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Biomedical subjects

L Verbist

Publications and source records attributed to L Verbist.

At least 91 records · Page 5Linked to original sources
PubMed1987

Comparative in-vitro activity of Ro 23-6240, a new trifluorinated quinolone.

The in-vitro activity of Ro 23-6240, a new quinolone, was tested in comparison with that of other quinolones against 486 recent clinical isolates. Ro 23-6240 displayed the typical features of the new quinolones: highest activity against Gram-negative bacilli, MBCs close to the MICs, minimum inoculum effect and rapid killing. Against Gram-negative organisms (Enterobacteriaceae, non-fermenters, Haemophilus influenzae and gonococci) the activity of Ro 23-6240 was between that of ofloxacin and norfloxacin; against staphylococci its activity was between that of ciprofloxacin and ofloxacin, and against streptococci it was similar to that of norfloxacin.

Anti-Bacterial Agents↗
PubMed1987

Norfloxacin versus thiamphenicol for treatment of uncomplicated gonorrhea in Rwanda.

In an open prospective study, single oral doses of norfloxacin (800 mg) and thiamphenicol (2.5 g) were used to treat, respectively, 122 and 46 consecutive patients with uncomplicated gonorrhea. Neisseria gonorrhoeae was eradicated from 119 (97.5%) patients treated with norfloxacin and from 35 (76.0%) patients treated with thiamphenicol. Norfloxacin treatment failure was not related to drug resistance or to insufficient absorption of the drug. Thiamphenicol failure correlated with low in vitro susceptibility of the infecting strain. In a single oral dose of 800 mg, norfloxacin appeared to be an excellent alternative treatment regimen for uncomplicated gonorrhea in an area with a high prevalence of penicillin-resistant gonococci.

Female↗
PubMed1987

Identification of novel erythromycin derivatives in mother liquor concentrates of Streptomyces erythraeus.

The identification of five novel compounds, pseudo-erythromycin A-6,9-hemiketal, 8,9-anhydro-pseudo-erythromycin A-6,9-hemiketal, 8,9-anhydro-pseudo-N-demethylerythromycin A-6,9-hemiketal, 5-O-beta-D-desosaminylerythronolide A and 15-nor-erythromycin C, in mother liquor concentrates of Streptomyces erythraeus is described. The pseudo-erythromycin derivatives are characterized by a 12-membered macrocyclic ring as a result of C13----C11 trans-lactonization. The five compounds have very little antimicrobial activity.

Bacteria↗
PubMed1987

[Comparative in vitro activity of 10 new 4-quinolones against enteropathogenic bacteria].

The susceptibility has been determined of 169 Shigella spp., 93 Salmonella spp., 68 Yersinia enterocolitica, 34 Vibrio cholerae 0:1, and 34 Campylobacter jejuni, isolated in Central Africa and in Belgium, to ten fluoroquinolones: ciprofloxacin, ofloxacin, norfloxacin, pefloxacin, enoxacin, amifloxacin, CI-934, A-56619, A-56620 and RO 23-6240. All quinolones were active against the strains tested, showing an MIC90 between 0.004 mg/l and 2 mg/l for strains susceptible to nalidixic acid and an MIC90 between 0.12 and 4 mg/l for resistant strains. Ciprofloxacin was the most active compound against Shigella spp., Salmonella spp. and Y. enterocolitica. A-56620 was the most active against C. jejuni; and both compounds were equal in activity against V. cholerae. The MBCs of all ten compounds were either similar to the MIC or one concentration higher. Killing curves show that the quinolones are bactericidal for the strains tested within 2 to 8 h of contact with concentrations corresponding to 2 or 8 times the MIC.

Anti-Bacterial Agents↗
PubMed1986

Quinolones: pharmacology.

The quinolones are synthetic antibiotics chemically related to nalidixic acid. Since its introduction, several structural analogues have been synthesized. A fundamental breakthrough was the addition of a fluorine atom. The quinolones interfere with bacterial DNA transcription by inhibiting the enzyme DNA gyrase, that so far has only been found in bacteria. The nature of the activity of the quinolones on DNA gyrase makes it highly unlikely that resistance is carried on plasmids.

