| two distinct antigenic types of the polysaccharide chains of helicobacter pylori lipopolysaccharides characterized by reactivity with sera from humans with natural infection. | we have purified lipopolysaccharides (lps) from 10 helicobacter pylori clinical isolates which were selected on the basis of chemotype and antigenic variation. data from immunoblotting of the purified lps with sera from humans with h. pylori infection and from absorption of the sera with lps indicated the presence of two distinct epitopes, termed the highly antigenic and the weakly antigenic epitopes, on the polysaccharide chains. among 68 h. pylori clinical isolates, all smooth strains possesse ... | 2000 | 10603381 |
| convenient test for screening metallo-beta-lactamase-producing gram-negative bacteria by using thiol compounds. | a simple disk diffusion test was constructed for detection of imp-1-type metallo-beta-lactamase-producing gram-negative bacteria. two kirby-bauer disks containing ceftazidime (caz) and a filter disk containing a metallo-beta-lactamase inhibitor were used in this test. several imp-1 inhibitors such as thiol compounds including 2-mercaptopropionic acid, heavy metal salts, and edta were evaluated for this test. two caz disks were placed on a mueller-hinton agar plate on which a bacterial suspension ... | 2000 | 10618060 |
| detection of clarithromycin-resistant helicobacter pylori strains by a preferential homoduplex formation assay. | it has been shown that resistance to clarithromycin, a major cause of failure in helicobacter pylori eradication therapy, is associated with point mutations in the 23s rrna gene. we sought to apply the preferential homoduplex formation assay (phfa), a novel technique for the efficient detection of point mutations, to detection of the mutations. phfa was performed on streptavidin-coated microtiter plates with biotin- and dinitrophenyl-labeled amplicons to detect the wild-type gene or each mutant ... | 2000 | 10618089 |
| impact of an urban effluent on antibiotic resistance of riverine enterobacteriaceae and aeromonas spp. | in order to evaluate the impact of an urban effluent on antibiotic resistance of freshwater bacterial populations, water samples were collected from the arga river (spain), upstream and downstream from the wastewater discharge of the city of pamplona. strains of enterobacteriaceae (representative of the human and animal commensal flora) (110 isolates) and aeromonas (typically waterborne bacteria) (118 isolates) were selected for antibiotic susceptibility testing. most of the aeromonas strains (7 ... | 2000 | 10618213 |
| intestinal protozoa in hiv-infected patients: effect of rifaximin in cryptosporidium parvum and blastocystis hominis infections. | in hiv-1 infected patients severe enteritis and chronic diarrhea are often documented as a consequence of multiple opportunistic infections. we analyzed 48 hiv-1 positive patients for the presence of intestinal pathogenic protozoa. patients with cd4 > or = 200/mm3 showed a higher prevalence of a single pathogenic protozoa than patients with cd4 < or =200/mm3, who showed the presence of multiple protozoal infections. patients who proved positive for only a single protozoa, cryptosporidium or blas ... | 1999 | 10632386 |
| cloning, nucleotide sequencing, and analysis of the gene encoding an ampc beta-lactamase in acinetobacter baumannii. | a clinical strain of acinetobacter baumannii (strain ab ryc 52763/97) that was isolated during an outbreak in our hospital and that was resistant to all beta-lactam antibiotics tested produced three beta-lactamases: a tem-1-type (pi, 5.4) plasmid-mediated beta-lactamase, a chromosomally mediated oxa-derived (pi, 9.0) beta-lactamase, and a presumptive chromosomal cephalosporinase (pi, 9.4). the nucleotide sequence of the chromosomal cephalosporinase gene shows for the first time the gene encoding ... | 2000 | 10639377 |
| decreased production of ampc-type beta-lactamases associated with the development of resistance to quinolones in citrobacter freundii strains. | the effect of fluoroquinolones in citrobacter freundii strains that results in a decreased expression of cephalosporin-hydrolysing beta-lactamases was studied. resistance to broad-spectrum cephalosporins and penicillins in two c. freundii clinical isolates was associated with moderate production of chromosomal ampc-type-beta-lactamase in addition to changes in the outer membrane proteins profile with respect to wild-type c. freundii strains. ten quinolone-resistant mutants were derived from the ... | 1999 | 10647079 |
| cloning, expression, and purification of a thermostable nonhomodimeric restriction enzyme, bsli. | bsli is a thermostable type ii restriction endonuclease with interrupted recognition sequence ccnnnnn/nngg (/, cleavage position). the bsli restriction-modification system from bacillus species was cloned and expressed in escherichia coli. the system is encoded by three genes: the 2,739-bp bsli methylase gene (bslim), the bsliralpha gene, and the bslirbeta gene. the alpha and beta subunits of bsli can be expressed independently in e. coli in the absence of bsli methylase (m.bsli) protection. bsl ... | 2000 | 10648519 |
| the sigma(70) transcription factor tyrr has zinc-stimulated phosphatase activity that is inhibited by atp and tyrosine. | the tyrr protein of escherichia coli (513 amino acid residues) is the chief transcriptional regulator of a group of genes that are essential for aromatic amino acid biosynthesis and transport. the tyrr protein can function either as a repressor or as an activator. the central region of the tyrr protein (residues 207 to 425) is similar to corresponding polypeptide segments of the ntrc protein superfamily. like the ntrc protein, tyrr has intrinsic atpase activity. here, we report that tyrr possess ... | 2000 | 10648532 |
| fragmentation of 23s rrna in strains of proteus and providencia results from intervening sequences in the rrn (rrna) genes. | intervening sequences (ivss) were originally identified in the rrl genes for 23s rrna (rrl genes, for large ribosomal subunit, part of rrn operon encoding rrna) of salmonella enterica serovars typhimurium lt2 and arizonae. these sequences are transcribed but later removed during rnase iii processing of the rrna, resulting in fragmentation of the 23s species; ivss are uncommon, but have been reported in at least 10 bacterial genera. through pcr amplification of ivs-containing regions of the rrl g ... | 2000 | 10648538 |
| association of qace and qacedelta1 with multiple resistance to antibiotics and antiseptics in clinical isolates of gram-negative bacteria. | clinical isolates of enterobacter cloacae, citrobacter freundii, pseudomonas aeruginosa, and stenotrophomonas maltophilia were tested for resistance to antibiotics and to the antiseptics benzalkonium chloride and cetyltrimethylammonium bromide. furthermore, they were examined for the presence of the resistance genes qace and qacedelta1. qacedelta1 was detected by pcr in 10% of all (n=103) and in 81% of multiply antibiotic-resistant strains (n=15). qace was found in only one of 37 p. aeruginosa s ... | 2000 | 10650208 |
| selective and sensitive method for pcr amplification of escherichia coli 16s rrna genes in soil. | a set of pcr primers targeting 16s rrna gene sequences was designed, and pcr parameters were optimized to develop a robust and reliable protocol for selective amplification of escherichia coli 16s rrna genes. the method was capable of discriminating e. coli from other enteric bacteria, including its closest relative, shigella. selective amplification of e. coli occurred only when the annealing temperature in the pcr was elevated to 72 degrees c, which is 10 degrees c higher than the optimum for ... | 2000 | 10653763 |
