Department of Pharmaceutical Microbiology, Faculty of Pharmacy, University of Ibadan, Oyo State, Nigeria.
Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Ibadan, Ibadan, Oyo State, Nigeria.
PLoS Negl Trop Dis. 2022 Oct 6;16(10):e0010809. doi: 10.1371/journal.pntd.0010809. eCollection 2022 Oct.
Enteroaggregative Escherichia coli (EAEC) is a predominant but neglected enteric pathogen implicated in infantile diarrhoea and nutrient malabsorption. There are no non-antibiotic approaches to dealing with persistent infection by these exceptional colonizers, which form copious biofilms. We screened the Medicines for Malaria Venture Pathogen Box for chemical entities that inhibit EAEC biofilm formation.
We used EAEC strains, 042 and MND005E in a medium-throughput crystal violet-based antibiofilm screen. Hits were confirmed in concentration-dependence, growth kinetic and time course assays and activity spectra were determined against a panel of 25 other EAEC strains. Antibiofilm activity against isogenic EAEC mutants, molecular docking simulations and comparative genomic analysis were used to identify the mechanism of action of one hit.
In all, five compounds (1.25%) reproducibly inhibited biofilm accumulation by at least one strain by 30-85% while inhibiting growth by under 10%. Hits exhibited potent antibiofilm activity at concentrations at least 10-fold lower than those reported for nitazoxanide, the only known EAEC biofilm inhibitor. Reflective of known EAEC heterogeneity, only one hit was active against both screen isolates, but three hits showed broad antibiofilm activity against a larger panel of strains. Mechanism of action studies point to the EAEC anti-aggregation protein (Aap), dispersin, as the target of compound MMV687800.
This study identified five compounds, not previously described as anti-adhesins or Gram-negative antibacterials, with significant EAEC antibiofilm activity. Molecule, MMV687800 targets the EAEC Aap. In vitro small-molecule inhibition of EAEC colonization opens a way to new therapeutic approaches against EAEC infection.
肠聚集性大肠杆菌（EAEC）是一种主要但被忽视的肠道病原体，与婴儿腹泻和营养吸收不良有关。对于这些异常定植者持续感染，没有非抗生素的方法来处理，它们会形成大量生物膜。我们从疟疾药物 Venture 病原体盒中筛选出抑制 EAEC 生物膜形成的化学物质。
我们使用 EAEC 菌株 042 和 MND005E 在基于结晶紫的高通量抗生物膜筛选中。在浓度依赖性、生长动力学和时间过程测定中确认了命中物，并针对 25 株其他 EAEC 菌株确定了活性谱。抗生物膜活性针对同源 EAEC 突变体、分子对接模拟和比较基因组分析用于鉴定一种命中物的作用机制。
总共发现了五种化合物（1.25%）可重复性地抑制至少一种菌株的生物膜积累，抑制率为 30-85%，而抑制生长率低于 10%。命中物在至少 10 倍于硝唑尼特（唯一已知的 EAEC 生物膜抑制剂）报道的浓度下表现出有效的抗生物膜活性。反映已知的 EAEC 异质性，只有一种命中物对两种筛选分离物都有效，但三种命中物对更大的菌株面板显示出广泛的抗生物膜活性。作用机制研究表明，化合物 MMV687800 的作用靶点是 EAEC 抗聚集蛋白（Aap）分散素。
本研究鉴定了五种化合物，它们以前没有被描述为抗黏附剂或革兰氏阴性抗菌剂，对 EAEC 具有显著的抗生物膜活性。分子 MMV687800 靶向 EAEC Aap。EAEC 定植的体外小分子抑制为 EAEC 感染提供了新的治疗方法。
