What are the two most common serotypes of Salmonella?

• A. Typhi and Paratyphi
• B. Saintpaul and Brazzaville
• C. Typhimurium and Enteritidis
• D. Newport and Heidelberg

Answer: (C)

Salmonella infections in humans are most often caused by a small set of serotypes, with two in particular standing out as the most frequent causes of non-typhoidal salmonellosis. Salmonella Typhimurium and Salmonella Enteritidis are the ones seen most commonly across a wide range of foods and outbreaks, making them the top culprits in surveillance data. Typhoidal serovars like Typhi and Paratyphi cause typhoid fever, which is a different, less common disease form and not the typical cause of the general Salmonella illnesses. The other listed serotypes can cause illness too, but they don’t occur as often as Typhimurium and Enteritidis. Enteritidis, in particular, is often linked to eggs and poultry, while Typhimurium is associated with a broad array of foods, helping explain why these two are the most prevalent.