This repository contains scripts used to analyze data generated for the manuscript described below, inlcuding comparative analysis and visualization of nanoparticle tracking (quantification) and proteomics (composition) data of Group B Streptococcus membrane vesicles across various antibiotic treatment conditions.
Macy E. Pell, Cole R. McCutcheon, Jennifer A. Gaddy, David M. Aronoff, Margaret G. Petroff, Shannon D. Manning
Raw proteomic data has been uploaded to the MassIVE database under dataset MSV000094926 and can be accessed via doi:10.25345/C5RV0DB88. All other dataset and sample information can be found within supplementary data files associated with the manuscript.
Group B Streptococcus (GBS) is an important bacterial pathogen during pregnancy, colonizing up to 35% of pregnant people recto-vaginally. Intrauterine GBS infection during pregnancy can cause preterm labor, early membrane rupture, and, if the fetus gets infected, stillbirth or early-onset neonatal disease (EOD). Intrapartum antibiotics are recommended to treat GBS-colonized pregnant patients during labor to prevent these outcomes, particularly EOD. However, persistent GBS colonization has been observed despite antibiotic treatment. One strategy employed by bacteria to promote antibiotic tolerance is the production of membrane vesicles (MVs). To understand how GBS MVs are affected by antibiotics and influence bacterial survival, we exposed a clinical GBS strain recovered from a pregnant patient with persistent colonization to antibiotics and examined the impact on MV production and composition. Using nanoparticle tracking analysis, microscopy, and proteomics, antibiotic treatment of GBS was found to significantly increase the production of MVs relative to untreated GBS (control) regardless of the antibiotic class (ampicillin; p=4.2x10-6, erythromycin; p=0.01). Moreover, antibiotic exposure yielded MVs with different protein composition compared to the untreated control, with 21 and 19 proteins unique to the ampicillin- and erythromycin-treated GBS, respectively. Increased abundance of antibiotic-specific protein targets was observed in the respective antibiotic-treated MVs, suggesting a mechanism for evading antibiotic-mediated killing. Together, these data suggest that antibiotic treatment alters both the production and composition of MVs, which can promote GBS survival in such conditions.
GBS vaginal colonization during pregnancy is the main risk factor for invasive disease in neonates. Although antibiotics are prophylactically administered to GBS-positive pregnant patients during labor, some people remain colonized with GBS after treatment. Persistent GBS colonization is an important public health concern, threatening the effectiveness of current treatment options and increasing the risk of severe GBS disease, especially for subsequent pregnancies. Mechanisms linked to persistent colonization and antibiotic tolerance are poorly understood in GBS; however, in other bacterial species, the production of membrane vesicles (MVs) has been shown to promote bacterial survival. Here, we demonstrated that two different antibiotics trigger changes in the production and composition of MVs in a persistent GBS strain, providing insight into the mechanisms used by GBS to rebound following antibiotic prophylaxis. Knowledge gained from this work can guide efforts in the development of more targeted and effective treatments for GBS disease.