Bacteria on raw poultry meat in the Netherlands may be a source of superbugs in people, according to a study that suggests the use of antibiotics in food animals is causing life-saving drugs to lose their potency.
Multidrug-resistant bacteria were found in 80 percent of raw chicken bought from grocery stores in the southern Netherlands. When the researchers compared the germs with specimens collected from hospital patients, they found the predominant resistance genes were identical.
The findings, reported in the July edition of the journal Emerging Infectious Diseases, indicate drug-resistant bacteria in food are leading to harder-to-treat infections in people. While human use of antibiotics in the Netherlands is among the lowest in Europe, the country is one of the region’s biggest users of the medicines in farm animals, the researchers noted.
“The Netherlands provides a good setting to monitor spread of drug resistance from an animal reservoir into the human population,” Ilse Overdevest, a physician in the microbiology laboratory at St. Elisabeth Hospital in Tilburg, and colleagues wrote.
Their research focused on a genetic component in bacteria that causes resistance to a range of antibiotics, including a class known as third-generation cephalosporins. These medicines, which include Sanofi’s Claforan and GlaxoSmithKline Plc (GSK)’s Fortaz, are used to treat bacterial meningitis, pneumonia as well as some infections caused by E. coli and other so-called Gram- negative bacteria. Pfizer Inc. (PFE) makes a similar product, called Excede, for use in cattle, swine and horses.
Hospital patients infected with a bacterium resistant to a third-generation cephalosporin typically stay five days longer than those without the resistant bugs. They are also 2.5 times more likely to die within a month of being infected, according to a 2010 study in the Journal of Antimicrobial Chemotherapy.
In the Dutch study, 262 samples of fresh chicken, beef, pork and ground meat were tested for drug resistance. Of 71 chicken samples tested, 80 percent carried bacteria producing an antibiotic-destroying enzyme known as ESBL. In comparison, ESBL- producing bacteria were found in fewer than 12 percent of the other meat types.
When rectal swabs were tested from 876 patients, the researchers found 4.9 percent of people harbored ESBL-producing bacteria in their bowels.
Among E. coli samples collected from patients in the Netherlands, resistance to third-generation cephalosporins increased to 4.3 percent in 2009 from 0.1 percent in 2000, according to data compiled by the European Antimicrobial Resistance Surveillance Network.
ESBL contamination of retail chicken meat in the Netherlands is a “plausible source” of the increase in multidrug-resistant infections in people, the authors said.
“Most samples of retail chicken meat contain transmissible drug resistance genes in bacterial species that are part of the normal human intestinal flora,” they said. “This finding may have a profound effect on future treatment options for a wide range of infections.”
The Netherlands is trying to reduce the volume of antibiotics used in food-animal production, Christianne Bruschke, the nation’s chief veterinary officer, said in an e-mail today. The government aims for a 20 percent reduction from 2009 levels this year, with a 50 percent cut targeted by 2013, she said.
“There is an increasing abundance of evidence showing superbugs such as ESBL E. coli are in the foods we eat and people get serious infections with them,” said Peter Collignon, head of infectious diseases at Australia’s Canberra Hospital, who serves on a World Health Organization panel studying antibiotic resistance in the food chain. “It’s time we banned the use of antibiotics in food animals that cause superbugs to develop and spread.”
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