Related Experiment Videos
Pseudomonas aeruginosa as a cause of infectious diarrhoea
P A Adlard1, S M Kirov, K Sanderson
1Division of Pathology, University of Tasmania, Hobart, Australia.
Abstract:
Pseudomonas aeruginosa is not generally considered a cause of infectious diarrhoea. However, it was the predominant organism isolated from the faeces of 23 unrelated, hospital outpatients investigated in the course of a year for persistent (> 1 week duration) diarrhoea. To investigate the possible aetiological role of P. aeruginosa, these patient histories were reviewed and a selection of their faecal isolates were investigated in vitro (n > or = 10) and in vivo (n = 2) for virulence. The patients had a mean age of 60 years, were receiving antibiotics and/or had an underlying illness. Extensive microbiological investigations identified no other potential or recognized enteropathogen in the faeces of 20 of these patients. More than 40% of the isolates tested were able to adhere to HEp-2 cells and exhibited twitching motility (type IV pili), properties indicative of their ability to colonize the human intestine. Cytotoxic activity was demonstrated in bacterium-free cell supernatants of over 80% of isolates; supernatants of four isolates tested in infant mice were weakly enterotoxigenic. Two isolates intragastrically inoculated into clindamycin pre-treated rats established persistent infections and induced signs and symptoms of enteritis. Overall these findings suggest that P. aeruginosa can cause diarrhoea particularly in immunodeficient individuals.
Insights
Pseudomonas aeruginosa, typically not a cause of diarrhea, was found in hospitalized patients with persistent diarrhea. This study suggests it can cause enteritis, especially in immunocompromised individuals.
Area of Science:
- Microbiology
- Infectious Diseases
- Gastroenterology
Background:
- Pseudomonas aeruginosa is rarely implicated in infectious diarrhea.
- Persistent diarrhea in hospital outpatients often lacks a clear enteropathogen.
- This study investigated P. aeruginosa as a potential cause of prolonged diarrhea.
Purpose of the Study:
- To determine the etiological role of Pseudomonas aeruginosa in patients with persistent diarrhea.
- To assess the virulence factors of P. aeruginosa isolates from these patients.
- To evaluate the potential of P. aeruginosa to cause intestinal infections.
Main Methods:
- Patient histories were reviewed for 23 hospital outpatients with persistent diarrhea.
- Faecal isolates of P. aeruginosa were tested for in vitro virulence (adherence, motility, cytotoxicity).
- In vivo studies included infant mice (enterotoxicity) and clindamycin-pretreated rats (intestinal colonization and enteritis).
Main Results:
- No other enteropathogen was identified in 20 of the 23 patients.
- Over 40% of P. aeruginosa isolates showed HEp-2 cell adherence and twitching motility.
- More than 80% of isolates produced cytotoxic activity; some were weakly enterotoxigenic in mice.
- Two isolates caused persistent enteritis in rats.
Conclusions:
- Pseudomonas aeruginosa possesses virulence factors suggesting intestinal colonization capability.
- The bacterium demonstrated cytotoxic and enterotoxigenic potential in vitro and in vivo.
- These findings indicate P. aeruginosa can cause infectious diarrhea, particularly in immunocompromised patients.