A large genomic epidemiology study by scientists in the United Kingdom has found that most bloodstream infections caused by drug-resistant Escherichia coli involve human-associated strains of the pathogen, with little contribution from the food chain.

The study, published yesterday in The Lancet Infectious Diseases, found that the extended-spectrum beta-lactamase-producing (ESBL) E coli sequence type (ST) 131 was the predominant strain found in bloodstream isolates, as well as in samples collected from human feces and sewage, while isolates from meat, veterinary diagnostic samples, and farm runoff were dominated by other ESBL E coli sequence types. Few drug-resistant E coli strains were shared among the animal and human isolates.

The authors of the study say the findings suggest that while ESBL E coli strains are widespread in humans, animals, and the environment, there’s little crossover between these strains, and efforts to reduce invasive ESBL E coli infections should focus on limiting human transmission.

Comparison of resistant E coli reservoirs

 

Credit: CDC

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