Selective Versus Non-selective Culture Medium For Group B Streptococcus Detection In Pregnancies Complicated By Preterm Labor Or Preterm-premature Rupture Of Membranes

The objective of this study was to identify group B streptococcus (GBS) colonization rates and compare detection efficiency of selective versus non-selective culture media and anorectal versus vaginal cultures in women with preterm labor and preterm-premature rupture of membranes (PROM). A prospective cohort study of 203 women was performed. Two vaginal and two anorectal samples from each woman were collected using sterile swabs. Two swabs (one anorectal and one vaginal) were placed separately in Stuart transport media and cultured in blood-agar plates for 48 hours; the other two swabs were inoculated separately in Todd-Hewitt selective media for 24 hours and then subcultured in blood-agar plates. Final GBS identification was made by the CAMP test. A hundred thrity-two cultures out of 812 were positive. The maternal colonization rate was 27.6%. Colonization rates were 30% for preterm PROM and 25.2% for preterm labor. Todd-Hewitt selective medium detected 87.5% and non-selective medium 60.7% GBS-positive women. Vaginal samples and anorectal samples had the same detection rate of 80.3%. Anorectal selective cultures detected 75% of carriers; 39% of GBS-positive women were detected only in selective medium. A combined vaginal-anorectal selective culture is appropriate for GBS screening in this population, minimizing laboratory costs. © 2006 by The Brazilian Journal of Infectious Diseases and Contexto Publishing. All rights reserved.104247250Schuchat, A., Zywicki, S.S., Dinsmoor, M.J., Risk factors and opportunities for prevention of early-onset neonatal sepsis: A multicenter case-control study (2000) Pediatrics, 105 (PART 1), pp. 21-26Hyde, T.B., Hilger, T.M., Reingold, A., Active Bacterial Core surveillance (ABCs) of the Emerging Infections Program Network. Trends in incidence and antimicrobial resistance of early-onset sepsis: Population-based surveillance in San Francisco and Atlanta (2002) Pediatrics, 110, pp. 690-695Benitz, W.E., Perinatal treatment to prevent early onset group B streptococcal sepsis (2002) Semin Neonatol, 7 (4), pp. 301-314Benitz, W.E., Gould, J.B., Druzin, M.L., Risk factors for early-onset group B streptococcal sepsis: Estimation of odds ratios by critical literature review (1999) Pediatrics, 103 (6), p. 77Schrag, S., Gorwitz, R., Fultz-Buts, K., Schuchat, A., Prevention of perinatal group B streptococcal disease. Revised guidelines from CDC (2002) MMWR, 51 (RR-11), pp. 1-22Mocelin, C.O., Carvalho, D.A.F., Brites, C., Isolamento de Streptococcus agalactiae de gestantes na regiäo de Londrina-PR (1995) RBGO, 17, pp. 915-918Beraldo, C., Brito, A.S.J., Saridakis, H.O., Matsuo, T., Prevalência de colonização vaginal e anorretal por estreptococo do grupo B em gestantes no terceiro trimestre (2004) RBGO, 26, pp. 543-549Philipson, E.H., Palermino, D.A., Robinson, A., Enhanced antenatal detection of group B streptococcus colonization (1995) Obstet Gynecol, 85, pp. 437-439Schuchat, A., Group B streptococcal disease: From trials and tribulations to triumph and trepidation (2001) Clin Infect Dis, 33 (6), pp. 751-756Jaureguy, F., Carton, M., Teboul, J., Risk factors and screening strategy for group B streptococcal colonization in pregnant women: Results of a prospective study (2003) J Gynecol Obstet Biol Reprod, 32 (2), pp. 132-138Madani, T.A., Harding, G.K., Helewa, M., Alfa, M.J., Screening pregnant women for group B streptococcal colonization (1998) Infection, 26 (5), pp. 288-291Quinlan, J.D., Hill, D.A., Maxwell, B.D., The necessity of both anorectal and vaginal cultures for group B streptococcus screening during pregnancy (2000) J Fam Pract, 49 (5), pp. 447-448Platt, M.W., McLaughlin, J.C., Gilson, G.J., Increased recovery of group B Streptococcus by the inclusion of rectal culturing and enrichment (1995) Diagn Microbiol Infect Dis, 21 (2), pp. 65-68Gupta, C., Briski, L.E., Comparison of two culture media and three sampling techniques for sensitive and rapid screening of vaginal colonization by group B streptococcus in pregnant women (2004) J Clin Microbiol, 42, pp. 3975-3977Picard, F.J., Bergeron, M.G., Laboratory detection of group B Streptococcus for prevention of perinatal disease (2004) Eur J Clin Microbiol Infect Dis, 23, pp. 665-671Stoll, B.J., Schuchat, A., Maternal carriage of group B streptococci in developing countries (1998) Pediatr Infect Dis J, 17 (6), pp. 499-503Prevention of perinatal group B streptococcal disease: A public health perspective (1996) MMWR Recomm Rep, 45 (RR-7), pp. 1-24. , Centers for Disease Control and Prevention (CDC)Silver, H.M., Struminsky, J., A comparison of the yield of positive antenatal group B Streptococcus cultures with direct inoculation in selective growth medium versus primary inoculation in transport medium followed by delayed inoculation in selective growth medium (1996) Am J Obstet Gynecol, 175 (1), pp. 155-15