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Toxigenic bacterial diarrhea: nursery outbreak involving multiple bacterial strains
Insights
An outbreak of watery diarrhea in infants was linked to toxigenic bacteria producing cholera-like enterotoxin. This suggests a transmissible plasmid may be responsible for the illness in the special care unit.
Area of Science:
- Microbiology
- Pediatrics
- Infectious Diseases
Background:
- An outbreak of watery diarrhea affected 14 out of 15 infants in a special care unit.
- The cause of the outbreak was investigated due to its rapid spread and severity.
Purpose of the Study:
- To identify the causative agent of the infant diarrhea outbreak.
- To determine the role of bacterial enterotoxins in the observed illness.
Main Methods:
- Enterotoxin detection using the Chinese Hamster Ovary (CHO) cell assay.
- Bacterial and viral identification through stool culture, electron microscopy, and cell culture.
- Comparison of toxigenic bacterial strains from ill infants and healthy controls.
Main Results:
- 11 of 14 ill infants had toxigenic bacteria (E. coli, Klebsiella, Citrobacter) in their stools.
- Toxigenic bacteria were significantly associated with acute diarrheal illness compared to convalescent or control samples (p < 10^-5).
- No significant viral pathogens were detected in the affected infants.
Conclusions:
- The outbreak was likely caused by transmissible plasmid-mediated enterotoxin production in multiple enteric bacterial species.
- This highlights a potential public health concern regarding plasmid-borne toxins in pediatric settings.
Abstract:
An outbreak of watery diarrhea occurred in 14 of 15 infants in a special care unit over a four-day period. Using the CHO cell assay for enterotoxin, we found that 11 of these patients had toxigenic bacteria in their stools. These bacteria comprised nine different serotypes of three species of organisms: Escherichia coli, Klebsiella, and Citrobacter. None of the three serotypes of E. coli were classic enteropathogenic serotypes. Rectal swab specimens from all 15 infants were examined for the presence of viruses by electron microscopic and cell culture techniques as well as by studies in suckling mice. None had parvovirus- or reovirus-like agents and two had adenoviruses. No other viral agents were detected. Of 38 bacterial strains isolated from ten control infants without diarrhea, three Klebsiella strains from two individuals were found to be toxigenic. Analysis of a total of 136 enteric isolates showed that toxigenicity as measured by the CHO assay was strongly associated with strains isolated during acute diarrheal illness when compared with strains isolated in convalescence (p less than 10(-5)) or with strains from control infants without diarrhea (p less than 10(-5)). This study raises the possibility of an outbreak of disease caused by a transmissible plasmid responsible for a cholera-like enterotoxin production in several enteric bacterial strains.