Saturday, April 30, 2011

Walls have ears and bacteria have antibiotic resistance

Recently, I was having my lunch at a conference and couldn't help overhearing a conversation between two people sitting alonside me.  I suppose I should have tried not to listen, but their discussion was in my own field.

It appeared that one of them had read a survey conducted on the bacteria isolated from poultry in USA.  Even "organically grown" chicken contained bacteria that displayed multiple-antibiotic resistance.  This implies that the chicken farms may be using antibiotics in the flock rearing operation, though it doesn't necessarily prove the point.

Without getting into the rights and wrongs of using antibiotics in rearing of "organically grown" poultry, this does point to a wider concern: that farmers may be using sub-therapeutic levels of antibiotics widely to improve growth rates and yields of all meat animals.  Any bacteria that survive and grow in the presence of antibiotic are likely to be resistant to the chemicals and if these bacteria should go on to infect humans, those antibiotics will be useless for treatment.

I'm not sure if these people were talking about a survey*** conducted by the Translational Genomics Research Institute (TGen) in Arizona.  These scientists tested 136 samples of 80 brands of beef, chicken, pork and turkey collected from 26 retail stores in five US cities.  They found that nearly half of the samples contained Staphylococcus aureus and that just over half of these isolates were resistant to at least three classes of antibiotics.  Further analysis suggested that the bacteria were from the animals and not from the processing factories, again indicating that antibiotics had probably been used in rearing the animals.

It might make meat more expensive, but I believe that governments must force the reduction in the amount of antibiotics used in animal rearing if we are to avoid catastrophic consequences for the human population in the near future.  Remember: it has been estimated that the cost of getting a new drug onto the market is now between 2 and 3 billion dollars.  We aren't going to get many new drugs at that rate.



*** The full report is available at:

http://dx.doi.org/10.1093/cid/cir181

(The report is a technical report, intended to be read by other scientists, but anyone should be able to follow the discussion).

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