Monday, 28 July 2014

Antibiotic resistance and food (again)

'Mission San Juan Capistrano bells'
by Ballookey Klugeypop under a
CC license
Antibiotic resistance is the case where microorganisms become able to survive after exposure to antibiotics. Antibiotic resistance is not a new phenomenon. When resistance to multiple antibiotics is observed in pathogens then things become particularly alarming. Infections by multidrug resistant pathogens (superbugs) are very difficult - and sometimes impossible - to treat, especially when the patient's organism is weak.

I've written on superbugs before but recently antibiotic resistance re-surfaced in the news in a different way. As described by Maryn McKenna, seafood imported from South Korea to Canada was found with Pseudomonas bacteria, which turned out to carry a gene that enables the synthesis of a carbapenemase enzyme.  This is alarmingly important for a number of reasons:
  • Carbapenamase enzymes can inactivate carbapenem, an antibiotic of last resort.
  • Seafood is sometimes mildly processed, in some cases deliberately to retain flavour and texture, while in others it may simply be undercooked. In such cases, the bacterium found would be likely to survive.
  • Non-resistant bacteria can acquire antibiotic resistance from resistant ones via horizontal gene transfer involving plasmids
If consumed, the bacteria in question could possibly make it to the gut. As they are not pathogens they would not pose a direct problem themselves but they would be likely to transfer antibiotic resistance to the gut flora bacteria. I am not aware of the probability of such chain of events but should it happen in individual consumers, it would create inside them a population of bacteria resistant to a class of last resort antibiotics. That's not a good thing to happen!

Carbapenem resistance in the food production system has been a concern previously. Unfortunately, this needs to be considered in tandem with the occurrence of carbapenem resistant infections that seems to be on the rise in Europe (but still under control).

The Canada seafood case highlights a different route of concern, where the consumers may be exposed to resistant non-pathogens (with the potential to be found on a variety of foodstuffs) rather than resistant pathogens, directly, or antibiotic residues in food, which could - in turn - potentially invoke antibiotic resistance.

There is a need for better monitoring of the various routes that can lead to antibiotic resistance. This is no small challenge, though (and it comes with a certain price tag)! However, without any need to panic, it is essential we understand what the risk is and adapt our food processing (and healthcare) practices accordingly. Such approaches work on the prevention front. Hopefully, we'll also make some more breakthroughs on the antimicrobial front, as well!

No comments: