| 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 |
| variation in the composition and pore function of major outer membrane pore protein p2 of haemophilus influenzae from cystic fibrosis patients. | we investigated the relationship between susceptibility to beta-lactam antibiotics and variation in the major outer membrane protein p2 (ompp2; also called porin) of persistent nonencapsulated haemophilus influenzae isolated from cystic fibrosis patients. nine ompp2 variants were selected from two distinct h. influenzae strains from two patients extensively treated with beta-lactam antibiotics. the variants differed in their susceptibilities to at least two beta-lactam antibiotics. by detergent ... | 1999 | 9925510 |
| characterization of sfo-1, a plasmid-mediated inducible class a beta-lactamase from enterobacter cloacae. | enterobacter cloacae 8009 produced an inducible class a beta-lactamase which hydrolyzed cefotaxime efficiently. it also hydrolyzed other beta-lactams except cephamycins and carbapenems. the activity was inhibited by clavulanic acid and imipenem. the bla gene was transferable to escherichia coli by electroporation of plasmid dna. the molecular mass of the beta-lactamase was 29 kda and its pi was 7.3. all of these phenotypic characteristics of the enzyme except for inducible production resemble th ... | 1999 | 9925524 |
| 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 |
| beta-secondary and solvent deuterium kinetic isotope effects on catalysis by the streptomyces r61 dd-peptidase: comparisons with a structurally similar class c beta-lactamase. | beta-secondary and solvent deuterium kinetic isotope effects have been determined for the steady-state kinetic parameters v/k and v for turnover of a series of acyclic substrates by the dd-peptidase of streptomyces r61 and the class c beta-lactamase of enterobacter cloacae p99. although these enzymes are evolutionarily related and have very similar tertiary and active site structure, they are functionally very different-the former efficiently catalyzes the hydrolysis of beta-lactams but not acyc ... | 1999 | 9931012 |
| changes in the incidence and etiological patterns of bacteremia associated with acute leukemia over a 25-year period. | during the 25-year period from 1972-1996, 360 episodes of bacteremia occurred in 248 (45%) of a total of 548 patients with acute leukemia on our hematology ward, with the rate of occurrence remaining almost unchanged. patients with acute nonlymphocytic leukemia, however, had a significant decrease in the incidence of bacteremia during the last 5-year period. gram-negative bacilli decreased in relative frequency from 64% for the first 15-year period to 40% for the last 5-year period, whereas gram ... | 1998 | 9932631 |
| in vitro activity of meropenem against common pathogenic bacteria isolated in taiwan. | the in vitro antimicrobial activity of meropenem, in comparison with nine other antimicrobial agents, against 12 different common pathogenic bacteria were evaluated to know the susceptibility of common bacteria to meropenem in taiwan. meropenem was active against most gram-positive, gram-negative, and anaerobic bacteria, including methicillin-sensitive staphylococcus aureus, streptococcus pyogenes, enterococcus faecalis, escherichia coli, klebsiella pneumoniae, enterobacter cloacae, pseudomonas ... | 1998 | 9934544 |
| identification of a streptococcus pneumoniae gene locus encoding proteins of an abc phosphate transporter and a two-component regulatory system. | the escherichia coli pst system belongs to the family of abc transporters. it is part of a phosphate (pho) regulon which is regulated by extracellular phosphate. under conditions of phosphate limitation, the response regulator phob is phosphorylated by the histidine kinase phor and binds to promoters that share a consensus pho box. under conditions of phosphate excess, phor, pst, and phou downregulate the pho regulon. screening of a library of pneumococcal mutants with defects in exported protei ... | 1999 | 9973337 |
| pcr detection of dna specific for trichosporon species in serum of patients with disseminated trichosporonosis. | deep-seated trichosporonosis is a lethal opportunistic infection that disseminates rapidly and widely in immunocompromised patients, and early diagnosis is crucial for the treatment of this infection. we developed a novel nested-pcr assay that detects dna specific for clinically important strains of trichosporon in serum samples from patients with disseminated trichosporonosis. in this assay, two sets of oligonucleotide primers were derived from the sequence of 26s rrna genes of trichosporon asa ... | 1999 | 9986834 |
| spread of amikacin resistance in acinetobacter baumannii strains isolated in spain due to an epidemic strain. | sixteen amikacin-resistant clinical acinetobacter baumannii isolates from nine different hospitals in spain were investigated to determine whether the high incidence of amikacin-resistant a. baumannii was due to the dissemination of an amikacin-resistant strain or to the spread of an amikacin resistance gene. the epidemiological relationship studied by repetitive extragenic palindromic pcr and low-frequency restriction analysis of chromosomal dna showed that the same clone was isolated in eight ... | 1999 | 9986846 |
| 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 |
