Detection of antigens from gram-negative bacilli in urine of children with urinary tract infections. II. Thermostable bacterial proteins.

An enzyme immunoassay for detection of bacterial antigens in urine specimens from urinary tract infections (UTI) was developed. The antigens detected in infections by Enterobacteriaceae: Escherichia coli, Enterobacter aerogenes, and Proteus sp. were different from the enterobacterial common antigen (ECA). They were digested by trypsin and were characterized by remarkable thermostability; their molecular weights were approximately 34,000 and 31,000. They were detected by means of antisera to ECA or to suspension of E. coli. The frequency of positive results with urine specimens from enterobacterial UTI was 87-99%. In contrast, the urine specimens of UTI by Pseudomonas aeruginosa were positive in fewer than 20% with anti-E. coli sera, but were positive in more than 85% in tests with antiserum to P. aeruginosa. The possible diagnostic application of the described tests was discussed.