Toxinogenic potential of Proteus mirabilis strains.

Live bacterial suspensions, original as well as concentrated filtrates of Proteus mirabilis cultures caused positive reaction in the rapid skin test (vascular permeability reaction) and also in the delayed test (combination of haemorrhagic reaction, dilatation of vessels and induration) as well as in the test of mice-foot edema. The test on suckling mice did not prove the presence of thermostable enterotoxin. After separating the concentrated culture filtrates the biologic activity appeared in fraction 1 (relative molecular mass over 100 000) concerning the delayed skin test and in the fraction 2 (relative molecular mass approx. 40 000) in the rapid skin test. The activity localized in the fraction 1 can be ascribed to a lipopolysaccharide. The fraction 2 with an expressed activity in the rapid skin test showed also cytotoxic and proteolytic activity. In both fractions the presence of active antigen substances with different mobility and different antigen specificity was demonstrated.