Which statement is NOT true about Pasteurella multocida?

Which statement is NOT true about Pasteurella multocida?

• A. Most common human infections occur in soft tissues, bones, and joints.
• B. Humans harbor the organism as part of their normal flora.
• C. It is the most virulent of the species in the genus.
• D. It grows on sheep blood agar.

Answer: (B)

Pasteurella multocida is a Gram-negative coccobacillus that lives as part of the normal oral flora of many animals—especially cats and dogs—but not in healthy humans. In people, infections occur after animal bites or scratches and most commonly involve soft tissues, with possible spread to bone and joints. Because of this zoonotic pattern, the idea that humans harbor the organism as part of normal flora is not true. The organism grows well on sheep blood agar in routine culture, which helps with identification from wound samples. While it is a notable pathogen within its genus, labeling it as the most virulent is not a precise clinical statement, as virulence depends on multiple factors. The key point is that humans are not normal carriers.

Pasteurella multocida is a Gram-negative coccobacillus that lives as part of the normal oral flora of many animals—especially cats and dogs—but not in healthy humans. In people, infections occur after animal bites or scratches and most commonly involve soft tissues, with possible spread to bone and joints. Because of this zoonotic pattern, the idea that humans harbor the organism as part of normal flora is not true. The organism grows well on sheep blood agar in routine culture, which helps with identification from wound samples. While it is a notable pathogen within its genus, labeling it as the most virulent is not a precise clinical statement, as virulence depends on multiple factors. The key point is that humans are not normal carriers.