Development of a Microbiological Paper-Based Analytical Device to Detect Fecal Contamination of Water in Resource-Limited Settings

Abstract

Microbial contamination of water is a significant burden to public health, particularly in low- and middle-income countries. To develop an affordable and user-friendly method for detecting microbial water contamination in resource-limited settings, a business card-sized device, named the MicroBioPAD, was developed using filter paper saturated with the chromogenic sugar X-Gal. This device was compared to the standard most probable number (MPN) test and a plate culture-based test to assess fecal pollution of water in Nepal. A total of 120 water samples were collected from the Central (Kathmandu) and Southern (Chitwan) regions; these included 36 samples from three major rivers and 84 samples from various drinking water sources. The MPN and plate culture tests revealed fecal contamination in 93.1 and 27.3% of the samples collected in Kathmandu and Chitwan, respectively, with the levels of E. coli ranging from < 3 to ≥ 1100 CFU/100 ml in the Kathmandu water samples and < 3 to 160 CFU/100 ml in the Chitwan water samples. Compared to the standard culture-based tests, the MicroBioPAD produced positive results within a shorter time (24 h) and showed a 100% accuracy of detection for samples containing ≥ 3 E. coli CFU/ml, suggesting a detection limit of 3 E. coli CFU/ml when using only 100 μl of the sample. The MicroBioPAD will be useful as a relatively faster semi-quantitative device to determine water suitability for bathing, cleaning, and recreational purposes.