Multifunctional Paper-Based Analytical Device for In Situ Cultivation and Screening of Escherichia coli Infections

Sci Rep. 2019 Feb 7;9(1):1555. doi: 10.1038/s41598-018-38159-1.

Abstract

Point-of-care testing (POCT) for uropathogen detection and chemical screening has great benefits for the diagnosis of urinary tract infections (UTIs). The goal of this study was to develop a portable and inexpensive paper-based analytical device (PAD) for cultivating bacteria in situ and rapidly testing for nitrite on the same device. The PAD was fabricated using a wax printing technique to create a pattern on Whatman No. 1 filter paper, which was then combined with a cotton sheet to support bacterial growth. Nitrite detection was based on the principle of the Griess reaction, and a linear detection range of 0-1.6 mg/dL (R2 = 0.989) was obtained. Scanning electron microscopy (SEM) analysis demonstrated that the bacteria were able to grow and formed a cluster on the cellulose fibres within 2 hours. The enzyme β-glucuronidase, which is specifically produced by Escherichia coli, was able to convert the pre-immobilized 5-bromo-4-chloro-3-indolyl-β-D-glucuronide sodium salt (X-GlcA), a colourless substrate, generating a blue colour. Under optimum conditions, the proposed device allowed bacterial concentrations in the range of 104-107 colony forming units (CFU)/mL to be quantified within 6 hours. Moreover, the use of this device enables the identification of E. coli pathogens with selectivity in real urine samples. In conclusion, the PAD developed in this study for UTI screening provides a rapid, cost-effective diagnostic method for use in remote areas.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Colorimetry / methods*
  • Escherichia coli / growth & development
  • Escherichia coli / isolation & purification*
  • Escherichia coli Infections / diagnosis*
  • Escherichia coli Infections / microbiology
  • Microscopy, Electron, Scanning
  • Nitrites / analysis
  • Nitrites / chemistry
  • Paper*
  • Point-of-Care Testing

Substances

  • Nitrites