Arroyo-Moreno Sara, Cummings Matthew, Corcoran David B, Coffey Aidan, McCarthy Ronan R
Division of Biosciences, Department of Life Sciences, College of Health and Life Sciences, Brunel University London, Uxbridge, UB8 3PH, UK.
Department of Biological Sciences, Munster Technological University, Cork, Ireland.
NPJ Biofilms Microbiomes. 2022 Apr 19;8(1):29. doi: 10.1038/s41522-022-00285-0.
Bacterial vaginosis (BV) is a recurrent dysbiosis that is frequently associated with preterm birth, increased risk for acquisition of human immunodeficiency virus (HIV) and other sexually transmitted infections (STIs). The overgrowth of a key pathobiont, Gardnerella vaginalis, as a recalcitrant biofilm is central to the development of this dysbiosis. Overgrowth of vaginal biofilms, seeded by initial G. vaginalis colonization, leads to recurrent symptomatic BV which is poorly resolved by classically used antibiotics. In this light, the use of bacteriophages and/or their proteins, represents a promising alternative. Here we identify 84 diverse anti-Gardnerella endolysins across 7 protein families. A subset of 36 endolysin candidates were refactored and overexpressed in an E. coli BL21 (DE3) system and 5 biochemically and structurally diverse endolysins were fully characterized. Each candidate endolysin showed good lytic activity against planktonic G. vaginalis ATCC14018, as well as G. vaginalis clinical isolates. These endolysin candidates were assayed in biofilm prevention and disruption assays, with biofilm disruption at low microgram concentrations (5 μg/ml) observed. In addition to clonal G. vaginalis biofilms, endolysin candidates could also successfully disrupt polyspecies biofilms. Importantly, none of our candidates showed lytic activity against commensal lactobacilli present in the vaginal microbiota such as L. crispatus, L. jensenii, L. gasseri, and L. iners or against Atopobium vaginae (currently classified as Fannyhessa vaginae). The potency and selectivity of these novel endolysins constitute a promising alternative treatment to combat BV, avoiding problems associated with antibiotic resistance, while retaining beneficial commensal bacteria in the vaginal flora. The diverse library of candidates reported here represents a strong repository of endolysins for further preclinical development.
细菌性阴道病（BV）是一种复发性生态失调，常与早产、感染人类免疫缺陷病毒（HIV）及其他性传播感染（STIs）的风险增加相关。关键致病共生菌阴道加德纳菌过度生长形成顽固的生物膜，是这种生态失调发展的核心。由最初的阴道加德纳菌定植引发的阴道生物膜过度生长，会导致复发性症状性BV，而传统使用的抗生素对此治疗效果不佳。鉴于此，使用噬菌体和/或其蛋白质是一种有前景的替代方法。在此，我们在7个蛋白质家族中鉴定出84种不同的抗加德纳菌溶菌酶。36种溶菌酶候选物的一个子集经过改造，并在大肠杆菌BL21（DE3）系统中过表达，对5种生化和结构不同的溶菌酶进行了全面表征。每种候选溶菌酶对浮游的阴道加德纳菌ATCC14018以及阴道加德纳菌临床分离株均表现出良好的裂解活性。这些溶菌酶候选物在生物膜预防和破坏试验中进行了检测，观察到在低微克浓度（5μg/ml）下生物膜被破坏。除了克隆的阴道加德纳菌生物膜外，溶菌酶候选物还能成功破坏多种生物膜。重要的是，我们的候选物均未对阴道微生物群中存在的共生乳酸杆菌如卷曲乳酸杆菌、詹氏乳酸杆菌、加氏乳酸杆菌和惰性乳酸杆菌或阴道阿托波菌（目前分类为阴道范尼希菌）表现出裂解活性。这些新型溶菌酶的效力和选择性构成了对抗BV的一种有前景的替代治疗方法，可避免与抗生素耐药性相关的问题，同时保留阴道菌群中的有益共生细菌。此处报道的多样候选物文库是用于进一步临床前开发溶菌酶的强大资源库。
