[Interest of humoral antibodies assay for diagnosis and survey of urinary tract infections by gram negative bacilli and streptococcus D in children (author's transl)].

The assay of humoral antibodies during urinary tract infections of children is performed by passive haemagglutination. In gram negative bacilli infections (176 children) the antigens are derived from the patients' bacteria. For streptococcus D infections the antigen is a phenol extract, specifically tested and used for all streptococcus D urinary tract infections (40 children). The humoral antibodies assay is of first interest to distinguish between high urinary tract infections with renal parenchym bacterial involvement and low urinary tract infections. In high urinary tract infections the antibodies are significantly elevated and almost surely indicate renal infection for a 1/2 560 titre; they raise both in gram negative bacteria and in streptococcus D infections. There is however a difference in a rather higher number of cases of streptococcus D infections where it is impossible of connect high sera titres and clinical symptoms of pyelonephritis, contrary to gram negative bacilli infections. It seems to be due to aetiological differences in urinary tract infections by streptococcus D, which are more often secondary infections, during severe urologic diseases. In such cases the symptomatology of infections is less typical than in E. Coli urinary tract infections. Another interest is the capacity of survey by this method. Three kinds of courses of antibody titres are observed: the first is a clean break of titre lower than 1/160 after three months; the second is the continuance of the same high levels over three months; the third is continuance of high significative level after a first incomplete fall. In the last two cases it is highly probable that a pyelonephritis processes is engaged. This may be useful for treatment and survey of children with urologic diseases.