[Kinetic study on coagulase formation and growth of " XXXX ": comparative and combined action of antibiotics and gamma radiation (author's transl)].

@entity1138 @entity2755 @entity794 @entity4316
Coagulase production is preserved in @entity794 cultures although growth was strongly reduced after irradiation with 90,000 rads by a 60Co source. Kinetic studies on the growth and coagulase formation by non-irradiated and irradiated bacteria are reported, using various antibiotics such as @entity2755 , @entity4316 and @entity1138 . Both @entity2755 (1-50 microgram/ml) and @entity4316 (0.05-0.8 microgram/ml) added to @entity794 cultures reduce and finally inhibit growth rate and coagulase synthesis proportionally to their concentration in the medium; irradiated and non-irradiated cultures behave similarly to the inhibitory action of those antibiotics. @entity1138 between 0.2-9.6 microgram/ml reduces growth, but enzyme production is slightly affected; high levels of coagulase are observed in non-growing cultures. @entity1138 and gamma radiation affecting DNA give similar results: inhibition of growth but not of enzyme formation. Kinetics studies show that coagulase is synthesized during the first five minutes, either in irradiated or in non-irradiated cultures. Indication of a de novo synthesis, instead of a mere release of ready-formed enzyme, is given by using @entity2755 or @entity4316 which strongly inhibit coagulase production in irradiated @entity794 . Cultures treated by those antibiotics have their coagulase levels reduced to the same degree, were they irradiated or not; it is assumed that both types of cultures behave similarly, as far as enzyme production is concerned. A massive irradiation dose alone--or @entity1138 in high concentrations alone--may suspend bacterial growth although enzyme synthesis continues. A similar result is obtained by combining lower irradiation doses with an appropriate antibiotic. The combined and/or synergistic actions of gamma radiation and antibiotics could successfully differentiate between the two cellular functions: growth and enzyme synthesis.
