Detection of Salmonella enterica subsp. enterica via Quenching of Unincorporated Amplification Signal Reporters in Loop-Mediated Isothermal Amplification

Figure 1

Typical loop-mediated isothermal amplification (LAMP) workflow in clinical diagnosis setting. (1) A clinical sample (e.g., blood, serum, stool, nasal swab) from the patient is first collected and then subjected to (2) nucleic acid extraction, where the DNA or RNA from the sample is isolated, purified, and concentrated. (3) The extracted nucleic acid is then added to the LAMP reaction mixture and incubated isothermally for 60 minutes. (4) After amplification, the reaction tube is opened, and an intercalating dye (SYBR green dye) is put into the mixture. (5) Analysis can be done using the naked eye or by viewing through a blue LED light. Using the naked eye, positives appear yellow-green, and negatives appear orange. Through a blue LED light, positives appear as bright fluorescent yellow green, and negatives appear as dull and colorless. Agarose gel electrophoresis can also be performed to confirm the amplification of target products. Ladder-like bands are characteristic of LAMP products.