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Biomedical subjects

L Verbist

Publications and source records attributed to L Verbist.

At least 109 records · Page 6Linked to original sources
PubMed1985

In vitro activity of temocillin against clinical isolates.

The minimum inhibitory concentrations of temocillin against more than 1000 clinical isolates were determined by an agar dilution method. Temocillin showed excellent activity against Haemophilus influenzae, pathogenic Neisseria species and Branhamella catarrhalis, including beta-lactamase producing strains, but showed very low activity or was inactive against Gram-positive cocci and Campylobacter, Bacteroides, Acinetobacter and Pseudomonas species. Good activity was obtained against 702 Enterobacteriaceae, including isolates resistant to the other penicillins and first- and second-generation cephalosporins, with 92% of all the strains inhibited at a concentration of 8 mg/L. However, the most striking property of temocillin was its high beta-lactamase stability which resulted in both a very narrow range of MICs within which all the isolates were inhibited, and a small influence of inoculum size on the MICs.

Bacteria↗
PubMed1985

Antibacterial activity of temocillin in combination with other beta-lactam antibiotics.

The antibacterial interactions of temocillin with other beta-lactam antibiotics were tested by the checkerboard combination method in Mueller-Hinton agar against 146 strains of Enterobacteriaceae, 35 Pseudomonas aeruginosa strains, and 35 Staphylococcus aureus strains. Most combinations showed either a moderate degree of synergism or indifference. Strains showing occasional antagonism at a particular proportion of concentrations of the test combination, were found to only be indifferent when the mean index of the fractional inhibition concentration of all checkerboard combinations was calculated.

Anti-Bacterial Agents↗
PubMed1985

Temocillin sensitivity of Enterobacteriaceae species resistant to cefotaxime.

The in vitro activity of temocillin, cefotaxime, aztreonam and ceftazidime was tested against selected cefotaxime-resistant isolates (43 Enterobacter species, 37 Serratia marcescens, 16 Morganella morganii, 8 Klebsiella species) and cefotaxime-susceptible strains of the same species. Cross-resistance with a high degree of correlation was observed between cefotaxime and aztreonam or ceftazidime, but not between cefotaxime and temocillin.

Cefotaxime↗
PubMed1984

The pharmacokinetics of imipenem (thienamycin-formamidine) and the renal dehydropeptidase inhibitor cilastatin sodium in normal subjects and patients with renal failure.

The antibiotic imipenum (thienamycin-formamidine) is partially hydrolyzed during excretion by a renal brush border dehydropeptidase. The co-administration of imipenum with the renal dehydropeptidase inhibitor cilastatin results in an increase of the urinary recovery of the antibiotic, both in animals and humans. To study the pharmacokinetics of imipenem and cilastatin, subjects with normal renal function and patients with different degrees of renal insufficiency received intravenously 250 mg imipenum alone and 250 mg imipenem with 250 mg cilastatin. The mean plasma half-life of imipenem varied from 52 min in subjects with normal renal function to 173 min in subjects with end-stage renal failure studied while off-dialysis. The plasma half-life of imipenem was not affected by the co-administration of cilastatin. The mean plasma half-life of cilastatin varied from 54 min in normals to 798 min in patients with end-stage renal failure. The co-administration of cilastatin resulted in an increase of the urinary concentration and in the urinary recovery of imipenem, the effect being more pronounced in the subjects with normal or only mildly impaired renal function. The plasma clearance of imipenem was decreased when cilastatin was co-administered, possibly due to inhibition of tubular secretion of imipenem. Elimination studies performed during haemodialysis indicated efficient removal of both imipenem and cilastatin during a 4 h session. In view of the important increase in half-life of cilastatin as a function of increasing renal failure, a dosage reduction is proposed in patients with severe renal failure. It is recommended that the maximum dose of imipenem/cilastatin would be limited to either 1000/1000 mg twice daily or 500/500 mg four times daily in patients with a creatinine clearance of less than 15 ml/min. Also, a supplementary dose of imipenem and cilastatin after dialysis is recommended.

Adult↗
PubMed1984

Effect of temocillin in combination with other beta-lactam antibiotics.

The antibacterial interactions of temocillin with other beta-lactams were tested by checkerboard combination in Mueller-Hinton agar against 146 strains of members of the family Enterobacteriaceae, 35 Pseudomonas aeruginosa strains, and 35 Staphylococcus aureus strains. Most combinations showed a moderate degree of synergism. In only one Klebsiella strain was minor antagonism observed between temocillin and ampicillin.

Anti-Bacterial Agents↗
PubMed1984

In vitro activity and human pharmacokinetics of teicoplanin.

