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Show PHYLOGENETIC STUDY OF GROUP B STREPTOCOCCUS Rachel N. Woolston-Pendley, (Dr. John F. Bohnsack) Department of Pediatric Administration, University of Utah G roup B streptococcus (GBS) colonizes the vaginal tract of 15-35% of pregnant wo- men [6]. This pathogen can be passed from mother to infant, usually during delivery [1]. If the neonate does contract GBS, serious illness such as sepsis, meningitis or pneu-monia may result. The use of intrapartum prophylaxis helps keep the number of neo-natal GBS infections low [5], however, each year approximately 8,000 neonates develop a serious case of GBS, and about 800 die [1]. Mothers considered to be at risk for passing GBS to their baby are offered prophylaxis to help prevent the neonate from contracting GBS [5]. However, this is ineffective because it exposes more infants to antibiotics than would actually contract the disease. GBS was first described as a pathogen in-fecting bovine in 1887; only in the 1960's did GBS emerge as a human pathogen [2]. Re-cently there has been an investigation into the relation between human and bovine GBS. Preliminary studies on human sero-type III strains show that they may be closely related to bovine strains [2,4]. Nine serotypes of GBS are known to exist, I-IX. Our lab uses two main techniques to study the phylogenetic lineages of GBS, including Restriction Digest Patterning (RDP) and Multi-Locus Sequence Typing (MLST). Serotypes la, Ib, II, III, and V are particularly invasive and responsible for most neonatal infections. Recent work has focused on serotype V. Ac-cording to previous research, there are three subtypes of serotype V: V-l, V-2, and V-3. These serotypes differ in the type of infB al-lele they contain and the presence of GBSil in scpB-Imb [3]. We are investigating whether the infB allele and GBSil insert correctly iden-tifies all GBS serotype V lineages. The data collected on the RDP typing and MLST data will be compared. This information will help determine the different lineages of GBS, how divergent this species has become, and its relation to bovine GBS. Data obtained from the genetic studies of the different serotypes may also shed light on why some strains are particularly virulent and prone to infect neo-nates [3]. With this knowledge, health care professionals can be more effective in pre-scribing intrapartum prophylaxis. Works Cited 1. Awareness of a Group B Strep Infec-tion During Pregnancy. Retrieved July 11, 2003, from http://groupbstrep.org/gbs/ aboutGBSl.html 2. Bisharat, N., Crook, D. W., Leigh, L, Harding, R. M., Ward, P. N., Coffey, J. C. et al. (submitted for publication, 2003). Hyperinvasive Neonatal Group B Strep-ptococcus has Arisen From a Bovine An-cestor. 3. Bohnsack, John. (2002). Project Application-Thrasher Research Fund: Iden-tification of Pathogenic Populations of | Group B Streptococcus. Unpublished manuscript. 4. Bohnsack, J. F., Whiting, A. A., Martinez, G., Jones, N., Adderson, E. E., Detrick, S. et al. (submitted for publication, 2003). The Genetic Relationship between Serotype III Streptococcus agalactiae Isolated from Bovine Milk and Phylogenetic Lineages that Cause Neontal Infections. 5. Schrag, S. J., Zywicki, S., Farley, M., Reingold, A.L., Harrison, L.H., & Lefkowitz, L.B. et al. (2000). Group B Streptococcal Disease in the Era of Intrapartum Antibi--otic Prophylaxis. The New England Jour-nal of Medicine, 342,15-20. 6. Taylor, J.K., Hall, R.W., & Dupre, A.R. (2002). The incidence of group B strep-tococcus in the vaginal tracts of pregnant I women in central Alabama. Journal of I the American Society for Clinical Labora-tory Science, 15(1), 16-17. Pendley Chemistry Faculty Sponsor John Bohnsack MD |