| comparison of five pcr methods for detection of helicobacter pylori dna in gastric tissues. | five different pcr methods for the detection of helicobacter pylori were evaluated. the results of this study indicate that of the five pcr methods examined, the urec (glmm) gene pcr is the most sensitive and specific for the detection of h. pylori in gastric biopsy specimens. | 1999 | 9986850 |
| variation in structure and location of vana glycopeptide resistance elements among enterococci from a single patient. | forty-six vana glycopeptide-resistant enterococci (gre) from a single patient were investigated for variation in structure and location of vana resistance elements. together with identification to species level and pulsed-field gel electrophoresis, these data divided the gre into 10 groups and subgroups. combining data in this manner appears helpful when investigating the epidemiology of gre. | 1999 | 9986864 |
| when drug inactivation renders the target irrelevant to antibiotic resistance: a case story with beta-lactams. | by challenging the efficiency of some of our most useful antimicrobial weapons, bacterial antibiotic resistance is becoming an increasingly worrying clinical problem. a good antibiotic is expected to exhibit a high affinity for its target and to reach it rapidly, while escaping chemical modification by inactivating enzymes and elimination by efflux mechanisms. a study of the behaviour of a beta-lactamase-overproducing mutant of enterobacter cloacae in the presence of several penicillins and ceph ... | 1999 | 9987113 |
| high turnover rate of escherichia coli strains in the intestinal flora of infants in pakistan. | the escherichia coli flora of infants in developed countries is dominated by one or a few strains which persist for prolonged periods of time, but no longitudinal studies have been performed in developing countries. to this end, we studied the rectal enterobacterial flora in 22 home-delivered pakistani infants during their first 6 months of life. three colonies were isolated and species typed on each of 11 sampling occasions. e. coli isolates were strain typed using electromorphic typing of cyto ... | 1998 | 10030708 |
| degradation of nitrate ester and nitroaromatic explosives by enterobacter cloacae pb2. | | 1998 | 10047806 |
| 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 |
| in vivo activities of peptidic prodrugs of novel aminomethyl tetrahydrofuranyl-1 beta-methylcarbapenems. | a series of novel aminomethyl tetrahydrofuranyl (thf)-1 beta-methylcarbapenems which have excellent broad-spectrum antibacterial activities exhibit modest efficacies against acute lethal infections (3.8 mg/kg of body weight against escherichia coli and 0.9 mg/kg against staphylococcus aureus) in mice when they are administered orally. in an effort to improve the efficacies of orally administered drugs through enhanced absorption by making use of a peptide-mediated transport system, several diffe ... | 1999 | 10049251 |
| 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 |
| molecular and biochemical characterization of veb-1, a novel class a extended-spectrum beta-lactamase encoded by an escherichia coli integron gene. | a clinical isolate, escherichia coli mg-1, isolated from a 4-month-old vietnamese orphan child, produced a beta-lactamase conferring resistance to extended-spectrum cephalosporins and aztreonam. in a disk diffusion test, a typical synergistic effect between ceftazidime or aztreonam and clavulanic acid was observed along with an unusual synergy between cefoxitin and cefuroxime. the gene for veb-1 (vietnamese extended-spectrum beta-lactamase) was cloned and expressed in e. coli jm109. the recombin ... | 1999 | 10049269 |
| use of an isogenic escherichia coli panel to design tests for discrimination of beta-lactamase functional groups of enterobacteriaceae. | a study was designed to determine if an isogenic panel of escherichia coli strains containing many different beta-lactamases could be used for the preliminary screening of a large number of beta-lactam agents to identify which might be most useful in the development of a definitive test for specific beta-lactamases found among the members of family enterobacteriaceae. the susceptibilities of 46 strains, comprising the isogenic panel, to expanded-spectrum cephalosporins, cephamycins, and aztreona ... | 1999 | 10049278 |
| secretion, localization, and antibacterial activity of tasa, a bacillus subtilis spore-associated protein. | the synthesis and subcellular localization of the proteins that comprise the bacillus subtilis spore are under a variety of complex controls. to better understand these controls, we have identified and characterized a 31-kda sporulation protein, called tasa, which is secreted into the culture medium early in sporulation and is also incorporated into the spore. tasa synthesis begins approximately 30 min after the onset of sporulation and requires the sporulation transcription factor genes spo0h a ... | 1999 | 10049401 |
| type i beta-lactamases of enterobacter cloacae and resistance to beta-lactam antibiotics. | the interaction of type-i beta-lactamases from enterobacter cloacae with diverse beta-lactam compounds was examined. the ability of penicillin and cefoxitin to induce beta-lactamase production in this strain was assessed. the effect of beta-lactamase inhibitors was measured on beta-lactamase extracts and on intact cells. e. cloacae 78 strain is a stably derepressed mutant showing limited susceptibility to a number of antibiotics except imipenem. imipenem would therefore be the appropriate choice ... | 1998 | 10069013 |
