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.

水的微生物污染是公共卫生的重大负担，特别是在中低收入国家。为了开发一种经济实惠且用户友好的方法来在资源有限的环境中检测微生物水污染，使用饱和了生色糖X-Gal的滤纸开发了一种名片大小的设备，名为MicroBioPAD。将该设备与标准最可能发生数（MPN）测试和基于平板培养的测试进行了比较，以评估尼泊尔的粪便对水的污染。从中部（加德满都）和南部（奇旺）地区总共收集了120个水样；其中包括来自三大河流的36个样本和来自各种饮用水源的84个样本。MPN和平板培养测试显示93.1和27中有粪便污染。在加德满都水样中，大肠杆菌的含量范围从<3至≥1100 CFU / 100 ml，在奇旺旺水样中，大肠杆菌的含量在<3至160 CFU / 100 ml。与标准的基于培养物的测试相比，MicroBioPAD在较短的时间内（24小时）产生了阳性结果，并显示了对含≥3个大肠杆菌CFU / ml的样品的检测准确度为100％，表明检出限为3 E.大肠杆菌仅使用100微升样品时CFU /毫升。MicroBioPAD将作为一种相对较快的半定量设备，用于确定水是否适合沐浴，清洁和娱乐目的。