An automated bacterial concentration and recovery system for pre-enrichment required in rapid Escherichia coli detection

Lingcheng Hong,Tianyi Guo,Chang-Qing Xu,Yushan Zhang

doi:10.1038/s41598-018-35970-8

Abstract

One of the biggest challenges in rapid low concentration bacterial detection is the pre-concentration or pre-enrichment, which aims to increase bacteria concentration and reduce sample volume for easy bacterial detection. In practical bacterial detection, large-volume water samples with a pathogenic bacterial concentration of less than 1 CFU/mL have to be tested rapidly. The reported biosensors either have insufficient detection limit or have limited capability of handling a sufficiently large water sample. Therefore, a high-performance automated pre-enrichment process is strongly demanded in rapid practical bacterial detection. In this paper, a practical high performance automated bacterial concentration and recovery system (ABCRS) based on the combination of a ceramic membrane and tangential flow filtration technique was presented with short processing time (less than one hour), low pre-enrichment limit (≤0.005 CFU/mL), high concentration ratio (≥ 500), high recovery efficiency (~ 90%), and small final retentate volume (≤ 5 mL).

Highlights

Rapid detection of pathogenic bacteria has attracted a lot of attention as it has enormous impact on public health
Substantial amounts of initial water samples with low bacterial concentration need to be monitored in practical bacterial detection
Conventional bacterial culture and other time-consuming pre-enrichment methods are still necessary to increase the bacterial concentration for detection and the overall assay time is strongly affected

Summary

Introduction

Rapid detection of pathogenic bacteria has attracted a lot of attention as it has enormous impact on public health. Expensive equipment and highly-trained personnel are required for the PCR-based assays Rapid immunoassays, such as, enzyme-linked immunosorbent assays (ELISA) are labor-intensive and the detection limit of ELISA is usually high (104 ~ 106 CFU/mL)[11]. This relatively high detection limit still needs to be lowered to monitor the pathogenic bacteria at low concentration in drinking water. Considering the fact that large volumes of initial water samples (100 mL ~ 1000 L) are required for the tests in food industries and environmental monitoring[23], the total assay volume of these single-cell detection biosensors can handle is too small for practical rapid detection. The reported methods still need to be improved to satisfy the requirements for rapid low concentration bacterial detection

Methods

Results

Conclusion