Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0276640 (TEM)
 20,729 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two species of beta-lactamase determined by plasmids in enteric bacteria that show some resemblance to TEM enzymes are described. Both are distinct from all other plasmid-mediated beta-lactamases and differ from the TEM beta-lactamases in ability to hydrolyze some substrates, in isoelectric point, in immunological specificity, and in susceptibility to inhibition. One of the enzyme species, mediated by plasmid p453, has been briefly described previously. We have discovered that this beta-lactamase, designated SHV-1, is unique in its response to inhibition by the sulfhydryl group reagent p-chloromercuribenzoate, because the hydrolysis of cephaloridine but not that of benzylpenicillin is affected. This enzyme is found in a variety of plasmid types which were transferred from several bacterial species collected from a wide geographic range. The other enzyme species is novel; only a single plasmid determining this kind of beta-lactamase (designated HMS-1) has been detected.
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PMID:Types of beta-lactamase determined by plasmids in gram-negative bacteria. 37 31

A survey of 2036 strains of Escherichia coli was conducted in Oporto, Portugal, to establish the prevalence of resistance to beta-lactam antibiotics. Isolates were from hospital and clinical practice patients, and were further divided into urinary and non-urinary pathogens. A high level of resistance to aminopenicillins (55.3%) was observed. Further examination of the resistant strains showed that the frequencies of occurrence of known beta-lactamases were as follows: TEM-1 (78.2% of resistant strains); SHV-1 (7.9%); TEM-2 (0.45%); OXA-1 (1.5%); HMS-1 (0.18%); TEM-1 + SHV-1 (4.2%). Other pairs of beta-lactamases were also identified in less than 2% of the resistant strains. In addition, 4.7% of the resistant strains produced elevated levels of a presumed chromosomal cephalosporinase, while 0.9% produced a ceftazimidase of pI 5.8-5.9 which was similar to TEM-6.
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PMID:Characterization of beta-lactamases encoded by pathogenic strains of Escherichia coli from Portugal. 134 81

Recent reports that members of the family Enterobacteriaceae that produce high levels of certain beta-lactamases are often resistant to ticarcillin-clavulanate prompted this study to assess the relationship between type and amount of enzyme produced and susceptibility to ticarcillin-clavulanate, piperacillin-tazobactam, and cefoperazone-sulbactam. Agar dilution MICs were determined by using 73 strains of Enterobacteriaceae that produced a single beta-lactamase that had been characterized and quantified and a beta-lactamase-negative control strain of Escherichia coli. For E. coli and Klebsiella pneumoniae, MICs of each combination increased as levels of TEM, SHV-1, or class IV enzymes increased. However, the percentage of strains that were resistant was highest for ticarcillin-clavulanate (32%), with only 18 and 6% resistant to piperacillin-tazobactam and cefoperazone-sulbactam, respectively. Strains producing PSE-1, regardless of level, were resistant or moderately susceptible to ticarcillin-clavulanate but were susceptible to piperacillin-tazobactam and cefoperazone-sulbactam. HMS-1 and OHIO-1 beta-lactamases were associated with resistance to ticarcillin-clavulanate and piperacillin-tazobactam, respectively. High levels of class IV enzymes in Klebsiella oxytoca were associated with resistance to all three combinations. These results indicate that the level and type of beta-lactamase produced by members of the family Enterobacteriaceae are important determinants of susceptibility to beta-lactam-inhibitor combinations, especially ticarcillin-clavulanate.
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PMID:Beta-lactamase production in members of the family Enterobacteriaceae and resistance to beta-lactam-enzyme inhibitor combinations. 234 69

The aim of the present study was to determine which types of beta-lactamases codified by plasmids are transferred by conjugation from several species of enterobacteria. To this end, 352 strains of ampicillin-resistant enterobacteria from clinical samples from the Hospital Civil of Bilbao were evaluated. Their beta-lactamase activity and their capacity to transfer this capacity by conjugation were evaluated. The several types of plasmidic beta-lactamases in the strains that conjugated and in their respective transconjugants were characterized by analytic isoelectric approach, and also the sensitivity of these stains to 20 beta-lactamic antibiotics and the size of their plasmids. Twenty different types were detected, with a clear predominance of TEM 1. Type TEM 2 was found in 19% of the strains which conjugated, and much less commonly the types SHV 1, HMS 1 and a beta-lactamase of an approximate pl of 4.9 were found. The transfer of these beta-lactamases is mediated by a great variety of plasmids and is associated with variable levels of resistance to penicillins and unstable cephalosporins. The presence of betalactamases with activity on the more stable cephalosporins has not been detected.
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PMID:[Transfer of plasmid beta-lactamases in enterobacteria]. 249 Jun 96