| conversion of unsaturated fatty acids by bacteria isolated from compost. | a compost mixture amended with soybean oil was enriched in microorganisms that transformed unsaturated fatty acids (ufas). when oleic acid or 10-ketostearic acid was the selective fatty acid, sphingobacterium thalpophilum (nrrl b-23206, nrrl b-23208, nrrl b-23209, nrrl b-23210, nrrl b-23211, nrrl b-23212), acinetobacter spp. (nrrl b-23207, nrrl b-23213), and enterobacter cloacae (nrrl b-23264, nrrl b-23265, nrrl b-23266) represented isolates that produced either hydroxystearic acid, ketostearic ... | 1999 | 10069863 |
| cloning and expression in escherichia coli of an azoreductase gene from clostridium perfringens and comparison with azoreductase genes from other bacteria. | a genomic library of clostridium perfringens atcc 3626 was constructed in phage lambda gt11 and screened with an antibody against the c. perfringens azoreductase, which catalyzes the reduction of azo dyes to aromatic amines. a positive recombinant phage, containing a 3.8 kb dna fragment insert was selected and purified. lytic and lysogenic escherichia coli cultures infected with the recombinant phage had higher azoreductase activity than cultures infected only with the vector lambda gt11. the 3. ... | 1999 | 10071864 |
| [the clinical manifestation and drug sensitive tests of lower respiratory tract infection by enterobacter cloacae. the pulmonary infection and fibrosis group, thoracic society shanghai medical association]. | to study the clinical characteristics of lowar respiratory tract infection caused by e. cloacae and to investigate the drug sensitivities of e. cloacae strains. | 1997 | 10072803 |
| serum is more suitable than whole blood for diagnosis of systemic candidiasis by nested pcr. | pcr assays for the diagnosis of systemic candidiasis can be performed either on serum or on whole blood, but results obtained with the two kinds of samples have never been formally compared. thus we designed a nested pcr assay in which five specific inner pairs of primers were used to amplify specific targets on the rrna genes of candida albicans, c. tropicalis, c. parapsilosis, c. krusei, and c. glabrata. in vitro, the lower limit of detection of each nested pcr assay was 1 fg of purified dna f ... | 1999 | 10074503 |
| 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 |
| the effect of new disinfectant substances on the metabolism of enterobacter cloacae. | the antimicrobial mechanism of 16 new commercially manufactured disinfectant substances on an enterobacter cloacae strain was studied. the substances tested represent 11 quaternary ammonium salts (qas) and five combinated qas with other ingredients. the antimicrobial efficacy was characterized by influencing the growth of bacterial cells expressed by mic and ed50 values as well as by the inhibition of the incorporation rate of [14c] adenine and [14c] leucine. the disinfectants are divided into t ... | 1999 | 10075279 |
| phop-phoq-regulated loci are required for enhanced bile resistance in salmonella spp. | as enteric pathogens, salmonella spp. are resistant to the actions of bile. salmonella typhimurium and salmonella typhi strains were examined to better define the bile resistance phenotype. the mics of bile for wild-type s. typhimurium and s. typhi were 18 and 12%, respectively, and pretreatment of log-phase s. typhimurium with 15% bile dramatically increased bile resistance. mutant strains of s. typhimurium and s. typhi lacking the virulence regulator phop-phoq were killed at significantly lowe ... | 1999 | 10084994 |
| the major phase-variable outer membrane protein of escherichia coli structurally resembles the immunoglobulin a1 protease class of exported protein and is regulated by a novel mechanism involving dam and oxyr. | here we report the characterization of an escherichia coli gene (agn43) which encodes the principal phase-variable outer membrane protein termed antigen 43 (ag43). the agn43 gene encodes a precursor protein of 107 kda containing a 52-amino-acid signal sequence. posttranslational processing generates an alpha43 subunit (predicted mr of 49,789) and a c-terminal domain (beta43) with features typical of a bacterial integral outer membrane protein (predicted mr of 51, 642). secondary structure analys ... | 1999 | 10094691 |
| 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 |
| 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 |
| emergence of fosfomycin-resistant isolates of shiga-like toxin-producing escherichia coli o26. | we evaluated the susceptibilities of 129 shiga-like toxin-producing escherichia coli (stec) isolates to various antibiotics. the numbers of isolates for which mics were high (> or = 128 micrograms/ml) were as follows: 5 for fosfomycin, 14 for ampicillin, 1 for cefaclor, 6 for kanamycin, 22 for tetracycline, and 2 for doxycycline. for two isolates of stec o26 mics of fosfomycin were high (1,024 and 512 micrograms/ml, respectively). conjugation experiments and glutathione s-transferase assays sugg ... | 1999 | 10103182 |