| determination of escherichia coli contamination with chromocult coliform agar showed a high level of discrimination efficiency for differing fecal pollution levels in tropical waters of kampala, uganda. | escherichia coli, total coliforms, fecal coliforms, and sulfite-reducing anaerobic spore formers from different polluted sites in a tropical environment were determined in order to test for their indication ability for fecal contamination. quantification of e. coli contamination with chromocult coliform agar proved to be efficient and feasible for determining fecal pollutions in the investigated area within 24 h. the other microbial parameters showed a lower ability to differentiate sites and ca ... | 2000 | 10653767 |
| ability of the vitek 2 advanced expert system to identify beta-lactam phenotypes in isolates of enterobacteriaceae and pseudomonas aeruginosa. | the advanced expert system (aes) was used in conjunction with the vitek 2 automated antimicrobial susceptibility test system to ascertain the beta-lactam phenotypes of 196 isolates of the family enterobacteriaceae and the species pseudomonas aeruginosa. these isolates represented a panel of strains that had been collected from laboratories worldwide and whose beta-lactam phenotypes had been characterized by biochemical and molecular techniques. the antimicrobial susceptibility of each isolate wa ... | 2000 | 10655347 |
| problems related to determination of mics of oximino-type expanded-spectrum cephems for proteus vulgaris. | during in vitro susceptibility testing of clinical isolates of proteus vulgaris, we noted that the mics of several expanded-spectrum cephems were much higher in the broth microdilution method than in the agar dilution method (termed the mic gap phenomenon). here we investigated the mechanism of the mic gap phenomenon. cephems with the mic gap phenomenon were of the oximino type, such as cefotaxime, cefteram, and cefpodoxime, which serve as good substrates for inducible class a beta-lactamase (cu ... | 2000 | 10655366 |
| rapid diagnosis of bacteremia by universal amplification of 23s ribosomal dna followed by hybridization to an oligonucleotide array. | the rapid identification of bacteria in blood cultures and other clinical specimens is important for patient management and antimicrobial therapy. we describe a rapid (<4 h) detection and identification system that uses universal pcr primers to amplify a variable region of bacterial 23s ribosomal dna, followed by reverse hybridization of the products to a panel of oligonucleotides. this procedure was successful in discriminating a range of bacteria in pure cultures. when this procedure was appli ... | 2000 | 10655385 |
| specificity of a conductance assay for enumeration of escherichia coli from broiler carcass rinse samples containing genetically similar species. | experiments were conducted to evaluate the specificity of a rapid method for enumeration of escherichia coli from fresh broiler chicken carcasses. in three separate trials, e. coli, citrobacter freundii, salmonella enteritidis, and shigella sonnei were serially diluted and then inoculated into identical broiler chicken carcass rinses. inoculated rinses were mixed with double-strength coliform medium supplemented with 2% dextrose. this mixture was placed in a bactometer module in duplicate, and c ... | 2000 | 10678434 |
| in vitro activities of novel trans-3,5-disubstituted pyrrolidinylthio-1beta-methylcarbapenems with potent activities against methicillin-resistant staphylococcus aureus and pseudomonas aeruginosa. | the in vitro activities of the novel 1beta-methylcarbapenems j-111, 225, j-114,870, and j-114,871, which have a structurally unique side chain that consists of a trans-3,5-disubstituted 5-arylpyrrolidin-3-ylthio moiety at the c-2 position, were compared with those of reference antibiotics. among isolates of both methicillin-resistant staphylococcus aureus (mrsa) and methicillin-resistant coagulase-negative staphylococci (mrcons), 90% were inhibited by j-111,347 (prototype), j-111,225, j-114,870, ... | 2000 | 10681308 |
| ampr gene mutations that greatly increase class c beta-lactamase activity in enterobacter cloacae. | the ampc and ampr genes of enterobacter cloacae gn7471 were cloned into pmw218 to yield pku403. four mutant plasmids derived from pku403 (pku404, pku405, pku406, and pku407) were isolated in an ampd mutant of escherichia coli ml4953 by selection with ceftazidime or aztreonam. the beta-lactamase activities expressed by pku404, pku405, pku406, and pku407 were about 450, 75, 160, and 160 times higher, respectively, than that expressed by the original plasmid, pku403. these mutant plasmids all carri ... | 2000 | 10681318 |
| inactivation of the ampd gene in pseudomonas aeruginosa leads to moderate-basal-level and hyperinducible ampc beta-lactamase expression. | it has been shown in enterobacteria that mutations in ampd provoke hyperproduction of chromosomal beta-lactamase, which confers to these organisms high levels of resistance to beta-lactam antibiotics. in this study, we investigated whether this genetic locus was implicated in the altered ampc beta-lactamase expression of selected clinical isolates and laboratory mutants of pseudomonas aeruginosa. the sequences of the ampd genes and promoter regions from these strains were determined and compared ... | 2000 | 10681322 |
| adult citrobacter freundii meningitis: case report. | citrobacter is a distinct group of gram-negative bacilli belonging to the enterobacteriaceae family. central nervous system (cns) infections due to citrobacter are uncommon, though they occur more frequently in neonates and young children. in adults, citrobacter meningitis is extremely unusual with only 6 cases reported in the literature before 1998. this rare cns infection has been seen in patients with head trauma, following neurosurgical procedures, and in those who are immunocompromised. of ... | 1999 | 10695216 |
| [the resistance of recent clinical isolates against isepamycin, other aminoglycosides and injectable beta-lactams]. | clinical isolates collected from clinical facilities across japan in 1998 were tested against five aminoglycosides and three beta-lactams. the resistance of 50 strains each of methicillin sensitive staphylococcus aureus, methicillin resistant staphylococcus aureus (mrsa), staphylococcus epidermidis, escherichia coli, citrobacter freundii, klebsiella pneumoniae, enterobacter sp., serratia sp., pseudomonas aeruginosa and proteus sp. (p. mirabilis 25 strains and p. vulgaris 25 strains) to the amino ... | 2000 | 10709145 |
| pyridoxal 5'-phoshate schiff base in citrobacter freundii tyrosinephenol-lyase. ionic and tautomeric equilibria. | spectral properties of the internal schiff base in tyrosine phenol-lyase have been investigated in the presence of an activating cation k+ and a cation-inhibitor na+. the holoenzyme absorption spectra in the ph range 6.5-8.7 were recorded in the presence of k+. no apparent pka value of the coenzyme chromophore was found in this ph range, indicating that the internal schiff base does not change its ionic form on going from ph 6.5 to 8.7. to determine the ionic state and tautomeric composition of ... | 2000 | 10712616 |
| efficacies of imipenem, meropenem, cefepime, and ceftazidime in rats with experimental pneumonia due to a carbapenem-hydrolyzing beta-lactamase-producing strain of enterobacter cloacae. | the antibacterial activities of imipenem-cilastatin, meropenem-cilastatin, cefepime and ceftazidime against enterobacter cloacae nor-1, which produces the carbapenem-hydrolyzing beta-lactamase nmca and a cephalosporinase, and against one of its in vitro-obtained ceftazidime-resistant mutant were compared by using an experimental model of pneumonia with immunocompetent rats. the mics of the beta-lactams with an inoculum of 5 log(10) cfu/ml were as follows for e. cloacae nor-1 and its ceftazidime- ... | 2000 | 10722486 |
