USE OF THE CONJUGATE OF DISULFATED URSODEOXYCHOLIC ACID WITH P-AMINOBENZOIC ACID FOR THE DETECTION OF INTESTINAL BACTERIA

The disulphate ester of ursodeoxycholyl-p-aminobenzoic acid (PABA-UDCA ) was synthesised and compared with PABA-UDCA for its use in detection of intestinal bacteria. This compound, PABA-UDCA disulphate, had char acters in common with PABA-UDCA in that it was deconjugated by cholylg lycine hydrolase to release free PABA and bacteria that split glycocho lic acid deconjugated PABA-UDCA disulphate. Further, in rat experiment s urinary excretions of PABA were measured for six hours after oral ad ministration of 15 mg PABA-UDCA disulphate. Ten control rats excreted (mean (SE) 188.2 (13.6) mug of PABA; 10 rats with an intestinal stagna nt loop excreted more (530.1 (30.1) mug; p<0.001): whereas 10 rats in each of three groups pretreated by oral administration of various anti biotics excreted less (polymixin B+tinidazole, 4.9 (1-6) mug; kanamyci n, 31.0 (4.7) mug; clindamycin 40.9 (5.5) mug; p<0.001). By contrast w ith PABA-UDCA, PABA-UDCA disulphate was not actively absorbed from any part of the small intestine in everted gut sac experiments, and showe d poor recovery from bile after its intraileal instillation in rats. T his indicated that PABA-UDCA disulphate is a single pass type substanc e in the gut and its oral administration test reflects the sum of the activities of bacteria in the small intestine and colon. The disulphat e was easily soluble in water and this allowed its application in an i n vitro test involving PABA-UDCA disulphate incubation with intraperit oneal pus (PABA-UDCA disulphate incubation test) from patients with pe ritonitis. This test was carried out on six patients with peritonitis, and the severity of bacterial peritonitis was expressed quantitativel y. From the results obtained PABA-UDCA disulphate was considered a goo d material to detect intestinal bacteria.