Antibiotic resistance, illness and animals: the science is solid

We refer to the statement by Datuk Dr. Kamarudin Md. Isa, Director-General of the Department of Veterinary Services (DVS), which appeared in the dailies on May 16th 2016. Dr Kamarudin had said that ‘there are no plans to ban the use of antibiotics in the poultry industry’ as ‘no scientific research has proved that humans can suffer negative effects of antibiotics from eating meat’.

Since the United Kingdom’s 1969 Swann Report, hundreds of studies over the last few decades have shown links between the use of antibiotics in animal food production, the development and spread of antibiotic resistance and resulting human infections and even deaths.

We list the following studies to refute the statement of the D-G of DVS.

The UK’s 1969 Swann Report is remembered as one of the first recommending that antibiotic growth promoters (AGPs) and other drugs used without prescription in animal feeds should be restricted to antibiotics that have little use or are not used as therapeutic agents. The recommendation led to withdrawal of Penicillin, Streptomycin and Tetracyclines as AGPs in many European countries in 1972-1974.
In September 1976, Dr Stuart Levy’s groundbreaking study showed resistance to Tetracycline in chickens emerging within 36 to 48 hours after given the drug in feed. With time, chickens began to excrete bacteria resistant to not only Tetracycline, but unrelated antibiotics i.e. Sulfonamides, Ampicillin, Streptomycin and Carbenicillin. This phenomenon has been reported to occur in people only on long-term antibiotic use. Within five to six months, the farmers’ family and workers had a large increase in Tetracycline-resistant bacteria. In short the chronic use of a single antibiotic will produce an environment of multidrug resistance. The results were published in the New England Journal of Medicine.
In the 1980s, similar findings came from a large field study involving 35,000 people conducted by Ruth Hummel, Helmut Tschape, and Wolfgang Witte at the Robert Koch Institute in Wernigerode, then part of East Germany. They focused on transferable Streptomycin resistance that was associated with the use of Nourseothricin as a growth promoter in farm animals. Their findings corroborated those of Levy and his collaborators.
In February 2012, Dr Lance Price published another ‘smoking gun’ study that used whole genome sequencing to trace the origins of a new strain of livestock-associated Methicillin-resistant Staphylococcus aureus (MRSA), called ST398. Dr Price’s study provided compelling evidence that ST398 originated in humans as Methicillin-susceptible Staph (MSSA), then jumped into pigs where it became Methicillin resistant and subsequently began infecting humans with direct exposure to livestock. The antibiotic-resistant strain has since spread widely in the community, causing illnesses and even deaths in Europe. An August 2013 study used similar genomic sequencing techniques to reinforce these findings and document transmission of MRSA from cows to humans.

Scientific research also demonstrates that resistant bacteria spread from livestock to people via food.

In December 2011, a study coauthored by Dr. Peter Collignon found that ‘resistance in E. coli isolates from food animals (especially poultry and pigs) was highly correlated with resistance in isolates from humans. This supports the hypothesis that a large proportion of resistant E. coli isolates causing blood stream infections in people may be derived from food sources.’

In June 2007, Dr. James Johnson in his study found that antibiotic‐resistant E. coli in people was likely to have come from poultry. Other US studies published in October 2001 and September 2008 concluded that drug‐resistant E. coli strains in the human urinary tract may have an animal origin. In a study conducted in 1984 by the US Public Health Service, Food and Drug Administration, and Seattle‐King County found that Tetracycline‐resistant Campylobacter appeared ‘to flow from chickens to man via consumption of poultry products.’

In a landmark study in January 2010 it was shown that when poultry farmers in Quebec stopped routinely injecting Cephalosporins into eggs before they hatched, it was followed by an immediate and dramatic decrease in Cephalosporin-resistant Salmonella and E. coli in chickens, with a similar decrease in drug‐resistant Salmonella infections in people.

