Use of the directigen latex agglutination test for detection of Haemophilus influenzae, Streptococcus pneumoniae, and Neisseria meningitidis antigens in cerebrospinal fluid from meningitis patients.

Cerebrospinal fluid specimens from 257 persons were tested for the presence of bacterial antigens by counterimmunoelectrophoresis and the Directigen meningitis test (Hynson, Westcott & Dunning, Div. Becton Dickinson & Co., Baltimore, Md.). The specimens were obtained from 162 patients with meningitis caused by Haemophilus influenzae type b, Streptococcus pneumoniae, or Neisseria meningitidis serogroups A and C and from 95 patients without bacterial meningitis or meningitis caused by other bacterial agents. Directigen detected H. influenzae type b antigen in 83% (69 of 83) of the specimens obtained from patients with H. influenzae disease, pneumococcal antigen in 77% (30 of 39) of the specimens from patients with pneumococcal disease, and N. meningitidis antigen in 93% (37 of 40) of the specimens from patients with disease caused by N. meningitidis serogroups A and C. The comparable figures for counterimmunoelectrophoresis were 66% (55 of 83), 79% (31 of 39), and 78% (31 of 40), respectively. No false-positive reactions were reported with the Directigen reagents. Nonspecific reactions (agglutination with more than one of the four Directigen latex reagents) were noted with five specimens. The nonspecific reactions were resolved in four of the five specimens by heating (100 degrees C for 3 min). The accumulated data demonstrate that the sensitivity of the Directigen meningitis test is better than or at least equivalent to the sensitivity of counterimmunoelectrophoresis for the detection of antigens in cerebrospinal fluid.