Significance of urinary endotoxin concentration in patients with urinary tract infection.
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.
Matsumoto
T
T
Department of Urology, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Tanaka
M
M
Ogata
N
N
Mizunoe
Y
Y
Takahashi
K
K
Kumazawa
J
J
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*
D002863:Chromogenic Compounds; D004731:Endotoxins