| a canadian national surveillance study of urinary tract isolates from outpatients: comparison of the activities of trimethoprim-sulfamethoxazole, ampicillin, mecillinam, nitrofurantoin, and ciprofloxacin. the canadian urinary isolate study group. | ampicillin, trimethoprim-sulfamethoxazole, mecillinam, nitrofurantoin, and ciprofloxacin mean resistance rates for 2,000 urinary tract isolates collected from outpatients across canada in 1998 were 41.1, 19.2, 14.7, 5.0, and 1.8%, respectively. for escherichia coli isolates alone (n = 1,681) comparable rates were 41. 0, 18.9, 7.4, 0.1, and 1.2%, respectively. the majority of e. coli isolates resistant to ampicillin, trimethoprim-sulfamethoxazole, or ciprofloxacin were susceptible (mic, <16 micro ... | 2000 | 10722520 |
| a large toxin from pathogenic escherichia coli strains that inhibits lymphocyte activation. | the mechanisms by which bacteria resist cell-mediated immune responses to cause chronic infections are largely unknown. we report the identification of a large gene present in enteropathogenic strains of escherichia coli (epec) that encodes a toxin that specifically inhibits lymphocyte proliferation and interleukin-2 (il-2), il-4, and gamma interferon production in response to a variety of stimuli. lymphostatin, the product of this gene, is predicted to be 366 kda and shares significant homology ... | 2000 | 10722613 |
| role of tir and intimin in the virulence of rabbit enteropathogenic escherichia coli serotype o103:h2. | attaching and effacing (a/e) rabbit enteropathogenic escherichia coli (repec) strains belonging to serogroup o103 are an important cause of diarrhea in weaned rabbits. like human epec strains, they possess the locus of enterocyte effacement clustering the genes involved in the formation of the a/e lesions. in addition, pathogenic repec o103 strains produce an esp-dependent but eae (intimin)-independent alteration of the host cell cytoskeleton characterized by the formation of focal adhesion comp ... | 2000 | 10722617 |
| a two-component multidrug efflux pump, ebrab, in bacillus subtilis. | genes (ebrab) responsible for ethidium resistance were cloned from chromosomal dna of bacillus subtilis atcc 9372. the recombinant plasmid produced elevated resistance against ethidium bromide, acriflavine, pyronine y, and safranin o not only in escherichia coli but also in b. subtilis. it also caused an elevated energy-dependent efflux of ethidium in e. coli. ebra and ebrb showed high sequence similarity with members of the small multidrug resistance (smr) family of multidrug efflux pumps. neit ... | 2000 | 10735876 |
| the prevalence of gentamicin resistance among clinical isolates of enterobacteria in a danish region. | the susceptibility of enterobacteria to gentamicin was studied in the county of north jutland during 1993-1998. a total of 378 patients had a first-time gentamicin-resistant isolate. the annual number rose from 34 patients in 1993 to 89 in 1998. the prevalence of resistance per 1000 patients with isolates examined was 13.5 for escherichia coli, 15.8 for klebsiella pneumoniae, 26.1 for klebsiella oxytoca, and 150.4 for citrobacter freundii. e. coli accounted for 67% of gentamicin-resistant isolat ... | 2000 | 10737460 |
| evaluation of the sirscan automated zone reader in a clinical microbiology laboratory. | we compared readings of kirby-bauer plates by the sirscan, an automated image analyzer that measures zone diameters, to those of experienced clinical microbiologists measuring zones with a hand-held caliper interfaced to a computer and with a ruler. to read plates of escherichia coli, morganella morganii, and pseudomonas aeruginosa containing 12 antibiotic disks the sirscan took 11 s; technologists took 28 s by caliper and 39 s by ruler. reading times of four different technologists ranged from ... | 2000 | 10747172 |
| in vitro selected fluoroquinolone-resistant mutants of citrobacter freundii: analysis of the quinolone resistance acquisition. | ten quinolone-resistant mutants of citrobacter freundii, which were selected in vitro with fluoroquinolones from two clinical isolates, were studied. the parent isolates were susceptible to quinolones in spite of showing a single substitution in the gyrb (his-417 --> leu). no change was observed in the outer membrane proteins or in the lipopolysaccharide in any of the ten mutants studied with respect to their parent isolates. the development of quinolone resistance in selected mutants was associ ... | 2000 | 10747831 |
| analysis of the mechanisms of quinolone resistance in clinical isolates of citrobacter freundii | | 2000 | 10747842 |
| an immunoglobulin superfamily-like domain unique to the yersinia pseudotuberculosis invasin protein is required for stimulation of bacterial uptake via integrin receptors. | the binding of the yersinia pseudotuberculosis and yersinia enterocolitica invasin proteins to beta(1) integrin receptors allows internalization of these organisms by cultured cells. the c-terminal 192-residue superdomain of the y. pseudotuberculosis invasin is necessary and sufficient for integrin recognition, while a region located outside, and n-terminal to, this superdomain strongly enhances the efficiency of bacterial uptake. within the enhancer region is a domain called d2 that allows inva ... | 2000 | 10768991 |
| citrobacter freundii tyrosine phenol-lyase: the role of asparagine 185 in modulating enzyme function through stabilization of a quinonoid intermediate. | asn185 is an invariant residue in all known sequences of tpl and of closely related tryptophanase and it may be aligned with the asn194 in aspartate aminotransferase. according to x-ray data, in the holoenzyme and in the michaelis complex asn185 does not interact with the cofactor pyridoxal 5'-phosphate, but in the external aldimine a conformational change occurs which is accompanied by formation of a hydrogen bond between asn185 and the oxygen atom in position 3 of the cofactor. the substitutio ... | 2000 | 10775663 |
| ascending cholangitis as a cause of pyogenic liver abscesses complicated by a gastric submucosal abscess and fistula. | ruptures of nonamebic (pyogenic) liver abscesses into the thorax and peritoneum are very uncommon; but, hepatoduodenal and hepatocolonic fistulas are ever more rare. we report a case where ascending cholangitis was associated with pyogenic liver abscess formation and a gastric fistula. drainage into the stomach was demonstrated by gastroduodenal endoscopy for gastric bleeding. after fistula formation, we could successfully treat the inflammation caused by infection of citrobacter freundii and ca ... | 2000 | 10777197 |
| [detection of extended spectrum beta-lactamases producing enterobacteriaceae in feces]. | a study was made of 366 feces for detection of extended spectrum beta-lactamases producing enterobacteriaceae from feces. the selective agar was used for modified drigalski agar (eiken chemical co., ltd) with 2 micrograms/ml cefotaxime (esbl screen agar). 92 strains of enterobacteriaceae, 41 escherichia coli, 15 citrobacter freundii, 13 enterobacter cloacae, 11 klebsiella pneumoniae, and other 12, were isolated from esbl screen agar. and, r-plasmid that were selected by 2 micrograms/ml cefotaxim ... | 2000 | 10783580 |
| production and characterization of monoclonal antibodies against vegetative cells of bacillus cereus. | two monoclonal antibodies (mabs) against bacillus cereus were produced. the mabs (8d3 and 9b7) were selected by enzyme-linked immunosorbent assay for their reactivity with b. cereus vegetative cells. they reacted with b. cereus vegetative cells while failing to recognize b. cereus spores. immunoblotting revealed that mab 8d3 recognized a 22-kda antigen, while mab 9b7 recognized two antigens with molecular masses of approximately 58 and 62 kda. the use of mabs 8d3 and 9b7 in combination to develo ... | 2000 | 10788418 |
