[Evaluation of three rapid methods for intrapartum detection of group B streptococcus]. / Evaluación de tres técnicas rápidas para la detección intraparto del estreptococo del grupo B.

OBJECTIVE: The goal of this study was to evaluate three methods for rapid group B streptococcus (GBS) intrapartum vaginal detection. MATERIALS AND METHODS: In 330 women, at risk of delivering an infant with GBS disease, vaginal exudates were collected and a culture performed. The following rapid tests were also performed: 1) Equate Strep B immunoassay in 133 samples. 2) Icon Strep B immunoassay in 192 samples. 3) Co-agglutination with Phadebact Strep B, with a previous incubation (> 4 hours) of the vaginal swabs in Lim Group B Strep broth, in 88 samples. In some patients, two of these methods were performed simultaneously. RESULTS: GBS was detected in 37 women (11.2%) by culture. The sensitivity of Equate Strep B was 47%, Icon Strep B was 35% and co-agglutination with Phadebact Strep B was 38%. The specificity was 91%, 99% and 100% for each one of these methods. PPV 44%, 90% and 100%, respectively and NPV 92%, 91% and 90%, respectively. CONCLUSION: In conclusion, none of these methods was shown sensitive enough to be used for the routine detection of GBS. Therefore, in order to know the GBS carrier status and prevent its vertical transmission, the practice of vaginal culture during late pregnancy is mandatory.

[Characteristics of group b streptococcus vertical transmission]. / Características de la transmisión vertical madrefeto del estreptococo del grupo B.

OBJECTIVE: The goal of this study was to compare the characteristics of group B streptococcus (GBS) or Streptococcus agalactiae vertical transmission in woman, receiving or not intrapartum. antimicrobial prophylaxis, at risk of delivering an infant with GRS disease. MATERIALS AND METHODS: The study included 330 women, with risk factors for delivering an infant with GBS disease. The vaginal GBS colonization was studied by conventional culture. A clinical and microbiological follow-up was done in both women and neonates. RESULTS: GHS was detected in 37 women (11.2%). Among these, 21 (56.8%) received intrapartum antibiotics and 16 (43.2%) did not. Forty-one neonates were born from these 37 women. Of these, 11 showed signs of infection (3 with positive blood culture and 8 with blood culture negative for GBS) and 2 presented an asymptomatic bacteremia A GBS neonatal infection (with positive blood culture) was produced in 4.8% of newborns from mothers who received intrapartum antibiotics versus 25% of newborns from mothers who did not receive intrapartum antibiotics. However, this difference was not significant nor was the difference between external colonization by GBS between these two groups of newborns. On the contrary, significant differences were found in the percentage of clinically suspected sepsis (with negative blood cultures), which was more frequent among newborns from mothers without intrapartum antibiotics (30.4% vs 5.6%). A good correlation between the intensity of vaginal colonization and the incidence of microbiologically demonstrated sepsis, suspected sepsis an asymptomatic bacteremia in the newborn was found. CONCLUSION: In conclusion, in order to minimize the vertical transmission of GBS, the most efficient strategy seems to be to offer antibiotic prophylaxis to women identified as GBS carriers, since the antibiotic administration to women with "obstetric risks" often means that it is impossible that two hours elapse between antibiotic administration and delivery, resulting in the loss of efficacy of this second strategy.