Diagnosis of Mycoplasma hominis pyelonephritis by demonstration of antibodies in urine.

To evaluate the diagnostic significance of the demonstration in urine of antibodies to Mycoplasma hominis, 1,000 samples of urine with more than 5 leukocytes per high-power field were serologically investigated by indirect hemagglutination, using glutaraldehyde-fixed erythrocytes coated with M. hominis antigen. The samples were collected from 702 patients. Antibodies were demonstrated in the urine of nine patients, all of whom had signs of acute attack of pyelonephritis. In seven of these patients, characterized by mild or moderate clinical signs and absence of lower urinary tract symptoms, bacterial causes were not observed, whereas M. hominis organisms were isolated from the upper urinary tract in most cases and from the bladder urine in all cases. In two patients, characterized by severe clinical signs and presence of lower urinary tract symptoms, both M. hominis and bacteria were isolated from the upper urinary tract and ballder urine. The demonstration of antibodies to M. hominis in urine is of high diagnostic value as they were only observed in patients in whom M. hominis infection in the upper urinary tract was evident or likely and only in the presence of clinical signs of acute attacks of pyelonephritis.