Categorised as typhoidal and non-typhoidal serotypes.
Increasing resistance to various types of antibiotics.
Typhoidal: cause typhoid and para-typhoid fever.
Non-typhoidal: 1 of 4 key global causes of diarrhoeal diseases; most cases of salmonellosis are mild; but sometimes they can be life-threatening.
S. Typhi and S. Paratyphi A and B are highly invasive bacteria that pass through the intestinal mucosa of humans rapidly and efficiently to eventually reach the underlying lymphoid tissue and spread to other organs.