Can Pasteurella cause brain abscesses?

Can Pasteurella Cause Brain Abscess?

Yes, Pasteurella multocida can cause brain abscesses, though it is a rare cause compared to more common pathogens. 1, 2, 3

Pathogenesis and Epidemiology

Pasteurella multocida is a gram-negative bacterium commonly found in the oral flora of domestic animals, particularly cats and dogs. Brain abscesses caused by this organism typically occur through:

• Direct extension from adjacent infections (particularly chronic otitis media) 1, 3
• Hematogenous spread following animal bites or scratches 2
• Potential spread through undetected skull fractures 2

Clinical Presentation

When Pasteurella causes brain abscess, patients may present with:

• Headache and vomiting
• Fever
• Neurological deficits (depending on abscess location)
• Papilledema or other signs of increased intracranial pressure 1

Diagnostic Approach

For suspected brain abscesses, regardless of etiology:

• MRI with diffusion-weighted imaging is the recommended diagnostic modality (strong recommendation, high certainty) 4
• Blood cultures should be obtained (positive in approximately 28% of brain abscess cases) 4
• Surgical drainage is essential for both diagnostic confirmation and treatment 4

Treatment Considerations

For Pasteurella brain abscesses:

• Surgical drainage is the primary intervention, allowing for:

  • Definitive source control
  • Collection of samples for microbiological analysis 4
  • Identification of the organism (important as Pasteurella can be misidentified as other organisms like Haemophilus) 5

• Antimicrobial therapy:

  • Initial empiric therapy should include a 3rd-generation cephalosporin plus metronidazole 6, 4
  • Once Pasteurella is identified, targeted therapy based on susceptibility testing should be initiated 1
  • Duration typically 6-8 weeks, with initial intravenous therapy followed by oral antibiotics once clinical improvement is observed 4

Case Reports and Evidence

Several case reports document Pasteurella multocida causing brain abscesses:

• A 26-year-old man with chronic purulent otitis developed a brain abscess in the fronto-dextra cupular region from which P. multocida was isolated 1
• A 5-year-old child developed meningitis with cerebral abscesses caused by P. multocida, possibly from pet dog saliva or through an unnoticed skull fracture 2
• An elderly woman with chronic otitis media and a glomus jugulare tumor developed a P. multocida temporal lobe abscess 3

Monitoring and Follow-up

• Serial imaging (every 2 weeks) to assess treatment response 4
• Clinical monitoring for signs of treatment failure or complications 4
• Evaluation for potential sources of infection, including chronic ear infections or animal exposure

Important Caveats

• P. multocida can be misidentified in laboratory testing, leading to inappropriate treatment 5
• In cases of brain abscess with no obvious source, animal exposure history should be specifically elicited
• Premature discontinuation of antibiotics can lead to treatment failure 4

While rare, clinicians should consider Pasteurella multocida as a potential pathogen in brain abscesses, particularly in patients with a history of animal exposure or chronic ear infections.