Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
Microb Drug Resist. 2022 May;28(5):517-524. doi: 10.1089/mdr.2021.0238. Epub 2022 Mar 9.
(Group B , GBS) is a major agent of perinatal infections. Biofilms have been associated with GBS colonization and disease, as well as with infection persistence and recurrence. Although GBS remains susceptible to beta-lactams, it is still unknown how sessile cells respond to these antibiotics. Here, we evaluated the effect of different concentrations of penicillin (3-48 mg/L) on biofilm formation by four GBS strains belonging to serotype Ia/clonal complexes23 that were recovered from the oropharynx or urine of pregnant women and were previously characterized as strong biofilm producers. All four GBS strains were fully susceptible to penicillin (minimum inhibitory concentration = 0.023 mg/L), but penicillin was not able to fully prevent biofilm formation by these GBS strains. Biofilms formed in the presence of penicillin had reduced biomasses and thickness, but they were still classified as strong. Penicillin significantly reduced the density of live cells, but higher penicillin concentrations did not lead to improved prevention of biofilm formation. Biofilms formed in the presence of penicillin had no channels or long cocci chains observed in penicillin-free biofilms. Overall, results highlight the concerning possible impacts of biofilm formation in penicillin-based treatment and preventive strategies of GBS infections, even when the bacterial strain involved is fully antibiotic-susceptible.
（B 组链球菌，GBS）是围产期感染的主要病原体。生物膜与 GBS 定植和疾病以及感染持续和复发有关。尽管 GBS 仍然对β-内酰胺类药物敏感，但仍不清楚静止细胞如何对这些抗生素产生反应。在这里，我们评估了不同浓度青霉素（3-48mg/L）对 4 株来自孕妇口腔或尿液的属于血清型 Ia/克隆复合物 23 的 GBS 菌株生物膜形成的影响，这些菌株先前被表征为强生物膜生产者。所有 4 株 GBS 菌株对青霉素均完全敏感（最小抑菌浓度=0.023mg/L），但青霉素不能完全阻止这些 GBS 菌株的生物膜形成。在青霉素存在下形成的生物膜生物量和厚度减少，但仍被归类为强。青霉素显著降低了活细胞的密度，但较高的青霉素浓度并不能改善生物膜形成的预防。在无青霉素的生物膜中观察到的生物膜中没有通道或长球菌链。总的来说，结果强调了在基于青霉素的 GBS 感染治疗和预防策略中生物膜形成的令人担忧的可能影响，即使涉及的细菌菌株完全对抗生素敏感。