The combination of piperacillin and the beta-lactamase inhibitor tazobactam (formerly YTR 830) was studied to determine optimal disk concentrations and dilution testing conditions. In addition, the potency of the combination was compared to that of piperacillin alone. The spectrum of piperacillin was greatly expanded by the addition to tazobactam principally against beta-lactamase producing strains of Haemophilus influenzae, Escherichia coli, Morganella morganii, Proteus vulgaris, Providencia stuartii, Shigella spp., Neisseria gonorrhoeae, and Staphylococcus spp. Tazobactam was active alone against Branhamella catarrhalis (minimum inhibitory concentration [MIC] 50, less than or equal to 1 microgram/ml), gonococci (MIC 50, 0.5-4 micrograms/ml), and N. meningitidis (MIC 50, less than or equal to 1 microgram/ml). Studies with beta-lactamase-producing type strains showed tazobactam to have high affinity for plasmid-mediated enzymes (TEM-1 and 2, SHV-1, HMS-1, and some CARB or OXA types) and not chromosomal beta-lactamases. Piperacillin/tazobactam inhibited 93% of fluoro-quinolone resistant strains at less than or equal to 64/8 micrograms/ml but failed to suppress the growth of 15 strains producing stably depressed cephalosporinases. Comparisons of piperacillin/tazobactam results determined with 100/10-, 100/20-, and 100/30-micrograms disks established the 100/10-micrograms disk as most usable. Among five different MIC combinations the ratio of eight parts piperacillin to one part tazobactam or fixed concentration tests at greater than or equal to 4 micrograms tazobactam/ml were preferred, each producing very low occurrences (less than or equal to 1.6%) of false-resistance or -susceptibility when compared to disk test results. MICs determined by agar and broth microdilution methods were essentially the same. The recommended breakpoints for piperacillin/tazobactam MICs were identical to those now found in the NCCLS susceptibility testing standards with the following exceptions: (1) for tests with H. influenzae and Staphylococcus spp.--susceptible at greater than or equal to 21 mm (MIC less than or equal to 16/2 micrograms/ml) and resistant less than or equal to 20 mm (MIC less or equal to 32/4 micrograms/ml); and (2) all remaining nonspeudomonas isolates would be interpreted by the NCCLS piperacillin enteric bacilli susceptibility criteria. This newer beta-lactamase inhibitor combination appears to be worthy of further in vivo trials guided by these or similar tentative in vitro susceptibility testing parameters.
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PMID:Studies to optimize the in vitro testing of piperacillin combined with tazobactam (YTR 830). 256 Apr 22

The antimicrobial activity of BMY-28100 was tested against approximately 7,000 bacterial pathogens in a multicenter, multiphased collaborative investigation. The BMY-28100 spectrum and antimicrobial potency was most similar to that of cefaclor and superior to that of cephalexin among currently available cephalosporins. Species that had greater than or equal to 90% of clinical strains inhibited by BMY-28100 (less than or equal to 8.0 micrograms/ml) were: Citrobacter diversus, Escherichia coli, Klebsiella spp., Proteus mirabilis, Salmonella spp., Branhamella catarrhalis, Haemophilus influenzae, Neisseria gonorrhoeae, N. meningitidis, methicillin-susceptible Staphylococcus supp., Streptococcus pneumoniae, S. pyogenes, S. agalactiae, S. bovis, serogroup C and G streptococci, Listeria monocytogenes and gm-positive anaerobes. BMY-28100 inhibited 9% more of the 6286 fresh clinical isolates at less than or equal to 8.0 micrograms/ml than cefaclor at the same concentration. BMY-28100 was generally bactericidal, but MICs for some species were markedly increased when an inoculum concentration of 10(7) CFU/ml was used. Strains producing plasmid-mediated beta-lactamases (TEM, OXA, SHV, HMS) were susceptible to BMY-28100, cefaclor, and cefuroxime. BMY-28100 was less active against strains producing chromosomal-mediated beta-lactamases (Types I and IV). BMY-28100 was not hydrolyzed significantly by the tested plasmid-mediated beta-lactamases, but was destroyed by Type I cephalosporinases and Klebsiella K1 enzymes.
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PMID:BMY-28100, a new oral cephalosporin: antimicrobial activity against nearly 7,000 recent clinical isolates, comparative potency with other oral agents, and activity against beta-lactamase producing isolates. 325 89

