[Nuclease activity of microorganisms and control of auto-microflora state of operators in hermetically sealed environment].

A study was performed to investigate biological properties of pathogenic microorganisms (Shigella, Salmonella, Staphylococcus aureus) and potentially pathogenic microorganisms which were isolated from different people, i.e. clinically healthy people with normal microflora, somatically healthy patients with intestinal dysbacteriosis, and patients with acute intestinal diseases. The most important parameters of pathogenicity typical of the basic representatives of pathogenic microflora were DNA and/or RNA forming activity. The "critical" size of depolymerization zones of nucleic acids on dense nutrient media was found to be equal to 2 mm and greater from the colony edge. The critical size was shown to be significantly different in potentially pathogenic and normal intestinal microorganisms. Maximal microbial concentrations in the major biotopes of man were estimated to be: no more than 25%, 5% and 2% for nasal mucosa, back skin, and for the large intestine of the total amount of microorganism in the test. Verification of the method gave evidence that in can be applied for an alternative evaluation of automicroflora of the large intestine of operators in an enclosed environment. It is suggested that the normal parameters characteristic of clinically healthy people need to be verified and applied in space and undersea medicine.