Detection of strongyloides stercoralis in stool using the loop mediated isothermal amplification (LAMP) method

Strongyloides stercoralis is a parasitic nematode that can cause infections ranging in severity from the asymptomatic to fatal. Aim To investigate whether the loop mediated isothermal amplification (LAMP) of nucleic acid can be applied to the detection of S. stercoralis DNA in stool. Methods Primers were designed that were specific to the strongyloides 28S rRNA gene. The LAMP reaction was optimised using Strongyloides ratti , which was available through laboratory culture. LAMP products were characterised with restriction enzyme digestion and cloning with sequence analysis. Analytical sensitivity was determined using serial dilutions of a PCR product and human stool specimens spiked with S. ratti . Stool specimens with S. stercoralis were tested. Specificity was tested using a range of bacteria, fungi and parasites. Results S. stercoralis and spiked S. ratti were detected in human stool specimens. Tests showed a high degree of analytic sensitivity, between 11.75 and 2.35 copies of DNA, and good specificity. Discussion The most effective methods used to detect S. stercoralis in stool require live larvae. Nucleic acid detection may enable easier specimen transport and reduce the risk of laboratory acquired infections. This preliminary study indicates that LAMP may be a useful method to detect S. stercoralis in the stool.