Paper-based ELISA to rapidly detect Escherichia coli.

Abstract Escherichia coli is a generic indicator of fecal contamination, and certain serotypes cause food- and water-borne illness such as O157:H7. In the clinic, detection of bacteriuria, which is often due to E. coli , is critical before certain surgical procedures or in cases of nosocomial infection to prevent further adverse events such as postoperative infection or sepsis. In low- and middle-income countries, where insufficient equipment and facilities preclude modern methods of detection, a simple, low-cost diagnostic device to detect E. coli in water and in the clinic will have significant impact. We have developed a simple paper-based colorimetric platform to detect E. coli contamination in 5 h. On this platform, the mean color intensity for samples with 10 5  cells/mL is 0.118±0.002 ( n =4), and 0.0145±0.003 ( P E. coli , and possibly other pathogens when customized as appropriate, especially in areas that lack advanced clinical equipment.