EN
Urinary tract infections are frequently caused by Proteus mirabilis strains. In the previous studies there were defined the complete structures of O-polysaccharide parts of lipopolysaccharides from strains: P. mirabilis O3 (S1959), P. mirabilis O9 and P. mirabilis O18. In the present study it was investigated bactericidal effect of normal human serum (NHS) to P. mirabilis strains. We also focused on the diversity of outer membrane proteins (OMPs) being separated on a gel isolated from tested strains. Serial passage of P. mirabilis O18 in 90% normal bovine serum (NBS) contributed to over-expressing some classes of OMPs.