Assuntos
Antibacterianos/metabolismo , Staphylococcus aureus/enzimologia , beta-Lactamases/metabolismo , Antibacterianos/farmacologia , Cefalosporinas/farmacocinética , Cefalosporinas/farmacologia , Indução Enzimática/efeitos dos fármacos , Cinética , Testes de Sensibilidade Microbiana , Staphylococcus aureus/classificação , beta-Lactamases/biossínteseRESUMO
Although still there are Klebsiella strains which do not harbour plasmids and produce constitutive chromosomal beta-lactamases, recently clinical isolates were found in ever increasing numbers carrying mainly TEM-, CARB- and OXA type R-factors. We selected four chromosomal cephalosporinase producing Klebsiella strains to study the pI values of the enzymes and their simultaneous separability from accompanying proteins by chromatofocusing techniques. We compared pI values of the pure and the crude preparations: K. pneumoniae K1 SC 10436: pIpure = 6.4, pIcrude = 6.42; K. aerogenes K1 1082 E: pIpure = 6.5, pIcrude = 6.5; K. oxytoca 1082 E: pIpure = 6.42, pIcrude = 6.4; K. oxytoca 20: pIpure = 7.62, pIcrude = 7.6. Excellent agreement of the pI values among each other, but occasional differences with those obtained by analytical isoelectrofocusing are attributed to methodological diversities and to the presence of satellite enzymes, known to exist in Klebsiella.