Rapid identification of pregnant women heavily colonized with group B streptococci

Abstract

Pregnant women admitted to Tampa General Hospital, Tampa, Fla., were cultured for group B streptococci (GBS). Culture swabs were placed into enriched, selective Todd-Hewitt medium and were quantitated for GBS. The broth cultures were tested by slide coagglutination before incubation and after 5 and 20 h of incubation. Fifty-four (27%) of the 201 maternity patients cultured were positive for GBS and were identified as such by slide coagglutination. A strong correlation was found between the magnitudes of colonization and the times required to identify the broth cultures as GBS positive. Cultures from mothers heavily colonized (mean concentrations of 3 x 104 GBS per culture swab or greater) were identified after 5 h or less of incubation. Mothers lightly colonized with GBS (mean concentrations of 2 x 102 GBS per culture swab) were identified only after their broth cultures had been incubated for 20 h.

Reduction of morbidity and mortality rates for neonatal group B streptococcal disease through early diagnosis and chemoprophylaxis

“…Of these 204 women, 173 remained GBS positive at the time of admission in labor at ORMC. Forty-eight of these 173 GBS-positive women had 5-h positive vaginal cultures and could be considered heavily colonized as observed in previous studies (13,15); the remaining 125 women had 20-h positive vaginal cultures and were lightly colonized.…”

“…Recently we reported a laboratory procedure to rapidly diagnose GBS colonization in women and infants (13)(14)(15)17). This procedure uses an enriched, selective broth (Lim Group B Strep Broth) in combination with coagglutination to identify within 5 to 20 h women and infants colonized with GBS.…”

“…Processing of cultures. Maternal and infant culture swabs were processed as previously described (13)(14)(15)17). Culture swabs were inoculated into 5 ml of Lim Group B Strep Broth (GIBCO Laboratories, Madison, Wis.), incubated at 360C in 5% CO2, and tested for the presence of GBS by coaggluti-490 LIM ET AL.…”

“…Recently we described a new procedure to rapidly and * Corresponding author. selectively identify maternity patients heavily colonized with GBS and considered to be at high risk of delivering infants symptomatic for early-onset GBS disease (13)(14)(15)17). It was hypothesized in these previous reports that rapid identification of such high-risk wonien could be used to initiate early chemoprophylactic therapy.…”

Comparison of Rapid Tests for Detection of Group B Streptococcal Colonization

“…7 In an attempt to speed identification of GBS carriers and thereby limit the number of women treated, other investigators have studied the feasibility of quickly identifying GBS carriers by using a rapid coagglutination test. Jones and colleagues 8 found that most heavily colonized women (3 x 10 4 or more GBS/swab) could be identified in 5 hours by a broth incubation/slide coagglutination technique. Morales and associates 9 concluded that these women were at greatest risk for delivery of infants with symptomatic GBS disease and should receive intrapartum treatment.…”