Pasteurella Multocida Infection Workup

Updated: Jul 26, 2022
  • Author: Sara L Cross, MD; Chief Editor: Michael Stuart Bronze, MD  more...
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Laboratory Studies

Gram stain of purulent material or other fluid specimens including blood, sputum, and cerebrospinal fluid may show small, gram-negative, nonmotile, non–spore-forming pleomorphic coccobacilli.

Haemophilus species, N meningitides, Moraxella species, and Acinetobacter species have a morphology that is similar to that of P multocida infection and therefore can be easily confused with Pasteurella species.

Wright, Giemsa, and Wayson stains enhance bipolar staining. Some P multocida strains exhibit a mucous capsule.

The diagnosis is confirmed by identifying the organism in culture.

Pasteurella species are highly sensitive to several penicillins and cephalosporins. Susceptibility testing is indicated in immunocompromised patients and in the setting of treatment failure or drug allergies.


Imaging Studies

CT scanning and/or MRI: Evaluation of tenosynovitis, septic arthritis, osteomyelitis, and meningeal enhancement, when appropriate

Echocardiography: Evaluation of suspected endocarditis



Deep soft-tissue P multocida infections require debridement at times. Intraoperative cultures should be taken at time of surgery.

Lumbar puncture should be performed if meningitis is suspected.

Arthrocentesis should be performed if septic arthritis is suspected.

Abdominal paracentesis is required in patients with ascites to assess the possibility of spontaneous bacterial peritonitis, especially in those with significant clinical liver disease with a history of pet exposure.


Histologic Findings

When available, infected tissue has features consistent with an acute purulent inflammation with neutrophilic predominance and possibly necrosis.