Perfil de resistência antimicrobiana do Streptococcus agalactiae em parturientes atendidas em hospital público de Goiânia: implicações para a profilaxia intraparto

Abstract

This study aimed to assess the prevalence of Streptococcus agalactiae colonization among parturients admitted to a public referral hospital in Goiânia, Brazil, and to characterize the antimicrobial resistance profile of the isolates, emphasizing implications for intrapartum prophylaxis. A cross-sectional study was conducted with 206 pregnant women between 35 and 37 weeks of gestation at the Dona Íris Maternity Hospital. Identification of S. agalactiae was performed using Todd-Hewitt selective broth culture, confirmed by chromogenic agar and real-time PCR (qPCR). Antimicrobial susceptibility was determined according to the 2024 BrCAST/EUCAST guidelines using the disk diffusion method on Mueller-Hinton agar supplemented with 5% horse blood and β-NAD. The prevalence of maternal colonization was 25.7% by qPCR and 20.4% by culture, with the vaginal site being the most affected (41.8%) and combined vaginal–anal colonization accounting for 25.4%. High susceptibility was observed to β-lactam antibiotics—penicillin (85.5%), ampicillin (92.8%), and ceftriaxone (96.4%)—while significant resistance was detected to clindamycin (83.6%), erythromycin (54.6%), and tetracycline (70.9%). No sociodemographic or obstetric variables were significantly associated with colonization. In conclusion, β-lactams remain the first-choice agents for intrapartum prophylaxis, whereas high resistance rates to macrolides and lincosamides reinforce the need for individualized antimicrobial susceptibility testing in penicillin-allergic women. The progressive incorporation of rapid molecular methods such as qPCR, in association with conventional culture, can enhance screening accuracy and support evidence-based strategies for preventing S. agalactiae infections in obstetric care.