the inducer xanthosine. here we show that deoxyinosine can also function as an inducer in the wild type, although not to the same extent as xanthosine. we have isolated and characterized in detail the mutant ... | 1999 | 10400599 |
| the bacteriology of neonatal septicaemia in ile-ife, nigeria. | the incidence of septicaemia among neonates categorized as being at high risk was 55 per cent in ile-ife, nigeria. gram-positive organisms, specifically staphylococcus aureus, were predominant (33.8 per cent) among bacteria cultured from proven cases of septicaemia. other coagulase-negative staphylococci also contributed 21 per cent, with staphylococcus epidermidis occurring in 5 per cent of the isolates. listeria monocytogenes was cultured from 8.4 per cent of septic neonates. pseudomonas aerug ... | 1999 | 10401192 |
| susceptibility to levofloxacin of clinical isolates of bacteria from intensive care and haematology/oncology patients in switzerland: a multicentre study. | the objective of this study was to examine the susceptibility of clinical isolates to levofloxacin, a fluoroquinolone with extended activity against gram-positive bacteria, and other antibiotics in 12 swiss clinical microbiology laboratories using the nccls disc diffusion technique. isolates were prospectively collected from intensive care units (icus (59%), oncology wards (7%) and other units with haematology/oncology patients (34%) from june 1995 to march 1996. the levofloxacin breakpoints use ... | 1999 | 10404338 |
| biochemical identification of citrobacter species defined by dna hybridization and description of citrobacter gillenii sp. nov. (formerly citrobacter genomospecies 10) and citrobacter murliniae sp. nov. (formerly citrobacter genomospecies 11). | recent work describing six named species and two unnamed genomospecies within citrobacter has enlarged the genus to 11 species. dna relatedness and phenotypic tests were used to determine how well these species can be identified. one hundred thirty-six strains were identified to species level by dna relatedness and then identified phenotypically in a blinded fashion. by using conventional tests, 119 of the 136 strains (88%) were correctly identified to species level. three additional strains (2% ... | 1999 | 10405411 |
| detection of staphylococcus aureus and staphylococcus epidermidis in clinical samples by 16s rrna-directed in situ hybridization. | staphylococcus epidermidis and staphylococcus aureus are the most common causes of medical device-associated infections, including septicemic loosenings of orthopedic implants. frequently, the microbiological diagnosis of these infections remains ambiguous, since at least some staphylococci have the capacity to reduce their growth rate considerably. these strains exhibit a small-colony phenotype, and often they are not detectable by conventional microbiological techniques. moreover, clinical iso ... | 1999 | 10405419 |
| rare case of failure by an automated system to detect extended-spectrum beta-lactamase in a cephalosporin-resistant klebsiella pneumoniae isolate. | 1999 | 10408960 | |
| campylobacter jejuni 81-176 associates with microtubules and dynein during invasion of human intestinal cells. | campylobacter jejuni uptake into cultured int407 cells was analyzed kinetically over a wide range of starting multiplicities of infection (moi; from 0.02 to 20,000 bacteria/epithelial cell). the efficiency of internalization was the highest at moi of 0.02 and decreased steadily at higher mois, presumably due to reported c. jejuni autoagglutination at higher densities. total internalized campylobacter cfu increased gradually from an moi of 0.02 to a peak at an moi of 200 (reaching an average of t ... | 1999 | 10417189 |
| citrobacter freundii invades and replicates in human brain microvascular endothelial cells. | neonatal bacterial meningitis remains a disease with unacceptable rates of morbidity and mortality despite the availability of effective antimicrobial therapy. citrobacter spp. cause neonatal meningitis but are unique in their frequent association with brain abscess formation. the pathogenesis of citrobacter spp. causing meningitis and brain abscess is not well characterized; however, as with other meningitis-causing bacteria (e.g., escherichia coli k1 and group b streptococci), penetration of t ... | 1999 | 10417193 |
| alteration of the repressor activity of marr, the negative regulator of the escherichia coli marrab locus, by multiple chemicals in vitro. | marr negatively regulates expression of the multiple antibiotic resistance operon (marrab) in escherichia coli. in this study, it was demonstrated that sodium salicylate, plumbagin, 2, 4-dinitrophenol, and menadione-inducers of the marrab operon in whole cells-all interfered with the repressor activity of marr in vitro. it is proposed that these compounds can interact directly with marr to affect its repressor activity. | 1999 | 10419969 |
