1335 Group B streptococcal infections are the leading cause of early neonatal sepsis in most developed countries. The incidence of early-onset neonatal disease is 1 to 3 cases per 1000 live births, with a 5% to 20% mortality rate. 1-6 Perinatal group B streptococcal infection contributes to stillbirths and preterm deliveries. In addition, approxi- mately half of late-onset neonatal group B streptococcal infections are caused by intrapartum transmission. Ma- ternal group B streptococcal colonization rates range from 10% to 30%, and carriage may be persistent, inter- mittent, or transient. 1, 2 Intrapartum intravenous antibi- otic administration has been shown to prevent most early- onset group B streptococcal neonatal sepsis. 1-3, 7-12 Isolation of group B streptococci is enhanced by 50% through the use of selective broth medium. 1 Selective medium cultures have become the criterion standard for detection of maternal colonization, but their clinical use is somewhat limited by the 24 to 48 hours required for a final result. During the past 2 decades efforts have been made to create a sensitive and rapid test for detection of maternal group B streptococcal carriage. Rapid antigen detection test methods include coagglutination, latex particle agglutination, and enzyme immunoassay. The specificities range from 95% to 100% for most of these commercially available tests, but overall sensitivity varies widely, from 30% to 80%. 13, 14 With a relatively high maternal carriage rate and a po- tentially avoidable neonatal disease rate of 0.1% to 4.0%, we have been challenged to find timely and cost-effective screening and selective treatment strategies. During the early 1990s various investigators suggested universal an- From the Center for Perinatal Studies, Swedish Medical Center, a and the Dynacare Laboratory of Pathology. b Presented at the Sixty-sixth Annual Meeting of the Pacific Coast Obstet- rical and Gynecological Society, Cancun, Mexico, October 20-24, 1999. Reprint requests: Dale P. Reisner, MD, Division of Perinatal Medicine, 1229 Madison, No. 750, Seattle, WA 98104. Copyright © 2000 by Mosby, Inc. 0002-9378/2000 $12.00 + 0 6/ 6/ 106246 doi:10.1067/mob.2000.106246 Performance of a group B streptococcal prophylaxis protocol combining high-risk treatment and low-risk screening Dale P. Reisner, MD, a Michael J. Haas, MS, b Rosalee W. Zingheim, MN, a Michelle A. Williams, ScD, a and David A. Luthy, MD a Seattle, Washington OBJECTIVE: This study was undertaken to evaluate a group B streptococcal protocol in a large community hospital that combined treatment of high-risk patients with rapid screening of low-risk patients. STUDY DESIGN: In a prospective cohort study from 1994 through 1996 laboring patients in a level III com- munity hospital were considered to be at high risk for neonatal group B streptococcal transmission if they were at <37 weeks’ gestation, if they had rupture of membranes >12 hours, if they were known carriers of group B streptococci, if they had a temperature ≥100°F, if the gestation was complicated by fetal growth re- striction or was a multiple gestation, or if they had a previous neonate infected with group B streptococci. High-risk patients were treated intravenously with antibiotics during labor. Low-risk patients were screened for group B streptococcal antigen by means of a rapid optical immunoassay.Patients with positive screening results were treated. Neonatal morbidity and mortality were evaluated. RESULTS: Two of 9932 infants delivered had group B streptococcal sepsis diagnosed.In the 2 previous years without a protocol 9 cases of neonatal group B streptococcal sepsis had been diagnosed in 8188 deliv- eries (P = .0287 by Fisher exact test). The 2 cases of group B streptococcal sepsis during the protocol were as follows: 1 infant born to a high-risk mother with delay in treatment and 1 infant born to a low-risk mother with negative results of both culture and rapid screen during labor. During the previous period 7 infected in- fants had been born to high-risk mothers and 2 had been born to low-risk mothers. The maternal group B streptococcal carriage rate during the study was 18%. Group B streptococcal rapid optical immunoassay sensitivity was 81%. Elapsed time from screening to treatment was ≤2 1 ∕ 2 hours for 93% of patients. No mater- nal anaphylaxis, no increase in bacterial neonatal sepsis caused by organisms other than group B strepto- cocci, and no protocol-related group B streptococcal antibiotic resistance were noted. CONCLUSION: Successful implementation and maintenance of a protocol combining treatment of high-risk patients with rapid screening of low-risk patients during labor reduced neonatal group B streptococcal sepsis. (Am J Obstet Gynecol 2000;182:1335-43.) Key words: Group B streptococci, intrapartum screening, neonatal sepsis