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An outbreak (?) caused by Escherichia coli O126:K71:H5 in premature infants
Insights
A specific E. coli strain colonized premature infants, showing contagiousness and Vero cell toxicity. Despite these traits, it acted as an opportunistic pathogen, not a classic EPEC.
Area of Science:
- Microbiology
- Pediatric Infectious Diseases
- Bacterial Pathogenesis
Background:
- Escherichia coli (E. coli) strains are common causes of infant infections.
- Premature infants are particularly vulnerable to hospital-acquired infections.
- Understanding the pathogenic potential of E. coli strains in neonatal units is crucial.
Purpose of the Study:
- To investigate the recovery and characteristics of E. coli O126:K71:H5 in a premature infant nursery.
- To determine the virulence and pathogenic mechanisms of the isolated E. coli strain.
- To classify the E. coli strain as either an enteropathogenic E. coli (EPEC) or an opportunistic pathogen.
Main Methods:
- Stool and respiratory samples from hospitalized premature infants were collected over six weeks.
- E. coli O126:K71:H5 was isolated and identified.
- Pathogenic mechanisms including enterotoxin production (LT, ST), invasiveness, Vero cell toxicity, and hemagglutination were assessed.
Main Results:
- E. coli O126:K71:H5 was recovered from 69 of 147 stool samples and the respiratory tract of one infant.
- The strain exhibited low virulence and no clear link between clinical status and recovery.
- The strain produced a thermolabile toxin for Vero cells and possessed hemagglutinins but lacked defined EPEC virulence factors.
Conclusions:
- E. coli O126:K71:H5 demonstrated contagiousness and colonization capacity in premature infants.
- The strain's ability to produce a thermolabile toxin and colonize suggests opportunistic behavior.
- The findings indicate E. coli O126:K71:H5 functions as an opportunistic pathogen rather than a classic EPEC in this neonatal setting.
Abstract:
The strain E. coli O126:K71:H5 was recovered during a 6 week period, from stool samples of 13 premature infants hospitalized in the Premature Infants Nursery Unit. Of a total of 147 tested stool samples, 69 were positive. This strain was also recovered for a long period from the respiratory tract of one of the infants. The strain had a low virulence for the infants. No clear relationship could be demonstrated between clinical status and recovery of the strain. The strain did not possess any of the well defined pathogenic mechanisms, namely enterotoxins LT and ST, and invasiveness. The production of a thermolabile substance toxic for Vero cells was demonstrated. The strain possessed both guinea pig mannose-sensitive and human mannose resistant hemagglutinins. In spite of the production of thermolabile toxic substance for Vero cells and in spite of its contagiousness and intestinal tract colonization capacity, the strain displayed the characteristics of an opportunistic pathogen rather than classic EPEC.