Investigation of the ability of newer beta-lactam antibiotics to select resistant mutants from Serratia marcescens after mutagenesis with nitrosoguanidine.

Resistant mutants could easily be selected from a nitrosoguanidine-treated culture of Serratia marcescens with piperacillin, cefotaxime, cefoxitin, cefotetan, latamoxef (moxalactam) and aztreonam. Imipenem on the other hand was significantly less effective in mutant selection. Resistant clones broadly fell into two distinct classes.

Bioluminescence Assay for Measuring the Number of Bacteria Adhering to the Hydrocarbon Phase in the BATH Test.

A thorough validation of the bacterial adherence to hydrocarbons (BATH) test was performed by means of a bioluminescence assay. Ten different gram-negative strains were subjected to the BATH test. For the calculation of the adhesion index, several factors had to be taken into account: ATP leakage, the action of ATP-hydrolyzing enzymes, the change in the extraction efficiency of Nucleotide-Releasing Reagent for Microbial Cells (NRB; Lumac bv) after vortexing and the difference in light production after the addition of NRB.

Endotoxin testing.

Parenterals, sterile preparations intended to be injected in man or animal, should be free from pyrogenic substances which are able to raise the thermostatic setting in the hypothalamus. This article gives an up-to-date review of the principal detection and quantification methods for these agents, with special attention on the chromogenic Limulus Amebocyte Lysate assay.

Determination of endotoxins on hypodermic needles by means of a chromogenic Limulus amoebocyte lysate assay. Development of a test model.

A test model was developed in order to describe the determination of endotoxins on hypodermic needles in a reliable and reproducible manner. As in all in-vitro experiments one has to be very careful about extrapolating data to in-vivo situations. However by choosing a hydrophilic (Salmonella typhimurium ATCC 14028) and a hydrophobic bacterium (Acinetobacter calcoaceticus var.

In vitro antibacterial activity of BMY-28142, a new extended-spectrum cephalosporin.

The in vitro activity of BMY-28142 was compared with that of cefotaxime, ceftazidime, moxalactam, and imipenem against 639 clinical isolates and a number of in vitro-selected resistant mutants. BMY-28142 was the most potent compound against the members of the family Enterobacteriaceae with a MIC for 90% of the strains of 0.12 micrograms/ml.

Selection of resistant mutants of Citrobacter freundii by second and third-generation cephalosporins and imipenem.

Using a single-step selection procedure, resistant mutants could be obtained from three clinical isolates of Citrobacter freundii with two second-generation and four third-generation cephalosporins but not with imipenem. All mutants showed a drastically increased beta-lactamase activity and were cross-resistant to all the cephalosporins examined. Combinations of cloxacillin with the cephalosporins were markedly synergistic, suggesting the principal role of the cephalosporinase in the resistance of these mutants.

Reproducibility study of the pharmacokinetics of amikacin, gentamicin and tobramycin; a three-way crossover study.

The hypothesis that the pharmacokinetics of amikacin are more predictable than those of gentamicin or tobramycin was studied. In a three-way crossover design 58 volunteers received 7.5 mg/kg amikacin by iv infusion and either 1.

[Infectious agents : current concepts and perspectives].

The authors present a detailed discussion on infectious agents and their development in the immediate future and the anti-microbial strategies which need to be developed. After describing a series of new diseases and the suspected microbial aetiology of little known syndromes, they describe the major lines of development of chemotherapy: new products which need to be developed; microbial enzyme inhibitors; selective transport. The proper use of the range of drugs already available should not be underestimated.

[Comparison of methods of determination of serum doxycyline assessing relative bioavailability of two commercial formulations (author's transl)].

The present study was undertaken to evaluate the accuracy of the analytical results of an investigation of relative bioavailability of two doxycycline preparations. Six methods in four laboratories were applied: one fluorimetric, three high-pressure-liquid-chromatographic and three microbiological methods. The analyses were performed after coding the samples.

Amikacin in the treatment of gram-negative bronchopulmonary infections.

Six patients with acute gram-negative bronchopulmonary infection were treated with amikacin (15 mg/kg per day) administered intramuscularly in two equal doses at 12-hr intervals for 10-13 days. Two patients had underlying nonspecific pulmonary disease, two had advanced bronchocarcinoma, and two had extensive bronchiectasis (due to chronic aspergillosis in one patient). The pathogens were Pseudomonas aeruginosa in three patients, and Haemophilus influenzae, Klebsiella ozaenae, and Enterobacter cloacae each in one patient.

Pharmacokinetics of amikacin in patients with renal insufficiency: relation of half-life and creatinine clearance.

The half-life of amikacin after a single intramuscular injection was determined in patients with severe renal failure who received 3.75 mg of drug/kg and in patients with various degrees of renal function who received 7.5 mg of drug/kg.

In vitro activity of BL-s640 against gram-negative bacilli and Staphylococcus aureus compared with activity of four other semisynthetic cephalosporins.

The in vitro activity of BL-S640 (cefatrizine) was determined against 674 recent clinical isolates of Staphylococcus aureus and Enterobacteriaceae. Activity against S. aureus was less than that of cephapirin, cephalothin, and cefazolin, but greater than that of cephalexin.

In vivo comparison of two galenic forms of ampicillin-trihydrate.

In order to evaluate a new galenic form of ampicillin-trihydrate, individual blood serum levels and urine excretion of ampicillin-trihydrate were compared in a crossover study after oral absorption of 1-gram captab formulation (this being the new galenic form) versus 2x500 mg of the same product. Analyses performed by two different laboratories indicate that clinically insignificant slightly higher serum concentrations can be obtained with captabs, and that very individual absorption profiles should make one take a sceptic viewpoint as to mean serum concentrations computed from larger series of experiments. To obtain a valid blood serum level in as many patients as possible, a posology of 3-4 captabs, spaced over a 24-hour period is suggested for the treatment of infections with ampicillin-sensitive germs.

Urease activity of enterobacteriaceae: which medium to choose.

Detection and intensity of urease activity in enterobacteriaceae greatly varies as a function of the media or techniques used, or both. A comparative investigation on several solid and liquid media led us to the following conclusions. (i) Detection of Proteus spp.