| strength and regulation of the different promoters for chromosomal beta-lactamases of klebsiella oxytoca. | the two groups of chromosomal beta-lactamases from klebsiella oxytoca (oxy-1 and oxy-2) can be overproduced 73- to 223-fold, due to point mutations in the consensus sequences of their promoters. the different versions of promoters from blaoxy-1 and blaoxy-2 were cloned upstream of the chloramphenicol acetyltransferase (cat) gene of pkk232-8, and their relative strengths were determined in escherichia coli and in k. oxytoca. the three different mutations in the oxy beta-lactamase promoters result ... | 1999 | 10103190 |
| clavulanate induces expression of the pseudomonas aeruginosa ampc cephalosporinase at physiologically relevant concentrations and antagonizes the antibacterial activity of ticarcillin. | although previous studies have indicated that clavulanate may induce ampc expression in isolates of pseudomonas aeruginosa, the impact of this inducer activity on the antibacterial activity of ticarcillin at clinically relevant concentrations has not been investigated. therefore, a study was designed to determine if the inducer activity of clavulanate was associated with in vitro antagonism of ticarcillin at pharmacokinetically relevant concentrations. by the disk approximation methodology, clav ... | 1999 | 10103195 |
| development of resistance during antimicrobial therapy caused by insertion sequence interruption of porin genes. | we have demonstrated by using an in vitro approach that interruption of the ompk36 porin gene by insertion sequences (iss) is a common type of mutation that causes loss of porin expression and increased resistance to cefoxitin in klebsiella pneumoniae. this mechanism also operates in vivo: of 13 porin-deficient cefoxitin-resistant clinical isolates of k. pneumoniae, 4 presented iss in their ompk36 gene. | 1999 | 10103203 |
| microbiology of the oil fly, helaeomyia petrolei. | helaeomyia petrolei larvae isolated from the asphalt seeps of rancho la brea in los angeles, calif., were examined for microbial gut contents. standard counts on luria-bertani, macconkey, and blood agar plates indicated ca. 2 x 10(5) heterotrophic bacteria per larva. the culturable bacteria represented 15 to 20% of the total population as determined by acridine orange staining. the gut itself contained large amounts of the oil, had no observable ceca, and maintained a slightly acidic ph of 6.3 t ... | 1999 | 10103240 |
| 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 |
| direct quantification of the enteric bacterium oxalobacter formigenes in human fecal samples by quantitative competitive-template pcr. | homeostasis of oxalic acid appears to be regulated, in part, by the gut-associated bacterium oxalobacter formigenes. the loss of this bacterium from the gut flora is associated with an increased susceptibility to hyperoxaluria, a condition which can lead to the formation of calcium oxalate crystalluria and kidney stones. in order to identify and quantify the presence of o. formigenes in clinical specimens, a quantitative-pcr-based assay system utilizing a competitive dna template as an internal ... | 1999 | 10203513 |
| 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 |
| identification and characterization of a new porin gene of klebsiella pneumoniae: its role in beta-lactam antibiotic resistance. | klebsiella pneumoniae porin genes were analyzed to detect mutations accounting for the porin deficiency observed in many beta-lactam-resistant strains. pcr and southern blot analysis revealed the existence of a third porin gene in addition to the ompk36 and ompk35 porin genes previously described. this new porin gene was designated ompk37 and is present in all of the clinical isolates tested. the ompk37 porin gene was cloned, sequenced, and overexpressed in escherichia coli. in contrast to that ... | 1999 | 10217760 |
| bloodstream infections in a neonatal intensive-care unit: 12 years' experience with an antibiotic control program. | to assess the prevalence of gram-positive coccal (gpc), gram-negative bacillary (gnb), and fungal blood-stream infections (bsis) during a 12-year period in which a consistent antibiotic treatment protocol was in place; to evaluate the efficacy of these antibiotic policies in relation to treatment, to the emergence of bacterial or fungal resistance, and to the occurrence of infection outbreaks or epidemics. | 1999 | 10219874 |
| [comparative studies on activities of antimicrobial agents against causative organisms isolated from patients with urinary tract infections (1997). i. susceptibility distribution]. | the frequencies of isolation and susceptibilities to antimicrobial agents were investigated on 560 bacterial strains isolated from patients with urinary tract infections (utis) in 9 hospitals during the period of june 1997 to may 1998. of the above bacterial isolates, gram-positive bacteria accounted for 29.3% and a majority of them were enterococcus faecalis. gram-negative bacteria accounted for 70.7% and most of them were escherichia coli. susceptibilities of several isolated bacteria to antim ... | 1999 | 10221177 |
| 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 |
| an shv-derived extended-spectrum beta-lactamase in pseudomonas aeruginosa. | a clinical isolate of pseudomonas aeruginosa rp-1 produced the extended-spectrum beta-lactamase (esbl) shv-2a. its gene was expressed from a composite promoter made of the -35 region derived from the left inverted repeat of is26 and the -10 region from the blashv-2a promoter itself. the dna sequences immediately surrounding blashv-2a were homologous to plasmid pmpa2a from klebsiella pneumoniae kpzu-3, while further away and 3' to the blashv-2a gene, a sequence corresponding to the left end of tn ... | 1999 | 10223953 |
