Drug-resistant superbugs tied to food supplyby Lorna Benson, Minnesota Public Radio
St. Paul, Minn. — More than two dozen cases involving highly drug-resistant bacteria have been reported in Minnesota in the last year and a half.
These are not the same so-called superbugs originating in India that have sickened several patients in the U.S., but Minnesota health officials say the bacteria found here are just as worrisome and point out the need for changes in how antibiotics are used in humans, and in the food supply.
Earlier this week, health officials reported that three people were sickened by bacteria containing a new, highly mobile gene that makes the micro-organisms resistant to most antibiotics. All of the patients had received medical care in India, where resistance to antibiotics is common.
State epidemiologist Ruth Lynfield has known about the U.S. cases since June, when the Centers for Disease Control and Prevention first warned public health officials about the problem.
Lynfield said that in India, patients can get antibiotics over-the-counter, without a doctor's prescription, leading to widespread misuse and overuse of the drugs. When antibiotics are overused, bacteria develop resistance to the drugs creating what is called a 'superbug' -- one that is highly difficult to treat.
The question is whether the superbugs from India will find their way into Minnesota's population.
"We are worried. There are people who do go abroad," Lynfield said. "We don't have good figures on that, but that certainly is a concern."
The bacteria from India are alarming because they contain a gene that confers drug resistance and it can easily detach and hop onto other types of bacteria. It's conceivable that many more disease-causing bugs could develop antibiotic resistance, and it could happen very quickly due to the ease and speed of world travel.
Drug resistant bacteria are already a problem in Minnesota. Thirty highly-resistant bacteria cases have been reported since March of 2009, when the state began requiring labs to submit infection samples whenever they encountered a strain of bacteria that's especially resistant to treatment.
But curbing the use of antibiotics in humans may not be enough.
James Johnson, an infectious-disease physician at the V.A. Medical Center in Minneapolis, has noticed a growing drug resistance problem among his patients. Johnson, who studies the strains of E. coli that cause urinary tract and kidney infections, said he wondered if resistant E. coli in the food supply could be one cause.
"When we asked, 'Well, where could they have come from?' And we compare the human source bugs with the food source bugs, low and behold, the human resistant bugs look very much like the food source bugs," he said.
Here's how that could happen: Antibiotics are used in livestock production to promote growth and prevent illness. When the drugs are overused, bacteria such as E. coli in the animals become resistant. When consumers fail to properly cook those products, the bacteria can infect their intestines.
Johnson says ingesting products tainted with E. coli doesn't guarantee a bladder or kidney infection, but it could happen if a patient with a resistant bacteria strain takes an antibiotic to treat for example, a sinus infection.
That could set off a growth spurt for the dangerous microorganisms not killed by the antibiotic, resulting in a new bacterial infection that's hard to treat.
"Now when that person has a drug-resistant infection, is it the fault of the antibiotics that were given to the animal? Is it the fault of the antibiotics that were taken by the person?" Johnson said. "To me it's both. It's a two-hit thing."
Johnson says biologists and infectious disease doctors generally agree that antibiotic resistant bacteria in food are contributing to resistance problems in humans. The scientific evidence has so far failed to convinced livestock producers that it's time to cut back on antibiotics, he said.
Proposed guidelines from the Food and Drug Administration will call for more restraint in using antibiotics in animal agriculture. Johnson said that's great, but he's disappointed that the guidelines will be voluntary.
- Morning Edition, 09/16/2010, 7:25 a.m.