| comparison and recovery of escherichia coli and thermotolerant coliforms in water with a chromogenic medium incubated at 41 and 44.5 degrees c. | this study compared the performance of a commercial chromogenic medium, chromagarecc (cecc), and cecc supplemented with sodium pyruvate (ceccp) with the membrane filtration lauryl sulfate-based medium (mlsa) for enumeration of escherichia coli and non-e. coli thermotolerant coliforms (kec). to establish that we could recover the maximum kec and e. coli population, we compared two incubation temperature regimens, 41 and 44.5 degrees c. statistical analysis by the fisher test of data did not demon ... | 1999 | 10427079 |
| biodegradation of tannic acid by citrobacter freundii isolated from a tannery effluent. | a bacterial strain capable of utilizing tannic acid as sole carbon source was isolated from the effluent of a tannery and was identified as citrobacter freundii. this organism could grow at concentrations as high as 5% (w/v) of tannic acid and produced extracellular tannase to hydrolyze the same. when grown in minimal medium containing 1% tannic acid (w/v) at 30 degrees c, this strain produced 1.87 u/ml of tannase at 6 h. at that time, tannic acid degradation products, namely glucose and gallic ... | 1999 | 10427737 |
| construction and characterization of mutants of the tem-1 beta-lactamase containing amino acid substitutions associated with both extended-spectrum resistance and resistance to beta-lactamase inhibitors. | extended-spectrum tem beta-lactamases (esbls) do not usually confer resistance to beta-lactamase inhibitors such as clavulanate or tazobactam. to investigate the compatibility of the two phenotypes we used site-directed mutagenesis of the bla(tem-1) gene to introduce into the tem-1 beta-lactamase amino acid substitutions that confer the esbl phenotype: tem-12 (arg164-->ser), tem-26 (arg164-->ser plus glu104-->lys), tem-19 (gly238-->ser), and tem-15 (gly238-->ser plus glu104-->lys). these were co ... | 1999 | 10428907 |
| in vitro and in vivo activities of syn2190, a novel beta-lactamase inhibitor. | syn2190, a monobactam derivative containing 1,5-dihydroxy-4-pyridone as the c-3 side chain, is a potent inhibitor of group 1 beta-lactamase. the concentrations of inhibitor needed to reduce the initial rate of hydrolysis of substrate by 50% for syn2190 against these enzymes were in the range of 0.002 to 0.01 microm. these values were 220- to 850-fold lower than those of tazobactam. syn2190 showed in vitro synergy with ceftazidime and cefpirome. this synergy was dependent on the concentration of ... | 1999 | 10428909 |
| a novel type of ampc beta-lactamase, acc-1, produced by a klebsiella pneumoniae strain causing nosocomial pneumonia. | a klebsiella pneumoniae strain resistant to oxyimino cephalosporins was cultured from respiratory secretions of a patient suffering from nosocomial pneumonia in kiel, germany, in 1997. the isolate harbors a bla resistance gene located on a transmissible plasmid. an escherichia coli transconjugant produces a beta-lactamase with an isoelectric point of 7.7 and a resistance phenotype characteristic of an ampc (class 1) beta-lactamase except for low mics of cephamycins. the bla gene was cloned and s ... | 1999 | 10428914 |
| in vitro antibacterial activity of ljc 11,036, an active metabolite of l-084, a new oral carbapenem antibiotic with potent antipneumococcal activity. | ljc 11,036 is the active metabolite of l-084, a novel oral carbapenem that exhibits potent broad-spectrum activity. antibacterial activities of ljc 11,036 against clinical isolates from respiratory infections, such as streptococcus pneumoniae (n = 52), streptococcus pyogenes (n = 19), haemophilus influenzae (n = 50), klebsiella pneumoniae (n = 53), and moraxella catarrhalis (n = 53), and from urinary-tract infections, such as escherichia coli (n = 53) (mics at which 90% of the isolates were inhi ... | 1999 | 10428928 |
| tem-24 produced by four different species of enterobacteriaceae, including providencia rettgeri, in a single patient. | four species of members of the family enterobacteriaceae harboring extended-spectrum beta-lactamase (esbl) were recovered in a single patient hospitalized in an intensive care unit. among these isolates, we describe for the first time an esbl-producing providencia rettgeri strain. bacteria from the same species were shown to be genetically related by pulsed-field gel electrophoresis analysis. these strains produced the same tem derivative esbl, characterized as tem-24. this enzyme had the peculi ... | 1999 | 10428940 |