A rapid, simple assay for screening large numbers of Escherichia coli colonies for production of certain plasmid-mediated beta-lactamases (including TEM-1, TEM-2, HMS-1, SHV-1, OXA-1, PSE-1, PSE-4, and CEP-2) is described. The technique, a modification of the method of Slack et al. for detection of beta-lactamase in limited numbers of Haemophilus influenzae clinical isolates (Lancet ii:906, 1977), uses filter paper impregnated with benzylpenicillin and a pH indicator dye (bromocresol purple) that changes color in the presence of beta-lactamase activity. The test paper is briefly applied to an agar surface containing bacterial colonies which are subsequently scored individually on the paper by color: yellow indicates the presence of beta-lactamase, dark green its absence, and variegation (yellow and dark green) a mixed population. Concordance of the results of this assay with those of replica plating for antibiotic resistance was over 99%. Hundreds of colonies per plate can be scored quickly and remain viable for further evaluation. The assay appears to be useful for studies of the stability of plasmids encoding beta-lactamases and in cloning with vectors such as pBR322 in which insertion of DNA fragments can be detected by inactivation of the beta-lactamase gene. Whenever the assay is to be used, results should always be confirmed initially by another method, such as replica plating, because the test paper assay does not detect three beta-lactamases (OXA-2, OXA-3, and PSE-2) and also would miss intrinsic penicillin resistance.
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PMID:Rapid method for screening large numbers of Escherichia coli colonies for production of plasmid-mediated beta-lactamases. 634 Jun 5

Clays such as kaolinite and montmorillonite, are commonly used as an additive to modify the thermal properties of polymer. In the present work, the morphology, composition, shape and structure of montmorillonite and kaolinite were characterized and compared by various advanced techniques. The TEM/EDX data showed that the kaolinite has a larger particle size and a lower Si/Al ratio than montmorillonite. These clays were stacked by platelets. The TGA results revealed that montmorillonite loses significant weight (around 7%) from 60 to 90 degrees C due to the dehydration of absorbed water, however, kaolinite almost doesn't lose weight in this temperature range. Kaolinites loses its weight because of the loss of its structural OH groups at a lower temperature (around 510 degrees C) than montmorillonite (670 degrees C). The PAS-FTIR spectra showed that montmorillnite has a strong absorbance of hydroxyl group in hydrogen bond region at room temperature, which presents a strong ability to adsorb water on its surface. The results of varied infrared temperature and TGA showed that their structural OH group is very stable from 100 to 500 degrees C, and it is possible to form thermosetting PU/PLS composite by reaction with the isocynate group of polyurethane prepolymer.
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PMID:[Implication of structure for nano clays used in thermalsetting PU/PLS composite]. 1639 94

With Co(OAc)2 as Co source and hexadecylamine (HDA) as template, cobalt-containing hexagonal mesoporous silicas (Co-HMS) was successfully synthesized by a one-step co-condensation route at ambient temperature. Two different methods (calcination and solvent extraction) were separately utilized to remove the template molecules, and the effects on physical properties and application performance were studied in detail using the characterization of XRD, N2 adsorption-desorption, TEM, FT-IR, UV-vis diffuse reflectance techniques and catalytic activity measurement, respectively. The results showed that solvent extraction was more favorable for mesoporous structure maintaining. And in the liquid-phase oxidation of hydrocarbons, higher activities were obtained with Co-HMS-E being used.
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PMID:Effect of template removal methods on physical properties and catalytic performance of Co-HMS. 1944 77

Highly ordered 3D-hexagonal mesoporous silica HMS-3 and its vinyl- and 3-chloropropyl-functionalized analogues HMS-4 and -5, respectively, are synthesized under strongly alkaline conditions at 277 K. Tetraethyl orthosilicate, vinyltrimethoxysilane, and 3-chloropropyltrimethoxysilane are used as silica sources, and cetyltrimethylammonium bromide as the structure-directing agent. The 3D-hexagonal pore structures of HMS-3, 4-, and -5 were confirmed by powder XRD and high-resolution TEM studies. Brunauer-Emmett-Teller surface areas of these materials are 1353, 1211, and 603 m(2) g(-1) for HMS-3, -4, and -5, respectively. Among these materials, vinyl-functionalized mesoporous material HMS-4 adsorbs the highest CO(2) (5.5 mmol g(-1) , 24.3 wt%) under 3 bar pressure at 273 K. The 3D-hexagonal pore openings, very high surface area, and cagelike mesopores as well as organic functionalization could be responsible for very high CO(2) uptakes of these materials compared to other related mesoporous silica-based materials.
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PMID:3D hexagonal mesoporous silica and its organic functionalization for high CO2 uptake. 2273 Feb 69


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