Which statement about Salmonella serovars is true?

• A. Serovars are the same as species.
• B. Serovars are based on O and H antigens.
• C. Serovars are not used for classification.
• D. Serovars are unaffected by country.

Answer: (B)

Salmonella serovars are defined by differences in surface antigens. In serotyping, the Kauffmann-White scheme uses somatic O antigens and flagellar H antigens to categorize strains into distinct serovars. O antigens come from the lipopolysaccharide in the outer membrane and are relatively stable, while H antigens are flagellin proteins that can vary, even within the same strain, giving different antigenic profiles. Because each serovar is identified by a unique combination of these O and H antigens, this method, not the species name, determines serovar classification. So the statement that serovars are based on O and H antigens is the accurate one. In contrast, serovars are not the same as species, they are indeed used for classification, and their distribution can vary by country and geography as different strains circulate.