Superbugs rampant in China’s poultry products, study shows
Microbes that cannot be killed by antibiotics are found easily in entire production chain, according to multinational research
Drug-resistant bacteria can be found easily in China’s poultry production chain - from hatcheries to supermarkets – according to recent research by scientists from China, the US and Europe, underscoring the need for Beijing to control the use of antibiotics.
Superbugs are bacteria that are resistant to antibiotic drugs. A British government report last year estimated that antibiotic resistance would kill 10 million people yearly around the globe by 2050, more than cancer.
But the new study suggests a grimmer picture.
More than 87 per cent of the chicken meat sold in supermarkets in China’s Shandong province was contaminated by a superbug gene called mcr-1, according to a paper published in the journal Nature Microbiology on Monday.
Bacteria carrying the mcr-1 gene was resistant to colistin, one of the “last-resort” antibiotics used only after the failure of other drugs.
The researchers traced the spread of the bacteria from slaughterhouse to hatcheries. The highest detection rate was recorded in chicken farms, where 97 per cent of samples were contaminated.
Professor Timothy Walsh of Cardiff University, a lead scientist for the study, said people in China should watch what they eat.
“Generally, our bodies are able to break down DNA and kill bacteria in the process of eating and cooking,” he said.
“However, there is a possibility that herbs and salads can become contaminated,” he added.
The researchers detected the gene of another superbug strain, ndm-1, which originates in India and was rarely reported in poultry in China before.
The findings suggested that “the level of environmental contamination is underestimated”, the authors wrote in the paper.
Professor Feng Jie of the Institute of Microbiology at the Chinese Academy of Sciences said the study provided valuable information about superbug risk in China.
The high detection rate was a “surprise”, said Feng, who was involved in the research.
But the public should not panic, he added. Most bacteria would not survive proper cooking, because the drug-resistance DNA they carried would unbind or disintegrate under heat.
“I don’t think consumers need to avoid meat on the shelves,” she said.
“It would be useless. Each and every one of us already carries a considerable amount of drug resistant bacteria in our stomachs,” Feng added.
But the researchers said the government should still take action. They noted that Beijing would ban the use of colistin in the farming sector beginning in April, but said this was far from enough.
“I personally think colistin should be removed from all animal sectors ... across the globe and not just in China,” Walsh said.
“The fight will go on forever. Superbugs will keep growing and spread. All we can do is to slow down their pace,” Feng added.
Although new drugs can be developed, the pace of this development cannot catch up with the speed of bacteria evolution.
One new antibiotic was discovered last year – the first in three decades.
The researchers made other important discoveries, such as finding that flies in chicken farms carry a large amount of drug-resistant genes. It was the first confirmation that flies can transmit superbugs.
The flies’ “ability to contaminate the environment has immense public health concerns”, the authors warned.
Dogs on chicken farms were also found to carry superbug genes. They can pass the superbugs directly onto humans.
“Nobody is suggesting we should cull the dogs, but we do need to be more mindful of how we clean up dog faeces, and prevent access by flies who spread AMR [antimicrobial resistance] throughout China,” Walsh said.
He also said that the spread of certain superbug genes in China was “very puzzling”, and that there were some unique circumstance in the region that exacerbated the drug resistance problem.
“Europe has its issues, but these do not seem to be as pressing as in South Asia, Southeast Asia or China.”