Experimental retrograde pyelonephritis and cystitis induced in rabbits by a group D Streptococcus sp.: serum antibody assay by a hemagglutination test.

Experimental models of urinary tract infection caused by a group D Streptococcus sp. in rabbits are described: retrograde pyelonephritis was induced by injecting 10(9) group D streptococci into the renal pelvis and obstructing the ureter by ligature for 24 h; cystitis was induced by injecting 5.10(9) group D streptococci through a transurethral catheter. The animals were observed for 3 months. Microbiological data from the urine and from the renal parenchyma were well correlated in 12 of 14 animals. A hemagglutination test for titration of serum antibodies in these infected rabbits is described. Before the beginning of experimentation, hemagglutination titers for all animals were below 160. During experimentation, titers for rabbits with cystitis were always below 640; in those with pyelonephritis, the highest titer was much greater than 640. These results show a positive correlation between serum antibody levels and the localization of urinary tract infection.