| role of permeability in the activities of beta-lactams against gram-negative bacteria which produce a group 3 beta-lactamase. | the production of a group 3 beta-lactamase permitted escherichia coli to raise the mics of ceftazidime, cefpirome, and meropenem greatly but those of imipenem and piperacillin only slightly. the ratios of maximum rate of hydrolysis to k(m) of ceftazidime, cefpirome, and piperacillin were lower than those of meropenem and imipenem for the group 3 beta-lactamase. the permeability coefficients for piperacillin and meropenem were higher than those for ceftazidime and cefpirome. imipenem had the high ... | 1999 | 10428944 |
| intracellular growth in acanthamoeba castellanii affects monocyte entry mechanisms and enhances virulence of legionella pneumophila. | since legionella pneumophila is an intracellular pathogen, entry into and replication within host cells are thought to be critical to its ability to cause disease. l. pneumophila grown in one of its environmental hosts, acanthamoeba castellanii, is phenotypically different from l. pneumophila grown on standard laboratory medium (bcye agar). although amoeba-grown l. pneumophila displays enhanced entry into monocytes compared to bcye-grown bacteria, the mechanisms of entry used and the effects on ... | 1999 | 10456883 |
| invasive ability of an escherichia coli strain isolated from the ileal mucosa of a patient with crohn's disease. | crohn's disease (cd) is an inflammatory bowel disease in which escherichia coli strains have been suspected of being involved. we demonstrated previously that ileal lesions of cd are colonized by e. coli strains able to adhere to intestinal caco-2 cells but devoid of the virulence genes so far described in the pathogenic e. coli strains involved in gastrointestinal infections. in the present study we compared the invasive ability of one of these strains isolated from an ileal biopsy of a patient ... | 1999 | 10456892 |
| the 17-gene ethanolamine (eut) operon of salmonella typhimurium encodes five homologues of carboxysome shell proteins. | the eut operon of salmonella typhimurium encodes proteins involved in the cobalamin-dependent degradation of ethanolamine. previous genetic analysis revealed six eut genes that are needed for aerobic use of ethanolamine; one (eutr), encodes a positive regulator which mediates induction of the operon by vitamin b12 plus ethanolamine. the dna sequence of the eut operon included 17 genes, suggesting a more complex pathway than that revealed genetically. we have correlated an open reading frame in t ... | 1999 | 10464203 |
| activities of clinafloxacin, alone and in combination with other compounds, against 45 gram-positive and -negative organisms for which clinafloxacin mics are high. | time-kill studies indicated that clinafloxacin showed synergy after 24 h with ceftazidime, amikacin, and imipenem against 12, 8, and 10 of 33 gram-negative rods, respectively; with vancomycin, teicoplanin, cefotaxime, and amikacin against 3, 3, 1, and 1 of 9 staphylococci and enterococci, respectively; and with vancomycin, penicillin, and cefotaxime against 0, 2, and 2 of 3 pneumococci, respectively. the mics of clinafloxacin alone for most strains were >/=1 microg/ml. | 1999 | 10471582 |
| biocontrol of escherichia coli o157 with o157-specific bacteriophages. | escherichia coli o157 antigen-specific bacteriophages were isolated and tested to determine their ability to lyse laboratory cultures of escherichia coli o157:h7. a total of 53 bovine or ovine fecal samples were enriched for phage, and 5 of these samples were found to contain lytic phages that grow on e. coli o157:h7. three bacteriophages, designated kh1, kh4, and kh5, were evaluated. at 37 or 4 degrees c, a mixture of these three o157-specific phages lysed all of the e. coli o157 cultures teste ... | 1999 | 10473373 |
| construction of environmental dna libraries in escherichia coli and screening for the presence of genes conferring utilization of 4-hydroxybutyrate. | environmental dna libraries from three different soil samples were constructed. the average insert size was 5 to 8 kb and the percentage of plasmids with inserts was approximately 80%. the recombinant escherichia coli strains (approximately 930,000) were screened for 4-hydroxybutyrate utilization. thirty-six positive e. coli clones were obtained during the initial screen, and five of them contained a recombinant plasmid (pah1 to pah5) which conferred a stable 4-hydroxybutyrate-positive phenotype ... | 1999 | 10473393 |
