Pseudomonas aeruginosa

Last updated 21/12/19

Definition

Gram negative bacterial rod (bacilli) associated with severe infections and antibiotic resistance

Features

• Aerobic
• Member of Pseudomonadacae family
• Motile via flagellum
• Found in soil and water
• Also known as a plant pathogen
• Fast swimmmer
• Opportunistic pathogen
• Uncommon to infect through intact host defences
• Optimal growth at 37oC
• Predominantly a nosocomial infection
• May be found in hospital disinfectants, food, sinks, taps, toilets, showers
• Forms biolfilms
• Produces cytotoxins and haemolysins
• Produces pyoverdin (fluorescent) and pyocyanin (blue): fluorescent blue
• May be associated with bluish tingue to pus (sputum, wound, etc.)
• Fluorescent under ultraviolet light
• Pyocyanin impairs cila function, disrupts epithelium and stimulates proinflammatory effects of phagocytes
• Important pathogen due to its mortality (up to 50%) and morbidity, particularly in:
• Cancer
• Cystic fibrosis (CF)
• Burns
• Naturally resistant to many antibiotics
• Antibiotic resistance plasmids
• May be associated with efflux pumps and extended-spectrum beta-lactamases (ESBL)

Diseases

• Urinary tract infection (UTI)
• Including indwelling urinary catheter (IDC)/suprapubic catheter (SPC) associated
• Pneumonia
• Hospital acquired pneumoinia (HAP)
• Ventilator associated pneumonia (VAP)
• Commonly colonises respiratory tract of patients with CF
• Wound infection
• Otitis externa
• Keratitis
• Septic arthritis
• Osteomyelitis (OM)
• Gastroenteritis
• Bacteraemia
• Sepsis
• Febrile neutropaenia

Risk Factors

• Immunosupression
• Burns
• CF

Investigations

• MCS from suspected source

Management

• Antibiotics
• Natural resistance to wide range of antibiotics
• Fluoroquinolones
• Gentamicin
• Carbapenems

---

References

1. Kanj S, Sexton D. Epidemiology, microbiology, and pathogenesis of Pseudomonas aeruginosa infection. UpToDate. 11/11/2019
2. Todar K. Pseudomonas earuginosa. Todar's Online Textbook of Bacteriology - accessed online 25/12/2019