Typhoid fever is a systemic disease caused by Salmonella typhi. It is a worldwide public health problem especially seen in developing countries with a disease burden of about 22 million cases per year. Because proper sanitation and hygiene practices are difficult to achieve and problems of drug resistance have emerged, vaccination is now being considered as an essential tool in the prevention and control of the disease. The present study is a preliminary undertaking in the development of an edible vaccine based on the flagellar antigen of the organism. Specifically, the study determined the similarity of the vaccine candidate with some of the local isolates. Using primers based on the vaccine candidate which spanned the 3' end of the hypervariable region VI up to the end of the flagellin gene, a 470 bp fragment was amplified in the 19 local isolates. Results showed that the different isolates have a high measure of similarity with the candidate strain. In spite of the presence of the hypervariable region VI of S. typhi flagellin gene, the lengths of the fragments are rather conserved among the isolates tested. The observations, even with the limited sample size, demonstrated that the candidate flagellin gene can be appropriately used for vaccine development.

In: Acta Medica Philippina, 2006 vol. 40 (1) pages: 37-41