The in vitro activity of teicoplanin, a new antibiotic related to vancomycin, was determined against 456 gram-positive cocci. The activity of teicoplanin in comparison with that of vancomycin was similar against staphylococci but 4 to 40 times higher against enterococci and beta-hemolytic and viridans streptococci. The single-dose pharmacokinetics of teicoplanin were studied in six healthy volunteers after administration of 3 and 6 mg/kg intravenously and of 3 mg/kg intramuscularly. The kinetic parameters after both intravenous doses were very similar. The curves for concentration in plasma for the 3- and 6-mg/kg intravenous doses showed a triexponential decline with elimination half-lives of 47.3 and 44.1 h, respectively. The percentages of the doses recovered in urine (0 to 102 h) were 43.2 and 44.1%, respectively. The areas under the plasma curves were dose related: 256.5 and 520.9 micrograms/h per ml, respectively. The bioavailability of teicoplanin after injection of 3 mg/kg intramuscularly was 90%, and the peak level was 7.1 micrograms/ml. The mean levels in plasma 24 h after the 3-mg/kg doses were 2.1 and 2.3 micrograms/ml, respectively, and the mean level in plasma 24 h after the 6-mg/kg intravenous dose was 4.2 micrograms/ml.

Adult↗
PubMed1984

Relative bioavailability of enteric coated pellets, stearate and ethylsuccinate formulations of erythromycin.

In a randomized three-phase crossover study, 12 healthy male volunteers were given three 12-hourly 500-mg doses of erythromycin base, as enteric coated pellets in capsules (2 X 250 mg), erythromycin stearate tablet (1 X 500 mg), or erythromycin ethylsuccinate sachet (1 X 500 mg). The reaction time after administration of the pellets is significantly longer than after the stearate or ethylsuccinate formulations. The peak serum concentrations are higher for the pellets after both the 1st and 3rd dose. The time to reach peak concentrations is significantly longer for the pellets than for the stearate and ethylsuccinate formulations. The area under the serum concentration/time curve during 0-8 h after both doses is highest for the pellets. In conclusion, these findings indicate that despite the longer lag (1.8-1.2 h), the extent of gastrointestinal absorption and bioavailability of erythromycin is apparently greater for the base pellets than for the stearate and ethylsuccinate formulations.

Adult↗
PubMed1982

[Pharmacokinetics of mezlocillin. Comparison with ampicillin and influence of probenecid (author's transl)].

In a randomized cross-over study 10 healthy male volunteers received a single 1 g dose of 6-[R]-2-3-methylsulfonyl -2- oxo-imidazolisine -1- carboxamido) -2- phenyl-acetamido]-penicillanic acid sodium salt (mezlocillin) and of ampicillin, either intravenously or intramuscularly. Following the intravenous loading dose, mean peak serum levels of 101 micrograms/ml for mezlocillin and 91.5 micrograms/ml for ampicillin were recorded. The ultimate half-life t 1/2 of mezlocillin (46.4 min) was slightly shorter than that of ampicillin (52.4 min). Similarly, the total volume of distribution of mezlocillin (24.1 l) was slightly inferior to that of ampicillin (29.4 l). The proportions of the dose administered recovered in the urine of 24 hours were 50.4 % for mezlocillin and 69.9 % for ampicillin. The total clearances of the two antibiotics were not significantly different, but the renal clearance of mezlocillin (186.6 ml/min/1.73 m2) was significantly lower than that of ampicillin (309.5 ml/min/1.73 m2). Following intramuscular injection, the mean peak serum levels obtained were 15.6 microgram/ml with mezlocillin and 15.1 micrograms/ml with ampicillin. The half-lives of the antibiotics were 50.0 min and 57.2 min respectively. The bioavailable fractions of mezlocillin and ampicillin, as measured from the areas under the serum concentration curves wer 63 % and 75 % respectively of the values determined after intravenous injection. The oral administration of 1 g probenecid one hour before an intramuscular injection of mezlocillin increased the peak serum level and area under the curve by 65 % and decreased the total clearance, renal clearance and apparent volume of distribution by 38 %, 52 %, and 35 % respectively. However, the ultimate half-life was not significantly altered (50.5 min without, and 52.0 min with probenecid).

Adult↗
PubMed1982

In vitro activity of temocillin (BRL 17421), a novel beta-lactamase-stable penicillin.

The new in vitro activity of temocillin (BRL 17421), a new beta-lactamase-stable penicillin, was compared with those of other beta-lactam antibiotics for over 500 clinical bacterial isolates. Temocillin inhibited 94% of the Enterobacteriaceae organisms at concentrations of 0.5 to 8 microgram/ml, regardless of organisms resistance to ampicillin, ticarcillin, cefazolin, or combinations thereof. Most pseudomonas aeruginosa isolates and all staphylococci and streptococci tested were resistant to temocillin.

Anti-Bacterial Agents↗
PubMed1982

Comparative pharmacokinetics of ceftazidime and moxalactam.