Anti-Bacterial Agents↗
PubMed1986

In-vitro activity of pefloxacin against micro-organisms multiply resistant to beta-lactam antibiotics and aminoglycosides.

The in-vitro activity of pefloxacin was evaluated against 360 Enterobacteriaceae, 143 Pseudomonas aeruginosa and 124 staphylococci, selected for multiply resistance to different beta-lactam antibiotics and aminoglycosides. The MIC90 of pefloxacin against staphylococci and most Enterobacteriaceae was 0.5 mg/l or less. The MIC90 against Serratia marcescens and P. aeruginosa varied between 4 and 8 mg/l. Time-killing curves showed that pefloxacin at concentrations of four times the MIC decreased the viable counts by 3 logs or more within 1-8 h.

Aminoglycosides↗
PubMed1986

Susceptibility of ticarcillin-resistant gram-negative bacilli to different combinations of ticarcillin and clavulanic acid.

The susceptibility of ticarcillin-resistant and of ticarcillin-susceptible Gram-negative bacilli to different combinations of ticarcillin and clavulanic acid has been investigated. Susceptibility to ticarcillin has been restored in ticarcillin-resistant isolates in proportion to the amount of clavulanic acid in the combination and depending upon the species. The decrease in the MICs of ticarcillin was excellent to good in Proteus, Morganella, Providencia, Escherichia coli and Klebsiella, moderate in Enterobacter, Citrobacter and Serratia, but poor in Pseudomonas aeruginosa. An unfavourable effect of clavulanic acid on the MICs of ticarcillin was observed in some isolates belonging to species with inducible beta-lactamases.

Clavulanic Acid↗
PubMed1986

In-vitro activity of BRL-36650, a novel beta-lactamase-stable penicillin, against multiply resistant gram-negative organisms.

The in-vitro activity of BRL-36650, a novel beta-lactamase-stable penicillin was tested in comparison with that of cefotaxime, ceftazidime, aztreonam and imipenem against 559 multiply resistant Gram-negative organisms, some of which were also resistant to third generation cephalosporins. BRL-36650 and imipenem were the most active antibiotics. Against 342 Enterobacteriaceae the MICs90 were: imipenem 2 mg/l, BRL-36650 4 mg/l, aztreonam 8 mg/l and cefotaxime 32 mg/l. Against 122 Pseudomonas aeruginosa the MICs90 were: BRL-36650 4 mg/l, imipenem 8 mg/l, aztreonam and ceftazidime 64 mg/l.

Aminoglycosides↗
PubMed1986

Pharmacokinetics and tolerance after repeated doses of imipenem/cilastatin in patients with severe renal failure.

The pharmacokinetics of imipenem and cilastatin after repeated doses have been studied in six patients with severe renal impairment (mean creatinine clearance 10.4 ml/min/1.73 m2). The patients received nine iv injections of imipenem/cilastatin sodium (500/500 mg) at 12-hour intervals. The imipenem plasma concentration-time profile and the pharmacokinetic parameters on day 5 were similar in all respects to those on day 1. Therapeutic plasma levels of imipenem (greater than or equal to 4 mg/l) were maintained for 8-10 h after administration. Most pharmacokinetic parameters of cilastatin were similar on both days. However, the area under the plasma concentration curve (AUC) was significantly increased on day 5, as a result of some accumulation, but the trough levels stabilized after the third injection. Twice daily administration of imipenem/cilastatin 500/500 mg was felt to be a well tolerated and optimal dose regimen in patients with severe renal failure.

Adult↗
PubMed1986

Comparison of norfloxacin and nalidixic acid for treatment of dysentery caused by Shigella dysenteriae type 1 in adults.

