Pasteurella multocida

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Pasteurella multocida is a small, Gram-negative, non-motile coccobacillus that is penicillin-sensitive and belongs to the Pasteurellaceae family [1]. It can cause a zoonotic infection in humans, which typically is a result of bites or scratches from pets (such as cats and dogs). Many mammals and fowl harbor it as part of their normal respiratory microbiota, displaying asyptomatic colonization.

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[edit] History

Pasteurella multocida was first found in 1878 in fowl cholera-infected birds. However, it was not isolated until 1880, by Louis Pasteur - the man whom Pasteurella is named in honor of.

[edit] Disease

P. multocida is the most common cause of infection from animal injuries. (Pneumonia in cattle and pigs, atrophic rhinitt in pigs and goats and wound infections, specially after dog/cat-bites.) A high leukocyte and neutrophil count is typically observed, leading to an inflammatory reaction at the infection site (generally a diffuse localized cellulitis).[2] It can also infect other locales, such as the respiratory tract. In more serious cases, a bacteremia can result, causing an osteomyelitis or endocarditis. The bacteria may also cross the blood-brain barrier and cause a meningitis.[3]

[edit] Virulence, Culturing, and Metabolism

A bacteriophage encodes the toxin responsible for most P. multocida virulence factors. This toxin activates Rho GTPases, which bind and hydrolyze GTP, and are important in actin stress fiber formation. Formation of stress fibers may aid in the endocytosis of P. multocida. The host cell cycle is also modulated by the toxin, which can act as an intracellular mitogen.[4]
P. multocida will grow at 37 degrees Celsius on blood or chocolate agar, but will not grow on MacConkey agar. Colony growth is accompanied by a characteristic "mousy" odor due to metabolic products.
Being a facultative anaerobe, it is oxidase- and catalase-positive, and can also ferment a large number carbohydrates in anaerobic conditions.[5]

[edit] Treatment

This bacterium can be effectively treated with beta-lactam antibiotics, which inhibit cell wall synthesis. It can also be treated with fluoroquinolones or tetracyclines; fluoroquinolones inhibit bacterial DNA synthesis and tetracyclines interfere with protein synthesis by binding to the bacterial 30S ribosomal subunit. Because P. multocida is most often acquired as a result of a bite (notably dog), infections are frequently polymicrobial and involve anaerobic bacteria. As a result, amoxicillin-clavulanate (a beta-lactamase inhibitor/penicillin combination) is seen as the treatment of choice. Red Book®: 2006 Report of the Committee on Infectious Diseases - 27th Ed.

[edit] See also

[edit] References

  1. ^ Kuhnert P; Christensen H (editors). (2008). Pasteurellaceae: Biology, Genomics and Molecular Aspects. Caister Academic Press. ISBN 978-1-904455-34-9 . 
  2. ^ Ryan KJ; Ray CG (editors) (2004). Sherris Medical Microbiology, 4th ed., McGraw Hill. ISBN 0-8385-8529-9. 
  3. ^ Casolari C, Fabio U. Isolation of Pasteurella multocida from Human Clinical Specimens: First Report in Italy. European Journal of Epidemiology. Sept 1988; 4(3):389-90
  4. ^ [Lacerda HM, Lax AJ, Rozenqurt E. Pasteurella multocida toxin, a potent intracellularly acting mitogen, induces p125FAK and paxillin tyrosine phosphorylation, actin stress fiber formation, and focal contact assembly in Swiss 3T3 cells. J Biol Chem. 5 Jan 1996; 271(1):439-45.
  5. ^ Casolari C, Fabio U. Isolation of Pasteurella multocida from Human Clinical Specimens: First Report in Italy. European Journal of Epidemiology. Sept 1988; 4(3):389-90
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