| a pcr-colorimetric microwell plate hybridization assay for detection of mycobacterium tuberculosis and m. avium from culture samples and ziehl-neelsen-positive smears. | differentiation between mycobacterium tuberculosis and m. avium is essential for the treatment of mycobacterial infections. we have developed an easy and rapid detection assay for the diagnosis of mycobacterial diseases. this is a pcr-hybridization assay based on selective amplification of a 16s rrna gene sequence using pan-mycobacterium primers followed by hybridization of the amplification products to biotinylated m. tuberculosis and m. avium-specific probes. a total of 55 mycobacterial isolat ... | 2000 | 10790097 |
| occurrence and detection of ampc beta-lactamases among escherichia coli, klebsiella pneumoniae, and proteus mirabilis isolates at a veterans medical center. | ampc beta-lactamases are cephalosporinases that confer resistance to a wide variety of beta-lactam drugs and that may thereby create serious therapeutic problems. although reported with increasing frequency, the true rate of occurrence of ampc beta-lactamases in escherichia coli, klebsiella pneumoniae, and proteus mirabilis remains unknown. we tested a total of 1,286 consecutive, nonrepeat isolates of these three species and found that, overall, 45 (3.5%) yielded a cefoxitin zone diameter less t ... | 2000 | 10790101 |
| direct molecular typing of borrelia burgdorferi sensu lato species in synovial samples from patients with lyme arthritis. | since lyme arthritis was first described in the united states, it has now been reported in many countries of europe. however, very few strains of the causative bacterium, borrelia burgdorferi, have been isolated from synovial samples. for this reason, different molecular direct typing methods were developed recently to assess which species could be involved in lyme arthritis in europe. we developed a simple oligonucleotide typing method with pcr fragments from the flagellin gene of b. burgdorfer ... | 2000 | 10790118 |
| isolation of yersinia enterocolitica from cases of acute appendicitis and ice-cream. | seventy (70) appendiceal specimens and 80 ice-cream samples were analysed to detect yersinia enterocolitica using three different media. both y. enterocolitica and citrobacter freundii were recovered in appendiceal specimens (17.1% and 8.6%) and ice-cream (26.25% and 18.75%) respectively. thioglycollate medium was more selective and productive in isolating yersinia. y. enterocolitica was the major causative agent of acute appendicitis (11/25, 44%). it was sensitive to chloramphenicol, gentamicin ... | 1999 | 10793790 |
| structure and serologic properties of o-specific polysaccharide from citrobacter freundii possessing cross-reactivity with escherichia coli o157:h7. | citrobacter freundii ocu158 is a serologically cross-reactive strain with escherichia coli o157:h7. to explore the close relationship between two strains, we have analyzed the chemical structures of o-specific polysaccharides and antigenic properties of lipopolysaccharides (lpss) of both strains. the structure of o-specific polysaccharides from both strains was found to be identical by chemical and nuclear magnetic resonance analyses, in which d-pernac was 4-acetamido-4,6-dideoxy-d-mannose: [--> ... | 2000 | 10799808 |
| molecular beacons: a real-time polymerase chain reaction assay for detecting salmonella. | molecular beacons are oligonucleotide probes that become fluorescent upon hybridization. we developed a real-time pcr assay to detect the presence of salmonella species using these fluorogenic reporter molecules. a 122-base-pair section of the hima was used as the amplification target. molecular beacons were designed to recognize a 16-base-pair region on the amplicon. as few as 2 colony-forming unit (cfu) per pcr reaction could be detected. we also demonstrated the ability of the molecular beaco ... | 2000 | 10805535 |
| interaction of listeria monocytogenes with human brain microvascular endothelial cells: an electron microscopic study. | internalization of listeria monocytogenes into human brain microvascular endothelial cells (hbmec) has recently been demonstrated to be dependent upon the inlb gene. in the present scanning electron microscopic study we show that l. monocytogenes efficiently interacts with the surface of hbmec in an inlb-independent manner which is also different from invasion. the inlb-dependent invasion of hbmec by l. monocytogenes is accompanied by intracellular multiplication, movement, and production of bac ... | 2000 | 10816473 |
| carbapenemases of chryseobacterium (flavobacterium) meningosepticum: distribution of blab and characterization of a novel metallo-beta-lactamase gene, blab3, in the type strain, nctc 10016. | genes encoding carbapenemases in 15 reference strains of chryseobacterium (flavobacterium) meningosepticum from the united kingdom national collection of type cultures and in one recent clinical isolate were investigated. all the strains hydrolyzed imipenem, but their levels of resistance to carbapenems varied, with imipenem and meropenem mics ranging from 2 to >32 microg/ml. the blab gene, which encodes a molecular-class b carbapenemase, was detected in only six reference strains and in clinica ... | 2000 | 10817691 |
| biochemical-genetic characterization and regulation of expression of an acc-1-like chromosome-borne cephalosporinase from hafnia alvei. | a naturally occurring ampc beta-lactamase (cephalosporinase) gene was cloned from the hafnia alvei 1 clinical isolate and expressed in escherichia coli. the deduced ampc beta-lactamase (acc-2) had a pi of 8 and a relative molecular mass of 37 kda and showed 50 and 47% amino acid identity with the chromosome-encoded ampcs from serratia marcescens and providentia stuartii, respectively. it had 94% amino acid identity with the recently described plasmid-borne cephalosporinase acc-1 from klebsiella ... | 2000 | 10817695 |
| a between-species comparison of antimicrobial resistance in enterobacteria in fecal flora. | enterobacteria in fecal flora are often reported to be highly resistant. escherichia coli is the main species; resistance data on other species are rare. to assess the effect of the host's environment, antimicrobial resistance was determined in fecal species of the family enterobacteriaceae from three populations: healthy people (hp)(n = 125) with no exposure to antimicrobials for 3 months preceding sampling, university hospital patients (up) (n = 159) from wards where the antibiotic use was 112 ... | 2000 | 10817696 |
| activities of taurolidine in vitro and in experimental enterococcal endocarditis. | in vitro, the antimicrobial agent taurolidine inhibited virtually all of the bacteria tested, including vancomycin-resistant enterococci, oxacillin-resistant staphylococci, and stenotrophomonas maltophilia, at concentrations between 250 and 2,000 microg/ml. taurolidine was not effective in experimental endocarditis. while it appears unlikely that this antimicrobial would be useful for systemic therapy, its bactericidal activity and the resistance rates found (<10(-9)) are favorable indicators fo ... | 2000 | 10817739 |
| in vitro activity of gemifloxacin against a broad range of recent clinical isolates from the usa. | the antibacterial potencies of gemifloxacin (sb-265805) and 13 comparator compounds were determined by broth microdilution against a panel of 645 gram-positive and 995 gram-negative organisms collected from various usa sites. time-kill studies were performed and postantibiotic effect (pae) was determined for several organisms using trovafloxacin and ciprofloxacin as comparator compounds. based on mic(90)s, gemifloxacin was the most potent compound tested against gram-positive isolates: streptoco ... | 2000 | 10824027 |
| prevalence of salmonella spp. in poultry broilers and shell eggs in korea. | this study was conducted to determine the presence of salmonella spp. in raw broilers and shell eggs in korea. in total, 135 dozen shell eggs and 27 raw broilers were tested. none of the egg yolks were found to contain salmonella organisms but escherichia coli, escherichia hermanii, and citrobacter freundii were isolated from egg shells. salmonella spp. were detected in 25.9% of raw broilers, and salmonella serotypes isolated from raw broilers were salmonella enteritidis, salmonella virchow, and ... | 2000 | 10826725 |
