Summary
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 104 cfu/ml. Negative for endotoxin were 3 samples of culture positive for grampositive 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 falsenegative 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.
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Matsumoto, T., Tanaka, M., Ogata, N. et al. Significance of urinary endotoxin concentration in patients with urinary tract infection. Urol. Res. 19, 293–295 (1991). https://doi.org/10.1007/BF00299061
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DOI: https://doi.org/10.1007/BF00299061