The effect of intrapartum clindamycin on vaginal group B streptococcus colony counts

Intrapartum prophylactic efficacy of ampicillin versus clindamycin in preventing vertical transmission of group B Streptococcus

AIM

To compare the prophylactic efficacy of ampicillin and clindamycin against vertical transmission of group B Streptococcus from mothers to their infants by evaluating the rates of group B Streptococcus colonisation.

METHODS

We retrospectively extracted data for mothers who delivered at Showa University Northern Yokohama Hospital between 1 October 2017 and 31 March 2021 and tested positive for antepartum group B Streptococcus, and their infants. The chi-square test was used to compare the rates of group B Streptococcus colonisation, sepsis, and meningitis. We conducted a multivariate logistic regression analysis, including the time interval between membrane rupture and delivery, chorioamnionitis, and maternal intrapartum fever (≥38.0°C).

RESULTS

Two hundred fifty-nine mothers and their infants were eligible. Ampicillin and clindamycin were administered to 150 and 109 mothers, respectively. In the ampicillin and clindamycin groups, 12.0% (18/150) and 37.6% (41/109) infants were group B Streptococcus positive, respectively. The rate of group B Streptococcus colonisation among infants was significantly lower in the ampicillin group (p < 0.001). Multivariate regression analysis showed similar results (p < 0.001). No sepsis or meningitis cases were observed in either group.

CONCLUSION

Prophylactic efficacy of clindamycin against the vertical transmission of group B Streptococcus is lower than that of ampicillin.

Sorting Out the Risks and Benefits of the #797 Recommended Intrapartum Vancomycin Dosing Approach

ACOG Committee Opinion #797 proposed intrapartum vancomycin dosing guidelines in the absence of thorough evaluation of its risk versus benefit profile on the maternal and neonatal systems. The previously published serum and cord-blood concentration-time data of vancomycin given to mothers in the intrapartum period was analyzed in this work with a two-compartment pharmacokinetic (PK) model. Monte Carlo simulation was used to establish exposure for the studied population for doses of 1000 mg to 2000 mg every 8 h for gestational ages (GA) of 33 to 40 weeks and for birth times up to 4-h intervals. Probabilities of target attainment (PTA) were calculated for efficacy and toxicity indices unique to the peripartum maternal and neonatal population. Neonatal evaluations indicate uniformly high PTAs for the evaluated dosing regimens when the efficacy target is considered. On the other hand, the PTAs for potentially nephrotoxic exposure is expected to reach undesirable levels when three or more doses were to be administered. The risk is profoundly high in GA below 36 weeks and birth times beyond 20 h after the initiation of intrapartum prophylaxis and with doses greater than 1250 mg. Maternal vancomycin exposures seem reasonable up to two intrapartum doses given at 8 h intervals when the dose is kept to 1250 mg or less. Most mothers (up to 83%) who receive three or more doses of the commonly administered regimens are subjected to nephrotoxic exposures. Thus, it appears that the current recommendations by #797 for dosing of vancomycin pose considerable risk to mother and newborn alike, especially in cases with lengthy duration of preterm labor. Capping of doses at 1250 mg may be considered to minimize the need for therapeutic drug monitoring (TDM) interventions. Alternatively, and irrespective of the baseline maternal renal function, TDM for all cases requiring more than two doses of 1500 mg or higher must be assured.

Pregnancy-related pharmacokinetics and antimicrobial prophylaxis during fetal surgery, cefazolin and clindamycin as examples

Antimicrobial prophylaxis during surgery aims to prevent post-operative site infections. For fetal surgery, this includes the fetal and amniotic compartments. Both are deep compartments as drug equilibrium with maternal blood is achieved relatively late. Despite prophylaxis, chorio-amnionitis or endometritis following ex utero intrapartum treatment or fetoscopy occur in 4.13% and 1.45% respectively of the interventions. This review summarizes the observations on two commonly administered antimicrobials (cefazolin, clindamycin) for surgical prophylaxis during pregnancy, with emphasis on the deep compartments. For both compounds, antimicrobial exposure is on target when we consider the maternal and fetal plasma compartment. In contrast, amniotic fluid concentrations-time profiles display a delayed and much more blunted pattern, behaving as deep compartment. For cefazolin, there are data that document further dilution in the setting of polyhydramnios. Along this deep compartment concept, there is some accumulation during repeated administration, modeled for cefazolin and observed for clindamycin. The relative underexposure to antimicrobials in amniotic fluid may be reflected in the pattern of maternal-fetal complications after fetal surgery, and suggest that antimicrobial prophylaxis practices for fetal surgery should be reconsidered. Further studies should be designed by a multidisciplinary team (fetal surgeons, clinical pharmacologists and microbiologists) to facilitate efficient evaluation of antimicrobial prophylaxis.

Management of Infants at Risk for Group B Streptococcal Disease

Group B streptococcal (GBS) infection remains the most common cause of neonatal early-onset sepsis and a significant cause of late-onset sepsis among young infants. Administration of intrapartum antibiotic prophylaxis is the only currently available effective strategy for the prevention of perinatal GBS early-onset disease, and there is no effective approach for the prevention of late-onset disease. The American Academy of Pediatrics joins with the American College of Obstetricians and Gynecologists to reaffirm the use of universal antenatal microbiologic-based testing for the detection of maternal GBS colonization to facilitate appropriate administration of intrapartum antibiotic prophylaxis. The purpose of this clinical report is to provide neonatal clinicians with updated information regarding the epidemiology of GBS disease as well current recommendations for the evaluation of newborn infants at risk for GBS disease and for treatment of those with confirmed GBS infection. This clinical report is endorsed by the American College of Obstetricians and Gynecologists (ACOG), July 2019, and should be construed as ACOG clinical guidance.

Drugs for the Prevention and Treatment of Sepsis in the Newborn

Antimicrobial medications are the most commonly used medications in the neonatal intensive care unit. Antibiotics are used for infection prophylaxis, empiric treatment, and definitive treatment of confirmed infection. The choice of medication should be informed by the epidemiology and microbiology of infection in specific clinical scenarios and by the clinical condition of the infant. Understanding evolving pathogen susceptibility to antimicrobials and key pharmacotherapy determinants in neonates can inform optimal antibiotic use.