Properties of a deep Proteus R mutant isolated from clinical material

Some biological features of a deep P. mirabilis 17301 R mutant isolated from the urine of a patient with chronic UTI were studied and compared with similar features of P. mirabilis S forms and five induced Proteus R mutants of different chemotypes. There were no differences in lethal toxicity and adhesion to human uroepithelial cells. Of all the R mutants tested, two of them, 17301 and R4, exhibited strong cell-bound hemolytic activity. The P. mirabilis R 17301 was characterized as the most invasive (tested in L929 mouse fibroblasts) compared to the other Proteus S and R forms. The structure of PS from a clinical R mutant investigated and the results of serological studies prove that this mutant belongs to the Rc chemotype.