opTImisation of Methods for a human INfection model for Group B streptococcus (TIMING)

This study investigated longitudinal variation in GBS rectovaginal colonization, serum and vaginal GBS capsular polysaccharide (CPS)-specific antibody levels. Women will be recruited for screening for GBS in the UK and Uganda (250 at each site). At screening women will be consented for a vaginal and rectal swab to assess for GBS carriage and will also undergo an asymptomatic STI screen according to local usual practice. In both the UK and Uganda this screening will look for Chlamydia, Gonorrhoea, Trichomonas vaginalis, Bacterial Vaginosis, Candida and for Syphilis, HIV and Hepatitis B and C. Anyone who meets the full inclusion criteria following screening will be invited to take part in the sampling study until the recruitment targets are reached for each cohort: 50 GBS colonised and 50 GBS uncolonised women in each country. The recruited women were sampled every 2 weeks over a 12-week period. GBS isolates were taken from recto-vaginal swabs and serotyped by polymerase chain reaction. Serum and vaginal immunoglobulin G (IgG) and nasal immunoglobulin A (IgA) specific to CPS were measured by Luminex, and total IgG/A by ELISA.

本研究针对B群链球菌（Group B Streptococcus, GBS）的直肠阴道定植状态、血清及阴道样本中GBS荚膜多糖（capsular polysaccharide, CPS）特异性抗体水平的纵向变化展开了探究。本研究将在英国与乌干达两地开展GBS筛查招募工作，每地计划招募250名女性受试者。筛查阶段，受试者将签署知情同意书，接受阴道拭子与直肠拭子采样以评估GBS定植情况，并按照当地常规流程开展无症状性传播感染（Sexually Transmitted Infection, STI）筛查。两地的筛查项目均覆盖沙眼衣原体、淋病奈瑟菌、阴道毛滴虫、细菌性阴道病、假丝酵母菌，以及梅毒、人类免疫缺陷病毒（HIV）、乙型及丙型肝炎的检测。经筛查符合全部纳入标准的受试者将受邀参与后续采样研究，直至各队列达成招募目标：每个国家分别招募50名GBS定植阳性女性与50名GBS定植阴性女性。入组女性在为期12周的研究周期内，每2周接受一次采样。研究人员从直肠阴道拭子样本中分离得到GBS菌株，并通过聚合酶链式反应（Polymerase Chain Reaction, PCR）完成血清分型。采用Luminex平台检测血清及阴道样本中针对CPS的免疫球蛋白G（IgG）与鼻腔样本中针对CPS的免疫球蛋白A（IgA）水平，并通过酶联免疫吸附试验（Enzyme-Linked Immunosorbent Assay, ELISA）检测总IgG与总IgA水平。