[A rapid test procedure for the detection of B streptococci in the perinatal period]

At the Hospital of the Department of Gynaecology of the University of Heidelberg, a latex agglutination test (Strep B Patho Dx Test) was applied after extraction of antigens from amniotic fluid and gastric aspirate, parallel to the routine screening programme (vaginal and anal swabs) for maternal colonization with B streptococci. The latex agglutination test was applied in 1336 cases. Maternal vaginal colonization was detected in 14%, anal colonization in 17% of the cases. A comparison of the results obtained with the latex agglutination test and with conventional bacteriological procedures (no gradual bacteriology, incubation 48 hours) showed antigen identification in amniotic fluid in 54%, respectively 24%. In gastric aspirates a B streptococcal contamination was detected by bacteriology in 40% of cases, by the rapid latex agglutination test in 22%. If no streptococci were found in the mother, amniotic fluid or gastric aspirates were contaminated in 4% or 6%, respectively (agglutination test or bacteriology, respectively). With a sensitivity of approximately 50% and a specificity of 98%, the latex agglutination test proved superior to routine bacteriology. All clinically contaminated newborn (positive blood specimens) were clearly identified by this test. With this new latex agglutination test, a procedure is now available to detect B streptococcal contamination in newborns within less than half an hour, thus an intra- or postpartal antibiotic therapy can be applied early.