Pasteurella

Pasteurelly is one of several species: Haemophilus, Actinobacillus, Pasteurella.

These are plemorphic rods to cocci. They are gram-negative, immobile, aerophilic, microaerophilic, or even facultatively anaerobic. By fermentation, they form acids but do not form gas. They are oxidase (+) and catalase (+). The most important representatives are Pasteurella multocida. Pasteurelles used to include Yersinia pestis (the causative agent of plague), Francisella tularensis (the causative agent of tularemia) and Mannheimia haemolytica.

Pasteurella multocida
This representative is one of the commensals in the upper parts of the respiratory system, especially in domestic animals. It causes pneumonia in cattle, sheep or poultry. It has a non-pathogenic effect on cats and dogs and occurs in the nasopharynx.

In terms of morphology, P. multocida is a gram-negative, non-sporulating and immobile coccobacillus with bipolar staining. We prove it on a medium with blood, it ferments sucrose and glucose. A typical broad zone of growth inhibition called inhibitory zone around penicillin can be seen on the medium.

Transmitted by direct contact or inhalation. It reaches humans due to animal scratches (5 % through dogs and 30 % through cats). It obtains endotoxin, which causes tissue damage and is resistant to phagocytes. P. multocida mainly causes local wound infections and animal bites, which are often accompanied by complications such as abscesses, cellulitis, arthritis or osteomyelitis. It also causes pneumonia, CNS infections, endocarditis or meningitis.

Most antibiotics (amoxicillin  a clavunalate or ampicillin  a sulbactam) are used for therapy. It is resistant to macrolides.

Other representatives include P. aerogenes (transmission after a pig bite), P. bettyae (detected from urine, newborn blood) or P. canis and P. stomatis, which is transmitted via dog bite.

related articles

 * Yersinia pestis
 * Tularemia