Comparison of counterimmunoelectrophoresis, latex agglutination and bacterial culture for the diagnosis of bacterial meningitis using urine, serum and cerebrospinal fluid samples

ABSTRACT

Urine, serum and cerebrospinal fluid (CSF) samples from 98 children with clinical and laboratory diagnosis of bacterial meningitis were evaluated by counterimmunoelectrophoresis (CIE) and latex agglutination (LA) methods and the results compared to those obtained with bacterial cultures of the CSF samples. Antigens of Neisseria meningitidis groups A, B and C, Haemophilus influenzae type b and Streptococcus pneumoniae were determined by both immunological methods. Serum was diluted (14) with 0.1 M sodium EDTA pH 7.5, and held at 80 grade C for 10 min before assay. Polysaccharide of the urine samples was precipitated overnight using an equal volume of 11 ethanol-acetone followed by a heat-treatment with 0.1 M sodium EDTA, pH 7.5, at 80 grade C for 10 min. Sensitivity indices were 0.772 (CSF), 0.595 (urine) and 0.317 (serum) for CIE, and 0.914 (CSF), 0.930 (urine) and 0.683 (serum) for LA in relation to the 42 positive bacterial cultures. The optimal diagnostic efficacy reached 52% for CIE and 72% for LA when urine was concentrated 20-to 30-fold. These data show that immunological tests of urine samples were more effective than bacterial culture for diagnosing bacterial meningitis and may be indicated when negative results are obtained for tested by bacterial culture and immunoassay methods: