[Microbial changes as the cause of failures of the therapy of bacterial diseases of the urogenital organs of swine].

In long-term clinical and bacteriological controlled breeding sows of 15 stocks with a high rate of urinary tract infections in 41 sows (= 8.97%) of 457 chronic infected sows a spontaneous change of the causative microorganism was seen. In clinical trials to test the effectiveness of new chemotherapeutics in sows suffering from urogenital infections changes of bacteria were noticed during and after therapy. In selected cases the proceeding of change using a quinoxaline-di-N-oxide-derivative and an aminoglycoside-antibiotic is demonstrated. After parenteral application of the quinoxaline-di-N-oxide-derivative in 3 of 6 cases a change of the causative agent happened. Treating the sows with the aminoglycoside-antibiotic there was a change in 18.2% of urinary tract infections and in 25.0% of genital tract infections. The causes of changes of the causative microorganisms are discussed and conclusions are drawn for diagnosis and therapy of urinary and genital tract infections in the sow.