Category:Pseudomonas and Burkholderia species

Overview

• Organisms found in soil and water worldwide
• Burkholderia mallei causes glanders; rodents act as reservoir of infection
• Burkholderia pseudomallei causes meliodosis
• Pseudomonas aeruginosa, found on skin, mucous membranes and in faeces, causes opportunistic infections

Characteristics

• Gram-negative rods
• Obligate aerobes
• Oxidase and catalase positive
• Pseudomonas species and Burkholderia pseudomallei motile by polar flagellae
• Burkholderia mallei non-motile

Pseudomonas aeruginosa

Burkholderia mallei

Burkholderia pseudomallei

• Causes melioidosis - endemic in Asia and Australia
• Primarily infects rodents
• Pathogenesis:
  • Infection via ingestion, inhalation or skin wounds from environment
  • Exotoxin, dermonecrotic protease and lecithinase implicated in pathogenicity
  • Strain virulence and host immunosuppression important
• Clinical infections:
  • Opportunistic infection with stress and immunosuppression predisposing to disease
  • Abscesses develop in many organs including lungs, spleen, liver, joints, CNS, upper respiratory tract
  • Chronic, debilitating, progressive disease with long incubation period
  • Many animal species susceptible
  • Referred to as pseudoglanders in horses
• Diagnosis:
  • Specimens: pus from abscesses, affected tissues, blood
  • Fluorescent antibody technique on tissue smears
  • Blood agar and MacConkey agar plates, incubated aerobically
  • Colonies have musty smell
  • Lactose fermentation on MacConkey
  • Slide agglutination
  • ELISA, complement fixation and indirect haemagglutination tests for serum antibodies
• Treatment/control: slaughter of infected animals where exotic