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Relative importance of enterotoxigenic and invasive enteropathogenic bacteria in infantile diarrhoea
Abstract:
Swedish children and adults (648 patients) with acute diarrhoea were investigated for enterotoxigenic strains in stool cultures. A total number 74 strains were isolated from 28 patients and assayed in the rabbit intestinal loop test and the adrenal cell test. Only three of the enterotoxigenic E. coli (ETEC) isolates belonged to classical enteropathogenic serotypes of E. coli (EPEC). Two enterotoxigenic strains of Proteus morganii, two of Enterobacter hafniae and one of Citrobacter freundii were isolated. None of 67 EPEC strains were found to produce a heat-labile enterotoxin (LT) in either of the two test systems. A number of Yersinia enterocolitica and Pseudomonas aeruginosa strains from stool cultures often produced toxic effects in the cell test but no enterotoxin activity was detected for any of the strains investigated either in the adrenal cell test for heat-labile enterotoxin (LT) or the suckling mouse test for heat-stable enterotoxin (ST). All EPEC isolates were also tested for ST and for invasive properties in the Sereny test; each isolate was negative in both test systems. It is concluded that production of LT and ST enterotoxin were common in stool isolates from Ethiopian children but a rare phenomenon among Swedish children with acute infantile diarrhoea. Isolation of aerobic stool bacteria with invasive properties seems to be uncommon both in Ethiopian and Swedish children. However, since both LT and ST as well as invasive properties seem to be very unstable genetic properties in many of these stool isolates improved sensitive methods for the last two properties will probably change this picture in the future.
Insights
Enterotoxigenic E. coli (ETEC) and other bacteria producing heat-labile (LT) or heat-stable (ST) enterotoxins are rare in Swedish children with acute diarrhea. Invasive properties were also uncommon in these stool isolates.
Area of Science:
- Microbiology
- Pediatrics
- Infectious Diseases
Context:
- Acute diarrhea is a significant health concern, particularly in children.
- Understanding the etiological agents of diarrhea is crucial for effective treatment and prevention.
- Previous studies have highlighted the prevalence of enterotoxigenic bacteria in different geographical regions.
Purpose:
- To investigate the prevalence of enterotoxigenic bacterial strains in Swedish children and adults with acute diarrhea.
- To compare the enterotoxin production of bacterial isolates from Sweden with those from Ethiopia.
- To assess the presence of heat-labile (LT) and heat-stable (ST) enterotoxins and invasive properties in various bacterial species.
Summary:
- Stool cultures from 648 Swedish patients with acute diarrhea yielded 74 bacterial strains.
- Enterotoxigenic *E. coli* (ETEC) strains were rare, with only three isolates belonging to classical enteropathogenic *E. coli* (EPEC) serotypes.
- While some *Proteus*, *Enterobacter*, and *Citrobacter* strains showed enterotoxigenicity, EPEC strains did not produce LT or ST enterotoxins. *Yersinia* and *Pseudomonas* strains showed toxic effects but no enterotoxin activity.
- Enterotoxin production (LT and ST) was common in Ethiopian stool isolates but rare in Swedish isolates. Invasive properties were uncommon in both populations.
- The study concludes that LT and ST enterotoxin production is infrequent in Swedish children with acute diarrhea, contrasting with findings in Ethiopian children.
Impact:
- This research provides valuable epidemiological data on the causes of acute diarrhea in Sweden.
- The findings suggest regional differences in the prevalence of enterotoxigenic bacteria.
- The study underscores the need for sensitive diagnostic methods to detect enterotoxins and invasive properties, as these genetic traits can be unstable.