The pharmacokinetics of ceftazidime and moxalactam were compared after intravenous and intramuscular administration of single 1-g doses to eight healthy volunteers in a crossover study. The bioavailability of the antibiotics after administration by either route was almost complete. Both drugs had similar areas under the serum curves. Significant differences between ceftazidime and moxalactam were observed with respect to the apparent volume of distribution (18.4 and 24.1 liters, respectively), to the terminal half-life (1.6 versus 2.0 h), and to urinary recovery of the active compound (96 versus 79%). Ceftazidime was almost completely eliminated by renal excretion (greater than 96%), whereas about 20% of the moxalactam was eliminated by nonrenal mechanisms. The concentrations of ceftazidime and moxalactam in serum after a 1-g dose exceeded the concentrations required to inhibit 90% of the Enterobacteriaceae for about 8 and 10 h, respectively. The levels of ceftazidime and moxalactam in serum exceeded the 90% minimal inhibitory concentration of Pseudomonas aeruginosa for about 6 and 1 h, respectively.

Adult↗
PubMed1981

In vitro activity of Ro 13-9904, a new beta-lactamase-stable cephalosporin.

The minimal inhibitory concentration (MIC) of Ro 13-9904 against 245 clinical isolates was determined by an agar dilution method. The activity of Ro 13-9904 against most Enterobacteriaceae was similar to that of cefotaxime; it was slightly more active than cefotaxime against Proteus mirabilis, Providencia species, and Serratia marcescens, but slightly less active against Klebsiella species. Ro 13-9904 was twofold more active than cefotaxime and threefold more active than ticarcillin against ticarcillin-susceptible Pseudomonas aeruginosa, with a mean MIC of 7.2 micrograms/ml; isolates highly resistant to ticarcillin were inhibited by a mean MIC of 17.2 micrograms/ml. Ro 13-9904 was fourfold more active than ampicillin against susceptible Haemophilus influenzae and was equally active against beta-lactamase-producing isolates. Ro 13-9904 was highly active against pneumococci and moderately active (MIC, 4 micrograms/ml) against Staphylococcus aureus isolates, whether they were susceptible or resistant to penicillin G. Oxacillin-resistant S. aureus and Streptococcus faecalis were completely resistant to Ro 13-9904 (MIC, greater than 128 micrograms/ml).

Anti-Bacterial Agents↗
PubMed1981

In vitro activity of N-formimidoyl thienamycin in comparison with cefotaxime, moxalactam, and ceftazidime.

The in vitro activity of N-formimidoyl thienamycin (N-f-thienamycin) was compared with the activities of other B-lactam antibiotics, using over 500 clinical bacterial isolates. N-f-Thienamycin inhibited 90% of the isolates of the common Enterobacteriaceae between 0.006 and 2 microgram/ml, regardless of their resistance to amoxicillin, ticarcillin, or cephalothin. It was, however, fourfold less active than moxalactam and ceftazidime and eightfold less active than cefotaxime. N-f-Thienamycin was nearly as active as ceftazidime against Pseudomonas aeruginosa (mean minimal inhibitory concentration, 3.0 microgram/ml) and eightfold more active than cefotaxime and moxalactam. In contrast to cefotaxime, moxalactam, and ceftazidime, N-f-thienamycin was highly active against enterococci (mean minimal inhibitory concentration, 1.3 microgram/ml) and staphylococci. The oxacillin-susceptible Staphylococcus aureus were inhibited between 0.03 and 0.12 microgram/ml, and the oxacillin-resistant S. aureus were inhibited between 0.12 and 2 microgram/ml. The high activity of N-f-thienamycin against both of the most important gram-positive and gram-negative organisms makes it a very promising new antibiotic.

Anti-Bacterial Agents↗
PubMed1981

Comparison of in vitro activities of eight beta-lactamase-stable cephalosporins against beta-lactamase-producing gram-negative bacilli.

In vitro activities of eight beta-lactamase-stable cephalosporins, cefoxitin, cefuroxime, cefotaxime, moxalactam, SCE-1365, cefoperazone, ceftazidime, and cefsulodin, were compared against selected cephalothin-resistant or beta-lactamase-producing gram-negative bacilli or both. SCE-1365, cefotaxime, moxalactam, and ceftazidime had very similar activities against Enterobacteriaceae; SCE-1365 displayed the highest activity, and ceftazidime displayed the lowest activity. These four antibiotics were about 20 times more active than cefoperazone and 50 to 100 times more active than cefoxitin and cefuroxime. Against Pseudomonas aeruginosa and the other Pseudomonas species, ceftazidime showed the highest activity by far, followed by cefsulodin and cefoperazone. A close parallel resistance against P. aeruginosa isolates was observed between piperacillin on the one hand and cefoperazone and cefsulodin on the other.

Acinetobacter↗