| the macrocyclic peptide antibiotic micrococcin p(1) is secreted by the food-borne bacterium staphylococcus equorum ws 2733 and inhibits listeria monocytogenes on soft cheese. | staphylococcus equorum ws 2733 was found to produce a substance exhibiting a bacteriostatic effect on a variety of gram-positive bacteria. the metabolite was purified to homogeneity by ammonium sulfate precipitation and semipreparative reversed-phase high-performance liquid chromatography. electrospray mass spectrometry confirmed the high purity of the compound and revealed a molecular mass of 1,143 da. by two-dimensional nuclear magnetic resonance spectroscopy the substance was identified as mi ... | 2000 | 10831414 |
| molecular characteristics and epidemiological significance of shiga toxin-producing escherichia coli o26 strains. | fifty-five shiga toxin (stx)-producing escherichia coli (stec) o26:h11 and o26:h(-) strains isolated from humans between 1965 and 1999 in germany and the czech republic were investigated for their chromosomal and plasmid characteristics. all motile (n = 23) and nonmotile (n = 32) stec o26 strains were shown to possess the identical flagellin subunit-encoding gene (flic). we observed a striking recent shift of the stx genotype from stx(1) to stx(2) among the stec o26 isolates. while stx(1) was th ... | 2000 | 10834966 |
| enteropathogenic escherichia coli isolates in paediatric diarrhoea. | enteropathogenic escherichia coli (epec) are known to cause infantile enteritis. we studied the prevalence of epec in paediatric patients with acute and persistent diarrhoea. a total of 56 stool samples from paediatric patients were studied. there were 28 significant bacterial isolates. of these 21 were untypable e. coli, 5 were typable e. coli, four of which belonged to members considered to be enteropathogenic. non e. coli isolates grown in pure culture were one each of pseudomonas aeruginosa ... | 2000 | 10835962 |
| prevalence of virulence genes and clonality in escherichia coli strains that cause bacteremia in cancer patients. | phenotypic analysis of escherichia coli strains causing bacteremia in cancer patients suggests that they possess specific virulence properties. to investigate this hypothesis, we compared the frequency of the virulence-related genes cnf1, cnf2, papc, hlyc, and iut in 155 e. coli strains isolated from hospitalized cancer patients with epidemiologically unrelated cases of bacteremia to their frequency in 70 e. coli strains isolated from the feces of healthy unrelated volunteers. of the blood isola ... | 2000 | 10858212 |
| a novel ctx-m beta-lactamase (ctx-m-8) in cefotaxime-resistant enterobacteriaceae isolated in brazil. | to estimate the diversity of extended-spectrum beta-lactamases in brazil, 18 strains from different species of the family enterobacteriaceae exhibiting a positive double-disk synergy test were collected by a clinical laboratory from several hospitals in rio de janeiro, brazil, in 1996 and 1997. four strains (proteus mirabilis, enterobacter cloacae, enterobacter aerogenes, and citrobacter amalonaticus) hybridized with a 550-bp ctx-m probe. the p. mirabilis strain produced a ctx-m-2 enzyme. the e. ... | 2000 | 10858358 |
| in vitro activity of rifaximin, metronidazole and vancomycin against clostridium difficile and the rate of selection of spontaneously resistant mutants against representative anaerobic and aerobic bacteria, including ammonia-producing species. | rifaximin is a rifamycin derivative characterized by a wide antibacterial activity. this drug is neither absorbed by the gastrointestinal tract nor inactivated by gastric juices, and exerts its action entirely within the intestinal lumen. | 2000 | 10859431 |
| modification of the bile salts-irgasan-brilliant green agar for enumeration of aeromonas species from food. | the present study evaluated the productivity of bibg medium for the isolation of aeromonas spp. from food and describes a modification of the bibg medium (mbibg) (increased ph (8.7), replacement of xylose by soluble starch as a carbon source, decreased concentration of bile salts) to increase its selectivity and electivity. using the mbibg medium, growth of the majority of the enterobacteriaceae (9/10) was suppressed except for citrobacter freundii. the mbibg medium supported growth of pseudomon ... | 2000 | 10868682 |
| assessment of the microbiological quality and wash treatments of lettuce served in university restaurants. | one hundred and forty-four samples of lettuce from 16 university restaurants were analyzed. the mesophilic aerobic counts of all samples ranged from 3.01 to 7.81 log10 cfu g(-1). results of total coliforms ranged from < 0.47 to > 3.38 log10 most probable number (mpn) g(-1). of the lettuce samples, 25.7% harbored escherichia coli, 22.9% staphylococcus aureus and 84% group d streptococci. similarly, 10.4% of the samples harbored aeromonas hydrophila, 2.8% pseudomonas aeruginosa, and coliforms such ... | 2000 | 10898470 |
| involvement of a plasmid in virulence of campylobacter jejuni 81-176. | campylobacter jejuni strain 81-176 contains two, previously undescribed plasmids, each of which is approximately 35 kb in size. although one of the plasmids, termed ptet, carries a teto gene, conjugative transfer of tetracycline resistance to another strain of c. jejuni could not be demonstrated. partial sequence analysis of the second plasmid, pvir, revealed the presence of four open reading frames which encode proteins with significant sequence similarity to helicobacter pylori proteins, inclu ... | 2000 | 10899834 |
| cloning and dna sequence analysis of an immunogenic glucose-galactose mglb lipoprotein homologue from brachyspira pilosicoli, the agent of colonic spirochetosis. | colonic spirochetosis (cs) is a newly emerging infectious disease of humans and animals caused by the pathogenic spirochete brachyspira (formerly serpulina) pilosicoli. the purpose of this study was to characterize an antigen that was recognized by antibodies present in sera of challenge-exposed pigs. the gene encoding the antigen was identified by screening a plasmid library of human b. pilosicoli strain sp16 (atcc 49776) genomic dna with hyperimmune and convalescent swine sera. the predicted a ... | 2000 | 10899855 |
| expression of intimin gamma from enterohemorrhagic escherichia coli in citrobacter rodentium. | the carboxy-terminal 280 amino acids (int280) of the bacterial adhesion molecule intimin include the receptor-binding domain. at least five different types of int280, designated alpha, beta, gamma, delta, and epsilon, have been described based on sequence variation in this region. importantly, the intimin types are associated with different evolutionary branches and contribute to distinct tissue tropism of intimin-positive bacterial pathogens. in this study we engineered a strain of citrobacter ... | 2000 | 10899867 |
| constitutive expression of the vi polysaccharide capsular antigen in attenuated salmonella enterica serovar typhi oral vaccine strain cvd 909. | live oral ty21a and parenteral vi polysaccharide vaccines provide significant protection against typhoid fever, albeit by distinct immune mechanisms. vi stimulates serum immunoglobulin g vi antibodies, whereas ty21a, which does not express vi, elicits humoral and cell-mediated immune responses other than vi antibodies. protection may be enhanced if serum vi antibody as well as cell-mediated and humoral responses can be stimulated. disappointingly, several new attenuated salmonella enterica serov ... | 2000 | 10899868 |
