Development and evaluation of a one-pot CRISPR/Cas13-based assay for syphilis detection across multiple clinical sample types.

OBJECTIVES

To develop and evaluate a rapid, one-pot molecular assay for the detection of Treponema pallidum subspecies pallidum (TPA), addressing the limitations of current diagnostic methods influenced by sample type and pathogen load.

METHODS

A one-pot assay integrating recombinase polymerase amplification (RPA) and Cas13a-based collateral cleavage activity was established for isothermal detection of TPA. The assay targeted the tpp47/tp0574 gene and was validated using 186 clinical specimens, including whole blood, lesion exudate, and cerebrospinal fluid (CSF) samples.

RESULTS

The one-pot RPA-Cas13a assay demonstrated high analytical sensitivity and specificity for TPA detection. Clinical sensitivities were 58.97% in whole blood, 84.21% in lesion exudate, and 57.14% in CSF, with 100% specificity across all sample types.

CONCLUSION

This one-pot isothermal assay enables rapid and accurate detection of T. pallidum directly from diverse clinical samples. Its high specificity and field-friendly format make it a promising complementary tool to conventional diagnostic approaches, particularly for point-of-care testing and screening in resource-limited or high-risk settings.