Of late, a trend to a marked loss in antibacterial efficacy of some antibiotics, for instance gentamycin and carbenicillin, is noted. This is due to changes in the microflora composition and sensitivity to antibiotics, an increase in the number of polyresistant microorganism strains. As gentamycin is effective now only against E. coli, it is not appropriate to use it in urological hospitals. Cefatoxim (claforan), on the contrary, retains its high antibacterial potential and becomes a basic antibiotic in the treatment of bacterial infections in urology. Continuous microbiological control is needed over fluoroquinolones microflora resistance to which is on the increase. Correction of therapy may be also required in the presence of such pathogens as Pseudomonas aeruginosa.