| pulmonary infiltrates in liver transplant recipients in the intensive care unit. | a frequent dilemma is discerning the likelihood of pneumonia and the need for empiric antibiotic therapy in liver transplant recipients with pulmonary infiltrates in the intensive care unit (icu). | 1999 | 10232564 |
| 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 |
| 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 |
| rapid and reliable identification of streptococcus pneumoniae isolates by pneumolysin-mediated agglutination. | a pneumolysin-based agglutination test which allows an easy, rapid, cost-effective, and accurate (100% specific and 95% sensitive) discrimination between pneumococci and other related human and animal pathogenic bacterial strains has been assayed. | 1999 | 10325355 |
| extended-spectrum beta-lactamase producing strains of enterobacter cloacae transferring resistance to cefotaxime and ceftazidime. | transferability of ceftazidime resistance and of extended-spectrum beta-lactamase (esbl) production was recorded in three strains of enterobacter cloacae from frankfurt university clinics. all three strains were resistant to rifampicin, carbenicillin, cephaloridine, cefotaxime, ceftazidime, aztreonam, imipenem and meropenem. they transferred directly determinants of resistance to carbenicillin and cephaloridine to escherichia coli k-12 no. 185 nal+ recipient strain. all transconjugant colonies a ... | 1999 | 10326739 |
| 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 |
| 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 |
| presumed clostridial and aerobic bacterial infections of the cornea in two horses. | microscopic examination of gram-stained tissue specimens collected from severe corneal ulcers in 2 horses revealed large gram-positive rods suggestive of clostridium spp. clostridium perfringens was isolated from specimens collected from horse 1; anaerobic organisms were not detected in specimens from horse 2. aerobic bacterial culture revealed aeromonas hydrophila and enterobacter cloacae in specimens collected from horses 1 and 2, respectively. an insect exoskeleton was presumed to be the unde ... | 1999 | 10340080 |
| chemoselective nitro group reduction and reductive dechlorination initiate degradation of 2-chloro-5-nitrophenol by ralstonia eutropha jmp134. | ralstonia eutropha jmp134 utilizes 2-chloro-5-nitrophenol as a sole source of nitrogen, carbon, and energy. the initial steps for degradation of 2-chloro-5-nitrophenol are analogous to those of 3-nitrophenol degradation in r. eutropha jmp134. 2-chloro-5-nitrophenol is initially reduced to 2-chloro-5-hydroxylaminophenol, which is subject to an enzymatic bamberger rearrangement yielding 2-amino-5-chlorohydroquinone. the chlorine of 2-amino-5-chlorohydroquinone is removed by a reductive mechanism, ... | 1999 | 10347008 |
| role of pfka and general carbohydrate catabolism in seed colonization by enterobacter cloacae. | enterobacter cloacae a-11 is a transposon mutant of strain 501r3 that was deficient in cucumber spermosphere colonization and in the utilization of certain carbohydrates (d. p. roberts, c. j. sheets, and j. s. hartung, can. j. microbiol. 38:1128-1134, 1992). in vitro growth of strain a-11 was reduced or deficient on most carbohydrates that supported growth of strain 501r3 but was unaffected on fructose, glycerol, and all amino acids and organic acids tested. colonization by strain a-11 was signi ... | 1999 | 10347036 |
| 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 |
| characterization of novel antimicrobial peptoids. | peptoids differ from peptides in that peptoids are composed of n-substituted rather than alpha-carbon-substituted glycine units. in this paper we report the in vitro and in vivo antibacterial activities of several antibacterial peptoids discovered by screening combinatorial chemistry libraries for bacterial growth inhibition. in vitro, the peptoid chir29498 and some of its analogues were active in the range of 3 to 12 microg/ml against a panel of gram-positive and gram-negative bacteria which in ... | 1999 | 10348765 |
| efficacy of beta-lactam and inhibitor combinations in a diffusion chamber model in rabbits. | using a diffusion chamber in rabbits, we evaluated therapy with the combination of ceftriaxone plus the beta-lactamase inhibitor tazobactam in comparison with ceftriaxone alone. one sensitive and one resistant strain of escherichia coli, enterobacter cloacae and klebsiella pneumoniae were inoculated into one of the six diffusion chambers, implanted in the same animal. in order to simulate pharmacokinetics in humans, both substances were administered in decreasing doses. ceftriaxone was given 0, ... | 1999 | 10350378 |
| rupture of the spleen associated with enterobacter cloacae. | a 58-year-old male, with abdominal pain but no signs of sepsis, was admitted as a medical emergency. during hospitalization, spontaneous splenic rupture was diagnosed and splenectomy successfully performed. a smear revealed presence of enterobacter cloacae on the splenic surface; histopathology demonstrated granulocytous infiltration of the spleen. | 1999 | 10352739 |
