Evaluation of In-house Loop Amplification (LAMP) method for the diagnosis of Salmonella Typhi based on StgB gene

Introduction Salmonella Typhi (S.Typhi) is a causative agent for typhoid fever, a major health problem especially in developing countries. In Malaysia, the disease is still an endemic with the occurrence of 1–4 cases per 100,000 populations reported from year 1996–2006. Early detection of the agent is important since immediate treatment given to the patients will save many lives. However, current methods for the diagnosis of S.Typhi did not satisfy the requirements for a rapid, simple, and cost-effective detection mode. Objective Our study is aimed to develop an in-house LAMP method for a rapid, sensitive, specific and cost-effective detection of S.Typhi. Methods An In-house method of LAMP was developed and optimized using genomic DNA of Salmonella Typhi ATCC7251. The test was further evaluated for its specificity, sensitivity and application on field samples. The result was compared with those obtained by PCR assay and culture method. Results & Discussion In-house LAMP method has been successfully developed and optimized. This LAMP method was shown to be more sensitive than PCR assay and highly specific where no cross-reactivity was observed with other tested bacteria. Results of LAMP on clinical samples were in accordance to the results obtained by PCR assay and culture method. Conclusion In-house LAMP method developed in this study can potentially be used as a rapid, sensitive, specific and cost-effective detection of Salmonella Typhi especially at low-resource settings. However, this LAMP method need to be further validated using larger number of clinical samples.