ULTRASOUND-ENHANCED LATEX AGGLUTINATION FOR THE DETECTION OF BACTERIAL-ANTIGENS IN URINE

An ultrasound-enhanced latex agglutination technique has been applied to the detection of bacteria in urine. The approach combines the use o f ultrasound, the dilution of latex to allow agglutination with low le vels of antigen, and microscopy. Using commercially available latex co ated with antibody to Esch. coli 0157 or K1, ultrasound enhanced the d etection of Esch. coli strains carrying these antigens by x512 and x20 48 respectively, compared with the standard test card procedure. The l atex particles in the commercial kits were 0.4-1.0 mu m in diameter. A s larger particles are more effectively manipulated in a sound field, particles of 2.8 mu m diameter were coated with antiserum against a ur inary tract isolate of Esch. coli (SP3112). The application of ultraso und with these particles facilitated the detection of 6x10(3) cells/mL of Esch. coli SP3112 within 2 min, a >10000-fold increase in sensitiv ity compared with the normal agglutination procedure. The possible exp loitation of this technique in the clinical laboratory for the rapid, sensitive detection of bacterial antigens in urine is discussed.