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Background: The tcdA gene codes for an important toxin produced by Clostridioides difficile (C. difficile), but there is currently no simple and cost-effective method of detecting it. This article establishes and validates a rapid and visual loop-mediated isothermal amplification (LAMP) assay for the detection of the tcdA gene. Methods: Three sets of primers were designed and optimized to amplify the tcdA gene in C. difficile using a LAMP assay. To evaluate the specificity of the LAMP assay, C. difficile VPI10463 was used as a positive control, while 26 pathogenic bacterial strains lacking the tcdA gene and distilled water were utilized as negative controls. For sensitivity analysis, the LAMP assay was compared to PCR using ten-fold serial dilutions of DNA from C. difficile VPI10463, ranging from 207 ng/µl to 0.000207 pg/µl. The tcdA gene of C.difficile was detected in 164 stool specimens using both LAMP and polymerase chain reaction (PCR). Positive and negative results were distinguished using real-time monitoring of turbidity and chromogenic reaction. Results: At a temperature of 66 °C, the target DNA was successfully amplified with a set of primers designated, and visualized within 60 min. Under the same conditions, the target DNA was not amplified with the tcdA12 primers for 26 pathogenic bacterial strains that do not carry the tcdA gene. The detection limit of LAMP was 20.700 pg/µl, which was 10 times more sensitive than that of conventional PCR. The detection rate of tcdA in 164 stool specimens using the LAMP method was 17% (28/164), significantly higher than the 10% (16/164) detection rate of the PCR method (X2 = 47, p < 0.01). Conclusion: LAMP method is an effective technique for the rapid and visual detection of the tcdA gene of C. difficile, and shows potential advantages over PCR in terms of speed, simplicity, and sensitivity. The tcdA-LAMP assay is particularly suitable for medical diagnostic environments with limited resources and is a promising diagnostic strategy for the screening and detection of C. difficile infection in populations at high risk. [ABSTRACT FROM AUTHOR]

Background: This study aimed to investigate whether an increased proton pump inhibitor (PPI) dose enhanced the efficacy of Helicobacter pylori (H. pylori) eradication and determine the appropriate cutoff intragastric pH value that could predict H. pylori eradication with bismuth‐based quadruple therapy. Materials and Methods: A total of 207 H. pylori infected, treatment naive patients were enrolled in this prospective, open‐label, randomized controlled trial. Patients were randomly allocated into Eso40‐group (esomeprazole 40 mg bid) and Eso20‐group (esomeprazole 20 mg bid), and their CYP2C19 genotyping status was assessed. The 24‐h intragastric pH monitoring on day 7 was performed, and percentage of time gastric pH ≥ 3, ≥4, ≥5, and ≥6 (pH holding time ratios; HTRs) were measured. H. pylori eradication was evaluated using 13C‐urea breath test. Results: No significant difference in the eradication rates was observed between two groups. The median 24‐h intragastric pH value was not significant different between two groups but the Eso40 Group had a significant higher pH4 HTRs (91.11% [95%CI: 87.50%–95.83%] vs. 95.83% [95.83%–100%]; p =.002). Additionally, the median 24‐h intragastric pH value showed significantly difference between two groups in EM genotype (Eso20 Group 6.00 [95%CI; 5.75–6.15] vs. Eso40 Group 6.30 [6.05–6.30]; p =.019). Similar results were observed in pH4 HTRs. There were significant differences in intragastric pH value (6.10 [95%CI: 4.40–7.00] vs. 5.65 [4.85–5.95], p =.038) and in pH4 HTRs (96% [95%CI: 92.00%–96.00%] vs. 87.5% [67.00%–100.0%], p =.019) between eradication‐successful and eradication‐failed patients. Statistical analysis suggested that the median intragastric pH = 5.7 could identify the success of H. pylori eradication. Conclusions: Bismuth‐based quadruple therapy resulted in high H. pylori eradication rates either in PPI standard or double doses. Double dose of esomeprazole is associated with better intragastric acid suppression. A median 24‐h intragastric pH of 5.7 could be appropriate cutoff value for predicting the successful H. pylori eradication. [ABSTRACT FROM AUTHOR]