| survival of enterobacter cloacae and pseudomonas paucimobilis in yoghurts manufactured from cow's milk and soymilk during storage at different temperatures. | the survival of two microbial contaminants, enterobacter cloacae and pseudomonas paucimobilis, in yoghurts manufactured from cow's milk and soymilk was investigated during storage for 45 days at 4 and 12 degrees c. sensory panel tests performed before microbiological investigation, showed that the flavor of soy-yoghurts made with cocoa powder or malt added did not have the beany taste of soy beans. both contaminants were significantly resistant to low ph values during storage for 32 days at 4 de ... | 1999 | 10356792 |
| most enterobacter aerogenes strains in france belong to a prevalent clone. | the aim of this study was to determine the distribution in france of the enterobacter aerogenes prevalent clone isolated in the hospitals of the marseille area (a. davin-regli, d. monnet, p. saux, c. bosi, r. charrel, a. barthelemy, and c. bollet, j. clin. microbiol. 34:1474-1480, 1996). a total of 123 e. aerogenes isolates were collected from 23 hospital laboratories and analyzed by random amplification of polymorphic dna and enterobacterial repetitive intergenic consensus-pcr to determine thei ... | 1999 | 10364580 |
| 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 |
| markedly different rates and resistance profiles exhibited by seven commonly used and newer beta-lactams on the selection of resistant variants of enterobacter cloacae. | seven beta-lactam antibiotics (cefepime, cefoperazone, ceftazidime, ceftriaxone, cefamandole, imipenem and meropenem) were tested for their potential to select resistance in standard and clinical strains of enterobacter cloacae (n = 9). the strains were subcultured daily with the test antibiotics at doubling concentrations starting at 0.125 x mic. development of resistance throughout the passages was detected by a disc diffusion test. ceftazidime, ceftriaxone and cefamandole selected resistance ... | 1999 | 10381101 |
| identification of a putative p-transporter operon in the genome of a burkholderia strain living inside the arbuscular mycorrhizal fungus gigaspora margarita. | this article reports the identification of a putative p-transporter operon in the genome of a burkholderia sp. living in the cytoplasm of the arbuscular mycorrhizal fungus gigaspora margarita. its presence suggests that burkholderia sp. has the potential for p uptake from this environment. this finding raises new questions concerning the importance of intracellular bacteria for mycorrhizal symbiosis. | 1999 | 10383982 |
| in vitro activity of clinafloxacin against fluoroquinolone resistant spanish clinical isolates. | the in vitro activity of clinafloxacin against 162 ciprofloxacin-resistant clinical isolates was determined. isolates were selected when their mic to ciprofloxacin was 2 mg/l (intermediate) or > 2 mg/l (resistant). the following strains were tested: 61 escherichia coli, 12 klebsiella pneumoniae, 7 proteus mirabilis, 21 serratia marcescens, 4 enterobacter cloacae, 21 pseudomonas aeruginosa, 21 staphylococcus. aureus (resistant to methicillin) and 15 enterococcus spp. clinafloxacin, ciprofloxacin, ... | 1999 | 10389645 |
| 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 |
| class c beta-lactamases operate at the diffusion limit for turnover of their preferred cephalosporin substrates. | it has been suggested that class c beta-lactamases have evolved to carry out a metabolic reaction other than hydrolysis of beta-lactam antibiotics. it is demonstrated in the present study that the class c beta-lactamase from enterobacter cloacae p99 has reached the diffusion limit in its ability to hydrolyze its preferred cephalosporin substrates. the increase in the solution viscosity by addition of a microviscogen (sucrose) caused the decline in the parameter kcat/km for hydrolysis of cephalor ... | 1999 | 10390233 |
| 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 |
| in vitro activity of hsr-903, a new oral quinolone, against bacteria causing respiratory infections. | the in vitro activity of hsr-903, an oral quinolone, against 196 recent clinical isolates of respiratory pathogens was evaluated. hsr-903 was 2 to 32 times more active than ofloxacin, ciprofloxacin, and sparfloxacin against staphylococcus aureus, including methicillin-resistant strains, and streptococcus pneumoniae and was at least as active as the other quinolones against gram-negative pathogens. | 1999 | 10390240 |
| rapid detection, by pcr and reverse hybridization, of mutations in the helicobacter pylori 23s rrna gene, associated with macrolide resistance. | a pcr-based reverse hybridization system (research prototype kit inno-lipa for h. pylori resistance) was developed and evaluated for simultaneous detection of 23s ribosomal dna point mutations, associated with macrolide resistance in helicobacter pylori. fifty-seven h. pylori strains (51 natural, 6 laboratory-derived artificial, 52 resistant, and 5 susceptible strains) were tested by pcr-lipa (detecting mutations a2115-->g, g2141-->a, a2142-->g, a2142-->c, a2143-->g, a2143-->c, and a2143-->t), d ... | 1999 | 10390244 |
| 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 |
| peptidase activity of beta-lactamases. | although beta-lactamases have generally been considered as being devoid of peptidase activity, a low but significant hydrolysis of various n-acylated dipeptides was observed with representatives of each class of beta-lactamases. the kcat/km values were below 0.1 m(-1). s(-1), but the enzyme rate enhancement factors were in the range 5000-20000 for the best substrates. not unexpectedly, the best 'peptidase' was the class c beta-lactamase of enterobacter cloacae p99, but, more surprisingly, the ac ... | 1999 | 10393100 |
