Cutting boards used to prepare raw poultry may be an important source of drug-resistant bacteria in hospital kitchens and private homes, according to a new study.
The more bacteria are exposed to antibiotics, the higher the chance they will develop resistance to the drugs. Unnecessary exposure can happen in humans who take antibiotic drugs they don't need, like for the common cold, which is caused by a virus and not affected by antibiotics. It can also happen when large numbers of livestock are given feed laced with antibiotics to help them grow faster and larger.
According to the World Health Organisation, 75 per cent of antibiotics sold are destined for use in animals.
Drug-resistant bacteria originating from both humans and animals can cause infections, which are harder to treat than infections caused by non-resistant bacteria.
The fact that cutting boards were contaminated with drug-resistant bacteria is troubling, but not surprising, Dr. James R. Johnson said.
Johnson, an infectious diseases researcher at the Minneapolis VA Health Care System in Minnesota, was not involved in the new study.
"If other foods go on those boards before the boards get cleaned, or even after they're cleaned if the cleaning isn't 100 per cent effective, the other foods, which may not get cooked, or not as thoroughly as poultry, likely would get contaminated and so could possibly pose an even higher risk of transmission to humans than the poultry products themselves," he told Reuters Health in an email.
The new study took place in Europe, where growth-promoting antibiotics for animals are banned, but antibiotics can still be used in livestock "therapeutically." The US Food and Drug Administration announced the first move to phase out growth-promoting antibiotics in animals processed for meat in late 2013.
For 16 months, Dr. Andreas F. Widmer of University Hospital Basel in Switzerland and colleagues collected cutting boards and used gloves from their hospital's kitchen, which prepares meals for 650 patients daily, as well as for hospital staff.
They also collected cutting boards from kitchens in private homes in Switzerland, France and Germany, and swabbed for bacteria after the boards were used to prepare food and before they were cleaned.
Ten of the 154 cutting boards taken from the hospital kitchen tested positive for a type of drug-resistant E. coli bacteria, compared to five of the 144 boards taken from homes, according to results published in Infection Control and Hospital Epidemiology.
There were probably more bacteria in the hospital because hospital kitchens process much more meat than household kitchens, experts said.
"These E. coli are resistant to some of the last good drugs we have to treat them," Lance B. Price, who was not involved in the European study, told Reuters Health.
"The 'nightmare superbug' is just one step further than these," said Price, who studies antibiotic resistance at George Washington University in Washington, D.C.
That makes the results alarming, he said.
Half of the used gloves from the hospital also tested positive for drug-resistant bacteria, indicating that gloves and cutting boards could be sources of bacteria transmission, the authors write.
They recommend food service workers and home cooks be vigilant about washing their hands not only after handling meat, but also after handling used cutting boards.
For home cooks, hot water and detergent work well to sanitize used cutting boards, but a simple wipe-down with a dishrag will not suffice, Johnson said.
"For industrial kitchens, I'm not sure what's recommended, or the standard," he said. "I'd think a bleach solution, or other disinfectant, might be desirable, if the boards can't undergo high-temp detergent washing," which may be the case for wooden cutting boards permanently attached to a counter that can't be put in a dishwasher.
Price said people should never use their designated raw meat or poultry cutting board for preparing any other types of food.