A superbug resistant to last-resort antibiotics was found in imported squid, according to a report this week. This is a major development in antibiotic resistance – even if you don't eat squid. Here is why one small finding has serious implications.
What you need to know about "nightmare bacteria"
When the CDC released its antibiotic resistance report last year, at the top of the list was carbapenem-resistant Enterobacteriaceae, or CRE. The C in CRE is the key: carbapenem is an antibiotic of last resort. If you're unlucky enough to get an infection resistant to carbapenem, you're nearly out of options.
CRE is not particularly common, and it's mostly been confined to hospitals where antibiotic use abounds. That's why it's so surprising that Canadian researchers have found a different bacteria resistant to carbapenem in imported squid from South Korea. The report is published in this week's Emerging Infectious Disease, and Maryn McKenna first noticed it in her blog, Superbug.
The squid in question came from a Chinese grocery store in Saskatoon, Canada. While the bacterium was not CRE and not usually disease-causing, it was resistant to carbapenem. It's the first time carbapenem-resistant bacteria has been found in food in the US or Canada.
Even a harmless bacteria with antibiotic resistance is still a big deal
The problem is not necessarily the spread of antibiotic-resistant bacteria but antibiotic-resistant genes. Bacteria are capable of swapping small bits of DNA that carry genes like those for carbapenem resistance. One species could evolve resistance to carbapanem and then quickly pass it on to other species through gene swapping. This is exactly what is happening to antibiotic-resistance genes as they jump from one bacterium to another.
Remember that your gut is a teeming community of microbes. Once the carbapenem-resistant bacteria gets into the food supply and into our guts, it can pass those resistance genes onto the bacteria in us. And now there's a reservoir of carbapenem resistance in your body, laying low until you get a bad infection in the future. And as much as we hate to think about it, faecal bacteria sometimes contaminates our food, so resistance genes can keep spreading outward.
Monitoring resistance will need to change
Surveillance of antibiotics resistance has so far focused on hospitals, but this finding means we might need to look more carefully at the food supply, too. The Canadian team only tested squid at a Chinese grocery because they deliberately decided to expand their surveillance beyond poultry, beef, and pork, which are more commonly tested. International travel has helped spread antibiotic resistance, so it follows that international trade of food could, too. Indeed, we should watch what we eat. [CDC via Wired]
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