April 30, 2014
The emergence and rapid increase in bacterial resistance to antibiotics is a major public health threat, costing Americans tens of billions of dollars in avoidable healthcare bills and causing tens of thousands of deaths each year. If left unchecked, antibiotic resistance could result in devastating consequences, including deaths from simple injuries that until now have been easily treated by antibiotics.
Legislation currently passing through the California State Senate aims to restrict the non-therapeutic use of antibiotics in livestock a problem associated with increasing levels of antimicrobial resistance. This sets an important precedent: states can and should pass legislation that will protect their residents from the ever-growing threat of antibiotic-resistant bacteria. However, it remains to be seen whether states will be willing or able to fill the gaps left by federal legislation on the matter.
THE REASONS BEHIND RESISTANCE: Several factors are contributing to increasing levels of resistance. The misuse of prescribed antibiotics by patients and the overprescription of antibiotics by doctors are two of the commonly cited causes. Indeed, it is estimated that around half the antibiotics prescriptions in the US alone are not necessary for treating infections. A number of states, therefore, have implemented antibiotic stewardship requirements and guidelines for their health institutions and medical professionals.
It wasn t until late last year, however, that the US Food and Drug Administration (FDA) officially turned its focus to the non-therapeutic and dangerous use of antibiotics in food animals. Some estimates have revealed that the amount of antibiotics consumed worldwide is nearly double the amount consumed by humans. Furthermore, the quantity of antimicrobials including those that are medically important in humans used for nontherapeutic purposes in the US is estimated to be as much as eight times greater than the quantity administered for therapeutic use.
A HISTORY OF MISUSE: As our below graphic demonstrates, levels of antibiotic consumption among livestock animals in the US are not only high they are also increasing. To understand why this is the case, it must first be understood that antibiotic consumption in animals can be broadly classified into three categories: growth promotion, disease control and prevention, and treatment. While the therapeutic use of antibiotics applied properly for the treatment of individual animals tends to control the emergence and propagation of antimicrobial-resistant strains, in large part due to their relatively short-term application and relatively small numbers of animals treated, it is the extended application in large numbers of animals that favors emergence and propagation of large numbers of resistance genes. Indeed, the routine sub-therapeutic administration of antibiotics for both growth promotion and disease prevention in animals has been shown to be at fault for increasing levels antimicrobial resistance in animals a trend that is likely to affect humans as well.
How did we reach this point? Growth promotion became widespread in the early 1950s after farmers noted that animal growth could be accelerated by adding antibiotics to their feed a cheaper option than existing growth supplements at the time. With industrial methods of livestock production whereby animals were increasingly kept in cramped and unhygienic conditions becoming more prominent, adding sub-therapeutic doses of antibiotics to feed served the added bonus of preventing animals from contracting diseases.
FACING THE ISSUE: Compared to the European Union, where the use of antibiotics for growth promotion has been banned since 2006 and individual countries such as Denmark and Sweden enacted policies to prevent the use of antibiotics for growth promotion as early as the 1980s, the US has lagged in addressing the problem. With its Guidance for Industry #213, published in December 2013, the FDA took its first broad action to reduce the rampant and indiscriminate use of antibiotics in livestock in more than 30 years. With this document, the FDA requested that animal pharmaceutical companies stop labeling medically important antibiotics as appropriate for growth promotion in animals. Additionally, the guidelines called for greater veterinary oversight for therapeutic uses and to stop over-the-counter sales.
While the FDA s actions are a welcome step, critics have argued that they are inadequate. Unlike the bans on antibiotic growth promoters that are in place in many European countries, the FDA s guidelines are voluntary. This aspect of the guidelines in particular has come under fire, with researchers at the Johns Hopkins Center for a Livable Future writing that they are unlikely to reduce the widespread use of the drugs in food animals or address the public health crisis of increasing antibiotic resistance. They also identified a potential loophole that could enable drug companies to continue approving the use of medically important antibiotics in livestock production by simply changing the labels from growth promotion to disease prevention.
CALIFORNIA S LEGISLATION: In light of the growing threat of antibiotic resistance, the state of California is considering new legislation that could severely restrict the use of medically important drugs among food animals. California State Senate Bill 835 (SB 835) was introduced to the State Senate in January. SB 835 recently passed through the Appropriations Committee and is set for a third reading. If it passes in the Senate, it will move on to the State Assembly.
If passed, the bill would prohibit the Secretary of Food and Agriculture from registering medically important antimicrobial drugs for use in livestock unless certain requirements are met. These stipulations include:
- The removal of approval for use in growth promotion or feed efficiency from the drug label;
- The requirement of veterinary prescription (many drugs are currently OTC);
- The administration of these drugs can only occur under the supervision of a veterinarian to treat, prevent or control disease.
Additionally, the use of all medically important antimicrobial drugs currently registered with the Department of Food and Agriculture would need to be reevaluated by 2017. If they are found not to meet the above specified requirements, they would be removed from the register.
THE EFFECTS OF POLICY CHANGE: Just how hard are such policies, if passed, expected to have in farmers’ wallets? Not very, if previous research tells us anything. Evidence from Denmark, which has banned the use of antibiotics as growth promoters since 1995, has revealed that their use had little, if any, effect in productivity in the country s highly industrialized and intensive food animal production. The country has been able to continually improve its productivity and increase output, despite over 50% decline in the use of antibiotics in food production. Additionally, farmers have been able to prevent disease outbreaks by modifying their agricultural practices.
Additionally, a study by the US National Academy of Sciences in 1999 estimated the annual per capita economic cost of a ban on antimicrobial feed additives to be $5 to $10. However, these costs are significantly lower than those incurred by complications related to antimicrobial resistance.
The legislation being reviewed in the California State Senate, therefore, is an important step toward controlling the problem of antibiotic resistance. Taking into account the evidence of success EU countries have had in banning the use of antibiotics in livestock feed and the incredibly high costs of growing antibiotic resistance, more states should begin following California s lead and leave no room for pharmaceutical companies and livestock producers to squeeze through the federal legislation s potential loopholes.
Image via thornypop/Flickr.
