Pseudomonas aeruginosa

Snapshot

• A 55-year-old woman presents to the emergency department with fatigue and abdominal pain. Her symptoms are associated with dysuria, hematuria, and increased urinary frequency. Physical examination is remarkable for bilateral flank pain, suprapubic tenderness, and costovertebral angle tenderness. Urine studies are obtained and she is started on empiric antibiotics. Urine cultures grows Pseudomonas aeruginosa. (Pyelonephritis secondary to Pseudomonas infection)

Introduction

• Aerobic, non-lactose fermenting, oxidase-positive, gram-negative bacillus 
• Pathogenesis
  • phospholipase C
    • produced to degrade cell membranes
  • endotoxin, which leads to
    • fever
    • hypotension
    • disseminated intravascular coagulation
  • exotoxin A
    • this inactivates elongation factor 2 (EF-2), which stops protein synthesis via ADP ribosylation
  • pyoverdine and pyocyanin pigment 
• leads to a blue-green pigment

Treatment

• Prompt antibiotic administration is associated with improved mortality
• In addition to antibiotic treatment, source control is important (e.g., abscess drainage and removal of the catheter)
• Treatment options include
  • carbapenems
  • aminoglycosides
  • monobactams
  • polymyxins
  • fluoroquinolones
  • third and fourth generation cephalosporins
  • piperacillin