Lateral Flow Loop-Mediated Isothermal Amplification Test with Stem Primers: Detection of Cryptosporidium Species in Kenyan Children Presenting with Diarrhea

Figure 3

(a) Gel electrophoresis of stem LAMP product for C. hominis (L1) and C. parvum (L2), and their Ndel restriction enzyme digest (highly magnified). The predicted amplicon sizes based on the NdeI cutting site are ~104 bp (80 bp + primer B1 24 bp) and ~137 bp (115 bp + primer F1c 22 bp). NC = negative

(b) The multiple alignment of ~200 base sequence sections obtained after sequencing the uppermost amplicon from four samples that were positive with stem LAMP test but negative using other comparative tests. The F1c (boxed) and F2 (shaded grey) form FIP primer. A partial B2c sequence (shaded dark grey) is part of BIP primer. The sequence shows > 96% identity with the target sequence AB119646.1 for C. parvum, XM662396.1 for C. hominis, and AB119648.1 for C. meleagridis. The sequences obtained will differ depending on the band sequenced and whether the sequence was initiated by FIP or BIP primers