Negative vaginal and rectal GBS screening culture in late gestation during the current pregnancy, regardless of intrapartum risk factors
Intrapartum temperature � 1 OOAoF (�38.0°C)
FIGURE 64-6 Indications for intrapartum prophylaxis to prevent perinatal group B streptococcal (GBS) disease under a universal prenatal screening strategy based on combined vaginal and rectal cultures obtained at 35 to 37 weeks' gestation. (From Centers for Disease Control and Prevention, 201o0.) bacteriuria in the current pregnancy are also considered indications for prophylaxis.
Risk-Based Prevention. This approach is recommended for women in labor and whose GBS culture results are not known. It relies on risk factors associated with intrapartum GBS transmission. Intrapartum chemoprophylaxis is given to women who have any of the following: delivery <37 weeks, ruptured membranes � 18 hours, or intrapartum temperature � 100.4°F (�38.0°C). Women with GBS during the current pregnancy and women with a prior infant with invasive early-onset GBS disease are also given chemoprophylaxis.
At Parkland Hospital in 1995-and prior to consensus guidelines-we adopted and continue to use the risk-based approach for intrapartum treatment of women at high risk. Importantly, in addition, all term neonates who were not given intrapartum prophylaxis were treated in the delivery room with aqueous penicillin G, 50,000 to 60,000 units intramuscularly. Rates of early-onset GBS sepsis decreased to 0.4 to 0.66 per 1000 live births (Staford, 2012; Wendel, 2002). Non-GBS early-onset sepsis decreased from 0.66 to 0.24 per 1000 live births (Staford, 2012). Thus, this approach has results similar to those reported by the CDC (2010) for culture-based prevention.
Serotype-specific capsular antibody concentrations clinically correlate with GBS neonatal disease. Antibody-producing vaccines have been tested, but none are clinically available (Donders, 2016; Kobayashi, 2016; Madhi, 2016).
Preventive antimicrobials administered 4 or more hours before delivery are highly efective (Fairlie, 2013). Regardless of screening method, penicillin remains the first-line agent
TABLE 64-3. Regimens for Intrapartum Antimicrobial Prophylaxis for Perinatal GBS Disease
Recommended Penicillin G, 5 million units IV initial dose, then 2.5 to 3.0 million units IV every 4 hours until delivery
Alternative Ampicillin, 2 g IV initial dose, then 1 9 IV every 4 hours or 2 g every
Patients not at high risk for anaphylaxis Cefazolin, 2 9 IV initial dose, then 1 9 IV every 8 hours until delivery
Patients at high risk for anaphylaxis and with GBS Clindamycin, 900 mg IV every 8 hours until delivery susceptible to clindamycin
Patients at high risk for anaphylaxis and with GBS Vancomycin, 1 9 IV every 12 hours until delivery resistant to clindamycin or susceptibility unknown