Pasteurella

Pasteurella

Micrograph of Pasteurella species

Pasteurella is a genus of Gram-negative bacteria that are nonmotile, facultatively anaerobic, and coccobacilli. These bacteria are known to be pathogenic in animals and humans, causing a variety of diseases. The genus is named after the renowned French scientist Louis Pasteur.

Characteristics

Pasteurella species are small, nonmotile, and pleomorphic. They are typically coccobacilli, which means they are shaped like short rods or elongated cocci. These bacteria are facultative anaerobes, meaning they can grow in both the presence and absence of oxygen. They are oxidase-positive and catalase-positive, which are important characteristics used in their identification.

Pathogenicity

Pasteurella species are known to cause infections in both animals and humans. In animals, they are often associated with respiratory infections, such as pneumonia, and can also cause septicemia. In humans, Pasteurella multocida is the most common species associated with infections, typically following animal bites or scratches, particularly from cats and dogs. These infections can lead to cellulitis, abscesses, and in severe cases, systemic infections.

Transmission

The primary mode of transmission of Pasteurella to humans is through animal bites or scratches. The bacteria are part of the normal flora of the upper respiratory tract of many animals, including cats, dogs, and rabbits. When these animals bite or scratch humans, the bacteria can be introduced into the wound, leading to infection.

Diagnosis

Diagnosis of Pasteurella infections is typically made through culture and identification of the bacteria from clinical specimens. The bacteria can be isolated from wound swabs, blood, or other body fluids. Laboratory identification involves biochemical tests that demonstrate the characteristic features of Pasteurella, such as oxidase and catalase positivity.

Treatment

Infections caused by Pasteurella species are usually treated with antibiotics. Pasteurella multocida is generally susceptible to penicillin, which is often the antibiotic of choice. However, in cases of penicillin allergy, other antibiotics such as doxycycline or ciprofloxacin may be used. It is important to clean and disinfect animal bites and scratches promptly to prevent infection.

Prevention

Preventive measures include avoiding bites and scratches from animals, particularly those known to carry Pasteurella. Pet owners should ensure their animals are healthy and vaccinated. In the event of a bite or scratch, immediate cleaning and disinfection of the wound can help reduce the risk of infection.

Related pages

• Gram-negative bacteria
• Facultative anaerobe
• Louis Pasteur
• Zoonosis