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)

HR810 (Hoechst-Roussel Pharmaceuticals Inc., Somerville, N.J.) is a new, cyclical-pyridinium cephalosporin that appeared superior to numerous comparison drugs against 658 strains of aerobic and facultative anaerobic bacteria. Seventeen Enterobacteriaceae spp. were tested by broth microdilution methods, and the 50% MICs (MIC50S) and 90% MICs (MIC90s) were 0.03 to 0.12 and 0.03 to 2.0 micrograms/ml, respectively. Only one strain had an MIC greater than 8.0 micrograms/ml (99.6% is considered susceptible). HR810 inhibited 98% of Pseudomonas aeruginosa isolates at less than or equal to 16 micrograms/ml, and the MIC90 for Acinetobacter spp. was 4.0 micrograms/ml. It was also very active against Pseudomonas spp. and Staphylococcus aureus (MIC90, 0.5 micrograms/ml) but marginally active against methicillin-resistant staphylococcal strains (MIC90, 16 micrograms/ml) and enterococcus (MIC90, 32 micrograms/ml). Non-enterococcal streptococci had MIC50s ranging from 0.008 micrograms/ml for Streptococcus pyogenes to 0.12 micrograms/ml for pneumococci. All MICs of HR810 against Haemophilus and Neisseria spp. were less than or equal to 0.03 micrograms/ml (MIC50, 0.002 to 0.008 micrograms/ml). HR810 poorly inhibited beta-lactamases and was very stable against 11 tested beta-lactamases of plasmid (TEM, OXA, SHV-1, and PSE) and chromosomal (K1, K14, P99) types.
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PMID:In vitro evaluation of HR810, a new wide-spectrum aminothiazolyl alpha-methoxyimino cephalosporin. 661 Nov 35

The destruction of amoxycillin by beta-lactamase action represents an important mechanism of bacterial resistance to the drug. Data is presented to illustrate that clavulanic acid used in the form of its potassium salt inhibits the amoxycillin destroying action of many different types of beta-lactamase for example: the staphylococcal enzyme, the clinically important plasmid mediated enzymes of the TEM, SHV, OXA and PSE types and the chromosomally controlled enzymes produced by Proteus mirabilis and Klebsiella pneumoniae. The mechanisms by which clavulanic acid inhibits beta-lactamases and potentiates the antibacterial action of amoxycillin are discussed.
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PMID:Biochemistry and action of clavulanic acid. 676 60

The in vitro activity and beta-lactamase stability of ceftazidime were evaluated against 700 gram-positive and gram-negative bacteria. Ceftazidime was less active than penicillins or older cephalosporins against Staphylococcus spp. and Streptococcus spp., and it did not inhibit Streptococcus faecalis, Listeria, or anaerobic species. Ceftazidime was as active as ceftizoxime and moxalactam and more active than cefoperazone against Escherichia coli. Klebsiella, and Proteus mirabilis with minimal inhibitory concentrations of less than 0.2 mg/liter. Ceftazidime also inhibited Enterobacter, Citrobacter, Salmonella, and Shigella at concentrations below 0.2 mg/liter. Most Morganella, Proteus rettgeri, Proteus vulgaris, and Proteus inconstans were inhibited at concentrations below 1 mg/liter, similar to the concentrations for moxalactam, ceftizoxime, and cefotaxime. Ceftazidime was the most active agent tested against Pseudomonas aeruginosa, with a mean minimal inhibitory concentration of 1.6 mg/liter. It inhibited carbenicillin-, piperacillin-, cefoperazone-, and cefsulodin-resistant Pseudomonas. Minimal inhibitory and minimal bactericidal concentrations were similar, with the exception of some Pseudomonas values at 10(7) colony-forming units. Use of different media did not alter minimal inhibitory concentration values. Ceftazidime was not hydrolyzed by staphylococcal beta-lactamase or plasmid beta-lactamase of the TEM-1, TEM-2, SHV-1, OXA-1, PSE-1, PSE-2 types or by inducible beta-lactamases of the cephalosporinase type. Ceftazidime provides an extremely active agent against aerobic and facultative gram-negative bacteria.
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PMID:Antibacterial activity and beta-lactamase stability of ceftazidime, an aminothiazolyl cephalosporin potentially active against Pseudomonas aeruginosa. 680 21

The effects of acidic conditions on activities of seven beta-lactamases--TEM-1 (class A), KOXY (class A), IMP-1 (class B), AmpC (class C), MOX-1 (class C), OXA-5 (class D), and PSE-2 (class D)--and their inhibitors were measured. The enzymatic activities of KOXY, IMP-1, and MOX-1 at pH 5.8 were slightly lower than those at pH 7.5. However, the activities of PSE-2 and OXA-5 were greatly reduced at pH 5.8. All of the beta-lactamase inhibitors tested had poorer inhibitory activities at pH 5.8 than at pH 7.5 except clavulanic acid for TEM-1.
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PMID:Effect of pH on activities of novel beta-lactamases and beta-lactamase inhibitors against these beta-lactamases. 748 32

