Fig. 2.

Detection of H. pylori directly from stool samples using IFA, semi-nested PCR targeting vacA and real-time PCR targeting 16S rRNA. (A) Fluorescent photomicrograph of H. pylori in various concentrations (CFUs/0.1 g), NC and PC refers to negative (sterile Brucella broth) and positive control (H. pylori DMST 20165 in Brucella broth), respectively. (B) Semi-nested PCR targeting vacA in spiked stool samples. Lane M, 1 kb DNA ladder; Lane 1, negative control (PCR reagent without DNA); Lane 2, positive control (DNA sample from H. pylori DMST20165); Lanes 3–11, stool samples spiked with various numbers of H. pylori cells (10⁸–10⁰ CFUs/0.1 g). (C) Amplification curve of SYBR green real-time PCR targeting 16S rRNA in spiked stool samples. Black line, positive control (DNA sample from H. pylori DMST20165); Red line, 10⁶; orange line, 10⁴; blue line, 10³; purple line, 10¹ CFUs/0.1 g; grey line, Non-template control (PCR reagent without DNA)