Creti Roberta, Imperi Monica, Gherardi Giovanni, Alfarone Giovanna, Marani Ilaria, Vocale Caterina, Berardi Alberto, Truocchio Serena, Miselli Francesca
Antibiotic Resistance and Special Pathogens Unit, Department of Infectious Diseases, Istituto Superiore di Sanità, 00161 Rome, Italy.
Microbiology Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, 40138 Bologna, Italy.
Microorganisms. 2025 Jun 26;13(7):1496. doi: 10.3390/microorganisms13071496.
Maternal vaginal and rectal colonization by (group B streptococcus, GBS) is the main risk factor for the development of newborn early-onset GBS disease (GBS-EOD). Much effort is in place for its prevention, including the development of vaccines. Currently, both a hexavalent glycoconjugate GBS vaccine against the most prevalent serotypes and a protein subunit vaccine have completed phase two clinical trials. GBS surveillance in both maternal carriage and neonatal disease is therefore important in establishing the coverage of the potential vaccines and in setting up the basis for pre- and post-marketing surveillance. A single-site study was conducted in the years 2020-2021 on the characteristics of 325 GBS strains (serotype distribution; identification of the alpha-like protein family member; and resistance to macrolides, tetracycline, and high-level gentamicin) isolated from the vaginal/rectal site in women in late pregnancy as well as in seven cases of GBS-EOD and one case of GBS-related stillbirth occurring in the same location and time period. The study indicated that the coverage of the developing vaccines was excellent (97.2% for the hexavalent glycoconjugate vaccine and 98.7% for the alpha-like protein subunit vaccine). However, the detection of the serotypes VI, VII, and IX-not covered by current vaccine formulations-accounting for 3.0% of isolates, as well as of negative alpha-like GBS strains from maternal carriage (1.2%), should be closely monitored over time. The high rates of GBS resistance to erythromycin (33.5%) and to clindamycin (29.5% in maternal carriage and 57.1% in GBS-EOD) was mostly due to the ever-increasing spread of the multidrug-resistant ST-17 subclone of serotype III. This finding, along with the newly emerging high-level gentamicin resistance in carriers (4.0%), mainly in serotype IV strains, poses a threat for the continued effectiveness of antibiotic therapy in invasive disease.
孕妇阴道和直肠被B族链球菌（GBS）定植是新生儿早发型GBS疾病（GBS-EOD）发生的主要危险因素。人们为预防该疾病付出了诸多努力，包括研发疫苗。目前，一种针对最常见血清型的六价糖共轭GBS疫苗和一种蛋白质亚单位疫苗均已完成二期临床试验。因此，对孕妇GBS携带情况和新生儿疾病进行GBS监测，对于确定潜在疫苗的覆盖率以及建立上市前和上市后监测的基础至关重要。2020年至2021年开展了一项单中心研究，分析了从晚期妊娠女性阴道/直肠部位分离出的325株GBS菌株的特征（血清型分布；α样蛋白家族成员鉴定；对大环内酯类、四环素和高水平庆大霉素的耐药性），以及同期同地点发生的7例GBS-EOD病例和1例GBS相关死胎病例。该研究表明，正在研发的疫苗覆盖率很高（六价糖共轭疫苗为97.2%，α样蛋白亚单位疫苗为98.7%）。然而，目前疫苗配方未涵盖的血清型VI、VII和IX的检出率占分离株的3.0%，以及孕妇携带的α样GBS阴性菌株（1.2%），应长期密切监测。GBS对红霉素的高耐药率（33.5%）以及对克林霉素的高耐药率（孕妇携带中为29.5%，GBS-EOD中为57.1%）主要归因于血清型III多重耐药ST-17亚克隆的不断传播。这一发现，连同携带者中新出现的高水平庆大霉素耐药性（4.0%），主要见于血清型IV菌株，对侵袭性疾病抗生素治疗的持续有效性构成威胁。