Resistance to oxyimino cephalosporins was originally highlighted by the emergence of plasmid-encoded extended-spectrum beta-lactamases deriving by mutation from TEM-1, TEM-2 and SHV type enzymes (class A). The broader spectrum of resistance produced by these enzymes is related to more amino acid substitutions, but susceptibility to seven alpha-methoxyimino cephalosporins and carbapenems was preserved until recently. Clavulanate-sensitive extended-spectrum beta-lactamases are distributed worldwide, mainly among Klebsiella pneumoniae isolates. Novel clavulanate-sensitive extended-spectrum beta-lactamases deriving from other class A enzymes (e.g. MEN-1 from beta la OXY, OXA-11 in Pseudomonas aeruginosa from PSE-2) have been reported. Recently, clavulanate-resistant extended-spectrum beta-lactamases (class C) were encountered amongst single isolates, mostly Klebsiella pneumoniae. These cephalosporinases or cefamycinases (usually chromosomally mediated) have expanded the spectrum of plasmid-encoded resistance to include seven alpha-methoxyimino cephalosporins. Thus far, only two isolates (1 Pseudomonas aeruginosa, 1 Bacteroides fragilis), both recovered in Japan, with plasmid-mediated resistance to carbapenems have been found.
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PMID:Origin and impact of plasmid-mediated extended-spectrum beta-lactamases. 782

Three hundred and forty isolates of ampicillin-resistant Escherichia coli isolated from blood, bile and urine were collected during 1984 and 1988 in the Prince of Wales Hospital, Hong Kong and MICs of 21 beta-lactam antibiotics were determined. beta-Lactamases were identified by isoelectric focusing, and TEM-1 was found in 89.1% of isolates, PSE-1 in 3.2%, and OXA-1 in 2.9% of strains. Ten isolates (2.9%) possessed both TEM-1 and PSE-1. Five isolates (1.5%) produced only chromosomal enzymes and one produced an unidentified enzyme which focussed at pI 6.0. All but seven of 274 TEM-1 producers and all nine OXA-1 producers reacted with oligonucleotide probes in a colony blot technique. All isolates contained plasmids and 229 of 318 (72.0%) isolates transferred the ampicillin resistance factor. Of 42 transconjugants of TEM-1 producers selected for study, 39(92.9%) had only a single transferable plasmid bearing the TEM-1 gene.
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PMID:In-vitro antimicrobial susceptibility and beta-lactamases of ampicillin-resistant Escherichia coli in Hong Kong. 796 Dec 16

The effects of enterobacterial beta-lactamases were studied for biapenem (L627), a new carbapenem. Susceptibility tests were performed for isogenic mutant series of Citrobacter freundii, Enterobacter cloacae, Morganella morganii, Serratia marcescens and Proteus vulgaris which varied only in chromosomal beta-lactamase expression. beta-Lactamase-derepressed organisms in these series were as susceptible as beta-lactamase-inducible strains to biapenem; beta-lactamase-basal mutants were up to eight-fold more susceptible. Similar patterns of relative activity against the different expression types were noted for imipenem and biapenem. These data were related to direct induction and hydrolysis assays: biapenem, like imipenem, was a strong inducer of several Class I enzymes and of the P. vulgaris cefuroximase and, like the other carbapenems, was only very slowly hydrolysed by these enzymes. Moreover, like meropenem, biapenem reversibly deactivated these beta-lactamases. Piperacillin and the cephalosporins, tested as comparators, were more labile than carbapenems to the Class I enzymes, were weak inducers below their MICs and lacked deactivator function. In consequence their MICs were higher for derepressed organisms than for those with inducible or basal beta-lactamase expression. Unlike the carbapenems, they selected derepressed mutants from inducible populations. Biapenem, like imipenem and meropenem, retained full activity against most transconjugants of Escherichia coli K-12 that produced plasmid-mediated beta-lactamases, including extended-spectrum TEM mutants. Only production of OXA-10 (previously PSE-2) enzyme gave a slight reduction in susceptibility to the new carbapenem. Biapenem resistance (MIC 16 mg/L) did, however, occur in S. marcescens S6, which produced a chromosomal carbapenemase. This enzyme hydrolysed biapenem. Overall, our findings indicate that biapenem shares the favourable properties of imipenem and meropenem in its interactions with the most important beta-lactamases of enterobacteria.
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PMID:Comparative in-vitro activity of biapenem against enterobacteria with beta-lactamase-mediated antibiotic resistance. 804 Jan 11

