[Study of the bactericidal activity of pristinamycin ]. / Etude de l'activité bactéricide de la pristinamycine.

In vitro, the bacteriostatic activity of pristinamycin varies according to the relative proportion of its two components, P I and P II, following a bell-shaped curve reflecting their synergistic effect. In vivo, the pharmacological profile of both components could be different and their synergistic bacteriostatic effect may therefore vary. This led us to study the bactericidal activity of different concentrations of the two components. Strains of staphylococci of varying sensitivity to macrolides and to each of the two components, P I and P II, were tested in our laboratory. We studied the bactericidal effect of various relative concentrations of both components tested in nutrient broth and transferred on nutrient agar, using Millipore membranes (according to the modified Chabbert's technique of cellophane transfer). We showed that the synergistic bactericidal activity of the two components yields a curve quite different from that observed for their bacteriostatic activity: the bactericidal activity is excellent, irrespective of the relative proportions of P I and P II in the medium. For all tested strains and relative proportions of both components, the MIC/MBC ratio is equal to one. We can therefore conclude that the determination of the SBA is useless and can assume that, as far as the serum levels of both components are above the MIC for the pathogenic strains, the blood is bactericidal. We have previously shown that transient incubation of P II on its target (50 S ribosomal sub-unit) led to a binding strength which is high (bactericidal activity) and prolonged ("bacteriopause").

Secnidazole. A 5-nitroimidazole derivative with a long half-life.

The therapeutic activity of a single 2 g dose of secnidazole was studied in patients with urogenital trichomoniasis. In 140 patients, 97% were cured and the drug was well tolerated. In the laboratory, tests on sensitivity were made and the minimal inhibitory concentration (MIC) and the minimal trichomonacidal concentration (MTC) were determined on cultures that had recently been isolated at the clinic, and the pharmacokinetic properties of secnidazole in man were compared with those of tinidazole. The therapeutic efficacy of all the metronidazole derivatives was reviewed and a single-dose treatment is recommended. Therapeutic and prophylactic treatment is achieved by products with a long half-life. Secnidazole, with a half-life of 14.3 +/- 1.3 h (women) and 20.2 +/- 3.1 h (men), is particularly suitable for this type of treatment.

[Experimental pyelonephritis in rats: value in the comparison of antibiotics (author's transl)]. / Un modèle de pyélonéphrite expérimentale chez le rat: son apport dans la comparaison des antibiotiques

The author discusses the conditions which an experimental pyelonephritis must fulfill to provide therapeutic results which will allow the assessment of new therapeutic agents. He subjects the chosen model to the therapeutic effect of four antibiotics and three antimicrobial drugs. A numeric value is given to the bacteriuria recession slope observed during the experiment. A comparison of the results being obtained with the bacteriological and pharmacological data normally evaluated, the author demonstrates the value of the present study. The analysis of the results collected during the tests shows that comparison between antibiotics are of greater value when they are of the same family. Nevertheless, the experimental pattern, when applied to antibiotics as different as kanamycine and cephalosporins, give a very good correlation particularly when the overstepping coefficient, as proposed by Canetti, is calculated on the results expressed as free products.