| the role of glutamic acid-69 in the activation of citrobacter freundii tyrosine phenol-lyase by monovalent cations. | tyrosine phenol-lyase (tpl) from citrobacter freundii is activated about 30-fold by monovalent cations, the most effective being k(+), nh(4)(+), and rb(+). previous x-ray crystal structure analysis has demonstrated that the monovalent cation binding site is located at the interface between subunits, with ligands contributed by the carbonyl oxygens of gly52 and asn262 from one chain and monodentate ligation by one of the epsilon-oxygens of glu69 from another chain [antson, a. a., demidkina, t. v. ... | 2000 | 10913261 |
| a genomic sample sequence of the entomopathogenic bacterium photorhabdus luminescens w14: potential implications for virulence. | photorhabdus luminescens is a pathogenic bacterium that lives in the guts of insect-pathogenic nematodes. after invasion of an insect host by a nematode, bacteria are released from the nematode gut and help kill the insect, in which both the bacteria and the nematodes subsequently replicate. however, the bacterial virulence factors associated with this "symbiosis of pathogens" remain largely obscure. in order to identify genes encoding potential virulence factors, we performed approximately 2,00 ... | 2000 | 10919786 |
| exploitation of host cells by enteropathogenic escherichia coli. | microbial pathogens have evolved many ingenious ways to infect their hosts and cause disease, including the subversion and exploitation of target host cells. one such subversive microbe is enteropathogenic escherichia coli (epec). a major cause of infantile diarrhea in developing countries, epec poses a significant health threat to children worldwide. central to epec-mediated disease is its colonization of the intestinal epithelium. after initial adherence, epec causes the localized effacement o ... | 2000 | 10922038 |
| prediction of two- and three-amino-acid sequences of citrobacter freundii beta-lactamase from its amino acid composition. | the repeated amino-acid sequences in citrobacter freundii beta-lactamase may be indispensable for its function, because such repetitions cannot be simply attributed to a chance. in order to fully explore the functional units in citrobacter freundii beta-lactamase, it may need to analyse all the amino acid pairs, triplets, etc. along citrobacter freundii beta-lactamase from one terminal to the other terminal, to count their frequencies and calculate their probabilities. the amino-acid sequence of ... | 2000 | 10937436 |
| purification and characterization of the 1-3-propanediol dehydrogenase of clostridium butyricum e5. | 1-3 ppd dehydrogenase (ec 1.1.1.202) was purified to homogeneity from clostridium butyricum e5 grown anaerobically on glycerol in continuous culture. the native enzyme was estimated by gel filtration to have a molecular weight of 384 200 +/- 31 100 da; it is predicted to exist as an octamer or a decamer of identical molecular weight subunits. when tested as a dehydrogenase, the enzyme was most active with 1-3 propane diol. in the physiological direction, 3-hydroxypropionaldehyde was the preferre ... | 2000 | 10938419 |
| inactivation of the ampde operon increases transcription of algd and affects morphology and encystment of azotobacter vinelandii. | transcription of algd, encoding gdp-mannose dehydrogenase, the key enzyme in the alginate biosynthetic pathway, is highly regulated in azotobacter vinelandii. we describe here the characterization of a tn5 insertion mutant (ac28) which shows a higher level of expression of an algd::lacz fusion. ac28 cells were morphologically abnormal and unable to encyst. the cloning and nucleotide sequencing of the tn5-disrupted locus in ac28 revealed an operon homologous to the escherichia coli ampde operon. ... | 2000 | 10940024 |
| characterization of porphyromonas gingivalis insertion sequence-like element ispg5. | porphyromonas gingivalis, a black-pigmented, gram-negative anaerobe, is found in periodontitis lesions, and its presence in subgingival plaque significantly increases the risk for periodontitis. in contrast to many bacterial pathogens, p. gingivalis strains display considerable variability, which is likely due to genetic exchange and intragenomic changes. to explore the latter possibility, we have studied the occurrence of insertion sequence (is)-like elements in p. gingivalis w83 by utilizing a ... | 2000 | 10948151 |
| neisseria gonorrhoeae elicits membrane ruffling and cytoskeletal rearrangements upon infection of primary human endocervical and ectocervical cells. | neisseria gonorrhoeae is a strict human pathogen that is, primarily, transmitted by close sexual contact with an infected individual. gonococcal infection of the male urogenital tract has been well studied in experimental human models and in urethral cell culture systems. recent studies, using tissue culture cell systems, have suggested a role for the cervical epithelium in gonococcal infection of females; however, the nature of gonococcal infection of the normal uterine cervix remains controver ... | 2000 | 10948165 |
| functional analysis of the active site of a metallo-beta-lactamase proliferating in japan. | an r-plasmid-mediated metallo-beta-lactamase was found in klebsiella pneumoniae dk4 isolated in japan in 1991. the nucleotide sequence of its structural gene revealed that the beta-lactamase termed dk4 was identical to the imp-1 metallo-beta-lactamase which was mediated by a chromosomal gene of serratia marcescens tn9106 isolated in japan in 1991 (e. osano et al., antimicrob. agents chemother. 38:71-78, 1994). the dose effect of dk4 beta-lactamase production on the resistance levels indicated a ... | 2000 | 10952572 |
| ofloxacin-loaded liposomes: in vitro activity and drug accumulation in bacteria. | different ofloxacin-loaded unilamellar vesicles were prepared by the extrusion technique, and their antimicrobial activities were determined in comparison to those of the free drug by means of mic determinations with both american type culture collection standards and wild-type bacterial strains (six strains of enterococcus faecalis, seven strains of escherichia coli, six strains of staphylococcus aureus, and six strains of pseudomonas aeruginosa). the accumulation of ofloxacin and liposome-oflo ... | 2000 | 10952595 |
| molecular characterization of fox-4, a new ampc-type plasmid-mediated beta-lactamase from an escherichia coli strain isolated in spain. | a clinical strain of escherichia coli (ec gce) displayed resistance to cefoxitin, cefotetan, cefotaxime, and ceftazidime. susceptibility was not restored by the addition of clavulanic acid. two beta-lactamases with apparent pis of 5.4 and 6.4 were identified; the beta-lactamase with a pi of 6.4 was transferred by conjugation and associated with a 40-kb plasmid. analysis of the nucleotide sequence showed a new ampc beta-lactamase gene that is closely related to those encoding the fox-3, fox-2, an ... | 2000 | 10952615 |
| application of the 5'-nuclease pcr assay in evaluation and development of methods for quantitative detection of campylobacter jejuni. | campylobacter jejuni is recognized as a leading human food-borne pathogen. traditional diagnostic testing for c. jejuni is not reliable due to special growth requirements and the possibility that this bacterium can enter a viable but nonculturable state. nucleic acid-based tests have emerged as a useful alternative to traditional enrichment testing. in this article, we present a 5'-nuclease pcr assay for quantitative detection of c. jejuni and describe its evaluation. a probe including positions ... | 2000 | 10966425 |
| development of a rapid pcr assay specific for staphylococcus saprophyticus and application to direct detection from urine samples. | staphylococcus saprophyticus is one of the most frequently encountered microorganisms associated with acute urinary tract infections (utis) in young, sexually active female outpatients. conventional identification methods based on biochemical characteristics can efficiently identify s. saprophyticus, but the rapidities of these methods need to be improved. rapid and direct identification of this bacterium from urine samples would be useful to improve time required for the diagnosis of s. saproph ... | 2000 | 10970371 |