The activity of biapenem (L-627, LJC-10627), a new carbapenem, was investigated against Pseudomonas aeruginosa strains, mutants and isolates with known resistance mechanisms to other beta-lactams. The behaviour of biapenem closely resembled that of imipenem, although it showed minor differences compared with meropenem, Inducible (i.e. normal) or derepressed chromosomal beta-lactamase expression gave slight protection against biapenem and imipenem, but insufficient to raise the MICs above clinically significant limits. This behaviour correlated with the slight lability of these compounds to the purified enzyme and with their strong capacity to induce beta-lactamase synthesis. Inducible or derepressed enzyme gave no protection against meropenem, possibly reflecting this compound's particular ability to deactivate the enzyme. Biapenem also has some ability to reversibly deactivate the enzyme. None of several plasmid-mediated beta-lactamases (TEM-2, PSE-1, -3 or -4; OXA-3,-6,-10,-11; NPS-1 or LCR-1) introduced into a P. aeruginosa PU21 recipient strain reduced susceptibility to biapenem or other carbapenems. Amongst permeability mutants, those lacking the D2 'carbapenem-specific' porin had reduced susceptibility to biapenem as well as to imipenem and meropenem. Biapenem and imipenem insusceptibility in these D2 porin-deficient mutants required continued expression of the chromosomal beta-lactamase, although this did not apply to meropenem. P. aeruginosa isolates and mutants with broad-spectrum insusceptibility ('intrinsic resistance') to penicillins, cephalosporins and unrelated drugs remained fully susceptible to biapenem and imipenem, whilst showing slightly reduced susceptibility to meropenem. Overall, these findings suggest that biapenem, like the earlier carbapenems, should prove to be a useful antipseudomonal agent, overcoming the mechanisms that commonly confer resistance to other classes of antipseudomonal beta-lactams.
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PMID:In-vitro activity of biapenem, compared with imipenem and meropenem, against Pseudomonas aeruginosa strains and mutants with known resistance mechanisms. 808 68

The X-PRESS, osmotic shock, chloroform treatment, lysozyme treatment and ultrasonic disruption methods to release five different plasmid-mediated beta-lactamases from Escherichia coli and one chromosomal beta-lactamase from Enterobacter cloacae were compared. The main activities of TEM-1, SHV-1, OXA-1, OXA-2, PSE-4 and chromosomal P99 beta-lactamases were found at the same isoelectric point irrespective of the method used. However, additional satellite bands were found with TEM-1, OXA-1, OXA-2 and PSE-4 beta-lactamases released by the lysozyme method. In addition, beta-lactamase released by osmotic shock treatment was found to be unstable during storage at -20 degrees C or during the 18 h period of iso-electric focusing at +4 degrees C. Chloroform treatment produced similar band patterns and at least as good an enzyme yield as ultrasonic disintegration and was equally simple and fast to perform.
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PMID:Evaluation of five different methods to prepare bacterial extracts for the identification of beta-lactamases by isoelectric focusing. 814 21

Pseudomonas aeruginosa ABD, which was isolated in October 1991 from blood cultures of a burn patient in Turkey, was resistant to cephalosporins, particularly ceftazidime (MIC, 512 micrograms/ml), penicillins, aztreonam, and meropenem, but not to imipenem. Cephalosporin and penicillin resistance transferred to P. aeruginosa PU21 and was associated with a beta-lactamase with a pI of 6.4 encoded by a 100-MDa plasmid designated pMLH52. Like extended-spectrum TEM and SHV beta-lactamases, this enzyme hydrolyzed penicillins and newer cephalosporins but did not hydrolyze cefoxitin or carbapenems. However, it differed from TEM and SHV derivatives in being a potent oxacillinase, and its encoding gene did not hybridize with probes to TEM and SHV genes. To characterize the enzyme, libraries of total DNA were cloned into plasmid pUC19 and were transformed into Escherichia coli DH5 alpha. Recombinant plasmids that gave ceftazidime resistance all contained a 3.65-kb BamHI fragment. Deletions from this fragment allowed the beta-lactamase gene to be located on a 1.4-kb section of DNA, which contained an open reading frame of 798 bases. This encoded a protein that was deduced to differ from PSE-2 beta-lactamase only in having serine instead of asparagine at position 143 and aspartate instead of glycine at position 157. It is concluded that the resistance of isolate ABD dependent on an extended-spectrum variant of the PSE-2 enzyme. The ability of this enzyme to cause ceftazidime resistance dependent primarily on a low Km for the compound; Vmax remained low. It is proposed that PSE-2 should be transferred to the OXA group as OXA-10 and that the new enzyme be designated OXA-11.
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PMID:OXA-11, an extended-spectrum variant of OXA-10 (PSE-2) beta-lactamase from Pseudomonas aeruginosa. 821 76


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