Pasteurella multocida

Characteristics and laboratory features

P. multocida appears as short rods or coccobacilli on microscopy and is typically Gram-negative. It is usually oxidase- and catalase-positive and can grow on standard laboratory media. Serological classification commonly recognizes several capsular types (for example A, B, D, E and F) that are associated with different disease syndromes in animals. Clinical isolates are often, but not universally, sensitive to beta-lactam antibiotics; many strains are described as penicillin-sensitive, though resistance and alternative therapies are documented.

Diseases and importance

In animals, P. multocida causes a range of conditions: fowl cholera in birds, atrophic rhinitis in swine, and hemorrhagic septicemia in cattle and buffalo are notable examples. It also contributes to secondary pneumonia in livestock and companion animals. In humans, the most common presentation is an acute skin and soft tissue infection after a cat or dog bite; more severe outcomes, including respiratory infections and sepsis, can occur particularly in immunocompromised persons.

• Typical reservoirs: domestic pets (cats, dogs), poultry and livestock.
• Common zoonotic route: bites, scratches, and close contact with secretions.
• Prevention: wound care, responsible animal handling, and vaccination programs in animals.

Diagnosis relies on culture and biochemical or molecular identification; treatment is guided by susceptibility testing and often includes beta-lactam antibiotics, though clinicians consider local resistance patterns. Control in agriculture combines vaccination, biosecurity and management practices to reduce outbreaks and economic losses.

History and naming

The organism was first associated with fowl cholera in the late 19th century and was isolated and studied by Louis Pasteur in 1880; the genus name honors his contributions to microbiology and vaccine development. Since then, P. multocida has remained important both as a subject of veterinary medicine and as a recognized zoonotic organism in human clinical practice. For more general background see sources on bacterial classification and historical microbiology, including biographical material on Louis Pasteur.