| automated 5' nuclease pcr assay for identification of salmonella enterica. | a simple and ready-to-go test based on a 5' nuclease (taqman) pcr technique was developed for identification of presumptive salmonella enterica isolates. the results were compared with those of conventional methods. the taqman assay was evaluated for its ability to accurately detect 210 s. enterica isolates, including 100 problematic "rough" isolates. an internal positive control was designed to use the same salmonella primers for amplification of a spiked nonrelevant template (116 bp) in the sa ... | 2000 | 10970396 |
| microbial evaluation of spanish potato omelette and cooked meat samples in university restaurants. | the focus of this study was to evaluate the microbial quality of spanish potato omelette and cooked meat samples including pork loin, chicken croquettes, long pork sausage, chicken breast, and meatballs from university restaurants. microbiological analyses of spanish potato omelette and cooked meat samples resulted in aerobic plate counts from <1.00 to 2.90 and from <1.00 to 6.04 log10 cfu g(-1), respectively. total coliforms ranged from <3 to 43 most probable number (mpn) g(-1) and from <3 to > ... | 2000 | 10983805 |
| animal and human multidrug-resistant, cephalosporin-resistant salmonella isolates expressing a plasmid-mediated cmy-2 ampc beta-lactamase. | salmonella spp. are important food-borne pathogens that are demonstrating increasing antimicrobial resistance rates in isolates obtained from food animals and humans. in this study, 10 multidrug-resistant, cephalosporin-resistant salmonella isolates from bovine, porcine, and human sources from a single geographic region were identified. all isolates demonstrated resistance to cephamycins and extended-spectrum cephalosporins as well as tetracycline, chloramphenicol, streptomycin, and sulfisoxazol ... | 2000 | 10991860 |
| cytotoxic necrotizing factor type 1 of uropathogenic escherichia coli kills cultured human uroepithelial 5637 cells by an apoptotic mechanism. | pathogenic escherichia coli associated with urinary tract infections (utis) in otherwise healthy individuals frequently produce cytotoxic necrotizing factor type 1 (cnf1), a member of the family of bacterial toxins that target the rho family of small gtp-binding proteins. to gain insight into the function of cnf1 in the development of e. coli-mediated utis, we examined the effects of cnf1 intoxication on a panel of human cell lines derived from physiologically relevant sites (bladder, ureters, a ... | 2000 | 10992497 |
| dna methylation at the cfrbi site is involved in expression control in the cfrbi restriction-modification system. | we have previously found that genes of the cfr:bi restriction-modification (r-m) system from citrobacter freundii are oriented divergently and that their promoter regions overlap. the overlapping promoters suggest regulation of gene expression at the transcriptional level. in this study the transcription regulation of cfr:bi r-m genes was analyzed in vivo and in vitro in escherichia coli. it was shown that in the presence of cfr:bi methyltransferase (m.cfr:bi), cell galactokinase activity decrea ... | 2000 | 11000275 |
| bacterial penetration across the blood-brain barrier during the development of neonatal meningitis. | bacterial pathogens may breach the blood-brain barrier (bbb) and invade the central nervous system through paracellular and/or transcellular mechanisms. transcellular penetration, e.g., transcytosis across the bbb has been demonstrated for escherichia coli k1, group b streptococcus, listeria monocytogenes, citrobacter freundii and streptococcus pneumonia strains. genes contributing to invasion of brain microvascular endothelial cells include e. coli k1 genes ompa, ibea, ibeb, and yijp. understan ... | 2000 | 11008113 |
| field evaluation of a semiautomated method for rapid and simple analysis of recreational water microbiological quality. | an early warning system using a rapid enzymatic semiautomated method suitable for fecal coliform detection in recreational waters within 8 h was developed further and evaluated in this study. this rapid method was compared to the standard method followed in the united kingdom. we used 1,011 samples originating from 206 different locations in wales. when we assessed the presence or absence of fecal coliforms, targeting very low levels of contamination, we obtained 83.9% agreement between the rapi ... | 2000 | 11010890 |
| structure and species composition of mercury-reducing biofilms. | mercury-reducing biofilms from packed-bed bioreactors treating nonsterile industrial effluents were shown to consist of a monolayer of bacteria by scanning electron microscopy. droplets of several micrometers in diameter which accumulated outside of the bacterial cells were identified as elemental mercury by electron-dispersive x-ray analysis. the monospecies biofilms of pseudomonas putida spi3 initially present were invaded by additional strains, which were identified to the species level by th ... | 2000 | 11010917 |
| evaluation of the microscan rapid neg id3 panel for identification of enterobacteriaceae and some common gram-negative nonfermenters. | the microscan rapid neg id3 panel (dade behring, inc., west sacramento, calif.) is designed for the identification of gram-negative bacilli. we evaluated its ability to accurately identify enterobacteriaceae that are routinely encountered in a clinical laboratory and glucose nonfermenting gram-negative bacilli. using 511 stock cultures that were maintained at -70 degrees c and passaged three times before use, we inoculated panels according to the manufacturer's instructions and processed them in ... | 2000 | 11015366 |
| rapid differentiation of fermentative from nonfermentative gram-negative bacilli in positive blood cultures by an impedance method. | rapid differentiation of fermentative gram-negative bacilli (fermenters) from nonfermentative gram-negative bacilli (nonfermenters) in positive blood cultures may help physicians to narrow the choice of appropriate antibiotics for empiric treatment. an impedance method for direct differentiation of fermenters from nonfermenters was investigated. the bacterial suspensions (or positive culture broths containing gram-negative bacteria) were inoculated into the module wells of a bactometer (biomérie ... | 2000 | 11015369 |
| 16s ribosomal dna sequence analysis of a large collection of environmental and clinical unidentifiable bacterial isolates. | some bacteria are difficult to identify with phenotypic identification schemes commonly used outside reference laboratories. 16s ribosomal dna (rdna)-based identification of bacteria potentially offers a useful alternative when phenotypic characterization methods fail. however, as yet, the usefulness of 16s rdna sequence analysis in the identification of conventionally unidentifiable isolates has not been evaluated with a large collection of isolates. in this study, we evaluated the utility of 1 ... | 2000 | 11015374 |
| detection and characterization of autoagglutination activity by campylobacter jejuni. | in several gram-negative bacterial pathogens, autoagglutination (aag) activity is a marker for interaction with host cells and virulence. campylobacter jejuni strains also show aag, but this property varies considerably among strains. to examine the characteristics of c. jejuni aag, we developed a quantitative in vitro assay. for strain 81-176, which shows high aag, activity was optimal for cells grown for < or = 24 h, was independent of growth temperature, and was best measured for cells suspen ... | 2000 | 11035721 |