A severe epidemic of dysentery began late in 1979 in northeast Zaire and spread to Rwanda, Burundi, and Tanzania. The epidemic strain is a multiply resistant Shigella dysenteriae type 1, which acquired resistance against trimethoprim and more recently against nalidixic acid in the course of the epidemic. A comparative open trial in Rwandan adults with Shiga dysentery involved 18 patients treated with norfloxacin at 400 mg twice daily and 12 patients treated with nalidixic acid at 1 g three times daily for 5 days. All isolates showed in vitro susceptibility to both drugs. Though norfloxacin eliminated Shigella organisms from stools more rapidly than nalidixic acid, its clinical superiority did not reach the level of significance. Norfloxacin is a promising drug and is more effective than nalidixic acid in the treatment of multiresistant shigellosis.

Adolescent↗
PubMed1986

In vivo uptake kinetics of aminoglycosides in the kidney cortex of rats.

The renal cortical uptake kinetics of four aminoglycosides were studied in vivo. Gentamicin, netilmicin, tobramycin or amikacin were administered to rats by continuous infusion over 6 hr achieving constant serum levels ranging from 0.2 to 100 micrograms/ml. Renal cortical concentrations at the end of the infusion were plotted against the steady-state serum levels. Steady-state elevations of serum gentamicin and netilmicin were associated with nonlinear increases in cortical levels, suggesting saturable uptake. Analysis of the data using Michaelis-Menten kinetics indicates that the apparent Km for gentamicin and netilmicin were 15.01 and 23.84 micrograms/ml and Vmax 149.83 and 178.36 micrograms/g of cortex per hr, respectively. The "initial" rate of uptake (at serum levels below 15 micrograms/ml) was highest for gentamicin. The cortical uptake of tobramycin was linearly related to elevations in serum levels [cortex concentration (conc) = 9.24 + 1.40 serum conc]. The initial rate of tobramycin uptake was considerably lower than that for gentamicin and netilmicin. For amikacin, the initial rate of uptake followed Michaelis Menten kinetics and the second phase of the titration curve was linear. The equation for total amikacin uptake was: cortex conc = 12.98 + 1.71 serum conc. Aminoglycosides exhibit differing kinetics for renal cortical uptake in the rat during constant infusions. These results indicate that more than one mechanism probably mediates the uptake of each aminoglycoside. Depending on which mechanism predominates, the kinetic pattern may be saturable, linear or mixed.

Aminoglycosides↗
PubMed1985

In-vitro activity of the combinations of ampicillin with mecillinam or with beta-lactamase inhibitors against strains resistant to ampicillin.

The in-vitro activity of ampicillin, of mecillinam and of combinations of ampicillin with mecillinam, clavulanic acid or 6 beta-bromopenicillanic acid has been studied against 126 Enterobacteriaceae resistant to ampicillin. The combination of ampicillin with mecillinam showed synergy or addition in 60% of the combinations tested. Synergy was seen especially when the strains were resistant to mecillinam, indifference when they were susceptible to mecillinam. The combination of ampicillin with mecillinam was more active than the combination with clavulanic acid against Escherichia coli, Klebsiella and Enterobacter, but not against Proteus, Morganella and Providencia. The combination of ampicillin with clavulanic acid was more active than the combination with 6 beta-bromopenicillanic acid in E. coli, Klebsiella and Enterobacter strains.

Amdinocillin↗
PubMed1985

Antibacterial activities of erythromycins A, B, C, and D and some of their derivatives.

The MICs of erythromycins A, B, C, and D and some of their derivatives were determined against 21 gram-positive and 15 gram-negative microorganisms. Antibacterial activity was confined to gram-positive and very few gram-negative bacteria. Erythromycin B was somewhat less active than erythromycin A, and erythromycin C and D showed about half that activity or even less. Most other derivatives had negligible activity. Determination of potency by diffusion and turbidimetric assays were in line with MICs. The examination of the results of these assays, however, revealed that there are differences between the data of different laboratories, depending on the microorganisms and conditions used.

Bacteria↗