Plasmid-mediated pristinamycin resistance. PAC IIA: a new enzyme which modifies pristinamycin IIA.

A wild strain of Staphylococcus aureus which inactivates a wide variety of antibiotics has been found to inactivate pristinamycin IIA, an antistaphylococcal antibiotic. This phenomenon has been demonstrated to be plasmid mediated. The plasmid directs the biosynthesis of an acetyltransferase which is able to O-acetylate the drug. We propose to call the new enzyme PAC (IIA): Pristinamycin acetyltransferase.

[Plasmidic resistance of "Haemophilus sp." to aminoglycoside antibiotics: isolation and study of a new phosphotransferase (author's transl)]. / La resistance plasmidique de Haemophilus sp. aux antibiotiques aminoglycosidiques : isolement et etude d'une nouvelle phosphotransférase.

Plasmid mediated phosphorylating activities have been found in Haemophilus sp. strains resistant to some aminoglycoside antibiotics. The enzymes responsible for this phenomenon have been purified and studied. They belong to the group of aminoglycoside phosphotransferases which are able to phosphorylate these antibiotics on the 3'- or 5"-hydroxyl group. The first enzyme studied is closely related to APH(3')I whereas the second one is different from the former on the basis of substrate specificities and physicochemical properties. We propose to call this second enzyme APH(3')Ib as compared to APH(3')I which will be called APH(3')Ia.

[Analysis of biospecific complexes by electrophoresis: antibiotics specific to bacterial ribosomes]. / Etude de complexes biospécifiques par électrophorèse: application aux antibiotiques spécifiques du ribosome bactérien

Electrophoresis is a widespread method in biochemistry. Apparently it has never been used in the study of interactions found in enzyme-substrates or drug-receptor complexes. The aim of this Note is to describe some possibilities given by this simple technique especially in the case of interactions found between some antibiotics and the bacterial ribosome. Chloramphenicol, pristinamycin are located in 50 S subunit whereas dihydrostreptomycin is found in 30 S particle (fig). Such results have been previously obtained by other methods. The distribution of the gentamicin and kanamycin components is quite different. This suggests that the mechanism of action of these molecules may be different from that of streptomycin group antibiotics.

[Immobilized antibodies: a possible technic for the epidemiological study of antibiotic resistant bacteria]. / Les anticorps immobilisés: un outil possible pour l'étude épidémiologique des bactéries résistantes aux antibiotiques

An antibody specific to a cephalosporinase responsible for the resistance of bacteria to cephalosporines has been immobilized on agarose beads by the iminocarbonate method. The resin thus obtained has been studied at a biospecific point of view. Its high thermostability is also demonstrated. This biospecific resin allows the performance of epidemiologic experiments of bacteria resistant to beta lactamines.