[Effects of solar and geomagnetic activity on the accuracy of laboratory methods in differentiation of Staphylococcus aureus and S. epidermidis].

The production of three obligatory enzymes (DNAse, RNAse, gelatinase) and of three facultative ones (lecithinase, a-hemolysin, plasma coagulase) by six strains of S. aureus, namely, 209, Smit, Wood 46, phagotype (3A, 3C, 71), (53, 75, 84, 85), and (52A, 79), was investigated, as was the activity of twenty taxonomic parameters in comparison with the cyclic changes of solar activity and magnetic field of the Earth. The follow-up period was two years, from 1988 through 1989. The measurements were taken once a month. Solar activity and geomagnetic field of the Earth were found to influence the autofluctuations of the parameters used to discriminate between S. aureus and S. epidermidis. The activity of formation of pathogenicity enzymes DNAse, RNAse, and gelatinase in the course of a year varied within a wide range: two- to ten-fold. Changes in the aggressive activity of staphylococci were characterized by a cyclic pattern with the cycle duration of about a year. Of the biochemical parameters the most labile were capacity to oxidize lactose, xylite, and D-melibiose, to hydrolyze urea, and the Voges-Proskauter test.