Neonatal Early-onset Group B Streptococcal Disease in the Era of Intrapartum Chemoprophylaxis: Residual Problems

Abstract

OBJECTIVE:To identify limitations of current strategies for intrapartum prophylaxis of neonatal early-onset group B streptococcal infection. METHODS:Retrospective review of infants with culture-proven early-onset group B streptococcal infection admitted to two nurseries and their mothers from July 1992, when ACOG and AAP guidelines for intrapartum prophylaxis were first issued, through December 2001. Information was recorded regarding clinical risk factors for early-onset group B streptococcal infection, collection and processing of specimens to assess maternal colonization, delivery of prophylaxis, duration of hospitalization before delivery, and outcome. RESULTS:Among 92 infants with early-onset group B streptococcal infection admitted from 23 institutions, 68 had received no intrapartum prophylaxis. Of these 68 who received no prophylaxis, 34 had identifiable risk factors before delivery (32 clinical, two positive maternal culture), while 34 had no risk factors. Prenatal culture for group B streptococcal colonization was performed in 22 of these women. Of the 18 cultures that were negative for group B streptococcus, 15 were obtained using suboptimal culture technique or were collected more than 6 weeks before delivery. Of the 68 with no prophylaxis, 14 required extracorporeal membrane oxygenation and three died. Of the 24 who received some intrapartum prophylaxis, nine had received Ztwo doses for Z4 hours immediately before delivery. Among the 24 receiving some intrapartum prophylaxis, two required extracorporeal membrane oxygenation and one died. No deaths occurred in those who received >4 hours of prophylaxis, although one such infant required extracorporeal membrane oxygenation. After the CDC guidelines were issued in May 1996, there was a decrease both in the number of cases of early-onset group B streptococcal infection (56 versus 36) as well as in the number with clinical risk factors but no intrapartum prophylaxis (24/56 (43%) versus 5/28 (18%)). CONCLUSIONS:The use of clinical risk factors alone will inevitably result in missed opportunity for intrapartum antibiotic prophylaxis. With maternal screening, false-negative results will be reduced but not necessarily eliminated by assuring that specimens are obtained from proper sites using selective media within 6 weeks of delivery. Better strategies are needed to assure timely administration when prophylaxis is indicated. The nine neonates with early-onset group B streptococcal infection despite intrapartum antibiotics for the recommended duration illustrate that disease may occur even when guidelines are implemented appropriately.

Sensitivities of Antigen Detection and PCR Assays Greatly Increased Compared to That of the Standard Culture Method for Screening for Group B Streptococcus Carriage in Pregnant Women

“…Inadequate specimen collection and transport from obstetrical clinics to the laboratory could also result in falsenegative results, especially in the presence of light colonization (19,25). The culture method is suspected to lack sensitivity, given that studies of confirmed early neonatal GBS infection have demonstrated disease in neonates born to mothers negative for GBS by culture (15,18), and our results confirm this hypothesis.…”

Estreptococo do grupo B: rastrear ou não rastrear no Brasil? Eis a questão

“…A impossibilidade de encontrar claros fatores de risco levou os autores a concluir que não é possível selecionar, pelos antecedentes, as gestantes que devem receber profilaxia no momento do parto e a recomendar a utilização das culturas pré-natais de triagem. Também Pinto et al 11 não foram capazes de identificar fatores de risco em 46% dos casos de sepse neonatal por EGB.…”

Prevention of Early-onset GBS Sepsis: Evaluation of a Changing Paradigm

“…3 as well as Pinto et al 4 evaluated the effectiveness of and residual problems associated with the culture-based and risk-based GBS prevention strategies.…”

“…In Riley's estimation, 50% of those women could have received antibiotics at least 4 hours before delivery. These authors recommended that patient education about GBS screening-culture results and strict attention to maternal GBS culture status upon presentation in labor would improve compliance with antibiotic administration within 4 hours of delivery.Pinto et al 4 reviewed 94 cases of early-onset GBS admitted to two regional level III NICUs from 07/92 through 12/01. Of these infants, 50 (53%) were born to women whose GBS colonization status was (i) unknown and who had no identified risk factors or (ii) whose GBS screening culture was reported as negative.…”