Development and application of isothermal amplification methods for rapid detection of F4 fimbriae producing Escherichia coli

Enterotoxigenic Escherichia coli (ETEC) is the causative agent of a wide range diseases, which are important cause illness and mortality in piglets. ETEC strains expressing F4 fimbriae frequently associated with post-weaning diarrhea (PWD) lead to great economic losses swine production industry worldwide. The aim this study was establish rapid effective isothermal amplification method for detection fimbriae. Loop-mediated (LAMP), Polymerase spiral reaction (PSR) cross-priming ampli- fication (CPA) were used develop optimize first time. Subsequently, specificity sensitivity these methods evaluated, clinical samples detected methods. All F4-positive could produce ladder-like amplifica- tions products chromogenic substrate SYBR Green I green fluorescence, while blank control negative lack pattern or remained orange. sensi- tivity LAMP CPA 10 times higher than PSR method. Meanwhile, three validated samples, 7 found positive, 125 negative, testing results consisted real-time PCR These findings suggested that based on rapid, sensitive under resource constrains.