LAMP using distance based paper device for quantitative detection of ESBL producing Escherichia coli in UTI patients

Extended-spectrum beta-lactamases (ESBLs) producing E. coli are the most critical cause of antimicrobial resistance (AMR) and multidrug resistance (MDR) producing prolonged hospitalization and burden in treating nosocomial infection, in which the conventional culture regularly constitutes the gold standard diagnosis. In this study, we developed and validated a simple and inexpensive distance-based paper device (dPAD) LAMP assay for simultaneous screening and semi-quantifying the resistant bacterial load of ESBL-producing E. coli in 427 urine samples of patients with urinary tract infection (UTI). The device could measure the LAMP amplicons of bla_TEM gene and semi-quantify the degree of ESBL-producing E. coli in heavy (≥ 10² CFU/mL), light (10¹-10² CFU/mL) and none (< 10¹ CFU/mL) using the fluorescent measurement of the migratory distance. The sensitivity and specificity exhibited reliable performances, achieving as high as 98.9 and 96.5%, respectively. The assay could be performed within 1 hour, which was comparatively faster than the culture method (> 48 h) and cheaper than qPCR. To empower early AMR diagnosis and fast treatment of MDR, this inexpensive dPAD LAMP assay is simple, reliably fast and practically portable for point-of-care settings, particularly in resource-limited areas that can be set up in all levels of healthcare facilities.