| [survey of the sensitivities of clinical isolates to antibacterial agents (annual report)]. | research groups were formed in 21 institutions nationwide to investigate carbapenem resistance. the activities of various antibacterial agents, principally carbapenems, were tested against clinical isolates collected from these institutions. the broth microdilution method was used to determine the minimum inhibitory concentrations (mic) of 17 antibacterial agents for 1,241 strains of 11 bacterial species isolated at all institutions between october and december 1996. the results were as follows: ... | 1999 | 10396685 |
| [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 |
| disseminated zygomycosis due to rhizopus schipperae after heatstroke. | a 21-year-old woman suffered heatstroke and developed diarrhea while trekking across south texas. the heatstroke was complicated by seizures, rhabdomyolysis, pneumonia, renal failure, and disseminated intravascular coagulation. the patient's stool and blood cultures grew campylobacter jejuni. the patient subsequently developed paranasal and gastrointestinal zygomycosis and required surgical debridement and a prolonged course of amphotericin b. the zygomycete cultured was rhizopus schipperae. thi ... | 1999 | 10405417 |
| emergence of multidrug-resistant enterobacter cloacae: nosocomial outbreak or change of microbial ecology? | frequent selection of mutants resistant to extended and broad spectrum cephalosporins in enterobacter cloacae is observed in hospital. as we noticed an unusual number of isolates of these strains and to answer the question arose whether these enterobacter had a common source, we retrospectivally studied 56 strains collected in 11 wards of the hospital. using pfge with spe 1 restriction analysis we identified a prevalent clone (11 patients) dispatched in 8 wards. we also obviously proved cross-co ... | 1999 | 10418014 |
| penetration of beta-lactamase inhibitors into the periplasm of gram-negative bacteria. | the effectiveness of a beta-lactamase inhibitor/beta-lactam combination against gram-negative pathogens depends on many interplaying factors, one of which is the penetration of the inhibitor across the outer membrane. in this work we have measured the relative penetrations of clavulanic acid, sulbactam, tazobactam and brl 42715 into two strains of escherichia coli producing tem-1 beta-lactamase, two strains of klebsiella pneumoniae producing either tem-1 or k-1, and two strains of enterobacter c ... | 1999 | 10418127 |
| colonization pattern of the biocontrol strain pseudomonas chlororaphis ma 342 on barley seeds visualized by using green fluorescent protein. | pseudomonas chlororaphis ma 342 is a potent biocontrol agent that can be used against several seed-borne diseases of cereal crops, including net blotch of barley caused by the fungus drechslera teres. in this study, strain ma 342 was tagged with the gfp gene (encoding the green fluorescent protein) in order to study the fate of cells after seed inoculation. the gfp-tagged strain, ma 342g2, had the same biocontrol efficacy as the wild type when it was applied at high cell concentrations to seeds ... | 1999 | 10427065 |
| 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 |
| 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 |
| comparative in vitro activities of ciprofloxacin, clinafloxacin, gatifloxacin, levofloxacin, moxifloxacin, and trovafloxacin against klebsiella pneumoniae, klebsiella oxytoca, enterobacter cloacae, and enterobacter aerogenes clinical isolates with alterations in gyra and parc proteins. | the in vitro activities of ciprofloxacin, clinafloxacin, gatifloxacin, levofloxacin, moxifloxacin, and trovafloxacin were tested against 72 ciprofloxacin-resistant and 28 ciprofloxacin-susceptible isolates of klebsiella pneumoniae, klebsiella oxytoca, enterobacter cloacae, and enterobacter aerogenes. irrespective of the alterations in gyra and parc proteins, clinafloxacin exhibited greater activity than all other fluoroquinolones tested against k. pneumoniae and e. aerogenes. | 1999 | 10428935 |
| 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 |
| the periplasmic murein peptide-binding protein mppa is a negative regulator of multiple antibiotic resistance in escherichia coli. | mppa is a periplasmic binding protein in escherichia coli essential for uptake of the cell wall murein tripeptide l-alanyl-gamma-d-glutamyl-meso-diaminopimelate. we have found serendipitously that e. coli k-12 strains carrying a null mutation in mppa exhibit increased resistance to a wide spectrum of antibiotics and to cyclohexane. normal sensitivity of the mppa mutant to these agents is restored by mppa expressed from a plasmid. as is observed in the multiple antibiotic resistance phenotype in ... | 1999 | 10438753 |
| structure of the extended-spectrum class c beta-lactamase of enterobacter cloacae gc1, a natural mutant with a tandem tripeptide insertion. | a class c beta-lactamase from a clinical isolate of enterobacter cloacae strain gc1 with improved hydrolytic activity for oxyimino beta-lactam antibiotics has been analyzed by x-ray crystallography to 1.8 a resolution. relative to the wild-type p99 beta-lactamase, this natural mutant contains a highly unique tandem repeat ala211-val212-arg213 [nugaka et al. (1995) j. biol. chem. 270, 5729-5735]. the 39.4 kda chromosomal beta-lactamase crystallizes from poly(ethylene glycol) 8000 in potassium pho ... | 1999 | 10441119 |
