There are two species of Salmonella. What are they?

• A. Two species: S. enterica and S. bongori
• B. One species: S. enterica
• C. Three species: S. enterica, S. bongori, S. choleraesuis
• D. Four species: S. enterica, S. bongori, S. choleraesuis, S. Typhi

Answer: (A)

Salmonella is categorized into two species: Salmonella enterica and Salmonella bongori. This distinction comes from genetic and ecological differences shown by research, leading scientists to group the majority of human and animal pathogens under S. enterica, while S. bongori represents the other primary lineage. The well-known disease-causing strains like Typhi or choleraesuis are not separate species; they are serovars within Salmonella enterica. So the correct statement is that there are two species, S. enterica and S. bongori.