GROUP-B STREPTOCOCCAL SCREENING WITH GBS MEDIUM IN OBSTETRICS

Pregnant women and newborn infants were screened for group B streptoco ccal (GBS) colonization by obtaining paired swabs from the cen ix and urethra for the former group and from the ear, nose, umbilical cord, g astric juice and membranes for the latter. One swab was cultured on bl ood agar; the other was inoculated into serum-starch broth (GBS medium ), which allows identification of GBS by production of a characteristi c orange-colored pigment. From the 2105 paired swabs obtained, a total of 158 were GBS positive by either method; of these, 154 (97.5%) were recovered by the GBS medium and 89 (56.3%) by blood agar plate. No fa lse positive color reactions were observed with GBS medium. 75% of the positive GBS media could be read within 24 h of incubation. The use o f GBS medium proved to be an easy and reliable method for screening of maternal and neonatal GBS colonization.