Pasteurella
المؤلف:
Cornelissen, C. N., Harvey, R. A., & Fisher, B. D
المصدر:
Lippincott Illustrated Reviews Microbiology
الجزء والصفحة:
3rd edition , p147
2025-07-16
499
Members of the genus Pasteurella primarily colonize mammals and birds, both domestic and feral. Therefore, Pasteurella infections are considered zoonoses. The major human pathogen in this genus is Pasteurella multocida ,which can cause either disease or asymptomatic infections. Pasteurellae are coccobacilli or rods that often exhibit bipolar staining, and some strains are encapsulated (Figure 1). Virulence factors include the organism’s capsule and endotoxin. Pasteurellae are aerobes or facultative anaerobes.
Fig1. Pasteurella multocida. A. Culture on blood agar showing small, translucent nonhemolytic colonies. B. Blood smear, Wright stain. (Note bipolar staining.)
A. Epidemiology
The majority of Pasteurella infections in humans are soft tissue infections that follow an animal bite or cat scratch. A smaller fraction of human Pasteurella infections occur either following a non-bite animal exposure or in the absence of any known animal exposure. The source of Pasteurellae in the latter infections is suspected to be nasopharyngeal colonization of the patient.
B. Clinical significance
P. multocida infection should be suspected in cases of acute, painful cellulitis that develop within 24 hours of an animal bite or cat scratch. Soft tissue infections are characterized by the rapid onset of acute local inflammation within hours of the bite or scratch. Lesions often begin to drain within 1 to 2 days. Manifestations of P. multocida infection include cellulitis, lymphangitis; lymphadenitis, fever, and local complications, such as osteomyelitis and arthritis, which can result in extended disability.
C. Laboratory identification
Laboratory diagnosis (essential in non–bite/scratch-associated cases) can be accomplished by culturing the organism on blood agar and performing appropriate biochemical tests.
D. Treatment
For soft tissue infections, wounds should be cleansed, irrigated, and debrided. Deep-seated infections require surgical drainage and pro longed antibiotic treatment. Penicillin is the drug of choice (Figure 2). Fatal infections are uncommon and usually reflect underlying host compromise.
Fig2. Antimicrobial agents useful in therapy of infections caused by Pasteurella multocida.1 Indicates first-line drugs; 2 indicates alternative drugs.
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