| bacterial growth state distinguished by single-cell protein profiling: does chlorination kill coliforms in municipal effluent? | municipal effluent is the largest reservoir of human enteric bacteria. its public health significance, however, depends upon the physiological status of the wastewater bacterial community. a novel immunofluorescence assay was developed and used to examine the bacterial growth state during wastewater disinfection. quantitative levels of three highly conserved cytosolic proteins (dnak, dps, and fis) were determined by using enterobacterium-specific antibody fluorochrome-coupled probes. enterobacte ... | 1999 | 10473432 |
| [citrobacter freundii endocarditis]. | infection by citrobacter appears in man only in certain circumstances, since it usually acts as contaminant or colonizer. bacteraemia by this bacillus can affect immunodeficient people, elderly people or those patients who have undergone invasive hospital processes. although incidence of bacteraemia is low (0.3-0.9%), the death rate is very high, about 48%. this bacillus is seldom the cause of endocarditis. that is why we describe a case of endocarditis by citrobacter freundii, in an aged person ... | 1999 | 10481339 |
| transposition of the endogenous insertion sequence element is1126 modulates gingipain expression in porphyromonas gingivalis. | we have previously reported on a tn4351-generated mutant of porphyromonas gingivalis (msm-3) which expresses enhanced arginine-specific proteinase activity and does not utilize hemin or hemoglobin for growth (c. a. genco et al., infect. immun. 63:2459-2466, 1995). in the process of characterizing the genetic lesion in p. gingivalis msm-3, we have determined that the endogenous p. gingivalis insertion sequence element is1126 is capable of transposition within p. gingivalis. we have also determine ... | 1999 | 10496872 |
| the propanediol utilization (pdu) operon of salmonella enterica serovar typhimurium lt2 includes genes necessary for formation of polyhedral organelles involved in coenzyme b(12)-dependent 1, 2-propanediol degradation. | the propanediol utilization (pdu) operon of salmonella enterica serovar typhimurium lt2 contains genes needed for the coenzyme b(12)-dependent catabolism of 1,2-propanediol. here the completed dna sequence of the pdu operon is presented. analyses of previously unpublished pdu dna sequence substantiated previous studies indicating that the pdu operon was acquired by horizontal gene transfer and allowed the identification of 16 hypothetical genes. this brings the total number of genes in the pdu o ... | 1999 | 10498708 |
| phylogenetic analysis of l4-mediated autogenous control of the s10 ribosomal protein operon. | we investigated the regulation of the s10 ribosomal protein (r-protein) operon among members of the gamma subdivision of the proteobacteria, which includes escherichia coli. in e. coli, this 11-gene operon is autogenously controlled by r-protein l4. this regulation requires specific determinants within the untranslated leader of the mrna. secondary structure analysis of the s10 leaders of five enterobacteria (salmonella typhimurium, citrobacter freundii, yersinia enterocolitica, serratia marcesc ... | 1999 | 10498727 |
| quorum-sensing cross talk: isolation and chemical characterization of cyclic dipeptides from pseudomonas aeruginosa and other gram-negative bacteria. | in cell-free pseudomonas aeruginosa culture supernatants, we identified two compounds capable of activating an n-acylhomoserine lactone (ahl) biosensor. mass spectrometry and nmr spectroscopy revealed that these compounds were not ahls but the diketopiperazines (dkps), cyclo(deltaala-l-val) and cyclo(l-pro-l-tyr) respectively. these compounds were also found in cell-free supernatants from proteus mirabilis, citrobacter freundii and enterobacter agglomerans [cyclo(deltaala-l-val) only]. although ... | 1999 | 10510239 |
| mechanism of repression of the arop p2 promoter by the tyrr protein of escherichia coli. | previously, we have shown that expression of the escherichia coli arop p2 promoter is partially repressed by the tyrr protein alone and strongly repressed by the tyrr protein in the presence of the coeffector tyrosine or phenylalanine (p. wang, j. yang, and a. j. pittard, j. bacteriol. 179:4206-4212, 1997). here we present in vitro results showing that the tyrr protein and rna polymerase can bind simultaneously to the arop p2 promoter. in the presence of tyrosine, the tyrr protein inhibits open ... | 1999 | 10515932 |
| development of a pcr assay for rapid detection of enterococci. | enterococci are becoming major nosocomial pathogens, and increasing resistance to vancomycin has been well documented. conventional identification methods, which are based on culturing, require 2 to 3 days to provide results. pcr has provided a means for the culture-independent detection of enterococci in a variety of clinical specimens and is capable of yielding results in just a few hours. however, all pcr-based assays developed so far are species specific only for clinically important enteroc ... | 1999 | 10523541 |
