Is drug resistance in humans coming from chickens?

[DainBramaged]

There’s a new paper out in the CDC’s journal Emerging Infectious Diseases that makes a provocative claim: There is enough similarity between drug-resistance genes in E. coli carried by chickens and E. coli infecting humans that the chickens may be the source of it.

If it is correct—and it seems plausible and is backed by past research—the claim provides another piece of evidence that antibiotic use in agriculture has a direct effect on human health.

Here are the details:

The paper is a collaboration by researchers from several hospitals in the Netherlands, plus the Netherlands’ National Institute of Public Health and Environmental Protection, the University of Birmingham and a section of the UK’s National Health Service. They isolated E. coli from patients in four Dutch hospitals over 2.5 months in 2009, and compared those with E. coli strains isolated from randomly chosen supermarket meat that was bought in the hospitals’ local areas during the same time period. They compared both those sets of isolates against a third set, of E. coli from blood cultures taken from patients in the hospitals during the same months.

In each set of samples, they were looking at the E. coli to see whether they harbored genes for the type of resistance known as ESBL, for “extended-spectrum beta-lactamase,” an enzyme that denatures a category of drugs used for serious infections that occur mostly in hospitals. When the extended-spectrum beta-lactams no longer work, only a few last-resort drugs are left. (Back in the 1980s, the most common genes for ESBL were blaTEM or blaSHV, but in the past 10 or so years there has been a rapid global increase in the occurrence of a different ESBL gene, blaCTX-M.)

http://arstechnica.com/science/news/2011/06/is-drug-resistance-in-humans-coming-from-chickens.ars