| on the importance of a methyl group in beta-lactamase evolution: free energy profiles and molecular modeling. | beta-lactam antibiotics are generally thought to inhibit their target enzymes, the bacterial cell wall-synthesizing dd-peptidases, because of their resemblance to d-alanyl-d-alanine peptides. although a favorable conformation of the latter does structurally resemble the beta-lactams with respect to backbone conformation, a significant difference is the presence of a d-methyl substituent on the penultimate alanine residue of the cell wall peptide. a classical beta-lactam antibiotic has a hydrogen ... | 1999 | 10441146 |
| impact of use of multiple antimicrobials on changes in susceptibility of gram-negative aerobes. | evaluation of antimicrobial usage vs. susceptibility relationships typically involves single agents. however, susceptibility profiles may be affected by multiple drugs. from 1992 through 1996, we studied relationships between drug usage and the susceptibility (only susceptibility rates of > or = 70%) of acinetobacter anitratus (baumannii), enterobacter aerogenes, escherichia coli, enterobacter cloacae, klebsiella pneumoniae, pseudomonas aeruginosa, proteus mirabilis, and serratia marcescens to 2 ... | 1999 | 10452628 |
| nosocomial gram-negative bacteremia in critically ill patients: epidemiologic characteristics and prognostic factors in 147 episodes. | although gram-positive organisms are the most common causes of nosocomial bloodstream infections, gram-negative bacteremia carries higher risks of severe sepsis, septic shock, and death among critically ill patients in intensive care units (icus). we performed a prospective epidemiologic analysis of nosocomial gram-negative bacteremia episodes among icu patients and sought to identify risk factors for mortality among these patients. all episodes of nosocomial gram-negative bacteremia documented ... | 1999 | 10462994 |
| identification of a conserved n-terminal sequence involved in transmembrane signal transduction in envz. | to determine whether n-terminal sequences are involved in the transmembrane signaling mechanism of envz, the nucleotide sequences of envz genes from several enteric bacteria were determined. comparative analysis revealed that the amino acid sequence between pro41 and glu53 was highly conserved. to further analyze the role of the conserved sequence, envz of escherichia coli was subjected to random pcr mutagenesis and mutant alleles that produced a high-osmolarity phenotype, in which ompf was repr ... | 1999 | 10464234 |
| inhibition of the broad spectrum nonmetallocarbapenamase of class a (nmc-a) beta-lactamase from enterobacter cloacae by monocyclic beta-lactams. | beta-lactamases hydrolyze beta-lactam antibiotics, a reaction that destroys their antibacterial activity. these enzymes, of which four classes are known, are the primary cause of resistance to beta-lactam antibiotics. the class a beta-lactamases form the largest group. a novel class a beta-lactamase, named the nonmetallocarbapenamase of class a (nmc-a) beta-lactamase, has been discovered recently that has a broad substrate profile that included carbapenem antibiotics. this is a serious developme ... | 1999 | 10464248 |
| phenotyping and genotyping methods applied to investigate the relatedness of brazilian isolates of enterobacter cloacae. | in order to evaluate the resolving power of several typing methods to identify relatedness among brazilian strains of enterobacter cloacae, we selected twenty isolates from different patients on three wards of a university hospital (orthopedics, nephrology, and hematology). traditional phenotyping methods applied to isolates included biotyping, antibiotic sensitivity, phage-typing, and o-serotyping. plasmid profile analysis, ribotyping, and macrorestriction analysis by pulsed-field gel electroph ... | 1999 | 10464382 |
| development of bacterial resistance to the third generation cephalosporins and their clinical use. | development of gram-negative rods resistance to the third generation cephalosporins (cefotaxime, ceftazidime, cefoperazone) in connection with their application at the university hospital in olomouc was evaluated in this study. the highest increase in resistance to cefotaxime was detected in enterobacter cloacae (from 22.9% in 1995 to 49.0% in 1997) and enterobacter agglomerans strains (28.0% - 40.5%). in addition, increased resistance to ceftazidime in acinetobacter baumannii (12.5% - 35.1%), e ... | 1999 | 10465127 |
| cloning of a chryseobacterium (flavobacterium) meningosepticum chromosomal gene (blaa(cme)) encoding an extended-spectrum class a beta-lactamase related to the bacteroides cephalosporinases and the veb-1 and per beta-lactamases. | in addition to the blab metallo-beta-lactamase, chryseobacterium (flavobacterium) meningosepticum ccug 4310 (nctc 10585) constitutively produces a 31-kda active-site serine beta-lactamase, named cme-1, with an alkaline isoelectric ph. the blaa(cme) gene that encodes the latter enzyme was isolated from a genomic library constructed in the escherichia coli plasmid vector pacyc184 by screening for cefuroxime-resistant clones. sequence analysis revealed that the cme-1 enzyme is a new class a beta-la ... | 1999 | 10471563 |