| rapid identification of burkholderia pseudomallei in blood cultures by a monoclonal antibody assay. | burkholderia pseudomallei is the causative agent of melioidosis. in northeast thailand, this gram-negative bacterium is a major cause of mortality from septicemia. the definitive diagnosis of this disease is made by bacterial culture. in this study, we produced a monoclonal antibody (mab) specific to the 30-kda protein of b. pseudomallei by in vivo and in vitro immunization of balb/c mice with a crude culture filtrate antigen. the mab could directly agglutinate with all 243 clinical isolates of ... | 1999 | 10523570 |
| citrobacter urinary tract infections in children. | citrobacter species have been described as the etiologic agents in cases of bacteremia, meningitis, diarrhea and brain abscess, but little is known of their role as a cause of urinary tract infections in children. the purpose of this study was to define the role of citrobacter species in pediatric urinary tract infections. | 1999 | 10530585 |
| outer membrane protein a-promoted actin condensation of brain microvascular endothelial cells is required for escherichia coli invasion. | escherichia coli is the most common gram-negative bacterium that causes meningitis during the neonatal period. we have previously shown that the entry of circulating e. coli organisms into the central nervous system is due to their ability to invade the blood-brain barrier, which is composed of a layer of brain microvascular endothelial cells (bmec). in this report, we show by transmission electron microscopy that e. coli transmigrates through bmec in an enclosed vacuole without intracellular mu ... | 1999 | 10531228 |
| safety and immunogenicity of vi conjugate vaccines for typhoid fever in adults, teenagers, and 2- to 4-year-old children in vietnam. | the capsular polysaccharide of salmonella typhi, vi, is an essential virulence factor and a protective vaccine for people older than 5 years. the safety and immunogenicity of two investigational vi conjugate vaccines were evaluated in adults, 5- to 14-year-old children, and 2- to 4-year-old children in vietnam. the conjugates were prepared with pseudomonas aeruginosa recombinant exoprotein a (repa) as the carrier, using either n-succinimidyl-3-(2-pyridyldithio)-propionate (spdp; vi-repa(1)) or a ... | 1999 | 10531232 |
| citrobacter rodentium espb is necessary for signal transduction and for infection of laboratory mice. | citrobacter rodentium is the causative agent of transmissible murine colonic hyperplasia and contains a locus of enterocyte effacement (lee) similar to that found in enteropathogenic escherichia coli (epec). epec espb is necessary for intimate attachment and signal transduction between epec and cultured cell monolayers. mice challenged with wild-type c. rodentium develop a mucosal immunoglobulin a response to espb. in this study, c. rodentium espb has been cloned and its nucleotide sequence has ... | 1999 | 10531262 |
| the distribution of enteric bacteria from australian mammals: host and geographical effects. | bacteria of the family enterobacteriaceae were isolated from 642 mammalian hosts, representing 16 families and 79 species, collected from throughout australia. escherichia coli was the most common of the 24 enteric species recovered and represented almost half of the isolates. association analysis revealed that most other species of bacteria were less likely to be recovered from hosts in which e. coli was present. the composition of the enteric community of a host was found to be determined by b ... | 1999 | 10537188 |
| the genetic structure of enteric bacteria from australian mammals. | a total of 246 isolates representing five species of the family enterobacteriaceae, taken from a variety of australian mammal species, were characterized using multi-locus enzyme electrophoresis. genome diversity estimates varied significantly among species, with the klebsiella pneumoniae sample exhibiting the lowest diversity and the citrobacter freundii sample the highest. multi-locus linkage disequilibrium estimates revealed that alleles were non-randomly associated in all five species sample ... | 1999 | 10537189 |
| regulation of inducible ampc beta-lactamase expression among enterobacteriaceae. | ampc ss-lactamases are active-site serine enzymes that are primarily cephalosporinases. in many gram negative organisms, including enterobacter spp.,citrobacter freundii, serratia marcescens, morganella morganii and pseudomonas aeruginosa, the expression of chromosomal ampc genes is low but inducible in response to ss-lactams and other stimuli. the current working model for ampc induction requires exposure of bacterial cells to ss-lactam drugs or other stimuli and is linked to the cell wall recy ... | 1999 | 10539994 |