Impact of Intrapartum Antibiotic Prophylaxis on Offspring Microbiota

Infants are born into a world filled with microbes and must adapt without undue immune response while exploiting the microbiota's ability to produce otherwise unavailable nutrients. The process by which humans and microbes establish this relationship has only recently begun to be studied with the aid of genomic methods. Nearly half of all pregnant women receive antibiotics during gestation to prevent maternal and neonatal infection. Though this has been largely successful in reducing early-onset sepsis, we have yet to understand the long-term consequences of antibiotic administration during gestation to developing infants. Studies involving antibiotic use in infants suggest that dysbiosis during this period is associated with increased obesity, allergy, autoimmunity, and chronic diseases in adulthood, however, research around the limited doses of intravenous antibiotics used for intrapartum prophylaxis is limited. In this mini review, we focused on the state of the science regarding the effects of intrapartum antibiotic prophylaxis on the newborn microbial colonization process. Although, the literature indicates that there is wide variety in the specific bacteria that colonize infants from birth, limited parenteral antibiotic administration prior to delivery consistently affects the microbiota of infants by decreasing bacteria in the phylum Bacteroidetes and increasing bacteria in the phylum Proteobacteria, thus altering the normal pattern of colonization that infants experience. Delivery by cesarean section and formula feeding magnify and prolong this effect. Our mini review shows that the impact of intravenous antibiotic administration during gestation has on early colonization, growth, or immune programming in the developing offspring has not been well studied in human or animal models.

Need for Intrapartum Antibiotic Prophylaxis in Women with Prior History of Group B Streptococcus Carriage

The incidence of early onset neonatal GBS(EOGBS) disease in the UK and Ireland is 0.57/1000 births. Intrapartum antibiotic prophylaxis (IAP) reduces the risk. Previous colonisation is associated with 50% carriage in the current pregnancy. In these women, RCOG recommends IAP with a history of neonatal infection, otherwise offering the option of screening at 35-37 weeks. In Ireland, there is no national consensus on IAP in prior GBS colonisation. Currently at University Hospital Waterford (UHW), all women with prior GBS colonisation receive IAP. Studies examining the use of point-of-care testing have shown reduction in the use of IAP and EOGBS rates. We aimed to examine the screening and IAP administration in maternal prior GBS colonisation and the incidence of GBS in this cohort in UHW. Data was collected retrospectively from laboratory, medical records and electronic patient manager systems. Women who received IAP between 1stJuly 2020 and 31stDecember 2020 were identified. Women who received IAP for current and prior GBS colonisation were included. Women who received IAP for preterm labour, preterm prelabour rupture of membranes and pyrexia in labour were excluded. Ninety-two women with current or prior GBS colonisation received IAP, of which only 15(16.30%) were current and 77(83.69%) were prior GBS colonisation. In women with prior GBS colonisation, 49(63.63%) were screened, 3/49(6.12%) were positive, 28 were not screened. Seventy-eight (84.78%) received benzyl-penicillin. Six (6.52%) received clindamycin. Twenty-two (23.91%) babies were admitted to the Neonatal Unit, however, only one cultured positive for gram-positive cocci. The incidence of EOGBS in this cohort is low. A risk-based approach or point-of-care testing should be considered to reduce unnecessary IAP administration.

Prevention of neonatal infection caused by group B streptococci

Objective. To evaluate the prevalence of vaginal carriage of Streptococcus agalactiae among pregnant women at 35–37 weeks of gestation and assess the efficacy of intrapartum antibiotic prophylaxis (IAP) for group B streptococcus (GBS) infection in newborns. Patients and methods. We examined 800 pregnant women at 35–37 weeks of gestation (bacteriological examination of vaginal microbiota with biomaterial collected from the posterior vaginal fornix). Identified carriers of S. agalactiae who had vaginal delivery (n = 50) received antibiotic prophylaxis to prevent infection in newborns. We also evaluated the frequency of vertical transmission of streptococci in all infants during the first hour of life (bacteriological examination of pharyngeal swabs and meconium). Identification of microorganisms was performed by direct protein profiling using MALDI-TOF mass spectrometry (FLEX series, Bruker Daltonic GmbH, Germany). Results. Maternal vaginal colonization with S. agalactiae in the third trimester was observed in 13.5% of patients tested (n = 108). Fifty women had vaginal delivery and received antibiotic prophylaxis to prevent infection in newborns. Postpartum samples of only 1 newborn gave scanty growth of S. agalactiae at bacteriological examination (1 × 101 CFU/mL in meconium and 1 × 103 CFU/mL in the pharyngeal sample), while the remaining 49 newborns had sterile samples. Thus, the frequency of S. agalactiae vertical transmission with intrapartum antibiotic prophylaxis was 2% (n = 1). Of note, infection in the newborn caused no inflammation. Conclusion. Relatively low prevalence of vaginal carriage of S. agalactiae among pregnant women gives no sufficient grounds for the inclusion of such bacteriological examination into compulsory screening for infections in pregnant women in the Russian Federation. However, intrapartum antibiotic prophylaxis is an effective method to prevent streptococcal infection in newborns; it should be used in women at risk of GBS infections. Kew words: vaginal carriage of bacteria, intrapartum antibiotic prophylaxis, neonatal sepsis, Streptococcus agalactiae, intrauterine infection, screening for infections