TIMOTHY CANAVAN, MARIJANE KROHN, SHARON HILLIER, PATRICIA FERRIERI, Magee Womens Hospital, Pittsburgh, Pennsylvania, University of Pittsburgh School of Medicine, Obstetrics, Gynecology, and Reproductive Sciences, Pittsburgh, Pennsylvania, University of Pittsburgh, Obstetrics, Gynecology and Reproductive Sciences, Pittsburgh, Pennsylvania, University of Minnesota, Lab Medicine & Pathology, Minneapolis, Minnesota OBJECTIVE: The most common invasive GBS serotype isolated from neonates is Ia (37%) followed by III (26%) and V (14%) and the most common serotype associated with late onset GBS is serotype III (62%). If risks for maternal colonization with these high-risk subtypes could be determined, women could be stratified for future vaccination and newborns of these women could be recommended to have closer surveillance for GBS infection. STUDY DESIGN: 1248 non-pregnant women, ages 18 to 30 years, were enrolled from 1998 to 2000. Vaginal swabs for GBS culture and demographic data were obtained. GBS was isolated by inoculating the swabs into broth and agar. Serotyping was done using the Ouchterlony double diffusion technique. Serotypes were compared against the number of sexual partners in the last year using logistic regression and reported as odds ratios (OR). RESULTS: The risk for colonization with subtypes Ia (OR 2.2 95% CI: 1.4, 3.5) and III (OR 4.3, 95% CI: 2.0, 9.1) increased significantly with 3 or more sexual partners in the last year. Serotype V did not (OR 0.7 95% CI: 0.4, 1.2) show an elevated risk. Subtypes Ib and II were not statistically associated with the number of sexual partners in the past year. CONCLUSION: These findings suggest that the serotypes, which are the most frequent neonatal pathogens, are sexually associated and the other serotypes are not. This information can be used to target women for polyclonal GBS vaccination when an effective vaccine becomes available. Pediatricians can use this information to watch for early and late onset GBS infection in high risk neonates. 191 MATERNAL CHARACTERISTICS ASSOCIATED WITH A VIRAL LOAD LESS THAN 1000 COPIES/ML AT DELIVERY IN HIV SEROPOSITIVE PREGNANT WOMEN JUDETTE LOUIS, SEAN BLACKWELL, DIANNE ALLEN, BERNARD GONIK, JERRIE REFUERZO, THEODORE JONES, Wayne State University, Obstetrics and Gynecology, Detroit, Michigan OBJECTIVE: The purpose of this study is to determine which maternal characteristics are associated with an increased likelihood of achieving a viral load (VL) less than 1000 copies/ml at the time of delivery in HIV seropositive pregnant women. RESULTS: During this time period, 93 women met study criteria. Women with a VL !1000 at the time of delivery had significantly higher rates of medication compliance, prenatal care and first trimester VL !1000. These women also had significantly lower rates of cocaine and alcohol use. CONCLUSION: Maternal clinical characteristics that are associated with improved antepartum care, especially medication compliance, prenatal care, low first trimester VL, and no substance abuse, may result in lower VL at the time of delivery. Such characteristics may have value in the identification of those pregnant women who may be at increased risk for maternal-to-neonatal transmission.