Which genus is typically nonmotile among the Enterobacterales?

Which genus is typically nonmotile among the Enterobacterales?

• A. Enterobacter
• B. Klebsiella
• C. Salmonella
• D. Serratia

Answer: (B)

Motility differences help separate genera within Enterobacterales. Klebsiella species are typically nonmotile because they lack functional flagella, which contrasts with the others in this group that usually have flagella and are motile. This nonmotile profile, along with their prominent capsule giving a very mucoid colony, is a key identifying clue. So, when you see a nonmotile, encapsulated Gram-negative rod within Enterobacterales, Klebsiella is the most likely genus, whereas Enterobacter, Salmonella, and Serratia are generally motile due to their flagella.

Motility differences help separate genera within Enterobacterales. Klebsiella species are typically nonmotile because they lack functional flagella, which contrasts with the others in this group that usually have flagella and are motile. This nonmotile profile, along with their prominent capsule giving a very mucoid colony, is a key identifying clue. So, when you see a nonmotile, encapsulated Gram-negative rod within Enterobacterales, Klebsiella is the most likely genus, whereas Enterobacter, Salmonella, and Serratia are generally motile due to their flagella.