Development and evaluation of loop-mediated isothermal amplification (lamp) for rapid detection of campylobacter...

To develop and evaluate a loop-mediated isothermal amplification (LAMP) assay for the rapid detection of Campylobacter jejuni in stool samples associated with acute diarrheal disease (ADD) and Guillain-Barré syndrome (GBS) for implementation in regional laboratories and primary health care centers.

Four sets of LAMP primers for C. jejuni were designed and initially evaluated with DNA from C. jejuni, Campylobacter coli, Salmonella Infantis, and Escherichia coli extracted using a commercial kit. The best-performing primer set was selected for assay optimization, determination of the limit of detection, and analytical validation with DNA from the aforementioned strains. Subsequently, clinical validation was performed using stool samples from patients with suspected ADD due to C. jejuni, applying the same standardized conditions used for the strain DNA samples. The sensitivity and specificity of the test were determined using real-time PCR (qPCR) as the standard.

The LAMP assay for the detection of C. jejuni in stool samples using a primer set for the cdtC region showed a sensitivity of 97% (CI: 81.49-99.83%), a specificity of 93% (CI: 75.79-98.80%), a positive predictive value of 94% (CI: 77.78-98.91%), and a negative predictive value of 96% (CI: 79.76-99.81%). Furthermore, a strong agreement was demonstrated between this LAMP assay and qPCR (k=0.9).

The LAMP assay based on the cdtC gene is a reliable and rapid method, with high sensitivity and specificity comparable to qPCR for the identification of C. jejuni associated with ADD and GBS, especially in low-resource areas, due to its low cost and ease of implementation.