New Research: Cow Pee Can Spread Antibiotic Resistance Through the Soil

[Gert van der Hoek]

See also: Antibiotic resistance gene spread due to manure application on agricultural fields


New Research: Cow Pee Can Spread Antibiotic Resistance Through the Soil

In the study, published last week in PLoS One, the team had the icky task of collecting urine and feces from cows dosed with ceftiofur. When they mixed up cocktails of excrement and soil, they found that urine from treated cows killed off normal E. coli and encouraged the spread of the resistant ones. Thus, simply contaminating a patch of soil with pee may be enough to create resistant bacteria in the wild. And when dairy calves were given bedding sprayed with resistant E. coli, within a matter of days they showed resistant E. coli in their guts as well, showing how easily bacteria made resistant outside the cow’s body can leap into the cow’s guts.

Bacteria are well-known for swapping antibiotic-resistance genes amongst themselves, and this particular kind of resistance has been found to move easily between different species of bacteria. Thus resistant E. coli in the soil could spread their powers to numerous other kinds of pathogens also present there, including others that infect humans through meat or produce.

More: Discover Magazine

Full article in PlosOne :

Urine from Treated Cattle Drives Selection for Cephalosporin Resistant Escherichia coli in Soil

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[Nika]

Re: New Research: Cow Pee Can Spread Antibiotic Resistance Through the Soil

its important to understand the probable causality here. the snippet above doesnt give us enough information to understand the situation.

Its not that the urine contains resistant bacteria or some infectious agent necessarily but that the urine carries a heavy burden of unmetabolized antibiotics which, when dumped on the soils (which presumably contains fecal bacteria that can be successfully reintroduced into the farm animal gut), will cause natural selection for resistant strains.

"we tested the hypothesis that excreted ceftiofur metabolites exert significant selection pressure for ceftiofur-resistant Escherichia coli in soil."

and

"urinary CFM (~13 ppm final concentration) is biologically degraded in soil within 2.7 days at 23°C, but persists up to 23.3 days at 4°C. Even short-term persistence in soil provides a >1 log10 advantage to resistant E. coli populations, resulting in significantly prolonged persistence of these bacteria in the soil (~two months). "

Interestingly..

"Ceftiofur metabolites in urine amplify resistant E. coli populations and, if applicable to field conditions, this effect is far more compelling than reported selection in vivo after parenteral administration of ceftiofur."

and a very sensible conclusion ..

"Because ceftiofur degradation is temperature dependent, these compounds may accumulate during colder months and this could further enhance selection as seasonal temperatures increase."