Streptococcus agalactiae: prevention and vaccine development.

Streptococcus agalactiae, group B Streptococcus (SGB), is the most important cause of morbi-mortality among newborn population, and an important pathogen among immunossupressed adult patients. Despite the advances in the treatment and prevention of neonatal infections as a consequence of implementation of national and international recommendations for prevention of infection, there are still some improvements for the final control of the disease. In this sense, the vaccination against SGB could be an effective measure for the prevention of disease in those cases where intrapartum prophylaxis is not useful and in adult patients with risk factors for invasive infection due to SGB. This review summarizes the efforts made until now in order to establish the control of the infection, and brings some information on the current state-of-the art of vaccines against SGB, in which different strategies in their design have been used.

Use of Granada medium to detect group B streptococcal colonization in pregnant women.

Direct inoculation onto Granada medium (GM) in plates and tubes was compared to inoculation into a selective Todd-Hewitt broth (with 8 microg of gentamicin per ml and 15 microg of nalidixic acid per ml) for detection of group B streptococci (GBS) in pregnant women with 800 vaginal and 450 vaginoanorectal samples. Comparatively, GM was found to be as sensitive as the selective broth for the detection of GBS in vaginal specimens and more sensitive than selective broth for the detection of GBS in vaginoanorectal samples (96 versus 82%). The use of GM improved the time to reporting of a GBS-positive result by at least 24 h and reduced the direct cost of screening. We have also found that the inconvenience of anaerobic incubation of GM plates can be avoided when a cover slide is placed upon the inoculum, because aerobic incubation in GM plates with cover slides causes GBS to develop the same pigmentation that it develops with incubation under anaerobic conditions. These data support the routine use of GM plates or tubes as a more accurate, easier, and cheaper method of identification of GBS-colonized women compared to the enrichment broth technique.