What is salmonella typhi?

Salmonella enterica subspecies enterica serovar Typhi (S. Typhi) is a bacterium that causes typhoid fever, a potentially fatal systemic infection characterized by prolonged high fever, headache, gastrointestinal discomfort and rash. S. Typhi can colonize both the gallbladder and the gastrointestinal tract and is transmitted orally by the ingestion of fecally contaminated food or water. It is endemic in many developing countries with poor sanitation and hygiene conditions. The bacteria invade and multiply within certain immune system cells where the immune system cannot readily clear it. This allows S. Typhi to become systemic and leads to the classical symptoms of typhoid fever. Treatment for uncomplicated typhoid fever typically involves antibiotics specifically effective against the bacterium