Friday, September 23, 2011

Bacteria on the Beach - The Seagull Menace

Antibiotic-resistant super-bugs aren’t just a problem in hospitals anymore. Unlike the antibiotic resistant bacteria we discussed previously, antibiotic misuse may not be the culprit. But, spending an afternoon at the beach may give you more than you bargained for.

Wired Magazine’s blog reported on a study that tries to determine what is causing the rapid and unpredictable spread of multiple-antibiotic resistant E. coli bacteria in Miami Beach, Florida. The answer may give us clues as to how resistant bacteria spread world wide.

Apparently, seagulls are becoming carriers (literally) of drug resistant strains of E. coli. Let’s face it, seagulls will eat just about anything. Just driving through a coastal city, you can see seagulls dumpster diving for a meal, fighting over scraps of trash to eat, and that’s just what we see. It’s not much of a stretch to imagine that they could eat something contaminated with E. coli. Once they get E. coli inside of them, the bacteria can mutate or simply “learn” resistance to antibiotics from other bacteria. Then, not only are they carrying this highly antibiotic resistant strain everywhere they fly, but they also drop off little colonies of them everywhere they go (in the form of poop).

The specific resistances of the bacteria in this study are called “extended-spectrum ß-lactamase” (ESBL) resistance. This mutation allows the bacteria to resist most of the commonly used antibacterial drugs. While E. coli itself is usually not deadly (with the exception of the O157:H7 strain), the spread of the resistant genes in any bacteria is cause for concern.

The dangers of a highly mobile (thanks to the seagulls) multi-drug resistant strain of bacteria are pretty clear. The more places these bacteria are “deposited”, the more likely it is that the antibiotic resistant genes will work their way into other local bacteria through the process of horizontal gene transfer. Suddenly, communities could face outbreaks of several different bacterial infections that are untreatable by most antibiotics.

A quick review of the literature shows that this is not just a local phenomenon in Florida. The very same resistant strains of E. coli have popped up around the world, documented in places all over the world like Sweden, Alaska, France, Portugal, and the United Kingdom, to name a few. In most of these cases, birds were suspected to be the culprits responsible for the unexpected spread of resistant bacteria. Drug resistant bacteria has been linked to birds (chickens) before, but seagulls are far more mobile than chickens and so present a much bigger problem.

This research sheds light on how antibiotic strains of bacteria spread around the world. Hopefully, we will be able to learn how to prevent widespread resistance to our antibiotic arsenal. Drug resistance is a worldwide problem and hopefully, this research will help to battle against the superbugs.

Researched and written by Dr. Rebecca Malamed, M.D. with assistance from Mr. Malcolm Potter.

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