| contribution of plasmid-encoded fimbriae and intimin to capacity of rabbit-specific enteropathogenic escherichia coli to attach to and colonize rabbit intestine. | attachment to the intestinal mucosa is an essential step in the pathogenesis of diarrhea caused by enteropathogenic escherichia coli (epec). fimbriae and intimin, the outer membrane protein product of the chromosomal eae gene, contribute to this process, but their relative roles and the nature of their interaction are not known. the aim of this study was to determine the relative contribution of plasmid-encoded fimbriae, termed ral, and intimin to the capacity of rabbit-specific epec (repec) to ... | 2000 | 11035762 |
| nucleotide sequence of the chromosomal ampc gene of enterobacter aerogenes. | the ampc beta-lactamase gene and a small portion of the regulatory ampr sequence of enterobacter aerogenes 97b were cloned and sequenced. the beta-lactamase had an isoelectric point of 8 and conferred cephalosporin and cephamycin resistance on the host. the sequence of the cloned gene is most closely related to those of the ampc genes of e. cloacae and c. freundii. | 2000 | 11036041 |
| a 1998 survey of extended-spectrum beta-lactamases in enterobacteriaceae in france. the french study group. | in a 3-month period in 1998, 79 consecutive isolates of enterobacteriaceae producing an extended-spectrum beta-lactamase (esbl) were collected. esbls were predominantly tem derivatives (74 of 79): tem-24-like (40 isolates), tem-3-like (29 isolates), tem-21 (3 isolates), and tem-4 and tem-52 (1 isolate each). four isolates produced shv derivatives shv-4 (three isolates) and shv-5 (one isolate), and one strain produced a ctx-m-3 enzyme. the high proportion of tem-24-like-producing enterobacter aer ... | 2000 | 11036046 |
| heterogeneity of ampc cephalosporinases of hafnia alvei clinical isolates expressing inducible or constitutive ceftazidime resistance phenotypes. | ten unrelated hafnia alvei clinical isolates were grouped according to either their low-level and inducible cephalosporinase production or their high-level and constitutive cephalosporinase production phenotype. their ampc sequences shared 85 to 100% amino acid identity. the immediate genetic environment of ampc genes was conserved in h. alvei isolates but was different from that found in other ampc-possessing enterobacterial species. | 2000 | 11036059 |
| identification by 16s ribosomal rna gene sequencing of an enterobacteriaceae species from a bone marrow transplant recipient. | to ascertain the clinical relevance of a strain of enterobacteriaceae isolated from the stool of a bone marrow transplant recipient with diarrhoea. the isolate could not be identified to the genus level by conventional phenotypic methods and required 16s ribosomal rna (rrna) gene sequencing for full identification. | 2000 | 11040945 |
| characterization of sepl of enterohemorrhagic escherichia coli. | the sepl gene is expressed in the locus of enterocyte effacement and therefore is most likely implicated in the attaching and effacing process, as are the products encoded by open reading frames located up- and downstream of this gene. in this study, the sepl gene of the enterohemorrhagic escherichia coli (ehec) strain edl933 was analyzed and the corresponding polypeptide was characterized. we found that sepl is transcribed monocistronically and independently from the esp operon located downstre ... | 2000 | 11053395 |
| detection and distribution of insertion sequence 1 (is1)-containing bacteria in the freshwater environment(1). | the distribution of insertion sequence 1 (is1)-containing bacteria was investigated in windermere (cumbria, uk), a freshwater body impacted by treated sewage discharge and run-off from the surrounding catchment. culturable is1-containing bacteria were recovered from the water column at three depths in windermere north basin (wnb) and south basin (wsb), and from sediment at both sites (at the sediment surface in wsb and to a depth of 12-13 cm in wnb). polymerase chain reaction amplification of is ... | 2000 | 11053739 |
| cloning and random mutagenesis of the erwinia herbicola tyrr gene for high-level expression of tyrosine phenol-lyase. | tyrosine phenol-lyase (tpl), which can synthesize 3, 4-dihydroxyphenylalanine from pyruvate, ammonia, and catechol, is a tyrosine-inducible enzyme. previous studies demonstrated that the tpl promoter of erwinia herbicola is activated by the tyrr protein of escherichia coli. in an attempt to create a high-tpl-expressing strain, we cloned the tyrr gene of e. herbicola and then randomly mutagenized it. mutant tyrr proteins with enhanced ability to activate tpl were screened for by use of the lac re ... | 2000 | 11055921 |
| use of hydrostatic pressure for inactivation of microbial contaminants in cheese. | the objective of this study was to determine the effect of high pressure (hp) on the inactivation of microbial contaminants in cheddar cheese (escherichia coli k-12, staphylococcus aureus atcc 6538, and penicillium roqueforti imi 297987). initially, cheese slurries inoculated with e. coli, s. aureus, and p. roqueforti were used as a convenient means to define the effects of a range of pressures and temperatures on the viability of these microorganisms. cheese slurries were subjected to pressures ... | 2000 | 11055940 |
| a novel selenite- and tellurite-inducible gene in escherichia coli. | selenium is both an essential and a toxic trace element, and the range of concentrations between the two is extremely narrow. although tellurium is not essential and is only rarely found in the environment, it is considered to be extremely toxic. several hypotheses have been proposed to account for the toxic effects of selenite and tellurite. however, these potential mechanisms have yet to be fully substantiated. through screening of an escherichia coli luxab transcriptional gene fusion library, ... | 2000 | 11055951 |
| outbreak of nosocomial infections due to extended-spectrum beta-lactamase-producing strains of enteric group 137, a new member of the family enterobacteriaceae closely related to citrobacter farmeri and citrobacter amalonaticus. | a member of the enterobacteriaceae initially identified as kluyvera cryocrescens by the microscan gram-negative combo 13 panel caused an outbreak of nosocomial infections in four patients (pneumonia, n = 2; urinary tract infection, n = 1; wound infection, n = 1) and urinary tract colonization in one patient. when the strains were tested by the enteric reference laboratory of the centers for disease control and prevention, biochemical results were most compatible with yersinia intermedia, kluyver ... | 2000 | 11060050 |
| detection and identification of mycobacteria by amplification of the internal transcribed spacer regions with genus- and species-specific pcr primers. | we evaluated the usefulness of pcr assays that target the internal transcribed spacer (its) region for identifying mycobacteria at the species level. the conservative and species-specific its sequences of 33 species of mycobacteria were analyzed in a multialignment analysis. one pair of panmycobacterial primers and seven pairs of mycobacterial species-specific primers were designed. all pcrs were performed under the same conditions. the specificities of the primers were tested with type strains ... | 2000 | 11060072 |
| gatifloxacin: a new fluoroquinolone. | gatifloxacin is a new 8-methoxy-fluoroquinoline antimicrobial agent. it has enhanced activity against gram-positive and atypical agents, while retaining broad-spectrum antigram-negative activity. for example, the mic(90) values for respiratory tract pathogens are < or = 0.5 microg/ml for organisms such as streptococcus pneumoniae (regardless of penicillin susceptibility), haemophilus influenzae (beta-lactamase positive or negative), moraxella catarrhalis (beta-lactamase positive or negative), le ... | 2000 | 11060784 |