An efficient, high-throughput enrichment system for the rapid detection of E. coli at low concentrations in water

Certain virulent strains of Escherichia coli (E. coli), notably the enterohemorrhagic serotype O157:H7, are recognized for causing diarrhea, gastroenteritis, and a range of illnesses that pose significant risks to public health and the safety of drinking water supplies. Early detection and management of E. coli, particularly at low concentrations, are critical for identifying potential sources of contamination. This proactive approach can prevent the spread of diseases, ensure the safety of drinking water, and maintain the hygiene of consumable products. However, detecting low concentrations of E. coli in water samples presents challenges, such as reduced sensitivity, prolonged analysis times, complex sample preparation, susceptibility to interferences, cost limitations, and result variability. To overcome these challenges, we developed an enrichment system that rapidly and efficiently concentrates low-concentration E. coli samples. This system consists of two modules: a primary enrichment module and a secondary enrichment module. The primary enrichment module uses Dean flow technology to enhance E. coli recovery through lateral flushing, achieving recovery rates between 82.7 % and 92.7 %. The secondary enrichment module employs double membrane filtration to further concentrate E. coli. This two-stage enrichment process can amplify E. coli concentrations up to 1000-fold, achieving a recovery rate of 61.8 % within just 30 min. This system enables ultra-high multiplicity enrichment of E. coli from low concentrations in water samples, providing small volumes of highly concentrated samples necessary for subsequent precise detection based on droplet microfluidic technology. The development of this system offers significant benefits for the enrichment and rapid detection of pathogenic bacteria in environmental samples.