title: Significance of urinary endotoxin concentration in patients with urinary tract infection.
abstract: Endotoxin is a component of the outer membrane of gram-negative rods (GNR). Since GNR are responsible for the majority of urinary tract infection (UTI), we measured the concentration of endotoxin in urine using chromogenic endotoxin-specific assay and examined its diagnostic utility in patients with suspected UTI. In all 18 urine samples with an endotoxin concentration exceeding 350 pg/ml and 2 samples with 10-350 pg/ml of endotoxin concentration, GNR were detected at a count of 10(4) cfu/ml. Negative for endotoxin were 3 samples of culture positive for gram-positive cocci (GPC), 2 samples containing various bacterial contaminants and all 37 samples with no growth on culture. Two urine samples collected 5 h after antibiotic dosage showed negative culture for GNR but a significant concentration of endotoxin. In an in vitro experiment, a residual concentration of antibiotic in urine inhibited bacterial growth, leading to a false-negative culture. These results suggest that chromogenic endotoxin assay is a reliable method for diagnosing UTI caused by GNR and detecting false-negative culture of GNR.
authors.affiliation: Department of Urology, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Matsumoto
authors.forename: M
authors.initials: M
authors.lastname: Tanaka
authors.forename: N
authors.initials: N
authors.lastname: Ogata
authors.forename: Y
authors.initials: Y
authors.lastname: Mizunoe
authors.forename: K
authors.initials: K
authors.lastname: Takahashi
authors.forename: J
authors.initials: J
authors.lastname: Kumazawa
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002863:Chromogenic Compounds; D004731:Endotoxins / Q000652:urine*; D005188:False Negative Reactions; D005260:Female; D016905:Gram-Negative Bacterial Infections / Q000175:diagnosis / Q000652:urine*; D006801:Humans; D008297:Male; D008875:Middle Aged; D014552:Urinary Tract Infections / Q000175:diagnosis / Q000382:microbiology / Q000652:urine*
chemical_list: D002863:Chromogenic Compounds; D004731:Endotoxins