In November 2015 The Lancet Infectious Diseases reported the disturbing discovery of a gene MCR-1 which is resistant to Colistin, a powerful antibiotic used as a drug of last resort to treat infections caused by multidrug-resistant bacteria such as E. coli. This MCR-1 gene has the ability to move easily from one strain of bacteria to another species of bacteria, which is alarming as it can cause many infections to become untreatable.

The study by Yi-Yun Liu and colleagues showed there is a chain in the spread of resistance from the use of Colistin in livestock feed to Colistin resistance in slaughtered animals, in food and human beings. This is extremely worrying as it reveals the emergence of the first polymyxin (a category of antibiotics to which Colistin belongs) -resistant gene which is readily passed between common bacteria such as E. coli and K. pneumoniae.

The nightmare is that this MCR-1 gene is creating a ‘pan resistant’ superbug capable of defeating every antibiotic available. The threat to public health worldwide is enormous and unimaginable. Malaysia is one of the first countries in which scientists found the MCR-1 gene. Our policy makers ignore this at their peril.

It can be seen that the scientific evidence linking the overuse of antibiotics in animal food production to antibiotic resistance is very clear. The fact that illness and death caused by drug-resistant foodborne disease-causing bacteria like Salmonella, Campylobacter and E. coli are linked to food animal use of antibiotics is beyond dispute.

In the words of Dr. Lance Price, a professor at George Washington University’s School of Public Health and Health Services, ‘There’s very clear, sound science showing that the multi-drug-resistant strains emerged from drug use in food animal production then spread to humans. Anyone saying that there’s no data is either deceiving themselves or lying.’

It would do well for Dr Kamarudin to heed the body of scientific evidence cited and to take this public health threat, considered one of the greatest crises facing humanity, seriously.

Antibiotic resistance in food animals is driven by intensive food production which is the nature of industrial farming. Animals are herded in close confined spaces; overcrowding, poor hygiene and poor diets cause stress to animals, making them more vulnerable to disease and set the stage for cross-contamination with infectious diseases. Given this situation, prevention of disease is justified to maintain animal health and increase productivity. On pure economic grounds it is a cheap way to prevent disease.

As well, the role of the drug industry in promoting excessive and unethical use of antibiotics with ‘growth promotion’ and ‘disease prevention’ claims while providing incentives to farms and veterinarians is a major problem.  It is no wonder that agriculture accounts for the highest volume of antibiotic use and industrialised farming is dependent on it.

However this need not be the case and the problem of antibiotic resistance can be reversed. When Denmark and Holland banned the non-therapeutic use of antibiotics in the livestock industry, antibiotic use dropped 50 percent in each country and resistant bacteria became less prevalent in animals and on meat, resulting in human health benefits.

In 2000 Denmark banned AGPs and officials observed a resulting decrease in resistant infections among people. Plus, production costs and consumer prices remained stable, while output increased. It shows that with good farming practices like appropriate housing design, good sanitation, isolation of sick animals and the use of vaccines, the morbidity and mortality of farm animals can be controlled without using antibiotics and consumers need not pay more for meat and poultry.

Since 1984 CAP has been calling on the government to introduce laws to control the use of drugs in the livestock industry. In October 2013 CAP again highlighted the growing problem of antibiotic resistance in food animals in Malaysia and called for a ban on the use of antibiotics in animal feed in light of the catastrophic threat to public health from antibiotic resistance both nationally and globally.

The serious problem of antibiotic-resistant bacteria in our meats and farm animals; the persistent recurrence of banned antibiotics like Chloramphenicol and Nitrofurans in our chickens, meat and recently prawns and shrimp; the frequent reports of food poisoning (or antibiotic-resistant foodborne infections) among the population resulting in hospitalisation and deaths; and the emergence of virulent antibiotic-resistant superbugs like MCR-1 in our midst clearly demonstrate the public health crisis we are facing.

The need for drastic and comprehensive policy actions to ban the use of antibiotics in animal food production for growth promotion and feed efficiency is long overdue. It demands serious attention and swift action from the highest levels of government.

Letter to The Editor, 25 May 2016