Perinatal group A streptococcal infection in vagina and its impact on pregnancy outcomes

To investigate the prevalence, antimicrobial susceptibility, and the effects on pregnancy and neonatal outcomes of Group A Streptococcal (GAS) infections in the vagina of perinatal women.

From June 2020 to October 2022, 270 perinatal pregnant women underwent vaginal swabs for GAS culture. The antibiotic sensitivity of the positive strains was assessed. Based on GAS detection results, the patients were divided into an observation group (GAS positive) and a control group (GAS negative). Clinical data from both groups were collected to compare the vaginal microecological changes. The adverse outcomes for pregnancy and infants in both groups were retrospectively analyzed. Univariate and multivariate analyses were used to identify the risk factors for adverse outcomes.

Among the 270 pregnant women, 30 tested positive for GAS and 240 tested negative, with a colonization rate of 11.1%. No resistance to penicillin, ampicillin, linezolid, vancomycin, or tigecycline was found among the GAS strains. The resistance rates to tetracycline and clindamycin were 73.3% and 70.0%, respectively. Higher vaginal pH (≥4.5), and increased incidences of bacterial vaginitis, aerobic vaginitis, and microecological imbalances were observed in the observation group compared to the control group (all P<0.05). The observation group also experienced more adverse pregnancy and infant outcomes, such as chorioamnionitis, postpartum infections, fetal distress, and neonatal pneumonia (all P<0.05). Univariate and multivariate analyses indicated that a vaginal pH≥4.5 and microecological imbalance were positively associated with poor maternal and infant outcomes in women with GAS infections (all P<0.05).

The study found no β-lactam resistant GAS strains. Additionally, a higher vaginal pH (≥4.5) and microecological imbalance were linked to an increased risk of adverse pregnancy and infant outcomes in women with GAS infections.